Space files

2009-12-22T17:39:00.001-05:00

Currently I have no time to continue this blog. However, you're still free to leave comments.

Space Shuttle launch seen from a passing airliner

2008-08-22T10:08:00.003-04:00

So that how a shuttle launch looks like from the air. Unfortunately, the video ends just short of the solid booster separation...

Lightning in slow motion

2008-08-08T05:18:00.000-04:00

Balloon remains found on a southwest ranch

2008-07-30T08:39:00.003-04:00

An object that just landed straight out from space:

And an image it took during its journey above our planet:

Done at the Oklahoma State University, see the rest of the images.

A drop in the void

2008-03-16T09:06:00.003-04:00

All the water on Earth is claimed to fit in the small blue sphere on the left - and all the air in the sphere on the right.

From the Science Photo Library.

Futurama theme song from 1967 with dancing transistors

2008-02-11T15:55:00.000-05:00

The original of the favourite series, Futurama's theme song is "Psyché Rock" by Pierre Henry.

Gamma error in picture scaling

2008-01-28T12:16:00.000-05:00

Apparently there's a simple, hard to notice error in almost every image processing software. Its effects range from the slightly annoying, if you're just meddling with your holiday photographs, to the more serious, if you forget about it while trying to infer some science from images. That's why I note it here, as the author mentions NASA images as well - where the error was also present, although not necessarily in images used for science.

Gamma error in picture scaling by Eric Brasseur.

2008-01-22T16:23:00.000-05:00

Found a very interesting blog post comparing different launch methods to orbit: Orbital Access Methodologies Part I: Air Launched SSTO.
There's also a second part of it.

Galactic neighbours from Spitzer

2007-12-24T17:01:00.000-05:00

See the high resolution (4200x3600) file (9.4 MB)

This is 75 nearby galaxies imaged by the Spitzer Space Telescope. They're ordered into a Hubble tuning-fork. Normally, you could observe that elliptical galaxies (grouped to the left) are redder and spirals (grouped to the right) are bluer. What use can see on this image is quite the opposite. However this color difference is something that can be observed in the optical wavelenghts. Since Spitzer is not an optical, but an infrared telescope, they created color composites of their data to show us. The galaxies in this poster are three-color composites where blue depicts the galaxies at a light wavelength of 3.6 microns, while 8.0 microns is green, and 24 microns is red. Therefore, on these images red lumps show clouds of warm dust and gas heated by radiation from newborn stars (glowing in infrared) - a characteristic of spiral galaxies.

Read the Spitzer group's article.

Moon transit

2007-12-23T16:05:00.000-05:00

Out of this colletcion at the Astronomy Picture Of The Day website and this one at the Bad Astronomy blog - selection s of the most memorable astronomy pictures of the year -, the one I like the most is not a picture but a video. The video shows a transit of the Moon in front of the Sun, as seen by the Stereo-B spacecraft. Its distance from the Moon and the Sun is different from that of the Earth, so instead of the total eclipse that can often be seen from Earth, the Moon happens to appear much smaller than the disk of the Sun. This video shows how alien, how different these objects can actually be from the way we perceive them everyday. Details on the Stereo website.

Scale comparison of the planets and the stars

2007-12-17T03:15:00.000-05:00

These tiny and not so tiny balls show how enormous are the differences between different astronomical objects.

If Earth is a glass ball...
...then Jupiter is a football...
...and you'd fit into the Sun...
...and Sirius would crush you

An other series:

We have no actual photographs of other stars than our Sun that show surface details, because they're just too far away, so the rest is artwork based on what we do know about them - their color and size.

VV cephei is the largest star known - it's diameter is about 2000 times our sun's
And yet even it is just a tiny dot compared to the Milky Way itself

And an animation of the same objects

Hotel Mauna Kea

2007-12-12T13:33:00.000-05:00

Welcome to the Hotel Mauna Kea. Five planetary astronomers bring you an original science music video about life at the observatory at the 14,000-foot summit of Mauna Kea volcano in Hawaii. The astronomers, stationed at the Infra-Red Telescope Facility, wrote the song while they investigated aurora in Jupiter's atmosphere and the composition of Mars' atmosphere. One songwriter says: "The emission line and the dip that are mentioned in the video are real, and they are interesting. We have never abandoned an observing run to go to the beach."
Credits: Juan Delgado (Flamenco guitar), Kelly Fast (vocal, videography, 12-string guitar), Ted Kostiuk (spoken vocal), Lyrics by John Annen, Juan Delgado, Kelly Fast, Ted Kostiuk, Tim Livengood

From the Science Friday website.

Small Chinese Mars news

2007-12-08T18:19:00.000-05:00

A few days ago China Daily reported that the Yinghuo-1 prototype is currently undergoing tests. Yinghuo-1 is China's small, 110 kg Mars probe, that will travel to Mars on the back of the Russian Fobos-Grunt mission, to be launched in 2009. Mars orbit insertion will also be performed by the Fobos-Grunt spacecraft, before their separation. The compatibility of the two spacecraft will be tested next spring.

The following presentation contains most of what's currently known about Yinghuo-1.

A model of Yinghuo-1 in Shanghai:

2007-12-08T09:58:00.000-05:00

Posts for the 32nd carnival of space can be found here.

The Solar System from above

2007-12-08T07:40:00.000-05:00

This animation shows the known objects of the outer Solar System. Blue squares are comets. They appear to be falling "in" until 2002 and "out" afterwards because only comets observable in 2002 are plotted, out of the full cometary catalogue. They can only be observed when close to the Sun, and their positions are calculated back and forward.

The position of the 4 major outer planets are shown, with their orbits. Centaurs (asteroids with orbits between Jupiter and Neptune) are orange triangles. Those with high eccentricities are shown with cyan triangles. Trans-Neptunian Objects (TNOs) in general are red circles. Plutinos (TNOs in 2:3 resonance with Neptune) are white circles, Pluto is denoted by a large crossed white circle. Scattered Disk Objects (with highly elliptical orbits) are magenta circles.

See more Solar System animations at the IAU Minor Planet Center.

Mexican Space Agency to be created

2007-11-29T17:31:00.000-05:00

The Mexican Congress approved a proposal to create a Mexican space agency. The Senate is expected to vote on the approval in December, 2007.

México, abr. 26, 2006.: La Cámara de Diputados aprobó el decreto por el que se expide la Ley que crea la Agencia Espacial Mexicana, AEXA, por sus siglas. Se espera a la aprobación de AEXA en la Cámara de Senadores por el diciembre de 2007.

Video de Noticieros Televisa del canal 2, el reportero Leonardo Ferrera, ha iniciado una serie de reportajes sobre el desarrollo espacial en México y la importancia de la creación de la Agencia Espacial Mexicana.

Para mayor informacion acerca del proyecto de la Agencia Espacial Mexicana por favor vaya a este link: http://aexa.divaac.org

Solar sail mission to rise again?

2007-11-29T09:51:00.000-05:00

Louis Friedman, Planetary Society co-founder and executive director has a new post, writing they have received a $250,000 grant from the Discovery Channel for the development of Cosmos-2.

Cosmos-2 will be a very similar replacement for Cosmos-1, the first solar sail propelled spacecraft that the Planetary Society managed to develop and build from donations. Unfortunately, the very economic choice of using a Volna rocket, launched from a Russian submarine - replacing the warhead with the Cosmos-1 spacecraft - turned out to be an unlucky one. 82 seconds after launch, the engine failed and the rocket aborted.

This happened in June, 2005. Ever since, the Planetary Society was ready to build Cosmos-2. This new grant makes it possible to start the work, but they need to raise about $4,000,000 for completion.

However, the history of Solar Sails goes back much longer. It's probably no surprise that NASA did studies as far back as the 70s. But there was a already a serious proposal in 1967, called Sunblazer. It even had mockups:

It would have been a very tiny spacecraft (less than 5 kg), that would observe the Sun from 0.5 AU (using radio transmission to probe the solar corona from solar opposition). It would use solar sails, aluminized mylar foils, for attitude controls. The project was cancelled in the late 60's.

Japan

Recently, Japan had a number of solar sail experiments. In 2004, they launched a suborbital experiment, testing the deployment of two different sails (see news article).

A clover-shaped sail
Succesful deployment at 122 km
The jettisoned film
Ground testing of a fan-shaped sail. The 7.5 micrometer thin film is deployed by the centripetal force.

February 22, 2006, the rocket of the Akari (ASTRO-F) mission carried a subpayload, a solar sail deployment experiment. However, the sail didn't deploy properly.

August 30, 2006, they tested deployment using balloons (see article at JAXA in Japanese).

Shortly before liftoff
The balloon, starting its rise to 37 km, where air density is already quite low
First stage of deployment - cross-shape
Second stage of deployment

The next experiment followed on September 23 2006. The Hinode spacecraft carried a Solar Sail Subpayload - SSSAT. Separation of SSSAT after launch was confirmed, but it likely malfunctioned.

Meanwhile in Europe...

ESA has a plan called GeoSAIL,
a solar sail spacecraft to study the Earth magnetosphere and tail. The so-called technology reference study is finished, but I don't know about the current state of the project.

I've found a short document though, a powerpoint slide titled
European Solar Sail Technology Status.

At the Planetary Society

Meanwhile in Russia... working with the Planetary Society, the Lavochkin design bureau created a solar sail experiment. Their first launch was in 2001, but it was a failure (likely cause is that the payload failed to separate from the 3rd stage). Undeterred, they expanded the film-expanding experiment into a full, 100kg spacecraft with eight 75 square meter foil blades. The launch slipped many times, until July 2005.

Packing the spacecraft

Each blade was 15 m long
It'd look like this in space

Last seen

...and ending in another launch failure.

But now they are ready for a next go - and this time on an extremely reliable rocket instead.

Meteorite impacts recorded

2007-11-26T17:38:00.000-05:00

Aristotle thought that the heavens were perfect and unchanging. He couldn't be farther from the truth. Three posts below I wrote about the interesting geological ( & atmospheric) processes going on in unexpected places of the Solar System, even on very small or extremely cold bodies.

Another process that is obviously reshaping the surface of planets and moons is meteorite bombardment. Notable events are rare, but nevertheless, some were observed directly on the Moon and on Jupiter (apart from Earth).

A meteoroid hits the Moon, May 2, 2006. See NASA news article

For a short summary on the topic, see: Cudnik, B. M.: The Status of Lunar Meteor Research (and Applications to the Rest of the Solar System), 38th Lunar and Planetary Science Conference. Available at http://adsabs.harvard.edu/abs/2007LPI....38.1115C.

Missing from that article is the artificial impact event created by intentionally crashing the Smart-1 spacecraft into the Moon. See telescopic observation of the impact here

An other recorded event was the impact of unlucky comet Shoemaker-Levy 9 on Jupiter in July 1994. Unfortunately the Galileo spacecraft would only arrive a few months later. On the other hand, we were fortunate to already have some capable telescopes with CCD cameras - both on Earth and the Hubble Space Telescope in space.

Collection of Shoemaker-Levy collision photos and animations.
An other collection here.

The impact of the first comet fragment can be seen to the lower left. The bright spot to the right is the moon Io. Created from infrared images taken at the German-Spanish observatory on Calar Alto.

2007-11-26T17:37:00.000-05:00

Carnival of Space #30 is online at Bad Astronomy.

Railguns as launchers?

2007-11-22T10:39:00.000-05:00

Check Advanced Nano's post on railguns. (What is a railgun?)

Can it be the future launch vehicle to space? He cites a European study, in which a suborbital launch is planned to 100 km, using a 20 meter long railgun (and an awful amount of electricity). The real showstopper is that the projectile, or whatever you launch, needs to have an orbital speed by the time it leaves the railgun. That means reaching a speed of about 8000 km/s in a few 10's or 100's of meters - in the study, an acceleration of 13,000 g's is mentioned.

This is may prove too much to bear for any complex and sophisticated hardware. Such high speed also means protection is needed from heat generated from air friction. The study calculates the required protection is easily within the reach of current hardwares. Their calculations are only for a very tiny payload, though. I don't know how does the needed heat protection capacity scale with size, but even if it can be solved - like it's solved on the Shuttle or on the Soyuz during their high speed return to Earth - it may increase costs, compared to an average hull of a satellite launcher rocket. (Or are my fears unfounded? Nevertheless, overall launch costs may still be lower than with a rocket..)

Another trick could be to launch a rocket from a railgun, with a high but not orbital speed, and then ignite it when its high enough. But can the delicate structure of a rocket bear these unusually high accelerations (and aerodynamic drag in the low atmosphere)?

So while it may be possible to one day send picosatellites to LEO using railguns... and as a next step, maybe ISS supplies (water tanks, etc)... well, we'll just have to find out the practical limits.

The quoted blog has links to other articles as well.

Best of the best images

2007-11-21T09:53:00.000-05:00

APOD, the Astronomy Picture of the Day site treats us with fantastic pictures this week.

APOD 2007 November 20: Earthrise from Moon-Orbiting Kaguya
Still images from Kaguya's HD TV video, showing Earthrise as the spacecraft circles the Moon. (The video itself is only released in low-resolution yet.) The logo on the original was bothering me so I tried to remove it. Here's another shot:

Earth Tele Shot

APOD 2007 November 19: Aurora in the Distance
Exposure Time: 30/1 sec
FNumber: f 4
ISO: 3200
Model: Canon EOS 20D

Auroras are very faint. APOD says this one wasn't even visible by eye. The camera must have been able to capture it because of the high ISO setting, I suppose.

APOD 2007 November 17: Forest and Sky
This is my favourite one. Stars in constellation Perseus, trees, a satellite streak, and comet Holmes (the fuzzy spot).

Activity in the outer solar system

2007-11-19T11:48:00.001-05:00

For a long time, our picture of the outer solar system was that apart from the four gas giants, it only consists of geologically dead bodies, moons, planets (=Pluto) and asteroids (like the Centaurs), cold clumps of ice and/or rock. Even if they differentiated in the past (like you could expect the largest of them, Ganymede), they are not expected to have interesting phenomena currently going on.

Only exception was Saturn's moon Titan, which in 1944 was discovered to have an atmosphere. Then in 1979, the Voyagers flew past Jupiter, and photographs of the moon Io showed not only a very young surface, and many volcanoes, but even actual plumes from volcanic eruptions!

Since then, slowly but steadily, many other objects turned out to be more interesting than ever imagined, with ongoing geologic processes, or some form of meteorology at least. Let's list them all!

Io

Io's Tvashtar volcano erupting, as seen by the New Horizons spacecraft in early 2007. The volcano itself is behind the limb, and also on the night side, sending material 330 km high and into our view, and also into the path of sunlight. The part in the shadow is only visible because of the reflected light from Jupiter.

Image sequence showing the eruption of Tvashtar. Io's dark side is illuminated by reflected sunlight from Jupiter.

Io also has a varying atmosphere, made up mostly of sulfur dioxide. It's very much dependant on the volcanoes, that supply the otherwise slowly escaping gases. Jupiter's magnetosphere sweeps up gas and dust from Io's atmosphere and they up in the radiation belts around the planet. See an article about Io's atmosphere (the "Ioan" atmosphere?).

Auroral glow on Io, the result of an energetic interaction between Io's atmosphere and Jupiter's powerful magnetic field.

Europa

Color compoiste of Europa. (c) NASA/Ted Stryk

Europa is thought to have a 10-30 km thick crust of water ice, which hides a (probably) 100 km deep ocean. Tidal heating is keeping it from freezing, and drives the geological processes. Crater counts lead to an estimate that the surface is less than 30 million years old. Some think that its long ridges are the ice based analogues of Earth's oceanic ridges, ice/water volcanoes spreading the crust.

Fractured surface. A sign of tectonism?

The closest view of Europa's surface, from Galileo

Ganymede

Global view of Ganymede

Ganymede, the largest satellite in the solar system, which is actually larger than Mercury or Pluto, shows extensive signs of tectonic processes. Its surface is a mix of two types of terrain: very old, highly cratered dark regions and somewhat younger (but still ancient) lighter regions marked with an extensive array of grooves and ridges. Ganymede is not thought to be active any more. However, it is the only moon that has magnetic field of its own. It is not fully understood yet, but it may be generated in a similar fashion to the Earth's, by movements in a molten metallic core.

Tiamat Sulcus region on Ganymede, imaged just after local sunrise.

Auroral glow on Ganymede

Callisto

Callisto from Voyager 2

Callisto has the oldest, most cratered surface of any body yet observed in the solar system; having undergone little change other than the occasional impact for 4 billion years. Callisto experiences the least tidal heating from Jupiter. However, high resolution images from Galileo show deformed craters, and a lack of small craters. Examination of the surface shows that there has been gradual slumping, or "relaxation" of the craters, and what is termed "sublimation-erosion" of the surface.

Close-up on Callisto by Galileo

See JPL news article.

Titan

To a human eye, Titan would only appear as a smooth, orange sphere, because of its thick, opaque atmosphere. Cassini is able to see through the atmosphere using a near-infrared filter.

Titan is the only moon with a real dense atmosphere. It was long theorized that methane and ethane may form clouds, fall to the surface as rain, and create rivers, lakes or oceans. The Cassini spacecraft did indeed discover what appear to be lakes, near the southern and northern polar regions. The moons surface is formed by the atmospheric processes, probably wind, rain, and maybe streams. Ice-volcanic activity is also suspected, but hasn't been confirmed yet. It looks like the basic processes are analogous to Earth's, with hydrocarbons taking the role of water, and ice/water taking the role of rock.

Titan's atmosphere is like a thick, orange smog. Due to the lower gravity, it extends much higher than Earth's. Hundreds of kilometers above the surface, a complicated structure of thin layers of haze are observed. They are composed of complex organic molecules.

These long ridges look like dunes created by wind that curve around obstructions.

Panorama of the boundary between the dark and bright areas. The mosaic was created from images taken by the Huygens probe during its decent onto Titan.

Lakes, based on radar maps (fake colors).

Rounded pebbles of about 10 cm, lying near the descended probe. They're probably made of ice

Enceladus

In 2005, the Cassini probe observed a localized atmosphere at the south pole of Enceladus, through a stellar occultation, and also from particle measurements. It also imaged a hot area, in that region, with its infrared spectrometer. Later it was able to directly observe the water vapour plumes emanating from the southern parts. (see here)

The geysers can be seen by Cassini camera (false colour image)

These stripes appear to be 10 degrees warmer than the surrounding area, as measured by Cassini

A model of the Enceladus geysers

Geysers that spew ice/water would mean that there's a source of liquid water. Is that possible at -200 °C that is the observed temperature of the surface? Well, the depths of Enceladus may be heated by remnant radioactivity or tidal heating.

However, another hypothesis was also put forward, which doesn't need a liquid layer, rather, simply the (violent) decomposition of clathrates (see article, and the original in Science).

The plumes of Enceladus are also replenishing Saturn's E Ring with tiny particles.

Dione

Color image of Dione from Cassini

Researchers are now looking for possible geysers on Saturn's smooth icy moon Dione - which appears to be a less active version of Enceladus (see article and
mission news).

Iapetus

Iapetus has an old equatorial ridge about 1,300 km long, 20 km wide and 13 km high, making the moon look somewhat walnut-shaped. Its origin is not explained yet.

Iapetus one of the weirder bodies in the Solar System. It's not just its weird equatorial ridge. It's not just that it's two-faced, with its leading hemisphere as dark as soot, and its trailing hemisphere among the brightest. It's even more intriguing that there's no grey part at all - no transition between the two sort of covering, as far as the highest resolution images show.

Is it white on black?

Is it black on white?

NASA scientists think this is a result of thermal segregation - a process in which the slightly darker ice absorbs more sunlight, thus it sublimates, only to become trapped on the colder surface of slightly brighter ice.

Dione

Color image of Dione from Cassini

Researchers are now looking for possible geysers on Saturn's smooth icy moon Dione too - which appears to be a less active version of Enceladus (see article and
mission news).

Ariel

Ariel, a satellite of Uranus, shows a young surface, with few ancient craters, and the existing ones distorted. It also has large faults, canyons, with smooth floors. It certainly underwent considerable activity in the past. A theory is that the driving force behind this was tidal heating, due to a different, more eccentric orbit in the past. Ariel has high water content, and the highest reflectivity of the Uranian moons. Can it be a result of fresh ice crystals on the surface, from cryovolcanism still going on? We don't know yet.

Other Uranian moons, Miranda and Titania also show a relatively young surface, compared with the other large moons in their neighborhood.

Triton

Neptune's largest moon, Triton has a surprisingly complex surface

Triton is Neptune's largest moon. It's the 7th largest satellite in the Solar System, with a diameter only 20% smaller than our Moon's. But it is much more alive than the Moon! It has a very young surface, it has polar caps, it has a very tenous atmosphere (estimated to have surface pressure of 0.01 mbar). A tenous atmosphere which nevertheless is enough to hold an observable cloud - which is created by cryovolcanism, as directly observed by Voyager-2!

Patches

A tenous cloud above Triton

A plume on Triton, with a 10 km high column that has a tail extending horizontally about 100 km.

Movie showing geysers on Triton

Pluto

Pluto's surface (determined from brightness variations during Pluto-Charon occultations)

Pluto's atmosphere was detected through stellar occultations. It varies considerably with time, as most of this atmosphere is thought to freeze out onto the surface as Pluto reaches its farther parts of its orbit around the Sun. However, recently, some spikes were observed in the density of the atmosphere, even though Pluto is right now receding (see article).

These polygonal structures near in the northern polar regions of Mars, are thought to be created by the movement (expansion&contraction) of an ice layer. Of course, Pluto's ice layer would be extremely thin, but given enough time, couldn't it also wear the surface?

Charon

Our best "map" of Charon

Unlike Pluto, its moon Charon has no atmosphere. However, it appears to be host to cryovolcanism, or ice geysers (see New Scientist's article, and original article). The source is probably a liquid water-ammonia layer.

Other KBO's

The presence fresh water ice crystals on the surface of Charon are inferred from its spectra. However, some of the Kuiper Belt Objects, recently discovered, appear to share this spectral feature with Charon. Its not impossible, that some of these objects also have cryovolcanic activity.

Rosetta flyby

2007-11-14T09:02:00.000-05:00

New images! Yesterday, on its way to comet Churyumov-Gerasimenko, the Rosetta spacecraft passed 5000 km above Earth - one of its many planetary flybys designed to boost its speed without spending too much propellants. Before its arrival in 2014, we'll see it again from close, during its last Earth swing-by maneuver in November 2009.

Rosetta from Earth (center of image).

Earth from Rosetta.

See more of these at
Rosetta's home.

Amsat P3-D countdown and launch video

2007-11-10T12:37:00.000-05:00

More about the P3-D (Amsat-Oscar 40)

X-vehicles 1 to 50

2007-11-10T11:59:00.000-05:00

An interesting list of American experimental airplanes:

American X-Vehicles: An Inventory — X-1 to X-50

Many of them have to do with technical research into spaceflight, like
X-15, X-17, X-23A, X-34, X-37, and some were planned to become actual spacecraft, like X-38 X-40A, X-30 and X-33 (VentureStar).

#28 Carnival of space & collecting antimatter

2007-11-10T11:35:00.000-05:00

The 28th carnival of space is now online at the Planetary Society's blog.

An especially interesting entry is about
collecting natural antimatter.

Antimatter readily annihilates when it contacts with normal matter, and releases the whole energy corresponding to its mass (E=mc²). This makes it especially useful for spacecraft propulsion.

The recently finished report for the Nasa Institute for Advanced Concepts says:

For example, 100 nanograms of antiprotons can be used to catalyze sub-critical nuclear reactions and drive a one metric ton of payload to 100 km/sec. [...] In comparison, if traditional chemical propellants were used for the same task, nearly 10⁹ metric tons of hydrogen and oxygen would have to be launched into space.

And that would mean about 500,000 shuttle launches.

Currently antimatter is generated at CERN and Fermilab, with capacities about 1 nanogram/year (10^-9 grams). The production costs are estimated to be about $100 trillion per gram.

The report investigates trapping and collecting the naturally produced antimatter in the environment of Earth and the other planets. It claims it would be both technically feasible, and would be able to bring down the cost of antimatter production by 5 orders of magnitude.

Pre-Dawn: The French-Soviet VESTA mission

2007-11-05T07:14:00.001-05:00

3D model of the asteroid Vesta
The Dawn spaceprobe was launched toward the asteroid belt a month ago now. Few people remember that the Soviet Union was also planning a multiple asteroid flyby mission in the 80's. After the successful cooperation between France and the Soviets on the VEGA Venus (and Halley comet flyby) mission in 1984-85, a new project was proposed. The Vesta mission would have consisted of two identical probes (just like earlier Soviet Venus missions), to be launched in 1991. Similar to the Vega mission, each spacecraft would deploy one or more landers or balloons into the Venusian atmosphere, and then proceed to its next target. At Venus, a French satellite dedicated to asteroid flybys would be released. It would return to us for an Earth swing-by, and then reach about 3-3.3 AUs from the Sun. There they would fly by some smaller asteroids, and Vesta, if possible, with a small probe landing there (that's why the mission was named VESTA). The exact targets depend, on the launch date, among other things. In the 1985 study, 2700 possible trajectories were analyzed for a launch date in 1991/1992. Considering all constraints, like maximum velocity increment, left about 12 candidate trajectories. Of course, the two identical spacecraft could choose different trajectories and targets. These included 5 Astraea, 53 Kalypso, 187 Lamberta, 453 Tea, 1335 Demoulina and 1858 Lobachevskij, and comet Encke.

VESTA spacecraft design

Just as the 1988-89 Fobos missions reflect the Soviet focus shifting to Mars, around 1985 Vesta was changed to be a Mars mission, with the asteroid-part unchanged. Detailed studies indicate each probe would have visited four small bodies, including asteroids belonging to different classes - providing a representative sample of the diversity of asteroids - and probably one or two comets as well. Visiting at least one Apollo-Amor (Earth-nearing) asteroid was also given a preference. Preliminary studies call for at least the following scientific instruments to be included:

- a wide angle camera (~6.5° field of view, 512x512 pixel CCD)
- a narrow angle camera (~0.5° field of view, 512x512 pixel CCD - 3.9 arcsec/pixel)
- a near-infrared spectrometer (measuring between 0.5-5 micrometers with lambda/delta lambda = 50, 5 arcminutes per pixel)

Possible further instrumentation:
-UV spectrometer (for imaging during a comet flyby)
-radar altimeter/radiometer
-a dust detector
-ion or neutral gas detector

Onboard memory is about 240 Mbits. Images at closest approach (which is typically 500 km) have a resolution of 10 m/pixel. Worst case downlink rate is 600 bit/second (if not using Deep Space Network (DSN)). The scientific payload is about 100 kg. The spacecraft has 750 kg dry mass, and carries 750 kg propellants, and possibly a 500 kg penetrator. 20 square meters of solar panels provide 350 Watts of power.

(For a comparison, 10-15 years later, the similarly sized solar arrays on the (similarly sized) Dawn spacecraft produce 1300 W at the target distance of 3 AU from the Sun (or 10 kW at 1 AU). It's well consumed though: the ion thrusters on Dawn work at maximum thrust at the (combined) consumption of 8 kW. Another improvement: Dawn has 8 Gbyte memory. It also carries two identical, 5.5° field-of-view, 1024x1024 pixel cameras, which provide 9 meter/pixel resolution from 100 km altitude.)

If DSN support can be obtained, Doppler tracking of the Vesta spacecraft's movement can be used to accurately determine the mass of the encountered bodies. In the other case, another possibility was considered: releasing a test mass, and observing its movement near the target asteroid.

The spacecraft's structure is derived from Telecom satellites (INMARSAT), having the required mass, volume, and delta-v capabilites. It's 3-axis stabilised, with a pointing platform with 2 axes of freedom, for some of the scientific instruments.

The Mars gravity assist(s) constrain the possible trajectories (flyby altitude at Mars should't be too high, not to jeopardize the main mission, flyby speed has to be slow enough for the insertion of the Mars craft). The asteroid penetrator also imposes limits on the speed of the approach of the target asteroid (must be less than 4 km/s). Nevertheless, 3 possible trajectories were designed, with 2 Mars gravity assists. A single Mars swing-by is also possible, but the double gravity assist increases the mass budget of the spacecraft by 30%, at the cost of an additional 1.8 year in travel time to the asteroid belt. The following trajectories are for the 1994 launch window. The size and spectral(?) type of each asteroid is also shown here:

Trajectory 1:
-launch from Earth
-Mars gravity assist
-flyby of 2335 James (a 10 km X-type asteroid) (an Amor-asteroid)
-Mars gravity assist
-109 Felicitas (C-type, 76 km)
-739 Mandeville (EMP(?) type, 110 km)
-4 Vesta (V-type, or Vestoid. Has a diameter of 570 km) flyby with 3.5 km/s. A penetrator is released.
Total delta-v: 450 m/s

Trajectory 2:
-launch from Earth
-Mars gravity assist
-flyby of the P/Tritton short period comet
-Mars gravity assist
-2087 Kochera (30 km?)
-1 Ceres (flyby & releasing a penetrator)
Total delta-v: 1150 m/s

Trajectory 3:
-launch from Earth
-Mars gravity assist
-1204 Renzia (10 km?) (an Amor-asteroid)
-Mars gravity assist
-435 Ella (U type, 30 km)
-46 Hestia (F type, 165 km)
-135 Hertha (M type, 80 km)
Total delta-v: 350 m/s

In other studies, 11 Parthenope, 19 Fortuna and 20 Massalia were also considered.

Certain orbits can mean additional constraints. For example, 739 Mandeville has an inclination of 20° to the ecliptic, so you have to be lucky to catch it (when it's near the ecliptic plane). Especially if you want more than a brief rendezvous! The Dawn spacecraft is parked around Ceres and Vesta for longer periods - however, that means it first has to match their speed. This prevents it from reaching 2 Pallas, the next obvious target, because of that asteroid's high inclination.

Update: I've heard it's not ruled out that Dawn will be directed to rendezvous with 2 Pallas (for a slow flyby) in 2018, after the main mission at Vesta and Ceres is completed and enough fuel is left.

Finally, a combination of factors, probably including changing Franco-Soviet relations, the partial failure of the Fobos mission, growing financial troubles, the disbanding of the Soviet Union, put this mission on the long shelf of never realized dreams. However, the idea kept floating around (and technology kept developing), and is now resurrected (in a completely different form) as the Dawn asteroid orbiter.

Dance of the radio telescopes

2007-11-03T08:09:00.000-04:00

The Paul Allen Telescope Array have begun work recently. The radio telescope, that currently has 42 dishes, is used for SETI research - that is, search for extraterrestrial intelligence. At the same time, it is also used for astronomical observations, see the Key Science Goals.

However, when I saw the above video, I thought there could be a third use to it as well. It's a perfect object for an art show, similar to the ballet of the cranes, that was organized in 1996 in Berlin. There, construction cranes were directed to dance to the music of an orchestra, playing the Ode to joy from Beethoven's 9th symphony.

2007-11-03T07:54:00.000-04:00

Check out the Carnival of Space this week. I liked this post, you can get a feeling of where you are in the Milky Way.

Video of the OSCAR-40 launch preparations from AMSAT

2007-10-31T06:30:00.000-04:00

A cool video of the AMSAT P3-D (AO-40) launch campaign in 2000. It is placed in the spare space near (under) a commercial PanAmSat communication satellite (the big black thing seen on the video) on an Ariane-5 launch vehicle. P3-D is eventually going to be the basis for their P5-A satellite to Mars.

P5A - An amateur satellite to Mars

2007-10-29T06:25:00.000-04:00

Archimedes

I have written before about the Archimedes project. Archimedes is a privately sponsored, designed, built and operated balloon probe to Mars. It is a creation of scientists at the Mars Society of Germany. In the past five years, they have gone from designing the mission, the components, and building them, to testing them on parabolic flights (in microgravity environment) and in space on a test vehicle. A 1:2.5 scaled, but complete version, called Miriam, is currently being prepared for a March 2008 flight test (when it will be launched by an Orion sounding rocket to an altitude of about 100 km, from the Esrange sounding rocket range in Sweden). If everything goes well, Archimedes will be able to catch the 2009 launch window to Mars.

Testing balloon inflation in the Olympiahalle Munich. 21 June, 2004

Experiments on a zero-G flight. 28-30 June, 2005.

First test in space. April 5, 2006.

Amateurs to the rescue

So far, Archimedes appears to be on track. But how is a small, privately funded group going to get the spacecraft to Mars? Apparently aboard another private spacecraft. AMSAT-DL, the radio amateur satellite organization in Germany is building an amateur satellite, that will carry Archimedes (which itself has no propulsion system) to Mars. But let them introduce themselves first. (I tried to translate the video, the text is below).

Hartmut Päsler (DL1YDD): Hello and good morning, I welcome you to the stand of Amsat Deutschland (AMSAT-DL), which is a collaboration, an association of interested radio amateurs, engineers, technicians and scientists, to build communication satellites on a non-commercial base since 1974, we celebrated the thirtieth anniversary not long ago. As a short summary, I should say that we took part in several satellite projects, and right now the so-called Phase 3-E satellite is under construction; the progress of the construction is relatively good, we want to have the satellite in a flight ready state by the end of the year at the latest, and are looking for a launch opportunity in the next year.

Let's check the poster of the project and we can see that the satellite has a mass of approximately 170 kg, it's greatest extent is about 2 meters, solar cells, a lot of communication payload, from 144 MHz to 47 GHz, very small mirrors can be seen on it as well, which are for the high microwaves frequencies. The satellite is being built in Marburg, where right now integration is being finished.

Furthermore, we are planning a project, a satellite to Mars, which of course wouldn't be a communication satellite, as the signal takes 40 minutes to Mars, so you can't make instant communication with it. We are trying to take there a scientific payload: a balloon project, in which a balloon probe should be deployed in the Martian atmosphere, and we would provide the communication relay to Earth. To be able to do that, we have reactivated an old, 40 years old radio telescope in Bochum, a 20 m parabolic dish. Last year we received the signals of Voyager-1, which was launched in 1977, and which is still active - it is about 15 billion km from
Earth at the moment. To make it clear, the signal takes 13 hours to reach us, one receives what was sent 13 hours earlier. It's worth to note that Voyager is the farthest object man has ever created.

This is a prototype of an antenna that can be used for example to track the Mars mission, or for other things, it's built by Freddy de Guchteneire from Belgium, to whom I hand over the microphone, to explain some basic things about this antenna.

Freddy de Guchteneire (ON6UG): AMSAT-DL, P5 mission to Mars - we've just started to build hardware, newly developed, for our Mars mission. Here you can see this looks like a normal parabolic dish, but it really isn't a normal parabolic dish, it's a so-called ADE, axio-displaced ellipse antenna, which has higher efficiency than a normal dish. A radio amateur's parabolic dish has about 50% efficiency...

H.P: AMSAT-DL, and AMSAT worldwide in general finances itself only from donations, from your engagement - that we're honoured by -, in part from industrial sponsors, but for the most part we have to cover our financial needs from donations. So we created his donation initiative, it can be seen on our homepage, www.amsat-dl.org, where one can send us more or less arbitrary sums, and book such pixels, that everybody can see on the internet. We hope to amend our financial situation a little, because the negotiation of the launch of the satellite is going on, which can entail great financial expenditures. Thank you very much for visiting our stand, I hope it was interesting for the viewers, and stirred interest in perhaps amateurs in general or radio amateurs, there are an unbelievabe number of technical challenges, one can learn a lot, you're invited.

The P3 satellites

AMSAT Germany (like AMSAT-North America), is an alliance of engineers, technicians, scientists, students, radio amateurs and space travel enthusiasts. They carried out several succesful missions in the past 30 years. In 16 November, 2000 their Phase-3 D (Amsat-Oscar 40) amateur radio satellite was launched from Kourou, French Guyana on an Ariane-5G rocket. With its diameter of 2.3 meters, height of 70 cm, and its span of 6.5 meters with unfolded solar panels, AMSAT-Phase 3-D was the largest amateur radio satellite so far. It was also the heaviest with a launch mass of 650 kg.

Assembly in Orlando, Florida
In Kourou, French Guyana. September, 2000
Mating begins. The P3D is only a secondary payload, the main one, a communications satellite for PanAmSat will come on top of it.
With solar panels unfolded

A little table of the Amsat Phase naming scheme:
- Phase 1: a short life, technology testbed satellite, with only battery power, no solar cells.
- Phase 2: with solar cells, designed to last for 1 year. Low Earth Orbit.
- Phase 3: A highly elliptical, Molniya-type orbit. This allows a much wider coverage. They appear to stay over one spot for several hours at a time, which is much more comfortable for the radio amateurs who want to use it.
- Phase 4: An amateur satellite in geostationary orbit. None have been built yet.
- Phase 5: Capable of lunar or interplanetary missions.

P3-D - that was operating until its failure in 2004 - is going to be the base for the interplanetary mission, Phase 5-A. P5-A is going to be a relay between Earth and the Archimedes probe. But it can also carry other, smaller scientific experiments. Actually, even P3-D carried three small experiments, for example one that was studying the Van Allen radiation belt. It also had two different cameras: YACE, a small black and white CMOS camera; and SCOPE, which was built by the Japan AMSAT Association.

Separation of an Ariane-5 adapter, filmed by the YACE camera on P3D
Earth, with North and South America facing us, imaged by the SCOPE camera from an altitude of 53000 km. December 2001.

Building the P3-E

However, AMSAT has to carry out more preparatory experiments before the Mars mission. Therefore, the successor of the now silent P3-D, the Phase 3-E amateur satellite, that is currently under construction, is going to serve as a testbed for these. Included are a star navigation camera, a new onboard computer and an ultra-stable reference oscillator, which can be used to improve communications. They will also have to simulate some procedures, like communication using very weak signals. P3-E is going to be finished by the end of 2007.

Earth, Sun sensors; Clamp band springs
Nutation dampers

P3-E in January 2007. Photos by Robert McGwier

P5-A

As it is explained in these documents, the P5-A spacecraft doesn't actually need to be more complicated than the P3-D. The main tricks are rather to get it to Mars, and to maintain communications. To get into space, they will use a cheap place on an Ariane launch to GTO (geostationary transfer orbit). However, being a secondary payload means they can't influence the launch date and time, and the launch may be in a bad time for a Mars departure. There appears to be a tricky solution to this. Moon flybys can be used to modify the orbit of the spacecraft, and this makes it possible to keep it in parking orbit for months, and then send towards Mars at the right departure window. The propulsion system of the P3-D is enough for these maneuvers, and for the subsequent insertion into orbit at Mars, 10 months later.

As for reliable communications, the refurbished telescope in Bochum already proved capable of receiving signals from Mars Odyssey, Mars Express, Rosetta, and Voyager-1.

A 50% scale model of the P5A Mars satellite
The 2 meter antenna of the P5-A. The frame itself is the same as for P3-D.

Nevertheless, there are still many challenges to be overcome. There aren't many details about attitude control yet. Thermal balance is also going to be different from an Earth orbiting satellite. At the distance of Mars, the solar constant is less than half of that in Earth orbit, which can cause a drop in the spacecraft's temperature of several tens of degrees. Power production from the solar panels also drops to its half.

We have to patiently wait for more details to emerge. Until then, information and news on the project's website (in German): Go to Mars with Amsat-DL.

Donations are possible for the P3-E amateur satellite here.
Donations are possible for the P5-A satellite to Mars here.

Wildfires as seen by Genesis I

2007-10-29T06:00:00.000-04:00

Genesis I, the first prototype space module of Bigelow Aerospace was launched into Earth orbit more than a year ago. The company has published these new images of the California wildfires taken by Genesis I, from a height of 500-600 km.

Dark circle near the south pole of Mars

2007-10-24T11:06:00.000-04:00

This circular feature lies only 200 km from the Martian south pole. It has been known from the Mariner 9 and Viking Orbiter images, but now the Mars Reconnaissance Orbiter has taken new, high resolution images of this area. The circle itself is about 4 km across and looks quite perfect. Can it be an impact crater? After all, an impactor has to have quite an inclined orbit to be able to hit near the southern pole. Well, the team writes about this image: Bright areas are covered by carbon dioxide frost, with a "swiss cheese" pattern common at the south polar residual cap. The circular evenness of the depression suggests an impact crater, but there is no evidence of a crater rim or debris unless it lies beneath the frost. While the depression may have formed by collapse, the image is missing the typical ground fractures that form around a collapse pit.

The HiRISE page has an even higher resolution image. (This is it) As can be seen, there's a cone near the center. The terrain around it is buried under something (probably ice?), making it hard to infer what's happening there. Is it an ice vent? Is it a pseudocrater? (A pseudocrater is not an actual crater made by lava eruptions, rather a similar looking form created by steam explosions, as lava is trying to cross a wet layer). Or it can be a pingo - a peak created by water upwelling and freezing below the ground, in a permafrost environment.

A pingo in Alaska

A pseudocrater in Iceland
Both processes could be responsible for the cone seen at the center of the dark circle on the HiRISE image. But liquid water is involved in both - how could it be present at the extreme cold of the southern pole? Maybe it's not water at all, rather carbon dioxide ice, or rather a CO₂-water complex (clathrate).

A Venus balloon prototype

2007-10-18T11:00:00.000-04:00

I'm really fond of using balloons for the exploration of other planets, even though only one such mission was realized, which was part of the French-Soviet Vega mission to Venus. However, new plans, designs, proposals keep appearing ever since. A somewhat promising example (as it's more than just paperwork) is a new prototype created by a team from the Jet Propulsion Laboratory, ILC Dover and NASA Wallops Flight Facility. ILC was the maker of the airbags for the Mars Exploration Rovers.

A balloon on Venus has to withstand the extreme heat, pressure and chemical environment. Actually the easiest is to design them to a specific atmospheric height, and of all the possibilities, specifically to fly at about 53 km, where conditions are fairly comfortable (temperature and pressure is earthlike). Still, intense radiation would come from underneath as well, as the white cloud layer reflects the strong sunlight. Anyway, the first thing about the balloon is its material. From Don Mitchell's site I learn the Soviet engineers fabricated balloons from Ftorlon (a form of teflon) cloth and film. The tether rope and straps between gondola compartments were made from Kapron (a form of nylon-6). It was filled with helium to 30 mbar overpressure.

JPL's prototype balloon is made of a layer of
materials: teflon (for protection from the sulphuric acid in the atmosphere), aluminium, to reflect sunshine and prevent overheating, mylar to prevent the escape of the tiny helium atoms from the balloon, and vectran, for strength. It is expected to be able to host a payload of 40 kg (that'd be the scientific instruments and the necessary equipment, computer, radio, etc. together). It's current warranty is about 12 days - enough for three circumnavigations of the planet.

The only question is, would NASA launch a solely aerobot-mission, or do they want to include it in a larger project - and in the latter case, which project? I'm not sure they have any missions at all to Venus in planning.

The 25th carnival of space

2007-10-18T10:56:00.000-04:00

Riding on an ocean of interesting posts in the Carnival of Space #25. And, by the way, all the previous editions at the Carnival of Space archive.

Tracking the ISS

2007-10-17T08:58:00.000-04:00

Astonishing video of the International Space Station passing overhead, tracked from a backyard. How to do it, and more interesting photographs can be found at Astrospider.

Ferrying space shuttles by aircraft

2007-10-15T11:20:00.000-04:00

Shuttle Carrier Aircraft

Some part of the STS (Space Transportation System, the official name of the shuttle) are transported on land and on sea (like the external tank), but the shuttle itself is carried by plane - one of the Shuttle Carrier Aircraft. Originally the C-5 Galaxy was planned for this task, but because of both technological and political reasons, NASA decided to buy two Boeing 747 instead, in 1974, and modified them. They are used to transport the space shuttle back to Florida if it lands at Edwards AFB in California (which doesn't happen very often, since the early 80's there were only two such cases, STS-114 (August 9, 2005) and STS-117 (June 22, 2007). But these airplanes also took part in the development of the Shuttle. The shuttle Enterprise - built for specifically this purpose - is seen during test flights.

Takeoff

In-flight separation

Myasishchev VM-T Atlant

The Soviets would use an Antonov aircraft for their Buran shuttle. But the largest, appropriate plane was still under construction, so they needed something else in the meantime. They considered using helicopters, but after test flights with test masses, they were deemed too unsafe (not surprising, as two helicopters would have to fly in formation and use cables to lift such a heavy cargo), and also uneconomic, as they could cover only short distances in one flight under these conditions, so a supporting infrastracture would have to be built, with airfields, etc. Instead, they turned to an existing aircraft. The Myasishchev M4, built to be a long-range bomber, appeared to suit this purpose. After considerable modifications - the most visible of them is the doubled tailfin, providing increased stability and also space for its huge cargo - and lot of flight tests, the Myasishchev VM-T Atlant became ready. Its first flight was in 1982, with parts (like the hydrogen and the oxygen tank) of the Energiya booster (part of the Soviet shuttle system) - one of many configurations. The diameter of the tanks is about 8 meters, while the aircraft fuselage is only 3 meters, which gives it a weird look.

3ГТ

0ГТ - the Atlant with the Buran piggybacked. Buran's tailfin was removed to save weight.

1ГТ

Buran is going to Baikonur

An-225 Mriya

The two Atlants were to be replaced in 1989 by the world's largest airplanes, Antonov's An-225 Mriya. They were designed for this task, and have more than enough capacity for it. They can carry 200 tons on their back or 250 tons inside. The Mriya is used to this day for transporting heavy and/or oversized cargo.

An Antonov-225 dwarfing other crafts. Near Kiev, from google maps.

Buran flying on Mriya

The GOCE satellite

2007-10-13T14:31:00.000-04:00

Part of ESA's Living Planet Programme are the Earth Explorer missions. One of these is the GOCE (Gravity field and steady-state Ocean Circulation Explorer) satellite. GOCE will provide data to determine the global and regional models of Earth's gravity field to an unprecedented accuracy. It is seeking to determine A global geoid of 1 cm accuracy at about 100 km spatial resolution and a gravity field model with 1-2 mGal precision accuracy and the same spatial resolution. The geoid is an equipotential surface of the Earth, as opposed to the shape of the actual crust. Without movements, the surface of the oceans would follow such an equipotential surface - the geoid. GOCE's measurements will be more than just an excercie in geodesy (which is very important in itself), but will bring important data to geophysicists, and even more importantly for oceanography.

The experiments requires basically just two components: the so-called Electrostatic Gravity Gradiometer (EGG) - which consists of ultra-sensitive accelerometers, and a GPS-based Satellite-to-Satellite Tracking System (SSTI). To be more sensitive, th^e satellite will be orbiting at a very low height of 250 km. However, the thin atmosphere at this height has an effect of a gentle push on the satellite. To compensate for these forces, it has high precision ion thrusters made by QinetiQ. These will be used in such a way that the satellite feels absolute free fall, without any net forces. The satellite itself doesn't contain any moving elements (so that they don't interfere with the measurements).

GOCE will be launched in spring 2008 from Plesetsk, Russia, to a sun-synchronous polar orbit.

GOCE flight model on the Estec test facility

Carnivals arrived

2007-10-12T03:57:00.000-04:00

Articles about space (detecting exoplanet atmospheres, how lunar exploration was imagined, benefits of colonizing Ceres, an imaginative history of evolution up to the MERs; percieved appeal of space tourism, if it makes the ISS useful - probably not enough. Also, remembering Robert Bussard. ..and more)

and articles about scepticism (too tired to list, lots of articles of puzzle-solving and myth-debunking).

JWST model

2007-10-11T06:36:00.000-04:00

Full-scale model of the James Webb Space Telescope (more photos here), on tour since 2005. JWST is going to be the successor of the Hubble Space Telescope, but much larger (with a primary mirror of 6.5 meters), and more complex.

All of these (even the segmented mirror) are going to be automatically unfolded in space

How do mishaps happen?

2007-10-10T10:07:00.000-04:00

It is estimated that minor and major mishaps between 1996 and 2006 cost NASA more than $2 billion in direct costs only.

The NOAA-N' weather satellite, that fell during assembly, because of a misunderstanding between two teams of technicians. The cost of this accident doesn't even fit here, but i'd mention that the spacecraft cost more than $200 million, and exactly 4 years later it still hasn't been fully rebuilt.

So obviously it's important to study the numerous Ways of Failure. I've found this presentation about the topic slightly interesting. After all, given how complex any space mission can be, it's a miracle that they don't all end in a spectacular - or boring - failure. Or rather, the result of hard job, as the presentation shows.

More on this subject at this website, dated in the future. (NASA Projects Management Conference)

Sounds of an aurora

2007-10-09T09:38:00.000-04:00

Often we forget that we're not alone. Our planet is surrounded by satellites we built, and usually they are the first to notice when the weather in space changes, like when the Sun sends us large flares. But even though we're quite well protected from these particles, nature provides a way for us too to see them, as they enter the upper atmosphere: the polar lights. And sometimes, on very rare occasions, to hear them too.

However, even if you travel north and catch an aurora, the chances of hearing it are apparently very slim - actually some even doubt that they have sound at all, and believe it's an "aural" illusion (if not auroral), tinnitus, or something similar, created by your brain. The other problem is, it's very hard to explain, as the atmosphere is so thin above 60km, where auroras reside, that no substantial amount of sound would be able to propagate down to the human listener. A theory is that the waves are brought to the ground as radio waves, that are generated in the aurora, some of which are in the audible frequency range (an established fact). Around you, these electromagnetic waves may be able to move things on the ground -leaves, grass, etc. - a tiny bit, and thereby transmit their frequency to them, which they reproduce as tiny artificial sound generators.

However, there's another, easier way to listen to polar lights, and sound recordist Steve McGreevy has been doing it since long: just take an appropriate radio with you!

Fairies, aliens and sociology

2007-10-06T11:36:00.000-04:00

I've found an interesting article in Swift, the newsletter of the James Randi Educational Foundation. It's contemplating on the similarities of the fairy folklore and the modern folklore of aliens. There may be interesting similarities - probably it'd worth a thorougher study.

The Evolution of the Little Green Man

UFOs seen during Apollo missions

2007-10-04T10:42:00.000-04:00

One of the legends of the space age is that during their flight to the moon, Apollo astronauts saw UFOs, or objects they couldn't identify but which were obviously floating in space somewhere close to them. This is rather a fact than a legend, as Buzz Aldrin confirmed it in numerous interviews. Just let him explain:

The spacey music, the commentator's style ("it could only have been on thing... a UFO!") and the "expert" may be a little annoying, but the fact remains that Aldrin says they saw something out there. Is there an official explanation? I quote from a NASA website:

What does NASA have to say in response to this? What were those objects they all saw?

I just talked to Buzz Aldrin on the phone, and he notes that the quotations were taken out of context and did not convey the intended meaning. After the Apollo 11 crew verified that the object they were seeing was not the SIVB upper stage, which was about 6000 miles away at that time, they concluded that they were probably seeing one of the panels from the separation of the spacecraft from the upper stage. These panels were not tracked from Earth and were likely much closer to the Apollo spacecraft. They chose not to discuss this on the open communications channel since they were concerned that their comments might be misinterpreted (as they are being now). Apparently all of this discussion about the panels was cut from the broadcast interview, thus giving the impression that they had seen a UFO.

David Morrison
NAI Senior Scientist
26 July 2006

Now it might seem too late to claim that Aldrin's words were edited out. But in an other interview, he does indeed say they came to this conclusion - that it was a panel of their own craft:

*

Here's another object caught on camera, this one from Apollo-16. This thing - described as "a saucer-shaped object with a dome on top" - was only noticed in the footage after landing:

A high resolution digital scan of a frame from the original film

It took a lot of efforts to explain it. First all the frames were scanned, corrected for camera movement/position, and then stacked together (co-added), to increase quality. The resulting image was clear enough to identify the object:

Can you recognize it? No? Then check these:

The position of the EVA floodlight (used to light the shadowy side of the spacecraft during a certain spacewalk)

Left: enhanced image. Right: EVA floodlight/boom from the perspective of a Command/Service Module window

Carnival of space #22

2007-10-04T09:39:00.000-04:00

The 22nd carnival of space is out. Also, happy 50th birthday for Sputnik-1!

Carancas meteorite, Peru

2007-10-02T09:37:00.000-04:00

This meteorite fell on September 15 in a very remote area of Peru, near the community of Carancas, 800 miles from Lima. Claims rose of 200 locals falling ill after visiting the site (they saw the thing on the sky and heard it as well, that's why they were searching for it). Discussion started on many forums about
1 can this be a meteorite crater at all?
2 if yes, what type of meteorite was it?
3 can it really make people ill?

Part of a BBC article:
"Increasingly we think that people witnessed a fireball, which are not uncommon, went off to investigate and found a lake of sedimentary deposit, which may be full of smelly, methane rich organic matter," said Dr Caroline Smith, a meteorite expert at the London-based Natural History Museum. "This has been mistaken for a crater."

However, it's not so easy to tell without actually being there.

After some scientists visiting the site and taking samples there are some answers. It is said that the water in the crater was boiling and sending a column of steam into the sky as the first people arrived at the scene (who were searching for it after hearing and seeing the thing in the sky). The National Geographic writes:

But the illness was the result of inhaling arsenic fumes, according to Luisa Macedo, a researcher for Peru's Mining, Metallurgy, and Geology Institute (INGEMMET), who visited the crash site.

The meteorite created the gases when the object's hot surface met an underground water supply tainted with arsenic, the scientists said.

Numerous arsenic deposits have been found in the subsoils of southern Peru, explained Modesto Montoya, a nuclear physicist who collaborated with the team. The naturally formed deposits contaminate local drinking water.

As for the meteorite itself:

"Based on the first-hand reports, the impact and the samples, this is a meteorite," Macedo, of INGEMMET, said.

Preliminary analysis by Macedo's institute revealed no metal fragments, indicating a rare rock meteorite. Metal stands up better to the heat created as objects enter Earth's atmosphere, which is why most meteorites are metallic.

So it was a non-metallic type meteorite... or was it?

Peru's La Republica newspaper reported today that Ronald Woodman, director of Peru's Geophysical Institute, stated that the meteorite which landed in Puno on Saturday had high levels of iron.

In addition, Woodman stated that astrophysicist José Ishitsuka of Peru's Geophysics Institute, had collected samples of the meteorite and had confirmed that it contained a high degree of iron.

"The specialist José Ishitsuka has confirmed, after analyzing pieces of the object, that it is a meteorite with a high degree of iron and (contains) magnetic properties, characteristic of these objects," explained Woodman.

It was reported that Ishitsuka retrieved a 3-inch magnetic fragment of the meteorite and has based his conclusion after studying its properties.

Well, probably it's too early to tell. But at least there are fragments found so it will be possible to study it further. Also it's likely now that it's
-not containing an alien species
-not a fallen American spy satellite
-not a strayed SCUD missile
as some people hinted.

The following video contains some closer shots of the crater itself:

Less confusing is the freshly available
initial technical report about the meteorite. Just one not-so-surprising thing: they found that reports (that appeared in every media) of "200 people fell ill" were way off...

Sputnik 1

2007-10-02T05:26:00.000-04:00

PS-1, or "simplest satellite" with a technician

Oct. 4, 1957 - Sputnik 1 is launched into Earth orbit. A project basically pushed by one man, Sergey Korolyov, one of the later chief designers. On the day of the launch, he was the only one who could understand that history came to a turning point. Space age - and also the space race - had begun.

Martian cave confirmed by HIRISE camera

2007-08-31T07:23:00.000-04:00

The Mars Reconnaissance Orbiter discovered several "holes" on Mars in May, that stirred a lot of interest. Here is the close up view of one of them (Jeanne).

A 500-feet... hole?

It's quite obvious that it isn't simply a crater, but what is it then? Is it a caldera filled with extremely dark matter, like the Wau Namus, that appears as a hole in the deserts of Lybia? Is it a lake of oil? Is it caused by sandworms?

The Sun's angle wasn't too low when the image was taken, so the fact that we can't see the walls means it can't really be a pit. The most likely explanation is that it is a sort of skylight, a hole in the ceiling of a cave, that also occur on Earth. If the cave is very deep and large, the illuminated floor can't be seen from exactly above, and we just see a black hole instead.

A skylight (photo by Gus Frederick)

The hole - and 6 others - lie on the slopes of one of the largest volcanoes in the Solar System, Arsia Mons. (More context here, but Arsia Mons is so large it still won't fit on the image). So probably the hole is on the ceiling on a horizontal lavatube.

Infrared measurements also confirmed that they should be caves indeed, as they appear colder than their surrounding during daytime, while warmer in the night.

Here's another feature, from a different region of Mars. This was interpreted as horizontal lavatube, the roof of which collapsed, except for a short section (forming a natural bridge):

A trough in Tartarus Colles, Mars

In the past weeks, the HIRISE team were now able to make another close-up image of Jeanne, with different illumination:

The same feature as the first image. Taken on 8 August.

Here it looks more like a vertical shaft, or just a deep pit. It has a diameter of about 150 meters, and a depth of least 78 meters. Luckily there are chances of peeking even deeper, when the Sun climbs higher on the Martian sky in a few months.

Aurora on Ganymede

2007-08-30T07:06:00.000-04:00

So aurorae have been observed on Earth, the gas giants, and even Jupiter's moon Io. And there are even more! In 1972, it was discovered that the largest Jovian moon, Ganymede has a tenuous oxygen atmosphere. Its source is thought to be not plants, as on Earth, but the solar radiation splitting water ice into oxygen and hydrogen (and the latter then escapes into space more easily). Since the visit of the Galileo orbiter, we also know that Ganymede has its own magnetic field (the only satellite known to have one!). So with both an own magnetic field and atmosphere, it's no surprise that Ganymede also has aurorae! The green glow on this picture, on and above this moon, has the same source as the green glow in the polar lights on Earth - transitions of excited oxygen.

2007-08-30T06:28:00.001-04:00

You can check out the 17th Carnival of Space blogs.

Space-X update

2007-08-24T04:59:00.000-04:00

Merlin engine test

Elon Musk has a long update about the activities of Space-X, and a lot about Falcon-9. And also cool pictures and the above video of a Merlin (1C) engine firing on the test stand. With cool sound!

A mission to Phobos: Fobos-Grunt

2007-08-22T12:40:00.000-04:00

Apart from the well known Mars Exploration Rovers, the current Mars Odyssey, Mars Reconnaissance Orbiter, the soon to arrive Phoenix Mars Lander, and ESA's Mars Express, and the various planned future Mars missions (even non-governmental ones, like the Archimedes balloon probe i mentioned earlier, apart from all those, there is also a plan to (re)visit a Martian moon, Phobos.

Russia, after having a lot of bad luck with Mars, planned a double Phobos mission in 1988. One of the two spacecraft did eventually reach Phobos, but then fell silent (the computers went wrong, likely because of insufficient shielding of the electronics). In 1989, money ran out, and all subsequent plans were shelved (except from a failed launch in 1996).

An image of Phobos and Mars, taken by Fobos-2 in 1989

Now it seems that new plans are on the drawing board again, with probably (hopefully) serious political backing. The new Phobos mission is called Фобос-Грунт (Fobos-Grunt, meaning "Phobos Soil"). As the name indicates, the spacecraft is intended to land on this tiny moon, take soil samples, and return the samples to Earth.

More interesting than words and numbers, the following video shows most of the details - it's quite easy to get even if you don't speak russian:

The project seems to be quite ambitious, given they had only one interplanetary probe in the last 18 years (and that was also destroyed after launch). However, if there's a chance that even a part of this mission will come true, it's already good news to any space enthusiast.

And there's more: nowadays Mars seems to be such a magnet for research that China also jumped on the bandwagon, and signed a deal with Russia, that they can include their own micro-probe on Fobos-Grunt. The Yinghuo-1 (萤火一号, named after Mars) spacecraft will be about 100 kg. It's going to be an orbiter with simple capabilities: taking pictures of the planet and making magnetic measurements.The next launch window will be in October 2009, so work should be already in progress, and probably we'll soon get some more infos...

Yinghuo-1

On-orbit and post landing image of space shuttle tile damage

2007-08-22T12:28:00.000-04:00

Armadillo's rocket crashed during testing

2007-08-22T12:14:00.000-04:00

Another accident at a private space company - no one is hurt, but Armadillo Aerospace' Texel craft is apparently destroyed during a test flight. The New Scientist has the full story.

No pictures have been released, these two videos show Pixel (Texel's twin) at the X Prize Cup in 2006 (which they nearly won):

Bigelow ads to be viewed from space

2007-08-04T11:29:00.000-04:00

Hmm, these Bigelow people are really crazy. They put a projector on their orbiter, so that they can project ads on the outside of the craft :-)

Shiveluch - measuring height from shadow

2007-08-04T09:34:00.000-04:00

What on Earth is that? This is a satellite image of an erupting volcano. What you can see is the plume from exactly above, before it got smeared by the winds.

Shiveluch volcano is on the Kamchatka peninsula, here are the details of this eruption in last winter, and a larger image.

Can we guess the height of the plume?

Well, we have to find out how high was the Sun (that casts this shadow) on the sky at that moment. The page says Aqua satellite took this picture at 02:00 UTC on March 29. Kamchatka is only about 20 degrees west from the date line (which is about opposite from the 0 meridian, just to appreciate how vast Russia is). The exact latitude and longitude of Shiveluch is 56°63' N, 161°32' E. That means local noon is about 161°/15° = 10.75 hours = 10 hours 45 minutes before noon in Greenwich (the Earth turns 360 degrees in 24 hours, or 15° in one hour). Or to put it another way, it's 10:45 later than the Universal Time. So the local time was 02:00 + 10:45 = 12:45, or 3/4 after noon, when the picture was taken. (Of course this is a perfectly "local time" defined by the apparent movement of the sun - we don't care for time zones that can be arbitrarily defined by authorities). However, we need a correction to this, because Earth's orbit is not a perfect ring, and that results in a slight change of the apparent speed of the Sun's movement on the sky (as for the effects of the eccentricity of Earth's orbit, see the explanation). This correction is never more than 15 minutes though, and on March 29 it is only about 5 minutes (see the explanation). Now let's make a small cheat here. Let's just say it was 12:00 local time, to make things easier. Local noon means the Sun is at its highest elevation (on a given day). The highest elevation depends on the part of the year - it climbs much lower in winter and higher in the summer. But note that March 19 was only 8 days after the spring equinox. So let's just say it was approximately spring equinox (our 2nd cheat). This we prefer because it's easier to tell, how high the Sun climbs. On equinox day, if you stand on the equator (latitude 0°), the Sun passes exactly overhead. If you stand on the North or the South pole (latitude 90°), the Sun circles exactly on the horizon. And if you stand on latitude 56° N, the Sun will appear to move around along a circle in a plane that is tilted by 56 degrees from vertical - or 90°-56°=34° above the horizon. So it reaches its highest elevation on the sky at 34°. So we know that at the time the above photo was taken, the Sun was 34° high on the sky. (actually i think the two cheats i made (it's a bit later in the day, but it's also a few days after equinox) somewhat cancel out each other, so this might be a fairly good approximation, if i didn't do any mistakes of course.) The photo appears to be oriented north (check an atlas or google maps), so the fact that shadows fall almost exactly up/north reassures us that it indeed was pretty close to noon. (Making the above calculations of the local time somewhat unnecessary...)

I measured the length of the shadow (the shadow of the whole big plume) to be 53.4 pixels on average, which equals to a length of 13 km. In the center of this ash cloud is an other shadow, which probably indicates a secondary, smaller plume (if it's possible at all) that rises above the large one, and casts a shadow maybe 6-12 pixels long or 1.5-3 km. Now knowing the sun was 34 degrees high, a simple trigonometry gives us tan(34°)*13 km = 7.8 km (4.9 miles) for the height of the main plume, or probably 8.7-9.6 km for the whole thing.

As you can see on the drawing above, this is the height of the plume compared to the plains around. The height of the volcano itself is about 3 km, so the height of the ash cloud may be a little less. From this image it seems that it's probably surrounded by low lying plains (I tried to check it on google maps but the surroundings of the volcano are clouded there by an other ash cloud!). So maybe it really rises 2-3 km above its surroundings.

Unfortunately i don't know much about eruptions. Is it realistic that 10 minutes after the eruption the plume is at 8-9 km? Probably yes.

This way, one could teach a little physics (or astronomy), armed with only this beautiful photograph. Actually you can go further. Like start thinking about why is the landscape so snowy in late March, when Kamchatka is about as far north as Denmark or Britain?

Phoenix photos

2007-08-04T09:28:00.000-04:00

NASA's Phoenix Mars Lander was succesfully launched today . You can see some images of it from its last moments in the cleanroom.

The last picture in the gallery is a little funny. You have to be really careful with accounting all the parts, not to forget something on the spacecraft that doesn't belong there...

Carnival of space

2007-08-02T20:29:00.000-04:00

Various posts at the 14th Carnival of Space.

One of them shows, how really easy it is today, to make astrophotos, using a telescope and your mobile phone : Stupid Mobile Phone Tricks.

It's also nice too see the counterparts of Martian blueberries in Utah.

Although research has recently very much shifted away from the Moon, and we're all excited about 1) how exciting Mars is 2) how much more exciting the outer solar system turns out to be than we thought ; it's good that someone shows, that our understanding of the Moon has changed as well, and looks like it also appears more and more interesting.

Oxygen from lunar dust

2007-07-31T14:13:00.000-04:00

During the Apollo missions that landed on the Moon, astronauts found that moondust was keen to get everywhere where they didn't need it - even into their lungs... But for future astronauts on the Moon, this dust may prove to be a vital source of breathable oxygen. That's because 43% of the dust that constitutes the upmost layer of the soil on the Moon is actually oxygen. Of course it is in a bond form, so you turn to some tricks if you want to breathe it.

Moondust consists of different oxides, such as silicon dioxide (sand), but it also contains a lot of ferro-, calcium, and magnesium oxides. The oxygen that is available in this form has to be simply taken out from these compounds that make up the soil, preferably in a way that can be carried out even on the Moon.

Eric Cardiff - who is leading a group at the NASA Goddard Space Flight Center that is searching for ways of providing oxygen for human Mars and Moon missions - says that we simply have to evaporate the soil. Cardiff is working on a technology that can heat the soil to a high enough temperature for it to release the oxygen bound in it. Every oxide has such a temperature, at which it simply disintegrates into its constituents. This technique is called vacuum pyrolysis (where pyro stand for "fire" that is used to decompose ("lysis") the stuff. A lot of reasons suggest that pyrolysis is the best method: it doesn't need materials that have to be brought there from Earth, or any sort of strange or expensive stuff. Lunar dust collected in place have to be heated and that's it, there's your valuable oxygen.

Cardiff and his group took to try out their theory in practice. They didn't use real lunar dust that has been brought back from the Moon by the Apollo astronauts, as it's very expensive. There's a chemically similar, but easily obtainable material, which is a mixture of a mineral called ilmenite (a titanium/iron ore), and a basalt called Minnesota Lunar Simulant, and ground glass. They heated this mixture to 2500 C degrees, which resulted in 20% of it evaporating into oxygen. The resultant slag is an oxygen-poor metallic, glass-like material, that can possibly used as building material, as an isolator against radiation, or such things. NASA's Langley Research Center is going to work on how to utilize the resultant slag, and how to shape it easily. Further experiments are going to try to make this method more efficient. At lower temperatures, and in a higher grade vacuum, less energy will be needed to extract the oxygen. In the first experiment, they used a one millionth bar pressure, their next aim is to go down to a thousandth of that, which is believed to create conditions in which significantly lower temperature would suffice for the decomposition.

There are also other groups working on extracting oxygen from lunar regolith. For a comparison, Mark Berggren's group at Pioneer Astronautics could extract 15 kg oxygen from 100 kg of lunar soil simulant, using a method that uses carbon monoxide. (with their method, carbon monoxide is added to the soil at high temperatures, which then releases carbon dioxide. Using hydrogen it is then separated to carbon monoxide and water, and the water can be harnessed through electrolysis)
NASA's Regolith Excavation Challenge will pay $ 250 000 if you can meet their rules (producing 10 pounds of oxygen in 8 hours, see the link). This event will be held in 2008, however the detailed rules are not prepared yet, apparently. The success of this challenge would be very important, as oxygen is not only used by humans, but it's also popular oxidizer in rockets. Being able to produce it economically on the Moon would save a lot of money.

Armadillo Aerospace

2007-07-30T16:41:00.000-04:00

Here's a little entertaining video from Armadillo Aerospace, the startup company of John Carmack. They were competitors for the Ansari X-Prize, and now for the Wirefly X-Prize Cup (and they're not bad!). If you watched the previous video, of Burt Rutan's talk, he mentioned the fast evolution of the first airplane designs. Armadillo try to do the same: they put the emphasis on a rapid build and test cycle.

Scaled Composites

2007-07-29T15:20:00.000-04:00

So, if you didn't know Burt Rutan, head of Scaled Composites, here's a talk he gave. His got his own style, but it's still an interesting video.

Deadly explosion at Scaled Composites' facility in Mojave

2007-07-29T14:30:00.000-04:00

Sad news. Apparently they were carrying out a test on the piping/plumbing system on a nitrous oxide tank (piping through 5 tons of oxidizer rapidly), when an explosion occured, which killed 3 and wounded another 3 persons. It looks like no space enterprise comes without such accidents. First the Russians, then the Americans, the Chinese, and now the private sector.

What can be gathered from the articles and pictures:

Nitrous oxide is one of the least dangerous oxidizing compounds.

Some said it sounded like a 500 lb. bomb. Eyewitnesses didn't report seeing smoke, which means that there probably wasn't much burning.
On the pictures, no crater is visible, so the explosion was likely a few meters above ground, and not very strong.

Victims were taken to hospital with wounds from metal and kevlar shrapnels.

Most people say it was most likely a pressure vessel rupture (without a detonation). Could be due to overpressure, overheating, maybe a problem with a valve, it will take a long investigation until they can tell.

This is likely the sort of tank seen on the pictures:

(from Scaled Composites)

Geekism.

2007-07-21T20:07:00.000-04:00

Allright, it looks like there aren'y many funny license plates out there that have anything to do with space, or even science. Too bad.

Serene beauty

2007-07-20T16:28:00.000-04:00

This is an interesting view of another world. Here's the explanation.

Stop-motion

2007-07-19T17:12:00.000-04:00

Radio telescope in Kalyazin, Russia, with a 64-meter (210 feet) dish.

Carnival

2007-07-19T10:42:00.000-04:00

The 12th Carnival of Space is out at Music of the Spheres.

Tumbleweed ball to Mars

2007-07-18T11:15:00.000-04:00

Allright, Archimedes may become a low cost real Mars balloon probe, but can we make an even simpler design?

What if we simply send an inflated airbag, containing simple sensors? It would be it's own parachute, landing airbag, and movement system. If it's light enough to be bouncing and/or to be carried by the wind, then we may not even want to have a complicated mechanism to control its movement. All the equipment for measurements would be inside. Maybe it will be possible to put a camera inside it, peeping out through a hole, although i'm not sure it'd be safe there, or whether it would't collect lot of dirt while rolling.

The Tumbleweed Rover is under development at NASA - although at a slow pace (apparently tests begun more than 6 years ago). At least they have gone through short tests at Antarctica, and lately also in a desert environment in Arizona.

A not too interesting video of the Tumbleweed at Antarctica

If you want to read more technicalities, check this report of the tests in Arizona. They even made some simple tests with solar cells on the outside of a ball.

DNA chirality detectable in Earthshine?

2007-07-17T18:12:00.000-04:00

From Slacker-astronomy:

RNA and DNA are chiral structures which lead to polarization of reflected light. Thus, light reflected off of vegetation covered areas on planets with life should be polarized. This was tested using Earthshine, sunlight reflected off the Earth to the Moon and then reflected back to the Earth. (This is why under dark conditions you can make out the entire Moon even when only a crescent is lit by the Sun.) They found expected polarity (a few percent) and now are looking at how to use this to search for life on extrasolar planets (which will obviously be orders of magnitude fainter). (Woolf)

Google yields this PDF of a talk, a little more information can be extracted from it. Interesting anyway.

Dust storm on Mars

2007-07-17T15:56:00.000-04:00

Since about three weeks now, there is a dust storm on Mars, that is now covering about a half hemisphere. It may very well develop into a global dust storm, as it has happened a few times since the exploration of Mars has begun. This time, however, we have two rovers there, that are in danger. The power of the storm doesn't pose any danger, however, the fine Martian dust that is kicked up will stay aloft (or may later settle onto the solar panels), and it can easily block out enough sunlight to starve the solar powered rovers. If the power output goes below about 200 Watts, it may prove to be to little to heat their internals, and they may freeze forever.

Atmospheric opaqueness is measured in 'tau', and the highest recorded values can be seen here:

This graph is from Jul 15 2007. Today tau rose above 5.

I composed these four images together, to see the effects of dust at Opportunity's site - not much yet (except from general darkening of the landscape, which cannot be seen here). The images are from
Opportunity's sol 1220, 1225, 1233 and 1235 (or to make it easier to compare with the graph above, Spirit-sol 1240, 1245, 1253 and 1255). The last two were taken from a little bit different position.

Dust conditions at Opportunity's site

On the last image, the hills on the horizon are clearly fading.

Let's hope both rovers will be able to survive.

Space simulators

2007-07-17T13:02:00.000-04:00

With its diameter of 100 feet and height of 122 feet (30x40 meters), NASA's Space Power Facility is the world's largest vacuum chamber. Among other things, it was used to test some ISS components and the Mars rover landing systems. It is now upgraded to make possible vibration/acoustic tests and electromagnetic interference tests. It will be able to simulate launch conditions for Orion, NASA's space shuttle replacement vehicle.

Image from space.com.

ESA's similar facility is called the Large Space Simulator. It is in the Netherlands, part of the European Space Research and Technology Centre. It is also basically a cylinder (with a height of 15 meters and a diameter of 10 meters). It can create conditions of vacuum, cold (-180 degrees Celsius (-300 F), by circulating liquid nitrogen in the chamber's walls), intense sunlight (using 19 xenon lamps of 20kW each). The thing that is tested - usually a satellite - can be moved (rotated) in a way to simulate its movement in orbit. Just in case you plan to send your spacecraft closer to the Sun, the lamps can be turned to higher power.

The INTEGRAL spacecraft in the Large Space Simulator

Artemis

Rosetta

Part of the Herschel Space Telescope in the LSS

Endeavour on the launch pad at KSC

2007-07-17T12:46:00.000-04:00

Endeavour sitting on launch pad 39A at Kennedy Space Center, while being prepared for its August launch. STS-118 is going to continue building the International Space Station.

Credit: NASA/Ken Thornsley

Image from space.com.

Venus Express’ infrared camera goes filming

2007-07-16T20:54:00.000-04:00

More movies of the Venusian South Pole vortices! Using a special configuration, scientists at ESA were able to create high resolution images, that contain both the day and night sides (without saturating the instrument). The resulting videos can be seen at the ESA science pages, here.

South Pole of Venus

2007-07-16T12:52:00.000-04:00

Of course, the success of any balloon probe depends on how turbulent and stormy the atmosphere is. Venus has 300-400 km/hour winds which make the clouds circle the planet in about 4 earth days. However, this wind speed, or the speed of uniformly moving air is not necessarily dangerous in itself, if you can catch up to and safely ride them, like planes do with jet streams on Earth.

Of course, even if this turns out to be the case, there can still be dangerous places to go. Like near this pair vortices that the Venus Express observed above the planet's South Pole:

Balloons to Venus

2007-07-16T12:02:00.000-04:00

Of course the Soviet VEGAs shouldn't be the last probes to fly above Venus. There is a lot of talk about new balloon probes to Mars, Venus, or even to Titan, and sometimes it's hard to tell hot air from real plans with a real chance of becoming reality.

So, for Venus, ESA has a study of a system consisting of (one or more) orbiter(s) and a balloon aerobot, which would function for at least 15 earth days. The balloon would operate at an altitude of 50-55 km, where conditions are much more convenient than on the surface. Pressure is less than 1 bar, the tempereture is between 0 and 50 °C. (surface conditions are 90 bars & 450°C) Study of the atmosphere in this altitude is in itself important enough, but the aerobot would also regularly drop tiny microprobes, that would relay data about wind and physical conditions in the lower layers.

Gondola layout of the ESA Venus Entry Probe

NASA/JPL also have a study of a balloon probe, the Venus Geoscience Aerobot Study (VEGAS). It is somewhat more ambitious, with much longer expected lifetime. It would be able to occasionally venture from the relatively safe conditions at 60 km down to the surface, through the acidic clouds, conduct useful measurements there, and then rise again.

Another balloon in space.

2007-07-13T07:08:00.000-04:00

It turns out that balloons that were inflated in space have been created before. However, these weren't intended to slow them down and sink into an atmosphere. PAGEOS, or Passive Geodetic Satellite, was put into a 4000 km high circular, polar orbit around Earth in 1966. It was a continuation of the very similar ECHO I and II satellite programs. These were simply just 30-40 m large balloons with reflective surface, without any active communication instruments. They were visible from more than one continents at the same time. More than 20 ground stations were observing them officially, and their measurements made it possible to determine the relative position of the observers - and the continents, after all - with a precision of a few meters. This was much more precise than by any other means available at the time.

PAGEOS eventually broke up in 1975, possibly weakened by micrometeoroid impacts. Since then, most pieces entered the atmosphere and burned up, but a few pieces are still tracked (maybe even be observed relatively easily?).

A christmas tree ball or a balloon satellite?

Carnival of space

2007-07-12T17:06:00.000-04:00

The 11th edition of the Carnival of Space is out at space4commerce.

Some of those posts:

Stereo images of the Sun on astroblogger.

An insightful critical post about archeological astronomy on Clioaudio.

Space cynics about manned spaceflight

Archimedes - a balloon probe to Mars

2007-07-11T07:55:00.000-04:00

Rovers are nice, and have been successful on the Moon and on Mars. However there are more ways to explore a planet. One of them is aerobots, or aerial robots. This is mostly thought of as a gondola with instruments, hanging from a balloon. Of course, it can only function on planets with substantial atmospheres: Venus, (Earth,) Mars, Saturn's moon Titan, and the gas giants. Of these, Venus - whith its dense atmosphere making it quite suitable for such a mission - has been visited twice by aerobots in 1985. They were built in French-Soviet cooperation, and were part of the Soviet Vega Venus probes.

Vega balloon in testing

Mars, which has a tiny atmosphere that has more than 100 times less pressure than that of Earth, is yet to be visited by such a probe. The Soviet/Russian program was scrapped in the 90's due to financial reasons. NASA/JPL also had some experiments in the 90's, but there's no such a real mission expected anytime soon.

However, a private group of space enthusiast, the Mars Society of Germany has proposed ARCHIMEDES, a short duration, low cost Mars balloon project, that would be launched as a piggy-back payload on AMSAT's P5-A orbiter. (About AMSAT P5A in german) Archimedes was named after the greek philosopher who discovered the floatation principle.

After considering other options, namely balloon deployment in air and balloon deployment after touchdown on the surface, it has been decided that the balloon would be deployed in space, its drag slowing down the probe to slowly sink to its operational altitude. This way, the ARCHIMEDES mission will demonstrate the technology for inflatable atmospheric drag devices on Mars. (This part of the design is novel.) This means it will provide valuable data even if later phases of the mission fail. By the way, the nominal duration of the mission is 10 sols (Martian days).

Apart from testing the technology and gathering data about airflow during entry, there will be three scientific experiments onboard.

A camera, provided by DLR (the German space agency), which will be based on the ROLIS camera on the lander of the Rosetta space probe. It will be able to achieve a resolution of up to 20 cm per pixel at a 7 km distance from the surface. While this resolution is not really stunning - HiRISE on the Mars Reconnaissance Orbiter almost reaches this at its highest resolution -, it will be able to take images from an oblique, 45 degree perspective.

The Rolis camera

A magnetometer, provided by the Technical University of Braunschweig. Measurements of Mars residual crustal magnetic field were last made by the Mars Global Surveyor space craft during the aerobreaking phase of the mission, in an altitude range between 100 km and 200 km. Archimedes would be able to make more local measurements. The combination of a high resolution camera and a magnetometer makes it possible to correlate magnetism and geological features. It would also be the first magnetic measurement below the ionosphere. It could also be compared to magnetic field measurements at the same time on board the orbiter.

Atmospheric sensors (thermometer, barometer, hygrometer), by the Finnish Meteorological Institute (FMI).

Due to weight and power supply constraints, the communication will be low power (few Watts), targeting the orbiter.

A series of experiments have already been carried out.

Testing balloon inflation in a stadium, in Munich

Tests in zero-g on three parabolic flights in 2005

REGINA

Regina - Residual Gas Inflation test for Archimedes. Its objective was to test balloon deployment in the vacuum of space and zero gravity, at about 100 km above Earth. Secondary objectives was testing onboard subsystems, computers & telemetry. Regina was launched from the Esrange in Kiruna, northern Sweden, as part of the Rexus-3, rocket for student experiments. All experiments went perfect except for one glitch: 160ms after the motor separation the payload hit the Regina module. The collision resulted in a tumbling motion of both, and Regina drifted away, leaving the field of view of the camera on the other module.

Launch

Regina in space over Sweden, drifting away, before the inflation of the balloon could be filmed

Regina was considered lost, as there were no funds for a complicated recovery effort in the far north environment. However, residents found the module and returned it to the Launch Center. The computer was recovered in such a good state that it will be used in the next experiment. After long and careful analysis of the data in the recovered module, taking months, it was decided that the experiment was successful, and the release and inflation of the balloon had gone as planned.

Regina parts recovered

More images about Regina here

MIRIAM

Next phase is going to be MIRIAM - a balloon probe that is a 1:2.5 scaled complete model of Archimedes. It will be launched in March 2008 from Sweden, to an altitude of 200 km.

If all goes well, launch of Archimedes to Mars can probably be expected to happen in the 2011 launch opportunity.

More about the Archimedes project at The Mars Society and The Mars Society, UK.

Auroras on Jupiter

2007-07-09T07:00:00.000-04:00

This is image of Jupiter, taken in UV band, shows its strong polar auroras. It was taken by Hubble in 1996. A close-up view:

It is a little different from terrestrial auroras in that at least some of the particles originate from Jovian moons Io and Europa. Io has lot of active volcanoes, that send charged particles into orbit around the planet. They carry strong electrical currents along magnetic lines into Jupiter's atmosphere.

But there's even more to this Galilean system! Although Io only has a thin temporary atmosphere, it also shows auroras, which are as colorful as the moon itself:

If not direct imaging, careful spectral analysis can show auroras on other planets, or, for example an other Jovian moon, Ganymede - see astro-ph/0003486.

Planetary auroras - Saturn

2007-07-09T06:06:00.000-04:00

Auroras have been detected on all four gas giant planets. Here's an image of a Saturnian aurora, imaged by the Hubble telescope.

Space shuttle backflipping

2007-07-08T22:05:00.000-04:00

A really cool maneuver - here this is STS-115 during a 360-degrees backflip, so that they can photograph its heat shield from all angles, from the space station.

Spacecraft recycling

2007-07-04T12:45:00.000-04:00

Very encouraging news on space.com:
Two "old" spacecraft are going to be directed to new targets.

Deep Impact finished its original mission - smashing an impactor into comet Tempel 1 and watching the results - in July 4, 2005. Now it is to be directed to meet comet Boethin in 2008.

The Stardust spacecradt collected dust from comet Wild 2 in 2004 (and also some interstellar dust). It neared Earth to return its samples in January 2006. Now using its remaining fuel, it is going to be directed to visit and reobserve comet Tempel 1.

Of course the use of these already in-space spacecraft is a lot cheaper than building and sending entirely new ones.

Simlation of the Deep Impact impactor's impact, and the real thing below:

Treasure trove containing UFOs, rockets and everything

2007-07-04T11:00:00.000-04:00

Skepchick writes about a database of recently declassified CIA documents. It has a search box, so it's easy to find a lot of interesting things, like a lot of reports about the Soviet space industry ...or even about observed UFOs. (Not so off topic here, as many UFOs turn out to be interesting atmospheric phenomena)

Some appetizing bits:

1/19/1973: Lunokhod roams again

12/1/1989:
Soviet options for a manned Mars landing mission

4/20/1988:
PRC: Scientists identify Xinjiang UFO as plasma fireball

An almost perfect Einstein-ring

2007-07-04T10:10:00.000-04:00

Using a simple algorithm, Belokurov et. al discovered this almost perfect Einstein-ring around a luminous red galaxy in the SDSS database:

They called it the Cosmic Horseshoe. The ring has a diameter of 10 arcseconds, which counts as large. The lensing galaxy has a mass of about 5 x 10¹² solar mass - about ten times the mass of the Milky Way! For comparison, here's an other lens, also from the SDSS, discovered serendipitously, the "8 O'clock Arc":

This is less ring-shaped, it has 3 images of the same background galaxy on the top and a fourth on the bottom. It shows a similar size, but the lensing galaxy is estimated to have a mass of about 1/5 of that in the center of the Cosmic Horseshoe.

A news article.
The scientific article.

Second bigelow launch: Genesis II

2007-07-02T23:08:00.001-04:00

Photos from Genesis II, the second demonstration version of what is going to be a manned space module from Bigelow Airspace:

The second image is of the expanded interior. (The size of the cylinder at launch is 4.4 m (14 feet) long x 1.6 m (5 feet) in diameter, which expands to a diameter of 2.5 m (8 feet) ) It was launched on June 28, 2007, from Russia.

Here are some larger images

Xichang catastrophe

2007-06-28T21:33:00.000-04:00

Imagine it's February 15, 1996. You're at the Xichang Satellite Launch Center, 64 km from Xichang, Sichuan province. It's 2:50 AM, and a Long March 3B rocket is just about to launch Intelsat 708, an American communications satellite. But it won't happen as planned. The results are going to be terrible.

The rocket immediately veered off course, and impacted in or near a village. Very embarrassing, as launches had only resumed a few months before, because there was a similar accident in January 1995 too, with 6 deaths. The Chinese government claimed there were only 6 deaths in this crash too - observers think it must have been more likely ten or hundred times that. The details of the two accidents are sometimes mixed, as i found while trying to search for more infoation. But it appeared on Discovery Channel:

I couldn't find any images about the accident for years, it's good that now someone uploaded these videos. Actually the only images are from a US Government Report. Why such a report? Some feared that the Chinese examined and stole technology from the crashed satellite. An investigation started, and the US companies were charged with export control violations by the State Department.

This event shows how important it is to launch from and over unpopulated areas. Also, at launches usually there's a person with a finger on the self-destruction button, should the rocket veer off course. I don't know if there wasn't any such system here or if it just didn't work.

Aurora australis

2007-06-26T06:24:00.002-04:00

I just found this image of a multi-color aurora, taken from aboard the Space Shuttle. It is a southern polar light, or aurora, photographed from above Australia, during the STS-111 mission in June 2002.

A stellar surface again

2007-06-25T22:25:00.000-04:00

Again there's an interesting article about a stellar surface. Maybe i'm going to like them after all.

New Scientist reports that Kochukhov et al. observed "weather" on alpha Andromedae. That star is known to have extra concentration of mercury. Known, because that mercury shows up as absorption lines of mercury in the star's spectrum. But it isn't necessarily distributed evenly accross the whole star. What they did was map this mercury concentration onto the surface using a technique called Doppler imaging. Because of the star's rotation (which is pretty fast, takes only about 2 days for a complete rotation), its light will be Doppler-shifted (some positively, some negatively, as some parts move in our direction and others away from us), and the mercury lines will be stretched to a broad profile. At each Doppler-shift wavelenght, the intensity of the line profile corresponds to the total mercury at those points of the surface that have a certain doppler-speed. Thus the line profile is a 1 dimensonal data yet. But you can measure the spectrum at different times (maybe a few hours apart), and have many different light profiles, corresponding to different orientation of the surface. So they did. Therefore they could map the line profile time series onto the 2 dimensional stellar surface.

Here are those maps, taken a few years apart:

Isn't that real fun?

Their article at astro-ph is actually more about the discovery that those mercury contrentration distributions changed substantially over the years. That was unexpected because the star is thought to lack the usual magnetic mechanisms responsible for creating such imbalaces. So these moving, morphing mercury "clouds" may be created by some processes that can be called a "weather".

Archive Moon

2007-06-25T20:58:00.000-04:00

This isn't a very recent, Astronomy-picture-of-the-day quality shot of the Moon. But it's still special: apparently it's the first photograph of the Moon ever taken!

Created by John W. Draper, an American chemist who was also meddling with early forms of photography. It was taken in 1839.

Map of Altair

2007-06-25T05:57:00.000-04:00

This is older news, but it really belongs here. Although i'm usually not so thrilled by stars. It's just so hard to imagine them. (And anyway, we can only see a few thousands with bare eyes, when conditions are good. And this while the Sun is within a spiral arm, dense with bright stars! What if we were a little farther out in the galactic plane? Or a little off-plane? Or if the atmosphere would be just a little denser? We could observe just a few stars without telescopes. Or none. Would astronomy still have evolved the way it did? Maybe Asimov already wrote about this, he liked these sort of questions...) So... maybe stars are just too pointlike to be easy to imagine them. Well, now its not all of them. Using optical interferometry, the surface of one of the nearest stars, Altair, has been mapped.

Its spinning so fast that it's quite oblate. And so the equator, that is further from the center, is also cooler. Here with thermal isophotes:

Here are the news and here is the scientists' article.

Imaging stellar companions

2007-06-24T20:57:00.000-04:00

Wow. A new technique for observing faint companions. The idea is simple: host star and telescope created image artefacts depend on the wavelength. In between those pixels lies buried the light of the companion - the position of which does not depend on the wavelenght. Therefore, the contaminating light can be removed. Here's the example by the inventors: left: before, right: after. On the right image, the host star has been removed.

Original article at ESO

A weird moon

2007-06-24T19:20:00.001-04:00

With dimensions of about 40 km, Atlas is on of the tinier moons of Saturn. Here's how the Voyager 1 spacecraft saw it in 1980:

Here's how Cassini saw it in October 2006 from a distance of 200 000 km:

From this angle it's not very different from other rocks. However, here are two more pictures of it by Cassini:

It's shaped like a discus (the second one is taken from above its pole). Its diameter across the poles is just 19 km, but a ridge goes around it's equator and its equatorial diameter is between 38 and 46 km! You could call it the highest mountain in the Solar System - in proportion to the moon itself. The most likely reason is that Atlas is close to the outer ridge of Saturn's A-ring. When it wandered close to it (or maybe through it, somewhen in the past), the particles of the ring sort of "snowed" down onto the equator. The ridge could be even narrower, because the thickness of the rings are between 5 and 50 meters! But its height is close to the Roche lobe of Atlas, which means that if you put some more material there, it probably wouldn't hold, it would fly away because of the moon's spinning.

Now, I remember there was another moon there, with some surface features connected to the rings. The moon Iapetus is famous for having different colors on its leading edge than its trailing edge. ("leading edge" is meaningful because its rotation is tidally locked to Saturn).

This is how it looks like (made by Cassini, on 31 December 2004):

Looking at it, it also has a long ridge! And it also turns out to be on its equator! It's about 13 km high and 20 km wide. One of the theories of the origin of these features is here: http://arxiv.org/astro-ph/0504653.
In short, it also suggests a past "collision" with a saturnian ring.

Maybe some of the other moons also have such a dust layer, or ring, or ridge.

Ceres & Vesta

2007-06-23T23:16:00.001-04:00

These are the latest images of Ceres and Vesta by the HST. They are the two largest asteroids in the asteroid belt (Ceres is 1000 km across), and will be visited by the Dawn spacecraft, that will launch in just two weeks. 4 years till it gets to Vesta, spends some time around it, then leaves and reaches Ceres in another 4 years. It's a funny consequence of celestial mechanics that if you do such missions, visiting and orbiting multiple bodies, you have to start with the smaller (and probably less interesting) and then go to the larger one (which risks that if the spacecraft is lost in the meantime - something not without precedence - , you missed the probably more interesting destination. But the other way around it would cost more fuel, because it takes more fuel to escape the larger body.

Not that Vesta isn't interesting. Actually it would probably make it to the podium of the weirdest bodies in the solar system. Here is its elevation map:

Well, maybe the photo above shows it even better. It actually has a crater almost as large as itself!

Vesta rotating (it takes about 5 hour for a complete rotation):

Magnificent

2007-06-23T22:15:00.000-04:00

Northern lights in Canada, time lapse movie.

Wikipedia says:
Light emitted by the Aurora tends to be dominated by emissions from atomic oxygen, resulting in a greenish glow (at a wavelength of 557.7 nm) and - especially at lower energy levels and at higher altitudes - the dark-red glow (at 630.0 nm of wavelength). Both of these represent forbidden transitions of electrons of atomic oxygen that, in absence of newer collisions, persist for a long time and account for the slow brightening and fading (0.5-1 s) of auroral rays. Many other colors - especially those emitted by atomic and molecular nitrogen (blue and purple, respectively) - can also be observed. These, however, vary much faster and reveal the true dynamic nature of auroras.

Sad that I couldn't find videos of polar lights with other colors.

This must be the oxygen glowing in different colors at different altitudes:

Now, on the video above, you can see three sorts of weird lights (well, apart from the aurora itself :-)). It's fun thing to identify what those actually are :-). Good exercise for the physics classes.

This one has some pink glow at the beginning, though not so breathtaking. (But this one lacks those spots and streaks)