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).