The Cosmic Mirror

of News events across the Universe

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Current mission news: Pathfinder + MGS (science!) + Cassini + Galileo + Equator S

That's what we've learnt from Pathfinder !

While some results were mere confirmations of established facts about Mars - e.g. that Ares Vallis has seen a major flood 3 billion years ago - or almost mirrored the respective data from the Viking missions (such as the weather observations), other findings have raised intriguing questions: Did the camera really spot rounded pebbles and conglomerate rocks that would point to an era even before the flood, when Mars must have had a warmer climate with stable liquid water on the surface? Does the existence of magnetized dust support this view? Are some of the rocks - e.g. Scooby Doo - actually sediments from that wet era?

The instrumentation of Pathfinder and Sojourner was too limited to yield clear answers to these fundamental questions - but here is what we do know, as reported in 7 papers in the Dec. 5th issue of Science magazine (also discussed here and here) and at a major Dec. 4th news conference at the Max Planck Institute for Chemistry in Mainz, Germany, by leading German researchers of the APXS and IMP instruments (also summarized here and mentioned here):

• The Alpha Proton X-ray Spectrometer from German, U.S. and Russian researchers (which got onto the Sojourner rover merely by chance - as a spin-off from a similar instrument built for the later ill-fated Mars'96 mission) told us the following:
  • The dust on Mars is virtually the same all over the planet: The chemical composition measured in Ares Vallis and at the two Viking landing sites is virtually identical. This means that global air transport, esp. the famous dust storms, mix and distribute the dust very efficiently.

  • All the rocks are more or less dusty, and since the very lightweight and technically simple APXS (with a mass of only 540 grams!) didn't carry a brush, the dust has to be subtracted mathematically from the rock spectra; this is indeed possible and quite reliable.

  • Having done that correction all measured rocks are alike, i.e. some media reports about two distinct chemical classes were premature and plain wrong. The chemical composition of all the rocks that Sojourner visited in Ares Vallis differed significantly both from the dust and from the 12 Martian meteorites found on Earth.

  • The Ares Vallis rocks are unexpectedly rich in silica (Si) and potassium (K), but low in Magnesium (Mg) - they seem to resemble in composition terrestrial andesites and are "close to the mean composition of Earth's crust," as R. Rieder et al. write in Science: "However, we cannot be certain that these rocks are igneous." There is also a possibility that they are sediments or metamorphic or even impact melts. Pathfinder didn't carry instrumentation to check for the necessary details.

  • In any case the APXS results demonstrate that Mars has different "geological provinces": There must be other regions on the planet where the rocks are much more primitive than those found in Ares Vallis and do actually resemble the Martian meteorites. The reasoning is simple: To make the ubiquitous dust with its composition in between the Ares Vallis rocks and the Martian meteorites, you have to mix material of both types.

  The story of the APXS isn't over yet, by the way: Because the reseachers had underestimated the influence of the Martian carbon dioxide atmosphere on the measurements of the lighter elements in the rocks, reliable data so far are available only for Mg, Al, K and Fe etc. But the data for lighter elements such as carbon will be recovered: Right now the lab version of the APXS is being re-calibrated in Mainz, with simulated Martian atmospheric conditions at the time the original rock data were taken. Results could be available by next spring.

• The IMP camera on the lander has revealed "a complex surface of ridges and troughs covered by rocks that have been transported by fluvial, aeolian and impact processes," say P. Smith et al., but mineralogical information from the images, despite the use of 24 color filters, was limited. An additional problem (and an itriguing scientific result of its own) was the significant change of Mars' sky color during the day. Nonetheless it seems that
  • There are 3 basic kinds of rocks and 4 kinds of soils in Ares Vallis, apparently representing different stages of weathering and other physical changes. Dark rocks like Barnacle Bill and Bamm-Bamm are more original and were probably placed on the surface by the meteorite impact that formed Big Crater 2.2 km away. Bright rocks are more weathered and dusted, pink rocks are actually compacted soils.

  • IMP has confirmed the minute amounts of water vapor in the atmosphere, but it is now becoming clear that the water is not completely mixed with the carbon dioxide: It has a different height structure. This indicates that there is a reservoir in the Martian surface that exchanges water vapor with the atmosphere in a daily cycle.

  • And there is also dust in the atmosphere, more than expected actually: The height profile could be measured when Mars' moon Phobos underwent a lunar eclipse and a detailled light curve could be measured - which is more complex than would have been expected from a simple model.

• Other key results from the Pathfinder mission, as summarized by its lead scientist M. Golombek et al. include the presence in IMP images of "rounded pebbles and cobbles and a possible conglometerate" which "suggest fluvial processes that imply liquid water in equilibrium with the atmosphere and thus a warmer and wetter past. The moment of inertia indicates a central metallic core of 1300 to 2000 kilometers in radius.

  Composite airborne dust particles appear magnetized by freeze-dried maghemite stain or cement that may have been leached from crustal materials by an active hydrological cycle." And Golombek is particularly proud that he predicted the conditions at the landing site, down to the size distribution and number of small rocks, quite well - just from remote sensing data.

Coming attractions:
More flight opportunities for MPF-proven instruments

• Another IMP and a camera on a robot arm of the MVACS Mars Surveyor 1998/1999 lander: This robot arm camera will look at the samples a shovel on the arm collects, with 20 micrometer per pixel resolution and three colors. This is the only Mars mission ever to target the South polar region of Mars, with an emphasis on Mars' volatiles and climate processes.
• On the Mars Surveyor 2001 there will be another rover with a far greater range than Sojourner - again equipped with an APXS and this time also some other instruments. This rover will also start collecting rocks for a possible sample return in 2005.
• Only next June will ESA decide whether it can afford its Mars Express mission in 2003 (there are contradictory reports in Nature of Nov. 27 and Science of Nov. 28, p. 325 and1553, regarding the chances). If it does, there will be an orbiter (with key instruments that also were on Mars'96) - and one or more landers. One of them could carry a tiny rover called Nanokhod, developped in Russia and Mainz, and also carrying an APXS and up to 5 other instruments.

Martian "bacteria" questioned:
Objects in ALH84001 just crystals?

R. Harvey et al., who used the same methods as the NASA researchers, report that most of the purported nanofossils or "worm-like images" are nothing more than lamellae, or fractured surfaces of pyroxene and carbonate crystals. "We have now found two different types of mineral forms in ALH84001 that look just like nanofossils, but they are strictly non-biological origins. Sometimes even nature has a perverse sense of humor," he added. The worm-like mineral lamellae are commonly found at the fractured surfaces of planar crystals. Harvey noted that lunar rocks -- in which there has been no evidence of life found -- contain these same formations.

Plasma satellite EQUATOR-S launched on Ariane

EQUATOR-S will fill a gap in the 3D coverage of Earth's magnetosphere, namely in the equatorial region; the mission had been approved by the (now-defunct) German space agency DARA only 3 years ago. That there is still room for innovative missions into the Earth's magnetosphere 40 years after its discovery with Explorer 1 and 3 in 1958 is proof that near-Earth plasma physics remains a 'hot topic'. (MPG PRI SP 3/1995)

More launches: Astra 1G on Proton, TRMM, ETS-7 on H-II

And the weather in Kazhakstan was so clear that the Proton could be followed optically for 8 minutes and a few seconds; the separations of the 1st and of the 2nd stage were clearly visible! This is the 7th satellite of the series of European direct-broadcast TV satellites - check here for the view the other 6 present in the sky over Germany!

Already on Nov. 27, a Japanese H-II had launched NASA's Tropical Rainfall Measurement Mission (TRMM) and NASDA's ETS-7 experimental satellite that will try out in-orbit rendezvous and docking maneuvers. In an unusual move, NASDA had partially insured ETS-7 against a mission failure (normally only commercial spacecraft are insured), but there would have been reimbursement only for a fraction of the $260 million cost. (AW&ST Nov. 24, 1997, p. 18)

More NASA cooperation with European countries?

• the Mars Sample Return mission NASA plans for about 2005. France has proposed to launch it on an Ariane 5, which could allow to bring back samples from two different sites;
• the Next Generation Space Telescope, the successor of the Hubble Space Telescope, in which many European astronomers have great interest, and
• the Crew Rescue Vehicle for the International Space Station. NASA wants one anyway, and there has been a lot of work in this field in Europe in the last 10 years, but France isn't interested anymore right now.

Briefly noted:

Columbia's astronauts had little trouble to capture the SPARTAN satellite - but there was not enough fuel left in the orbiter to risk another deployment and possible 2nd chase. Bringing back the reusable satellite and another EVA today had priority. Columbia is due back at KSC at 12:19 UTC on December 5th.

The current constellation of many of the bright planets close together has caused quite a stir in the news media - several U.S. TV networks covered the "Heavenly Bodies" (CBS) in their main news programs, although not always with the most convincing of graphics...

In a Nutshell: The timetable for Cassini has changed slightly due to the launch delay; the arrival at Saturn stays on July 1st, 2004, however. / Prices for Martian meteorites are still high: Ads in the NYT recently offered 0.02 grams of the Zagami for $ 98.- ... (New Scientist Nov. 22, 1997, p. 14) / Someone has proposed to project corporate logos onto the Moon with big mirrors - the latest weird idea in space advertising. (ibid p. 116)

Spacewalk to catch SPARTAN tonight!

"Dial up the Sky":
New surveys will revolutionize astronomy

Among the largest of the mega-sky surveys in the works are the Digitized Palomar Sky Survey (DSS), which promises a catalog of up to 2 billion stars and other objects, the Two-Degree Field Survey (2dF) with the Anglo-Australian Telescope, the huge Sloan Digital Sky Survey with an expected 100 million galaxy images and spectra, the UV survey from the just authorized GALEX satellite (one of the Small Explorers from Update #61), the Two Micron All Sky Survey (2MASS) and FIRST, a radio survey of hundreds of thousands of galaxies with the VLT. The amount of raw data expected from these surveys is staggering and ranges from "only" 120 Gigabytes to the 40 Terabytes expected from Sloan (which will fortunately shrink to 1.2 Terabytes in reduced form).

Few people would want to have complete copies of these data sets at home, and so central servers - accessible via the Internet - are the natural solution. But astronomers want even more: the merger of the surveys. And a system called sky tesselation is a likely answer: The objects catalogued in the vast data bases can be selected by e.g. proximity to a certain place, or color, or spectrum, or combination of all the above. Not only professional astronomers but also amateurs will be able to access this data superstructure - and the latter can still make contributions, too: e.g. with The Amateur Sky Survey that has already 23 volunteer participants! (Finkbeiner, Science Nov. 7, 1997, p. 1010-12)

ESA's space science plans in deep trouble

Now it seems inevitable that at least some of the smaller science missions might have to be sacrificed in order to save the major 'cornerstones'. Whether (or when) Europe could then afford e.g. its own Mars mission ("Mars Express") is uncertain. With no cash infusion from the larger ESA nations (like Germany) in sight, the only steps ESA can take is to increase the efficiency of its science program even further, i.e. to do more missions for less money. (Abott, Nature Nov. 6, 1997, p. 8)

Briefly noted:

ESA's science program may be in disarray (see above), but then there is the Euromoon proposal: Can engineers, scientists and private industry come up with the money (some 300 million ECU) for a semi-commercial mission to near the lunar South Pole? The lander could go down on a mountain that's always in sunlight (Peak of Eternal Light) and then set free some tiny rovers - for a rallye to the South Pole. A mission in 2001 is still deemed possible. (Nature Nov. 6, 1997, p. 8)

One more argument against the 'small comets' (see Update #61) has been made by Frank's critics - and it's both simple and strong. If the 10 m comets would exist, they would form an expanding cloud of water ice crystals when they break up close to the Earth - and these clouds would shine as bright in the sunlight as Venus or even the Moon! Every few minutes such a brilliant object would appear in the sky: Good out and look... (Rizk & Dessler, Preprint -> Geophys. Res. Lett. Dec. 15, 1997. More on the UVI-vs.-VIS debate can also be found in Kerr, Science Nov. 14, 1997, p. 1217-18)

Heavily armed gangsters in late October tried to steal 60 tons of ultrapure gallium from the Baksan Neutrino Observatory in Russia but failed: The scientists had recently installed high-security defenses! The reason: For the past year the government had tried to sell off the valuable material - a scientific scandal which has so far been avoided thanks to protests from the American collaborators in this solar neutrino observatory. (Allakhverdov & Pokrovsky, Science Nov. 14, 1997, p. 1220-21)

In a nutshell: Some observers in Europe were successful in catching a rare occultation of Saturn by the Moon recently. / A fire has severely damaged the HEGRA gamma observatory in the Canary Islands. / NASA chief Dan Goldin gave an interview to German radio during a visit to Europe. / The European far infrared satellite ISO has detected the emission of cold dust in the Coma galaxy cluster - the first direct evidence for intergalactic dust. / And finally, for German TV viewers who suffered through the "Asteroid" mini-series on RTL, here are two funny pages on this disaster of a movie... :-)

Mars Global Surveyor is aerobraking again

but so slowly that the mapping mission will only start in 1999!

As expected the mission of the Mars Pathfinder has come to an end, although there will still be attempts once in a while to reestablish contact. The spacecraft had returned 2.6 billion bits of information, including more than 16,000 images from the lander and 550 images from the rover, as well as more than 15 chemical analyses of rocks and extensive data on winds and other weather factors. Now the mission will be honored with a stamp!

Finally, there are now more detailled models of the past Martian climate: A blanket of dry ice clouds may have kept ancient Mars warm enough to let water flow on its surface, and may have encouraged life in its caves and oceans.

Briefly noted:

The Earth's inner core us turning independently, but more slowly than previously thought: The inner core's independent rotation is thought to be caused by a process called convection in the molten iron outer core that surrounds the inner core and that produces the Earth's magnetic field.

Space station Mir is in fine shape after a number of internal and external spacewalks which have restored power to nearly full levels. It now seems that the station will be used until at least 1999 and possibly beyond 2000.

The "mini-comets" - case closed?

Not so, say G. Parks et al. (preprint, to appear in GRL): They operate the UVI instrument on Polar that had shown the same dark spots as Frank's VIS instrument. But a detailed analysis of the UVI images and especially a comparision with calibration images taken before launch has now shown that the dark spots must be instrumental: "there is no scientific evidence from UVI shat snowballs pelt Earth." Will the non-detection of the "atmospheric holes" by UVI drag the VIS "detections" down as well, and will the bizarre affair of the "mini-comets" be over? Stay tuned...

Ariane 5 - success with the 2nd launch!

NASA close to giving up Mars Pathfinder

Meanwhile the Mars Global Surveyor will resume its aerobraking very carefully on Nov. 7th, in order not to endanger the solar panel that started behaving strangely in October and was probably damaged. This decision means, however, that the final mapping orbit will be reached only several months after the initial target date of mid-March, 1998 - and what this orbit will look like is still unclear. Even now, however, the MGS is delivering exciting data, including this fine view of Olympus Mons, the big Martian volcano.

Briefly noted:

Two new satellites of Uranus have been discovered with the 5 m Hale telescope by Cornell and Canadian astronomers, bringing the total number of satellites to 17. Meanwhile there is a story of the Galileo mission for children on the web.

The first Brazilian attempt to launch a rocket was a failure on Nov. 2nd: The VLS had to be destroyed when one of its 4 first stage engines failed to ignite. Meanwhile yet another small U.S. satellite named STEP 4 is in deep trouble and could be a loss.

During yet another spacewalk the Mir cosmonauts not only removed an old solar array but also deployed a replica of Sputnik 1 to celebrate the 40th anniversary. (By the way: Today is already the anniversary of Sputnik 2 with the dog Laika.) Meanwhile former Mir cosmonaut Mike Foale has talked about the Mir experience and given a thumps up to the station, as has the Russian-German Mir'97 crew during a tour through Germany.

In a nutshell: Flashes from the Iridium satellites have been seen quite frequently by satellite observers, while a remarkable image of several co-positioned geostationary satellites. has been taken in Germany. / Learn about the most exotic space telescope on the drawing board, the Terrestrial Planet Finder. / You can now book a 'space ride' with Zegrahm Space Voyages - a few minutes of micro-g (this is suborbital) for $ 98000.-... / Another long report on a trip to the Russian eclipse has turned up on the web: The author went to Chita, just like we did!

Go to the previous 10 issues. Other historical issues can be found in the Archive.