Saturday, June 30, 2007

Dust storm threatens rovers

A powerful new dust storm is developing on Mars and may threaten the safety of the Spirit and Opportunity rovers. The storm is thought to now be several thousand miles in diameter and is some 560 miles (900 KM) east of Opportunity, which is presently working at Meridiani Planum. The fear is that the storm will become global in nature, as last happened in October 2001, when a giant storm blanketed the entire planet in an impenetrable gloom. Ironically, high winds have been the saviour of the rovers before, as dust accumulating on their solar panels appears to have been blown off, restoring power that had been steadily in decline. The storm is not yet big enough to worry mission planners unduly, but a press conference called for Thursday will discuss the possibility that a planned drive by Opportunity into the massive Victoria Crater may be cancelled.

Friday, June 15, 2007

Martian tilt may explain lost ocean

When the Viking spacecraft arrived over Mars in the 1970's they saw what appeared to be the ancient shorelines of a long dead Martian ocean, but this theory was largely discredited bv the later Mars Global Surveyor mission of the 1990's. The far more sensitive Mars Global Surveyor imaged the surface to a resolution of a few hundred metres, and that seemed to prove that the opposite shores of the "ocean" varied in elevation by several kilometres, making for a very unusual ocean indeed, in fact an ocean that simply could not have existed. Until now this is the view that has prevailed, but scientists at the University of California, Berkeley, the University of Toronto and the Carnegie Institution in Washington have now re-accessed the data, and their startling conclusion once again puts an ocean on Mars, and a very deep one at that. The scientists have changed their mind because a new theory suggests that Mars has undergone some major upheavals, at the heart of which is an exotic event called true polar wander, a process in which the very poles of the planet shifted, resulting in massive deformation of the surface. If this is the case, then those improbable shorelines may indeed be the edges of an ancient ocean, one that once covered an entire hemisphere of the planet to a depth of several kilometres. If that is the case, then the next question to answer is, where did all the water go? The Independent Newspaper has an excellent indepth article on the new theory.

Wednesday, June 13, 2007

ESA opts for big Mars mission

In a further sign of the importance national space agencies are assigning to exploration of the red planet, the ESA has moved a step further forward approving a much enhanced vision for the 2013 ExoMars mission. The proposed upgrade would see a 205kg robot lift off on a heavy-lift rocket such as an Ariane 5 or a Proton. The probe would carry a 16.5kg instrument package, including a weather station (or Geophysics/Environment Package - GEP) but a request to include an orbiting communications platform was not approved. This means that ExoMars will be reliant on aging American hardware already in orbit about Mars. The project teams now have the go-ahead to refine the concept over the coming months, though the final design may still be subject be rejection when it comes up for final review in a years time. More information can be found on the BBC website.

ESA air bags demonstrates less bounce

In an important step toward a European mission to Mars, scientists have successfully tested a new kind of air bag landing system that they believe could bring the proposed ExoMars mission to a much speedier and safer stop than previous designs. The American Spirit and Opportunity rovers presently on Mars used airbag technology, but the method employed required the landers survive up to 25 bounces and travel some 200 metres before coming to a standstill. The ESA design, known as a vented, or dead-beat system, uses sensors to deflate the squashable bags on touchdown, reducing the bounce factor and meaning that the payload can be delivered right side up. There is still a lot of testing to be done, but if successful, the bags will also mean a significant weight saving, leaving more room for the science payload. The BBC website has an extensive story.

Sunday, June 10, 2007

Storm in a puddle growing on Mars

The prestigious publication New Scientist magazine is reporting on controversial findings that open water was found on the surface of Mars two years ago. Open water should not be possible on Mars due to the harsh surface conditions, (though very strong photographic evidence has been found for occasional small flash floods) so if true, this is a real bombshell. Physicist and Lockheed engineer Ron Levin has looked at images returned several years ago by the Opportunity Rover while it was exploring a crater called Endurance. Creating stereoscopic reconstructions from paired images from the rover's twin cameras, he seems to have found some compelling evidence. The picture shows a one metre square area with a distinctly bluish tint, and indeed it looks just as you would imagine water would look if it were puddling in low depressions in the ground. It is also free of dust and other detritus, suggesting that if it is water or ice, it formed recently. Levin has previously theorised that water might exist briefly on the surface in a regular daily cycle, evaporating away as the day progresses. This however is a very contentious theory, as it would require some very precise circumstances to come about. It is worth mentioning that Levin's father Gilbert Levin was one of the scientists on the old Viking missions to Mars, which found no official evidence for life, though both father and son have been vigorous proponents of the idea that the scientific instruments on Viking did find life, but the results were incorrectly interpreted. I mention this because Levin may well have an axe to grind here, and just as conspiracy theorists are constantly finding signs of an ancient civilisation on Mars, this may be a case of the eye seeing what the mind wants it to see. However, it is equally fair to say that the picture is compelling, so here is hoping that NASA is open minded enough to take a look at this, and have Spirit and Opportunity keep their cameras trained for further examples. As Levin has pointed out, it only requires that they poke the surface with the Rover’s drilling tool to test out his theory. If it’s water, then the drill will make no visible impression. If it’s anything else, it will leave a mark.