The ExoMars mission to Mars has been the subject of intense discussion over the last few days, as European Space Agency delegates attempt to finalise the design for the ambitious probe. At the heart of the discussion is the proposal by mission scientists to beef up the mission in order to address several worries they have. The most costly change is the request to send a combined orbiter and lander configuration, a proposal driven by several imperatives. For one thing, scientists are concerned that without an orbiter to relay data back to Earth, the ExoMars mission will be relying on American orbiting hardware for the crucial link home, and another failure such as recently befell Mars Global Surveyor would be catastrophic. Equally concerning, a recent change to the launch date from 2011 to December 2013 now means ExoMars would arrive in 2014, at a time of increased dust storm activity. Without an orbiter to wait out the storms, the lander would have to risk a perilous descent in these conditions. These changes mean a far bigger payload requiring a more powerful launch vehicle. That all adds up to substantial cost increases, and that means the member nations of the ESA will have to dig a lot deeper into their pockets to fund it. The worry is that some ESA members may decide to cut and run, threatening the entire project, which is a key plank of highly ambitious European plans to explore and eventually return material from Mars. The discussions to date appear to be veering toward acceptance of the more expensive option, but a final decision has been deferred to a later meeting on June 11th.
It was an entirely accidental event, but when a gummed up wheel on the Spirit rover scuffed up some Martian dirt it revealed something that literally had NASA scientists gasping with amazement. Beneath the regular dirty red Martian earth was a layer of intensely bright material, which analysis revealed to be extremely high in silica, so much in fact (90 percent) that it almost certainly required water to produce. One possible origin for the silica may have been volcanic activity, with the silica brought about through the interaction of water, the soil, and acid vapours from the volcano. The material could also have formed in water in a hot spring environment. Either way, it offers yet more compelling evidence for a high water presence on Mars in the past, and that can only increase speculation that Mars may once have enjoyed an environment much closer to Earth than it does today.
The Chelsea Flower Show is an institution in Britain amongst dedicated gardeners. For one week in May, the cream of the countries garden designers descend on London to show off their skills, but this year something a little odder has landed. "600 Days with Bradstone" is the title of a garden designed by Sarah Eberle for a 600 day stay on Mars, and it's scooped the top Gold award for 2007 and "best in show." Sitting beneath an imaginary dome, the garden is divided into two distinct parts. At one end of the garden is a section designed to draw water from the Martian permafrost; at the other a section designed with the mental well being of the astronauts in mind. The design of the garden has been closely modelled on Mars, and even the plants have been picked for their likely survival properties in the harsh Martian environment. Alas all the tickets are gone, but for more detail on the winning garden, you can visit the website of the Royal British Horticultural Society or take a look at the official 600 days with Bradstone website.
The Spirit rover, incredibly still working on Mars over 1000 days after its arrival, has made another important discovery, spotting what appears to be a "bomb sag." This may not sound terribly interesting, but to a geologist, this is heady stuff. A bomb sag is a kind of material formed in volcanic explosions on Earth. Rock is ejected up by the explosion and then falls into soft deposits, deforming as it lands. Spirit has snapped just such an object, preserved in layered rocks on the lower slopes of a plateau called Home Plate. Also spotted by Spirit are signs in the surrounding rock of of tiny spherical particles that look like accretionary lapilli. These are coagulated bits of ash that typically rain down after a volcanic explosion, so the evidence suggests that this was a genuine volcanic explosion, rather than the fallout from a meteor strike. What has the scientists interested is that they are seeing lots of evidence from photographs snapped from orbit that this sort of feature is very common, so it looks like Mars had a very violent past. Additional evidence places water at the scene as well. There is for instance a great deal of chlorine evident, which points toward the presence of a briny fluid, and it looks like the bomb sag landed with a splat. The fact that the material it sits on is basalt is also telling. Basalt is not normally associated with explosions, except when it meets water and you then get a steam-driven blast.
The August launch of the Phoenix Mars Lander has taken another important step forward with the arrival of the craft at the Kennedy Space Centre, where it will be prepared for a launch on August 3rd. The Phoenix lander is the latest in a series of probes built on the mantra of "follow the water." Equipped with a robotic digging tool, it is hoped the probe will touch down on a Martian ice plain, but at a time of year when the ice will have receded sufficiently so as to have revealed fresh soil. The probe comes equipped with a number of scientific instruments that may solve one of the big mysteries of mars; what happened to all the water scientists think the planet was once blessed with. Amongst the experiments planned, soil will be dissolved to look for salt deposited in ancient floods and an oven will be used to break down samples for chemical analysis. The mission is planned to last 3 months, but on past experience, there is every chance the lander may last longer.