It looks like the Phoenix Mars lander is dead. Scientists have not heard anything from it for over a week now, and they have acknowledged the inevitable: the scrappy lander is out of power, and unable to do any more experiments, and incapable of reporting them anyway. They have declared the mission operations phase of Phoenix to be complete.
Designed to only last 90 days, it actually kept going for about twice that long. It landed in late May 2008, and the last signal was detected in early November. The primary science mission was to look for ice beneath the surface of Mars and to examine the soil directly. It had a scoop that picked up samples of the "soil" and dropped them into an oven. Baking them released chemicals that could be analyzed.
As it sat near the Martian north polar cap, Phoenix did in fact find ice just below the surface (not too surprising, really, but nice to confirm). It found the soil was alkaline, and also detected perchlorates. These are oxidizers, and if concentrated enough can kill terrestrial biological organisms. However, oxidizers are also needed for life; I've often wondered if you could have a sophisticated biochemistry using them on other planets. Clays and calcium carbonates found by Phoenix also indicate that water was once present at the site.
The science it did was very cool, but one of the more interesting stories was the detection of falling snow in the atmosphere of Mars. Somehow, Earthlike weather on Mars brought this story home.
Weather brought down Phoenix as well. It wasn't designed to last forever. It used solar panels, and winter was setting in. The lowering Sun and bitter cold made things difficult, but in late October a sand storm may have done the final deed.
But the mission was a success. It was a tricky landing, a difficult mission, and the science was delicate. But it delivered, and now we know more about Mars than we did before. Still, the search continues. Why did Mars die? What happened to its atmosphere, where is all the water we know was there, why did it evolve so differently than Terra Mater? And what implications do these have for our own home planet?
Phoenix itself is almost certainly dead (we might get a tiny bit more out of it if conditions are just right, though probably not), but we will continue to explore, to reach out to our sister world. Someday I'd like to see the view from an astronaut's helmet camera. That won't be for decades, for sure, and until then we'll continue to send our robot proxies there. With Phoenix we've literally only scratched the surface of the Red Planet.
Image credit:NASA/JPL/University of Arizona/Max Planck Institute.