It was always expected to end like this. If there's anything much going on with the water currently on Mars, chances are good it's happening at the poles, so NASA directed its latest lander, the Phoenix, to that region of the planet. Unfortunately, that inevitably meant that the lander would run short on sunlight to power its solar panels once the long, cold Martian winter set in.

About an hour ago, Phoenix's Twitter page broke the news: "From Phoenix mission ops: Phoenix is no longer communicating with Earth. We'll continue to listen, but it's likely its mission has ended." Power for the lander had been getting short, and it was taking longer to recharge its batteries; the loss of contact was a sign that the batteries had fully run down. There was never really a chance that the lander would run long past its expiration date (unlike the rovers, which operate in sunnier climes), but the exact date of its demise had been anyone's guess.

In its time on the red planet, Phoenix had a good view of the polar weather, but its work focused on the chemistry of the polar regions. Right off the bat, the lander's robotic scoop appeared to hit solid ice just below the surface, and scientists were rewarded with time-lapse images of ice subliming into the thin Martian atmosphere from one of the trenches it dug.









Images: NASA/JPL-Caltech/University of Arizona/Texas A&M University

We'll have a better sense of what precisely Phoenix has found when the scientific papers start coming out, but the lander had already made one key discovery: the public's really interested in the prospect of life on Mars. Back in August, rumors about a major discovery with implications for life on Mars became so intense that NASA had to hold a press conference to dispel them. It turns out they'd discovered lots of a compound that contains chlorine but, as of last check, they were still unsure what it was.

Phoenix is one of those rare cases where NASA got exactly what it had planned on: spotless operation in precisely the place they intended to land it. Unfortunately that location ensured that, no matter how well-engineered the hardware was, the winter would bring its operation to an end.