NASA's Phoenix Mars lander: Long may it rest in peace

The Phoenix spacecraft appears to have finally passed away, although not before accomplishing its main NASA missions around exploring the terrain and weather conditions of the so-called "Red Planet."

On Monday, managers of the NASA spacecraft announced they are suspending any operations related to the vehicle until next spring, given that they haven't received any transmissions from it for a week.

The death of the Phoenix wasn't unexpected, since the Martian winter had set in and the Phoenix's solar panels had started to generate less energy. Still, NASA managers had hoped to eek out a few more weeks of performance from the craft.

The Phoenix arrived on Mars on May 25 to explore the terrain and weather conditions on the northern arctic plains of that planet. Originally slated to end in August, the $428 million mission went so well, on the whole, that NASA extended it twice.

But right after the Phoenix completed its last major experiment on October 27, an unanticipated dust storm struck, and on-board batteries -- already strained by running the experiment -- started to give way.

The space vehicle put itself into a low-energy safe mode, and then stopped sending signals. The Phoenix started to come back to life intermittently on October 30, but never managed to completely recharge its batteries, finally fading away.

Still, during its more than five months of operation on Mars, the Phoenix did uncover a layer of ice close to the surface, along with carbonates and clays, suggesting that liquid water might have existed on Mars at some point. Further exploration revealed that the soils in the region are actually very similar to the upper dry soils in Antarctica on our own planet.

The Phoenix also discovered perchlorates, a type of chemical that can act as food for some microbes, but that can also be toxic to life in high doses.

When spring arrives on Mars again in 2009, NASA will again try to revive the spacecraft. But hopes are not high that the Phoenix will ever rise again, after the vehicle has spent a number of months encased in carbon dioxide ice and surrounded by temperatures as low as minus 300 degrees Fahrenheit.