Right back where we started from: Dead for now - but could it return to life next summer, much like it's mythical namesake?
Credit: NASA
Remarkable image: Taken by the Mars Reconnaissance Orbiter, the photo shows Phoenix being lowered to the surface by parachute.
Credit: NASA
Covered in a rime of frost, NASA's Phoenix Lander sits at the edge of the polar cap on the northern plains of Mars, where it awaits the fall of winter.
Once the Martian winter truly arrives, Phoenix's solar panels may crack and break under the weight of the crystallised water and carbon dioxide snow, and eventually it may be encased in solid ice. Whether it will survive the winter, no-one knows.
When the ice evaporates back into the atmosphere with the arrival of spring, Phoenix has a tiny chance of being able to phone home to let us know that it has been reborn, like its mythical namesake, but not even the most optimistic members of its team are placing solid bets on it being able to do that.
Some people have left comments on the Phoenix blog sites saying things like: "why bother with a lander, with such a limited limited life-span?", considering that NASA's Opportunity and Spirit Mars Rovers are now almost five years into their "90-day" missions.
But the truth is that Phoenix was never meant to last forever. It was designed to live fast, die young, and do good science.
Phoenix was sent to the northern plains of Mars to provide definitive answers to two important questions. First: is there water on Mars, and what form is it found in? And second: was Mars ever habitable, and what could live in its soils?
After a 15-month journey from Earth, Phoenix landed at 68 degrees north on the Martian surface on 25 May 2008.
Its landing was photographed by NASA's Mars Reconnaissance Orbiter in what is, perhaps, the most evocative image ever returned from another planet. The image showed parachutes lowering Phoenix – still encased in its protective backshell – clearly visible against the backdrop of Heimdal Crater (press 'play' to see second image, right).
The first look at its surrounding, sent back only a few hours after landing, showed a terrain surprisingly like the frozen tundra of Siberia or northern Canada - strange polygons of frozen and uplifted soil, suggestive of repeated cycles of freezing and thawing of a water-rich environment.
With a peek under its belly five days after it had landed, Phoenix gave us the first glimpse at the solid water ice that lies less than 15 cm below the surface of the plains.
With a scoop of the soil, delivered to its ovens, Phoenix confirmed that this is, without a shadow of a doubt, water ice, and has proved that should humans land on Mars, they will be able to make oxygen to breathe, and hydrogen to fuel their power plants.
Sniffing and tasting the water and soil, repeatedly over the next few months, Phoenix found that if it had been on Earth, you'd almost have been able to grow plants in the soil surrounding its landing site.
Using its weather station, Phoenix sent back daily weather reports, and with its LIDAR (a laser-based version of radar) it recorded the first snow ever detected falling on another planet.
It survived dust storms and whirlwinds, and while some of its instruments didn't exactly work perfectly the first time, as in the case when soil from Phoenix's scoop refused to neatly fall into its ovens, the mere fact that the soil was "clumpy" has told scientists much about the soil they would never have learned otherwise.
Sure, it didn't get up and climb to the top of a hill, but Phoenix has done exactly what it was designed to do, and done it almost perfectly.
Spirit and Opportunity would not have lasted more than a few months if they'd been sent to where Phoenix landed, as their greater solar power needs could not have been met at such an inhospitable landing site. They too would not have survived the winter at 68 degrees North.
Built with components initially designed for the failed Mars Polar Lander mission and the cancelled Mars Surveyor Lander (along with new instruments from Canada, France, the U.S., Denmark and the U.K.), Phoenix is a shining example of international cooperation on a space mission, built on a shoe-string budget.
NASA's next Mars rover to be launched in 2011, the Mars Science Laboratory, has a budget more than five times greater than that of Phoenix.
Phoenix finally stopped communicating with Earth on 10 November 2008, two weeks earlier than its controllers had hoped, but by then it was well into extended mission time. Its 90-day primary mission had been successfully completed in late August, anything after that was a bonus.
It appears to have been finally silenced by a dust storm, the dust falling on the solar panels proved to be too much, and its power fell to below the critical limit needed to keep it alive and communicating.
To the south, much closer to the equator, the same dust storm has caused Spirit to be put into "conservation" mode, only doing limited observing, and communicating with Earth only when absolutely necessary.
Was the mission a success? Most definitely yes. Nothing has previously ventured as far North on Mars, and nothing has previously been able to so decisively prove the presence of water on Mars and the habitability of the Northern Plains.
This is one mission that will be long remembered by all those who look up at Mars in the night sky. Phoenix is the mission that has seen our hopes of eventually sending humans to Mars reborn anew from the ashes of the phrase "it's never going to happen."
Marion Anderson is an expert in the mineralogy and geomorphology of Mars, based at Monash University in Melbourne, Australia.
