To live and die on Mars

The Phoenix Mars Lander has not communicated since Nov. 2, and engineers from the mission assume the vehicle is now completely out of power. Therefore, at a news conference today, mission managers announced the Phoenix the mission is now officially over. "At this time we're pretty convinced the vehicle is no longer available for us to use, and we're declaring the end of the mission," said Barry Goldstein, Phoenix project manager. "We've been surprised by this vehicle before, and we're still listening. We'll try to hail Phoenix, but no one has the expectation we'll hear from it again. We're completely proud of what we've accomplished. We've achieved all of the science goals and then some."

Designed to last only 90 days, the two rovers have survived for nearly five years on the Red Planet. Both are showing their age, but Jake Matijevic, chief of rover engineering at NASA's Jet Propulsion Laboratory in Pasadena, California, says they still are doing fine.

With its solar array yielding only a feeble 240 watt-hours of energy per day, Spirit stayed in place until mid-October recording a 360-degree colour panorama named after famed space artist Chesley Bonestell and collecting science data. Its next destinations are a hill dubbed Von Braun and a small crater called Goddard some 200 to 300 metres away.

Once it started moving, Spirit was able to climb slopes to 30°, making prospects look good for reaching those targets. However, two weeks of movement has not dislodged the dust that limits the power generated by its solar arrays.

It will begin the main part of its trek after a two-week interruption in communications from 29 November to 15 December, when the Sun will lie between Mars and the Earth.

Winds have blown dust off Opportunity's solar panels, so they generate more than 600 watt-hours of energy per day and allow the rover to move faster.

But it must navigate carefully across terrain that includes soft dunes where it could get stuck. The rover can travel up to 100 metres in an hour, but it can only see 20 to 30 metres ahead. That means it has to stop regularly to image the terrain so controllers can pick out a safe path.

In the coming months, when sunlight disappears entirely in the northern plains, temperatures will fall to minus-240 to minus-300 degrees Fahrenheit, and the Phoenix will become encased within carbon dioxide ice. When spring returns, NASA plans to try reviving the Phoenix again, but the expectation is that the spacecraft’s electronics will not survive the long, deep freeze.