NASA probe lands on Mars

PASADENA, Calif. — ­ NASA's Phoenix Mars spacecraft appears to have made a safe landing on Mars.

Just before 8 p.m. Eastern time, mission controllers at the Jet Propulsion Laboratory here received a radio signal from the Phoenix on the ground in the icy plains north of Mars' Arctic circle.

Because the signal was relayed via the Mars Odyssey orbiter, the controllers would have to wait another couple of hours, until Odyssey's next pass over the landing site, for additional word of the Phoenix's condition, including whether it had successfully unfolded its solar panels and possibly the first photographs.

If all is operating properly, the next few days will be spent checking out the instruments aboard the lander. Then, it will begin the first upclose investigation of Mars' north polar regions. That area became a prime area of interest for planetary scientists after NASA's orbiting Odyssey spacecraft discovered in 2002 vast quantities of water ice lying a few inches beneath the surface in Mars' polar regions.

All of Mars' surface is currently far too cold for life to exist, but in the past, Mars' axis may have periodically tipped over so that its north pole pointed at the sun during summer. That conceivably could have warmed the ice into liquid water.

With liquid water comes the possibility of life.

On Phoenix, a robotic arm with a scoop at the end will dig into the permafrost terrain into the ice. Instruments on the spacecraft included a small oven that will heat the scooped-up dirt and ice to 1,800 degrees Fahrenheit. Analyzing the vapors will provide information of the minerals, and that will, in turn, provide clues about whether the ice ever melted and whether this region was habitable for life.

"We see Phoenix as a stepping stone to future investigations of Mars," said Peter H. Smith of the University of Arizona, the principal investigator of the mission.

I wish the little robot well on its mission and I congratulate the scientists and engineers who designed and built it and launched it on its way.

I somehow doubt that they will find any firm proof that there was ever life on Mars (not even Sam Tyler's leather jacket) but the effort is still worthwhile.