Mars Lander, Still for a Day, Stirs Again
Before coming back to life Thursday evening, NASA’s Phoenix Mars lander had put itself in “safe mode” after its power reserves dipped too low.
Succumbing to a swirling dust storm and the cold of an encroaching Martian winter, the Phoenix Mars lander fell quiet for a day, before coming back to life Thursday evening, albeit weakly.
The lander’s batteries appeared to have drained, mission managers said, with all systems, including its heaters, shut down. The mission managers had instructed the spacecraft to wake up and send word of its condition at 12:30 a.m. Thursday via the Mars Reconnaissance Orbiter, which was passing overhead. It did not.
But the spacecraft is programmed with a so-called Lazarus mode that enables it to resuscitate itself and recharge its batteries during the day.
Once restarted, the lander conserved its energy for 17 hours, then tried to communicate for two hours with any orbiter passing overhead, repeating the cycle until it received new instructions.
The lander successfully communicated with the Mars Odyssey orbiter Thursday evening.
A NASA statement said: “The communication reinforced a diagnosis that the spacecraft is in a precautionary mode triggered by low energy. Mission engineers are assessing the lander’s condition and steps necessary for returning to science operations.”
The Phoenix landed in May, during spring in the Martian northern polar region, to study a vast expanse of ice just below the surface. It has found signs that the ice may have melted in the past — the presence of carbonates, which form in the presence of liquid water — but its measurements also show current conditions to be very dry.
The lander’s last experiment, using a small oven to cook a sample of soil, was completed over the weekend. Data from the experiment was sent back before the shutdown and could answer whether the Martian soil contains organic compounds.
The Phoenix’s mission was scheduled to last three months but was extended to allow scientists to squeeze every bit of data from the spacecraft.
Now, with the dwindling sunlight of the Martian winter, the lander’s solar panels will produce less energy.
A dust storm on Monday further reduced the amount of power the panels could produce. Coupled with the energy drain from the last experiment and surface temperatures as low as minus-141 degrees Fahrenheit at night, the spacecraft put itself into its safe mode on Tuesday, shutting down nonessential activities.
The lander also shut down one of its two batteries and switched to backup electronics systems, and some energy-saving commands sent to the primary electronics were not performed.
Even though the lander revived, its demise is probably less than a month away. Peter H. Smith of the University of Arizona, the mission’s principal investigator, said it would be nice to watch winter develop through the lander’s instruments. “But that’s gravy,” Mr. Smith said. “We got what we came for.”
After a weekend of rumors that the White House had been informed of a major discovery bearing on the possibility of life on Mars, NASA held a hasty telephone news conference on Tuesday to announce the tentative identification of a class of minerals that has nothing directly to do with the habitability of Mars
Scientists find that the soil on the northern arctic plains of Mars is full of mineral nutrients that plants would need to survive.
June 27, 2008
“We basically have found what appears to be the requirements, the nutrients, to support life whether past, present or future,” said Samuel P. Kounaves of Tufts University, who is leading the chemical analysis, during a telephone news conference on Thursday. “The sort of soil you have there is the type of soil you’d probably have in your backyard.”
Mars today is cold and dry, and the surface is bombarded by ultraviolet radiation, making life unlikely, but conditions could have made the planet more habitable in the past. Plants that like alkaline soil — like asparagus — might readily grow in the Martian soil, provided that other components of an Earth-like environment including air and water were also present.
The preliminary findings from Phoenix do not answer whether life ever existed on Mars (or might still exist somewhere underground), only that conditions, at least at this location, are not the harshest imaginable. The soil, taken close to the surface, was similar to what is found in parts of Antarctica, Dr. Kounaves said. The soil elsewhere on the planet could well be very different; even the soil farther down in the ground could turn out to be acidic or otherwise vary in composition.
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