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NASA’s Phoenix Mars Lander tripped into safe mode yesterday in response to a low-power fault, and unexpectedly switched on to the ‘B-Side’ of its redundant electronics, shutting down one of its two batteries in the process.
During safe mode, the lander stops non-critical activities and awaits further instructions from the mission team. Engineers were able to kick start battery charging by sending commands from Earth to the failing lander, but the harsh weather conditions are taking their toll.
NASA's Mars Phoenix Lander is slowly shutting down as winter sets in. The mission, already in its fifth month of a 90 day mission, suffered a fault yesterday due to the
deteriorating weather conditions. Image: NASA/JPL-Calech/University of Arizona.
"This is a precarious time for Phoenix," says Phoenix Project Manager Barry Goldstein. "We're in the bonus round of the extended mission, and we're aware that the end could come at any time. The engineering team is doing all it can to keep the spacecraft alive and collecting science, but at this point survivability depends on some factors out of our control, such as the weather and temperatures on Mars."
Phoenix has recorded the lowest temperatures yet, dipping to -96 degrees Celsius at night and barely rising above -45 degrees Celsius in the day. Dust-storms and water-ice clouds add additional challenges, reducing the amount of sunlight reaching Phoenix’s solar panels, thereby restricting the amount of power the lander can generate. On Tuesday, low temperatures triggered Phoenix’s emergency battery heaters into action, creating another drain on precious power supplies.
"It could be a matter of days, or weeks, before the daily power generated by Phoenix is less than needed to operate the spacecraft," says JPL mission manager Chris Lewicki. "We have only a few options left to reduce the energy usage."
Only this week did mission leaders announce plans to turn off four heaters, one at a time, in an effort to preserve power. The faults experienced yesterday forced the engineers to shut down two heaters instead of one as originally planned, ceasing operations of the robotic arm, robotic arm camera and the thermal and evolved-gas analyser. The second heater served the lander's pyrotechnic initiation unit, which hasn't been used since landing.
Science activities will remain on hold for the rest of the week to allow the spacecraft to recharge and conserve power. It is still hoped that Phoenix will be able to perform meteorological observations at the very least, for some weeks to come.
from:http://www.astronomynow.com/081030phoenixinprecarioustimesfollowingpowerfault.html
