After a two-day silence, NASA's Spirit rover resumed communication with Earth on 23 January after "waking up" for the morning on Mars. The signal from Spirit, detected by NASA's Deep Space Network antenna complex near Madrid in Spain, lasted 10min at a data rate of 10bits/s. NASA, meanwhile, was preparing for the arrival of its twin, Opportunity, on the opposite side of the planet on 25 January.
Spirit, which landed on Mars in 3 January, had last transmitted data early on 21 January, although the rover sent a simple radio signal on 22 January acknowledging it had received a command from Earth. NASA's Jet Propulsion Laboratory in Pasadena, California was unable to replicate the situation with its testbed rover, and was considering the possibility of corruption of either flight software or computer memory.
The rover sent a signal via NASA's Mars Global Surveyor orbiter on the evening of 21 January, but the transmission did not carry any data. Spirit did not make contact with NASA's Mars Odyssey orbiter as scheduled later that night or the next morning, and did not send a pre-programmed signal indicating that its computer recognised a communications problem. NASA elicited the simple acknowledgement signal on the third attempt at direct communication using the Deep Space Network.
Spirit rolled off its lander on 15 January, then turned through 40¡ and drove about 2m (7ft) to its first target, a football-sized rock dubbed Adirondack, on 17 January. The rover began a close-up examination of the rock on 20 January using a microscope and two spectrometers mounted on the end of its robotic arm, transmitting almost 100mb of data to Earth via Mars Odyssey before falling silent.
Source: Flight International
