NASA's having another shot at regaining communication with the Mars rover Spirit, bogged down in a Martian crater for the last eighteen months.
After the rover became stuck in soft sand, all attempts to free it failed. In March, it missed a planned communication session, indicating that it had gone into a power-saving hibernation mode. In this, it carries out no activity other than charging and heating its batteries and keeping its clock running.
But NASA's stepping up its efforts to get back in communication - partly because the temperature will drop sharply in March, making reestablishing communication even more unlikely.
"The amount of solar energy available for Spirit is still increasing every day for the next few months," says project manager John Callas. "As long as that's the case, we will do all we can to increase the chances of hearing from the rover again."
Unfortunately, in hibernation mode, Spirit's internal temperature is likely to have dipped lower than ever. This will have caused damage, such as impaired electrical connections, that would prevent reawakening or reduce its capabilities.
The rover team has been sending commands to elicit a response from the rover even if it's lost track of time, and has stepped up efforts to find a signal.
It's started listening at times when Spirit might mistake a signal from NASA's Mars Reconnaissance Orbiter as a signal from Earth and respond to it. It's also sending commands for a beep from Spirit at other times of day, on the off-chance that Spirit might awaken. And NASA's listening on a wider range of frequencies in case the temperature has affected Spirit's radio systems.