Just like E.T., Spirit has called home, NASA scientists reported Friday. After a worrisome period of silence, the Mars rover sent information back to the control room at the Jet Propulsion Lab in Pasadena, Calif., at a low rate of data transfer. "The spacecraft sent limited data in a proper response to a ground command, and we're planning for commanding further communication sessions later today," project manager Peter Theisinger says.

Since its landing on the Red Planet on January 3, the robotic rover has been sending back large amounts of information, including colorful images of the Martian landscape. Attempts by NASA to contact the rover with instructions on Wednesday morning showed signs of trouble, however. Scientists thought that a thunderstorm over the Canberra station in Australia was to blame for the bad connection, but neither did the next scheduled connection a few hours later go as planned. Spirit then missed opportunities to return meaningful information both through the Mars Global Surveyor and Odyssey spacecraft and through direct-to-Earth transmission. In terms of trying to explain what has gone wrong, Theisinger remarked that "there is no one single fault that explains all the observables."

On Thursday morning, the Mars rover successfully sent a simple radio signal acknowledging receipt of a transmission from Earth, but a Friday morning call from Earth elicited no response. As NASA scientists were preparing to send a second beep, however, the rover contacted them. In all, Spirit spent 35 minutes talking to its handlers. A newly formed anomaly team will attempt to get Spirit back up and running properly even as its twin, Opportunity, prepares to land on the opposite side of the planet late Saturday night and early Sunday morning. For the next several days, scientists will contact Spirit to gather more data about its problems, propose theories of what when wrong and test them against observations of the spacecraft. "I think that we should expect that we wont be restoring functionality to Spirit for a significant period of time," Theisinger notes, "perhaps many days, even a number of weeks, even under the best of circumstances from what we see today." Overall, Theisinger is cautiously optimistic about the rovers reinstatement, but "the chances that it will be perfect are not good."