Communications between the Mars Pathfinder and NASA were restored today, clearing the way for scientists to begin receiving data from the Red Planet for the first time in two days.
Relieved mission controllers replied to the lander's transmissions by ordering it to begin sending the information with its low-gain antenna. A session using the high-gain, or high-speed, antenna was to follow.
Controllers relaxed after communications were restored.
"Believe me, there were a lot of happy faces when we saw that blip," said project manager Brian Muirhead at the National Aeronautics and Space Administration's Jet Propulsion Laboratory in Pasadena. "It was exactly what we expected it to be. It went off at precisely the right time."
Scientists had last received a signal from the probe at 4 a.m. Sunday, but it was weaker than expected and provided no scientific data. Then no signal was heard during a session three hours later.
Scientists had been hoping to retrieve data missed Saturday because of a misconfigured Earth antenna. The material included pictures, rock analyses and a weather report.
Both the lander and its rover, Sojourner, were believed to be healthy, Muirhead said. The rover is still safely parked at a whitish rock nicknamed "Scooby Doo."
"It's just sitting there wondering what's going on," Muirhead said.
The latest problem may be related to Saturday's glitch, when a wrongly set radio antenna in Madrid, Spain, didn't capture data from the lander. Or it could be something more complicated on Mars, Muirhead said.
Muirhead said the latest problem is not believed to be related to three earlier computer resets aboard the lander that disconnected communications.
A computer program "patch" that was supposed to be relayed to the lander over the weekend to fix a software bug was postponed.