14 Hours Late, Magellan ‘Phones Home’ : NASA: The long silence from the spacecraft sent to map Venus had scientists holding their breath.

Scientists at the Jet Propulsion Laboratory lost contact with Magellan, the sophisticated radar-mapping spacecraft that entered orbit around Venus just last Friday, for 14 hours before communications were regained today.

During a routine orientation test Thursday night, the spacecraft turned its antennas from Earth and pointed a small on-board telescope at two bright stars whose positions provide reference marks for the spacecraft’s internal gyroscopes. “We didn’t get a signal back,” JPL spokesman Allen Wood said today.

This suggests that the spacecraft may have inadvertently locked on to a different, third star, disorienting its internal reference system so that it could no longer point its antenna toward Earth.

Researchers said the spacecraft is in no immediate danger. “We’re pretty certain it is not tumbling,” Wood said, because Earth-based receivers would pick up intermittent radio signals if it were.

Loss of Magellan would have been a shattering blow to NASA, which has already been rocked this summer by the grounding of its shuttle fleet because of hydrogen leaks and defects in its highly touted Hubble Observatory.

Project manager Tony Spear was in the midst of a news conference today to outline the loss of contact when excited engineers ran in to announce a signal had been received from Magellan, the centerpiece of a $551-million mission to map the hidden surface of Venus.

“It is Magellan’s signal,” project engineer Steve Wall said. “It is in lock. It has been verified to be Magellan’s signal. This is slow telemetry (but) the spacecraft looks healthy.”

However, both of Magellan’s high-data-rate radio transmitters were off, indicating that the spacecraft was or had been operating in a computer-induced state of hibernation called a “safe mode.”