Tag Archives: safe mode

Dawn’s arrival at Ceres delayed one month

Though engineers have solved the problems caused when a radiation blast disabled Dawn’s ion engine and put it into safe mode for a week, the fix will cause a one month delay in its arrival at the asteroid Ceres.

Controllers discovered Dawn was in safe mode Sept. 11 after radiation disabled its ion engine, which uses electrical fields to “push” the spacecraft along. The radiation stopped all engine thrusting activities. The thrusting resumed Monday (Sept. 15) after controllers identified and fixed the problem, but then they found another anomaly troubling the spacecraft.

Dawn’s main antenna was also disabled, forcing the spacecraft to send signals to Earth (a 53-minute roundtrip by light speed) through a weaker secondary antenna and slowing communications. The cause of this problem hasn’t been figured out yet, but controllers suspect radiation affected the computer’s software. A computer reset has solved the issue, NASA added. The spacecraft is now functioning normally.

Two days after its flyby of Earth, Jupiter probe Juno remains in safe mode.

Two days after its flyby of Earth, Jupiter probe Juno remains in safe mode.

The Juno spacecraft is in a healthy and stable state, with its tractor-trailer-size solar panels pointed toward the sun. The mission team is in communication with Juno and has seen no sign of any failures in the probe’s subsystems or components, said project manager Rick Nybakken of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. So Juno’s handlers plan to take their time and do a thorough investigation before attempting to bring all of the spacecraft’s systems back online.

In other words, there is no rush to take the spacecraft out of safe mode. It is far better to figure out exactly what is going on first.

Another computer glitch has put Curiosity back in safe mode.

Another computer glitch has put Curiosity back in safe mode.

The problem this time appears to be different from the previous computer issue that shutdown Curiosity’s A computer. Since it occurred on the backup B computer now in use, however, it is a problem that cannot be taken lightly.

Kepler is back in operation after a ten day rest to safe the mission.

Kepler is back in operation after a ten day rest to save the mission.

When Kepler launched in March 2009, it had four reaction wheels — three for immediate use, and one spare. But one wheel (known as number two) failed in July 2012, so a major problem with the currently glitchy wheel (called number four) could spell the end of the $600 million Kepler mission. It’s unknown at the moment if the 10-day rest period will bring wheel number four back into line. “Over the next month, the engineering team will review the performance of reaction wheel #4 before, during and after the safe mode to determine the efficacy of the rest operation,” Hunter wrote.

Engineers have successfully tested a spare reaction wheel on Mars Odyssey in their effort to bring the spacecraft back into full operation.

Engineers have successfully tested a spare reaction wheel on Mars Odyssey in their effort to bring the spacecraft back into full operation.

After more than 11 years of non-operational storage, the spare reaction wheel passed preliminary tests on Wednesday, June 12, spinning at up to 5,000 rotations per minute forward and backward. Odyssey engineers plan to substitute it for a reaction wheel they have assessed as no longer reliable. That wheel stuck for a few minutes last week, causing Odyssey to put itself into safe mode on June 8, Universal Time (June 7, Pacific Time).