False alarm sent Kepler into safe mode: team

Jan 10, 2011
Artist concept of Kepler in space. Image credit: NASA/JPL

The Kepler Project Team successfully returned the spacecraft to normal operations on Jan. 6, 2011. The team determined the condition was caused by unexpected noise in the signal from Kepler's sun sensors that erroneously indicated Kepler might be pointing too close to the sun. This was a false alarm, but the team treated it seriously.

The Response Team narrowed down the probable cause for the sun sensor noise to a virtual ground circuit in a pair of onboard electronics boxes, called Subsystem Interface Boxes (SIB), referred to as SIB-1 and SIB-2. The engineering team determined that input from the sun sensors caused unexpected variations in the ground circuit. The circuit that experienced variations on Dec. 22, 2010, tripped the fault protection and caused Kepler to enter safe mode. This was the first and only time that Kepler experienced noise from its sun sensors. The team was able to determine that the noise is not related to any part failure and is inherent to the design of the virtual ground circuit.

Having narrowed the cause to the design of this circuit, and understanding the extent of the vulnerability, the operations team concluded that it was safe to return to normal operations, including science data collection. They have sufficient workarounds to prevent a recurrence from this cause.

was not able to collect science data for the duration of the anomaly from Dec. 22, 2010, to Jan. 6, 2011. Engineers will continue to analyze telemetry from the event to determine if any further mitigations are possible and necessary. Kepler's next science data download is scheduled for February 2011.

Explore further: Computer simulation suggests early Earth bombarded by asteroids and comets

add to favorites email to friend print save as pdf

Related Stories

Kepler experienced 'safe mode' event

Dec 23, 2010

On Dec. 22, 2010, Kepler experienced a safe mode event. A safe mode is a self-protective measure that the spacecraft takes when something unexpected occurs. During safe mode, the spacecraft points the solar ...

Experts investigate Kepler's condition

Jan 04, 2011

In response to the Dec. 22, 2010 Safe Mode event on the Kepler spacecraft, the mission team has brought in several experts and begun a detailed anomaly investigation.

Kepler Mission Update

Nov 06, 2009

(PhysOrg.com) -- Kepler completed another science data download over October 18-19. In this download, a month's worth of science data was transmitted through the NASA Deep Space Network and into the Science ...

Kepler Mission Update

Sep 23, 2009

(PhysOrg.com) -- Kepler is approximately 18 million kilometers (11 million miles) from Earth, and continuing its drift-away orbit. All systems are operating normally. Last week, the Kepler project team completed ...

Recommended for you

Exploring Mars in low Earth orbit

13 hours ago

In their quest to understand life's potential beyond Earth, astrobiologists study how organisms might survive in numerous environments, from the surface of Mars to the ice-covered oceans of Jupiter's moon, ...

Lifetime of gravity measurements heralds new beginning

15 hours ago

Although ESA's GOCE satellite is no more, all of the measurements it gathered during its life skirting the fringes our atmosphere, including the very last as it drifted slowly back to Earth, have been drawn ...

NASA's IceCube no longer on ice

19 hours ago

NASA's Science Mission Directorate (SMD) has chosen a team at NASA's Goddard Space Flight Center in Greenbelt, Maryland, to build its first Earth science-related CubeSat mission.

User comments : 0