The Kepler spacecraft remains stable as the process of returning it to science continues. The cause of the anomaly, first reported on April 8, remains under investigation.
Since Sunday morning the spacecraft has remained safely “parked” in a stable pointed configuration called Point Rest State. In this state, fuel usage remains low and the communication link to Earth is good. As of Tuesday, mission operations engineers had downlinked all the necessary data from Kepler to triage the situation and plan the steps toward recovery.
The recovery to science began with a thorough assessment of the data, which took a couple days, after which the team had learned all they could about the state of the spacecraft from the data. It was then time to turn back on and test the components deemed low-risk to spacecraft health. Testing begins on the Kepler spacecraft simulator at the flight planning center at Ball Aerospace in Boulder, Colorado. With the ground-based simulation a success, we were ready to conduct the tests on Kepler, 75 million miles away. The engineers sent the instructions, along with commands for the spacecraft to protect itself and enter a safe operating mode if there was a problem, and waited for the spacecraft to report back.
The spacecraft returned a response that is the equivalent of ‘so far, so good.’ It did not experience any faults from switching on the components, and all the data suggest the components are working normally. The spacecraft is another step closer to returning to scientific observations for the K2 mission.
The photometer – Kepler’s camera – and the solid state recorder are powered on. The subsystem interface box, which is the interface between the spacecraft sensors and the main computer, was only briefly powered on for an initial assessment, but should be back online early next week. The team will continue recovering the components, as they are deemed safe and low-risk to the spacecraft.
Over the weekend, NASA’s Deep Space Network (DSN) will remain in contact with the spacecraft while the team gets some much-needed rest. To watch the worldwide array of antennae communicate with the spacecraft, tune-in to DSN Now.
The recovery started slowly and carefully, as we initially merely tried to understand the situation and recover the systems least likely to have been the cause. Over the last day and a half, we’ve begun to turn the corner, by powering on more suspect components. With just one more to go, I expect that we will soon be on the home stretch and picking up speed towards returning to normal science operations.
4/11, Update 1: Kepler Recovered from Emergency and Stable
Mission operations engineers have successfully recovered the Kepler spacecraft from Emergency Mode (EM). On Sunday morning, the spacecraft reached a stable state with the communication antenna pointed toward Earth, enabling telemetry and historical event data to be downloaded to the ground. The spacecraft is operating in its lowest fuel-burn mode.
The mission has cancelled the spacecraft emergency, returning the Deep Space Network ground communications to normal scheduling.
Once data is on the ground, the team will thoroughly assess all on board systems to ensure the spacecraft is healthy enough to return to science mode and begin the K2 mission’s microlensing observing campaign, called Campaign 9. This checkout is anticipated to continue through the week.
Earth-based observatories participating in Campaign 9 will continue to make observations as Kepler’s health check continues. The K2 observing opportunity for Campaign 9 will end on July 1, when the galactic center is no longer in view from the vantage point of the spacecraft.
K2’s previous science campaign concluded on March 23. After data was downlinked to the ground, the spacecraft was placed in what is termed Point Rest State (PRS). While in PRS, the spacecraft antenna is pointed toward Earth and it operates in a fuel-efficient mode, with the reaction wheels at rest.
The Emergency Mode began approximately 14 hours before the planned maneuver to orient the spacecraft toward the center of the Milky Way for Campaign 9. The team has therefore ruled out the maneuver and the reaction wheels as possible causes of the EM event. An investigation into what caused the event will be pursued in parallel, with a priority on returning the spacecraft to science operations.
The anomalous EM event is the first that the Kepler spacecraft has encountered during its seven years in space. Mission operations at NASA’s Ames Research Center in California’s Silicon Valley, Ball Aerospace and the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder remain vigilant.
It was the quick response and determination of the engineers throughout the weekend that led to the recovery. We are deeply appreciative of their efforts, and for the outpouring of support from the mission’s fans and followers from around the world. We also recognize the tremendous support from NASA’s Deep Space Network, managed by the Jet Propulsion Laboratory in Pasadena, California, and to NASA’s other missions that surrendered their scheduled telemetry links in order to provide us with the resources needed to protect the Kepler spacecraft.
April 8, Original Report: Kepler in Emergency Mode
During a scheduled contact on Thursday, April 7, mission operations engineers discovered that the Kepler spacecraft was in Emergency Mode (EM). EM is the lowest operational mode and is fuel intensive. Recovering from EM is the team’s priority at this time.
The mission has declared a spacecraft emergency, which provides priority access to ground-based communications at the agency’s Deep Space Network.
Initial indications are that Kepler entered EM approximately 36 hours ago, before mission operations began the maneuver to orient the spacecraft to point toward the center of the Milky Way for the K2 mission’s microlensing observing campaign.
The spacecraft is nearly 75 million miles from Earth, making the communication slow. Even at the speed of light, it takes 13 minutes for a signal to travel to the spacecraft and back.
The last regular contact with the spacecraft was on April. 4. The spacecraft was in good health and operating as expected.
Kepler completed its prime mission in 2012, detecting nearly 5,000 exoplanets, of which, more than 1,000 have been confirmed. In 2014 the Kepler spacecraft began a new mission called K2. In this extended mission, K2 continues the search for exoplanets while introducing new research opportunities to study young stars, supernovae, and many other astronomical objects.