Spaceflight Insider

Kepler space telescope recovered from Emergency Mode


Artist’s concept of NASA’s Kepler space telescope. The spacecraft went into Emergency Mode on April 7 but was put in a stable condition by mission operators on April 10. Image Credit: NASA

Mission operators successfully recovered NASA’s Kepler space telescope after the spacecraft entered Emergency Mode (EM) over the weekend. According to the space agency, the spacecraft is currently safe and in a stable condition.

On April 7, during a scheduled contact session with the spacecraft, mission operators discovered that Kepler was in EM, its lowest operational level—a mode that uses an intensive amount of fuel. Teams then declared a spacecraft emergency, which gives priority access to the Deep Space Network (DSN)—a worldwide system of large ground-based antennas.


Kepler and Earth-based observatories on six continents will survey millions of stars near the center of the Milky Way. Kepler will use gravitational microlensing to look for exoplanets that are far from their host star or, in some cases, not orbiting a star at all. Image Credit: NASA

This was the first EM event that the planet-hunting telescope had encountered in its seven years in space.

In a news release, Charlie Sobeck, Kepler’s mission manager, said the team soon discovered that the spacecraft went into EM 36 hours prior to the April 7 check-in. This was about 14 hours before the spacecraft was set to orient itself toward the center of the Milky Way for a gravitational microlensing observation campaign, which aims to look for planets using gravitational lensing. Since the telescope had yet to rotate, engineers believe that the maneuver and reaction wheels did not cause the crisis to occur.

Kepler is 75 million miles (120 million kilometers) from Earth. At this far out, communications to and from the spacecraft takes 13 minutes. The team worked throughout the course of this past weekend to put the telescope back in a stable state with the antenna pointed toward Earth in order send back telemetry and event data.

“It was the quick response and determination of the engineers throughout the weekend that [led] to the recovery,” Sobeck said in a statement. “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.”

Engineers will assess the systems on board Kepler, ensuring that the spacecraft is healthy enough to return to science mode. This check-out is expected to last throughout the week. An investigation into what caused this anomaly will run in parallel with science operations.

Once back in a normal science mode, Kepler will be pointed toward the galactic core where it will stay until July 1 when the center of the galaxy is no longer in view from the vantage point of the spacecraft.

Kepler and other ground-based observatories will be conducting a global experiment to look for exoplanets using gravitational microlensing. This is part of an effort to start discovering exoplanets near the outer regions of host stars. It is hoped that this technique could even be used to discover rogue planets—planets that don’t orbit a star and drift in space.

“The chance for the K2 mission to use gravity to help us explore exoplanets is one of the most fantastic astronomical experiments of the decade,” Steve Howell, project scientist for Kepler, said in a news release. “I am very happy to be a part of this K2 campaign and look forward to the many discoveries that will be made.”

Video courtesy of NASA Ames Research Center


Derek Richardson is a student studying mass media with an emphasis in contemporary journalism at Washburn University in Topeka, Kansas. He is currently the managing editor of the student run newspaper, the Washburn Review. He also writes a blog, called Orbital Velocity, about the space station. His passion for space ignited when he watched space shuttle Discovery leap to space on Oct. 29, 1998. He saw his first in-person launch on July 8, 2011 when the space shuttle launched for the final time. Today, this fervor has accelerated toward orbit and shows no signs of slowing down. After dabbling in math and engineering courses in college, he soon realized that his true calling was communicating to others about space exploration and spreading that passion.

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