How Kepler's team recovered the exoplanet-hunting spacecraft OrlandoSentinel
By Emilee Speck • April 14, 2016, 10:14 PM
An undated artists concept provided by NASA shows the Keplar Spacecraft moving through space. The treasured spacecraft, responsible for detecting nearly 5,000 planets outside our solar system, slipped into emergency mode sometime last week. (NASA)The team behind NASA's exoplanet-finding spacecraft could sigh with relief Friday night after they were able to start communicating with the Kepler spacecraft in crisis more than 75 million miles from Earth.
What started as a scheduled contact last Thursday led the team to find the spacecraft in Emergency Mode.
"We expected it would be pointed at the science attitude," said Kepler mission manager Charlie Sobeck from NASA's Ames Research Center in California. "Instead we found it in Emergency Mode."
A step before Emergency Mode is known as Safe Mode, explained Sobeck. Safe Mode allows for another failure, but in emergency the next failure would have lost the 7-year-old spacecraft.
Kepler's team did not think they would ever encounter Emergency Mode on the Kepler2 mission, said Sobeck.
"The Emergency Mode is a scary place to be, but once we're there we take a deep breath and go from there," he said.
After finding the spacecraft in trouble Kepler's teams at NASA's Ames Research Center, Ball Aerospace and the Laboratory for Atmospheric and Space Physics at the University of Colorado worked together to regain communication with the spacecraft.
Once Kepler entered Emergency Mode the solar panels pointed directly at the sun and it slowly turns, like on a spindle, explained Sobeck.
Kepler's team needed to find the signal from Kepler's antennae pointed towards Earth, but because the spacecraft was spinning they would find a signal and then it would already be six minutes old and communication from Kepler to ground and back takes about 13 minutes.
The team needed to determine "what's on, what's off, how do we send a command," said Sobeck. "It took a few rotations to understand."
By the end of Friday, they had successfully established a connection and placed the spacecraft into Safe Mode.
Kepler was found in Emergency mode 14 hours before a planned maneuver to turn the spacecraft toward the center of the Milky Way for a new mission objective.
The new campaign of the redesigned Kepler2 mission was scheduled to begin in the next few weeks. Kepler will survey stars towards the center of the Milky Way galaxy searching for more exoplanets. Kepler is famous for the dozens of exoplanets it has discovered, including the first Earth-sized planet within a life-sustaining distance of a star, known as Kepler-186f.
This isn't the first time mission control has needed to take action to save Kepler.
During its first mission the spacecraft lost one of its four reaction wheels used for balancing the spacecraft. A year later when another reaction wheel went out they were ready with a plan to stabilize the spacecraft using the pressure of sunlight.
Kepler's team will now work to correct any problems onboard and get back to collecting science. Although delayed, Sobeck estimated Kepler should be able to begin its new mission in the near future.
So why did this happen?
Sobeck and his team were able to downlink data logs that will explain what happened before, during and after the failure event triggering Emergency Mode, but they already have theories as to what caused the spacecraft to go into distress.
"The spacecraft got overwhelmed by a number of fault indications that overwhelmed the fault protections," said Sobeck.
Similar to the smoke alarms inside a house, most of the time they trigger before there is an actual fire, explained Sobeck. The fault alarms on Kepler were likely triggered out of caution, but they are designed to be sensitive, he added.
"The thing to keep in mind is K2 had been remarkably trouble free and I think we’ll be trouble free going forward," said Sobeck. "I don't believe this signals the end of the mission at all."
Kepler2's discoveries could be future targets of study for the Hubble Space Telescope and the coming James Webb Space Telescope, looking for life-supporting atmospheres on these planets.
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