A faulty steering apparatus may bring an early end to NASA’s Kepler space telescope, a $600 million tool in the space agency’s quest for life elsewhere in the universe.
Kepler is the first NASA mission capable of finding Earth-size planets in or near the habitable zone, the range of distance from a star where the surface temperature of an orbiting planet might be suitable for liquid water. Launched in 2009, it has discovered thousands of such planets, including a pair just 1,200 light years away.
Called Kepler-62-e and Kepler-62-f, the news of their discovery came about one month ago. But yesterday, Kepler’s mission ran into trouble.
'Unfortunately, Kepler isn’t in a place where I can go up and rescue it.'
- John Grunsfeld, associate administrator, NASA's science mission directorate
Kepler is powered by four solar panels, and the spacecraft must execute a 90-degree roll every 3 months to reposition them toward the sun while keeping its eye precisely aimed. Kepler launched with four wheels to control that motion -- and one of them failed last year.
Yesterday, a second wheel appears to have failed as well, and the space telescope was placed in “thruster-controlled safe mode” yesterday, said NASA spokesman J.D. Harrington.
“Unfortunately, Kepler isn’t in a place where I can go up and rescue it,” John Grunsfeld, associate administrator, science mission directorate at NASA said during a hastily arranged press conference Wednesday afternoon.
NASA talks to Kepler twice a week. Earlier this week, during one of those communications, NASA noticed that it was in safe mode, something that has happened several times during its mission already.
“Our normal response to that … is to command it back to wheels. We did that and we initially saw some movement of the wheel,” explained Charles Sobeck, deputy project manager with Ames Research Center. That movement quickly ground to a halt, he said.
“This is indicative of an internal failure within the wheel.”
Kepler will continue working for the next few months, and NASA will look to reduce fuel consumption during that time to extend the lifespan of the spacecraft. For example, a different mode of steering Kepler will enable NASA to extend its life by years, Sobeck said.
“We’re not down and out. The spacecraft is safe, it is stable,” Sobeck said. And regardless, Kepler is already a win for NASA.
“The mission itself has been spectacularly successful,” he added. “the next question is going to be what the future of the mission looks like.”
Other scientists agreed. Even if the Kepler Space Telescope mission ends early, it has performed more than admirably.
“Kepler is just one of these wonderful stories, where folks didn’t believe we would be able to find … planets, and here we are, having achieved all of the milestones that we really wanted to with the Kepler mission in four years,” Grunsfeld said.
The quest for “exoplanets” has generated enormous interest among the public and with scientists, he noted. It will continue, explained Paul Hertz, astrophysics director for NASA.
A second mission will launch in 2017 and will use the same method that Kepler has used to continue the mission, he said, and will seek the closest exoplanet -- which may be under two dozen light years away.
The James Webb Space Telescope will also help in the quest for life in the universe.