DAVID GREENE, HOST:
Now, some sad news from beyond our own atmosphere. NASA says its Kepler space telescope can no longer carry out its mission. Until this, Kepler was successfully hunting for planets as it made its yearly orbit around the sun. But now it has permanently lost its ability to keep its gaze on target. And as NPR's Andrew Prince reports, the space agency hopes to come up with another mission for this hobbled probe.
ANDREW PRINCE, BYLINE: The Kepler spacecraft launched in 2009 with a noble goal, to search other solar systems for Earth-like planets. These planets are in what's called the Goldilocks zone, where the planet is neither too close to its star where it's too hot for life, nor too far, where it's too cold. Four years in, Kepler has found possibly thousands of planets, and scientists are wading through that data to see how many might be Goldilocks planets.
But in July of last year, Kepler started having some problems. It uses a system of four gyroscope-like wheels to keep it pointed in the right direction, and one of these wheels stopped working. Then this past May, a second one broke down. Since then, NASA has been sending commands to Kepler to get it back into full working order.
This week, NASA announced it's giving up. But the space agency thinks there still might be some life left in Kepler yet. It's going to look into what other kinds of science Kepler might be able to do with just half of its wheels. To that end, NASA's put out a call for what it's calling two-wheel science proposals. Andrew Prince, NPR News.