Quantcast
Channel: Hacker News 50
Viewing all articles
Browse latest Browse all 9433

Equipment Failure Imperils Kepler’s Quest for Other Earths - NYTimes.com

$
0
0

Comments:"Equipment Failure Imperils Kepler’s Quest for Other Earths - NYTimes.com"

URL:http://www.nytimes.com/2013/05/16/science/space/equipment-failure-may-cut-kepler-mission-short.html?emc=na&_r=0


NASA/JPL, via Associated Press

The Kepler telescope, seen in an artist rendition, has been shut down after the failure of one of the wheels that keep it pointed.

NASA’s planet-hunting Kepler spacecraft has been shut down by the failure of one of the reaction wheels that keep it pointed, the space agency announced Wednesday.

“I wouldn’t call Kepler down and out yet,” said John Grunsfeld, a former astronaut and Hubble repairman who is NASA’s associate administrator for space science, at a news conference.

But he and others said that if engineers could not restore the wheel or find some other way to keep the spacecraft’s telescope precisely pointed, the failure could end one of the most romantic and successful of NASA’s missions: the search for Earth-like planets in habitable orbits around other stars. Just last month, astronomers reported that Kepler had found two planets, only slightly larger than Earth, orbiting a star 1,200 light-years from here in the Goldilocks zone, where liquid water is possible.

More potentially habitable planets, even smaller and more Earth-like, lurk in the pipeline, astronomers say, but have not yet been confirmed. “We believe there are planets there that we haven’t found yet,” said William Borucki of NASA’s Ames Research Center, the founder and leader of the Kepler effort.

As word leaked about the possible loss of Kepler, the mood in the astronomical community was grim. “It was one of those things that was a gift to humanity,” said one astronomer, who spoke on condition of anonymity before NASA made the news public. “We’re all going to lose, for sure.”

Kepler, launched in March 2009, orbits the sun at roughly the same distance as Earth. Its mission is to determine the fraction of stars in the galaxy that harbor Earth-like planets by carrying out a survey of some 150,000 stars in the constellations of Cygnus and Lyra, looking for the dips in starlight caused by planets passing, or transiting, in front of their suns. The spacecraft has identified 130 planets and 2,740 other candidates. About 230 are the size of Earth, and 820 others are only twice as big as Earth and are probably rocky worlds similar to our own, Mr. Borucki said.

Kepler’s mission has cost $600 million so far. It was designed to operate for four years, but last year it was extended three more years, until 2016.

Since the Earth transits the Sun only once a year, two more years would give astronomers a chance to see more transits of the planets they are looking for, ones with orbits similar to our own. Without the extra time, the data will be noisy, astronomers say, so the answer will be a little more uncertain than it might have been. Geoffrey Marcy, a Kepler astronomer at the University of California, Berkeley, said that without more data coming from Kepler, he thought astronomers would be “right on the edge” of answering the question of how common other Earths are, but with less statistical certainty than originally desired.

In January, engineers noticed that one of the reaction wheels that keep the spacecraft pointed was experiencing too much friction. They shut down the spacecraft for a couple of weeks to give it a rest, in the hope that the wheel’s lubricant would spread out and solve the problem. But when they turned it back on, the friction was still there. Until now, the problem had not interfered with observations, but on Tuesday, the spacecraft went into a so-called safe mode, and the engineers determined that the reaction wheel had stopped.

Kepler was launched with four reaction wheels, but one failed last year after showing signs of erratic friction. Three wheels are required to keep Kepler properly and precisely aimed, and now there are only two. The lack of three working wheels probably robs it of the ability to point precisely enough to detect Earth-size planets.

Project managers hope to remedy the situation by rocking the wheel back and forth, or perhaps resurrecting the wheel that failed last year, an effort that will probably take several months, according to Kepler’s deputy project manager, Charles Sobeck of the Ames Research Center. It would take that long as well to figure out what else the telescope, which is itself in fine condition, can be used for if it can no longer hunt planets.

Mr. Borucki said that the Kepler project had been a long journey — and a phenomenal success — and that he was not ready to pronounce it over. When Kepler was conceived, he said, nobody knew if any other stars had planets; now we know that almost every star in the galaxy has a planet and that the nearest exoplanet might be only 10 light-years away. “I’m delighted and surprised with what we have done,” he said.

For Mr. Grunsfeld, who played mechanic to the Hubble telescope during several lengthy spacewalks, the Kepler malfunction looked particularly frustrating. “Unfortunately, it’s not in a place where I can go and fix it,” he said.


Viewing all articles
Browse latest Browse all 9433

Trending Articles