Technical problem cripples the Kepler space telescope
DOI: 10.1063/PT.4.2463
By Steven T. Corneliussen
In April, journalists planetwide celebrated news from the Kepler space telescope. The New York Times‘s front page , for example, extolled discovery of ‘the most Earth-like worlds yet known in the outer cosmos, a pair of planets that appear capable of supporting life and that orbit a star 1,200 light-years from here.’ Now journalists planetwide are reporting, and lamenting, news that a technical problem is severely hobbling Kepler‘s capacity for further observations of exoplanets.
The problem lies in the positioning system of four reaction wheels that enable Kepler to point precisely. News reports can mainly only rehash statements from NASA, which says the following:
We will take the next several days and weeks to assess our options and develop new command products. These options are likely to include steps to attempt to recover wheel functionality and to investigate the utility of a hybrid mode, using both wheels and thrusters.
With the failure of a second reaction wheel, it’s unlikely that the spacecraft will be able to return to the high pointing accuracy that enables its high-precision photometry. However, no decision has been made to end data collection.
Kepler had successfully completed its primary three-and-a-half year mission and entered an extended mission phase in November 2012.
Even if data collection were to end, the mission has substantial quantities of data on the ground yet to be fully analyzed, and the string of scientific discoveries is expected to continue for years to come.
This excerpt from Reuters summarizes more of the basic story:
Launched in 2009, the Kepler space telescope revolutionized the study of so-called exoplanets, with discovery of 130 worlds orbiting distant stars and 2,700 potential planets still awaiting confirmation.
The telescope was designed to gaze at about 100,000 distant sun-like stars, searching for planets passing by, or transiting, relative to its line of sight. Detecting slight dips in the amount of light from a planet crossing the face of its parent star requires extremely precise pointing.
The telescope, the cornerstone of a $650 million mission, lost that ability on Tuesday when a second steadying spinning wheel stopped working.
The telescope needs at least three of its four wheels operating to hunt for planets. It lost use of its first wheel last year.
At the New York Times, Dennis Overbye’s report characterizes Kepler as ‘one of the most romantic and successful of NASA’s missions.’ Coverage of the loss has appeared all across the US and around the world, including at China’s Xinhua news agency , Qatar’s Al Jazeera , and the UK’s Guardian.
The Guardian ends its report by explicitly addressing reactions: ‘Scientists who have no role in Kepler mourned the news,’ the article says. It quotes Alan Boss of the Carnegie Institution of Washington: ‘This is one of the saddest days in my life.’
The Washington Post‘s article ends by quoting William Borucki, whom it calls ‘Kepler’s lead scientist and the driving force behind the telescope':
‘I don’t think I’d be a pessimist here,’ Borucki said. ‘The mission has been phenomenally successful, and I really wouldn’t write it off at this point.’
Asked at the end of the news conference how he felt about this latest turn of events, he sounded more emotional than before.
‘It’s been a very long journey. Coming up with an idea that basically very few people believed in,’ he said. ‘But right now, I’m really delighted with all it’s accomplished. It was designed to operate for four years. It operated for four years.... I’m just elated with what we’ve accomplished. I’m not feeling sorry at all.’
A quotation from John Grunsfeld, NASA’s associate administrator for space science, appears regularly in the coverage: ‘I wouldn’t call Kepler down and out yet.’ But Overbye reports, ‘As word leaked about the possible loss of Kepler, the mood in the astronomical community was grim.’
Overbye consulted Geoffrey Marcy, a Kepler astrophysicist at the University of California, Berkeley, who ‘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.’
Marcy ‘expressed his grief through poetry,’ the Los Angeles Times reported, by reworking the four verses of the British poet W. H. Auden’s ‘Funeral Blues.’ Here’s one of Marcy’s verses:
Kepler was my North, my South, my East and West, My working week, no weekend rest, My noon, my midnight, my talks, my song; I thought Kepler would last forever: I was wrong.
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Steven T. Corneliussen, a media analyst for the American Institute of Physics, monitors three national newspapers, the weeklies Nature and Science, and occasionally other publications. He has published op-eds in the Washington Post and other newspapers, has written for NASA’s history program, and is a science writer at a particle-accelerator laboratory.