Down but not out

The Kepler space telescope is fighting for its second life,  but NASA’s Steve Howell is confident it has a bright future almost all of them. As for exoplanets, K2 won’t be able to do a long-term survey, but we will search for planets orbiting nearby red dwarf stars or stars bright enough to be visible to the naked eye. We hope to begin finding planets that are suitable for detailed follow-up studies with large groundbased telescopes. How can you aim the telescope with only  two of its reaction wheels still functioning? PROFILE Steve Howell is an astrophysicist at the NASA Ames Research Center in Moffett Field, California, and the project scientist for the Kepler mission, launched five years ago this week. The proposed K2 mission could revive the crippled telescope What is happening with the Kepler telescope? After four years of successful operation, Kepler lost the second of its four reaction wheels in May 2013. It can’t be accurately pointed at the original field of view any more, so it hasn’t been collecting any new data. But we still have huge amounts  of data to analyse – enough for another two or three years of discoveries. In fact, colleagues just announced they had found 715 exoplanets. But you are still working on a K2 mission that will have Kepler collecting data once more. Last summer, we asked the global astronomical community to suggest ways to use the crippled telescope to do valuable research. We received 42 proposals on extrasolar planets, galaxies, solar system science – everything you can name. Based on those proposals and the spacecraft’s abilities, we designed the K2 mission concept. Would K2 cover all those things? Obviously we won’t be able to do everything that was suggested, but K2 will be able to accomplish We won’t regain the original pointing accuracy, but by reorientating Kepler in such a way that the minute pressure of sunlight is distributed evenly over the spacecraft, we can get pretty close. As deputy project manager Charlie Sobeck says, it’s a bit like stabilising a kayak upstream in a river.  In a sense, we’re using the pressure of sunlight as a third reaction wheel. To achieve this, Kepler has to be oriented more or less tangentially to  its orbit, pointing to the plane which contains the 12 constellations of the zodiac and in which the planets orbit the sun. We know that this method works because the telescope recently spotted  a known transiting exoplanet, WASP-28b. What new possibilities does pointing the telescope in this way offer? Some of the time the spacecraft will look away from our own Milky Way, which means we will  be able to observe many more distant galaxies. Also, observing in the ecliptic will vastly increase the number of rocky asteroids and icy Kuiper Belt objects that can be studied. It’s still up in the air whether Kepler will  be kept alive for the K2 mission. Are you confident that NASA will give the green light? A decision on funding the mission will be made between mid-May and early June. K2 will have to compete with other NASA astrophysical missions, but we think our chances are very high. This  has been such an incredibly successful mission, wand K2 is an extraordinary way to build on Kepler’s legacy. I’d give it a 150 per cent chance.