Michael Cooney
Senior Editor

NASA’s broken planet-hunter spacecraft given second life

Opinion
May 16, 20144 mins

NASA will pay for Kepler space telescope fix

NASA today said it would fund the technology fixes required to make its inoperative Kepler space telescope active again and able to hunt for new planets and galaxies.

Kepler you may recall was rendered inoperable after the second of four gyroscope-like reaction wheels, which are used to precisely point the spacecraft for extended periods of time, failed last year ending data collection for the original mission. The spacecraft required three working wheels to maintain the precision pointing necessary to detect the signal of small Earth-sized exoplanets, which are planets outside our solar system, orbiting stars like our sun in what’s known as the habitable zone — the range of distances from a star where the surface temperature of a planet might be suitable for liquid water, NASA stated.

With the failure of a second reaction wheel, the spacecraft could no longer precisely point at the mission’s original field of view where it would look for these exoplanets.

According to a post on the agency’s website, based on a recommendation from the agency’s 2014 Senior Review of its operating missions, NASA will for two years fund what’s known as Kepler Second Light or K2, which is basically a work-around that will let Kepler once again point  into space and gather data.

Last Fall, NASA Kepler and Ball Aerospace engineers say they have developed a way of recovering this  pointing stability by maneuvering the spacecraft so that  solar pressure – the pressure exerted when the photons of sunlight strike the spacecraft — is evenly distributed across the surfaces of the spacecraft.

NASA says by orienting the spacecraft nearly parallel to its orbital path around the sun, which is slightly offset from the ecliptic, the orbital plane of Earth, it can achieve spacecraft stability. The ecliptic plane defines the band of sky in which lie the constellations of the zodiac.

This technique of using the sun as the ‘third wheel’ to control pointing is currently being tested on the spacecraft and early results look good, NASA said.  During a pointing performance test in late October, a full frame image of the space telescope’s full field of view was captured showing part of the Sagittarius constellation.

K2 would study a specific portion of the sky for up to 83 days, until it is necessary to rotate the spacecraft to prevent sunlight from entering the telescope. Each orbit or year would consist of approximately 4.5 unique viewing periods or campaigns.  The first K2 science observation run, scheduled to begin May 30.

While it currently isn’t sending data, NASA scientists are still evaluating data sent by Kepler when it was fully operational.  In April in fact, NASA  said Kepler Space Telescope had  spotted what the agency called the first Earth-size planet orbiting a star in the “habitable zone” — the range of distance from a star where liquid water might pool on the surface of an orbiting planet.

NASA said that the  discovery of what will be called Kepler-186f confirms that planets the size of Earth exist in the habitable zone of stars other than our sun. While planets have previously been found in the habitable zone, they are all at least 40% larger in size than Earth and understanding their makeup is challenging. Kepler-186f is more reminiscent of Earth.  Although the size of Kepler-186f is known, its mass and composition are not. Previous research, however, suggests that a planet the size of Kepler-186f is likely to be rocky, NASA said.

Check out these other hot stories: