Kepler's Second Light: How K2 Will Work
The conception illustration depicts how solar pressure can be used
to balance NASA's Kepler spacecraft, keeping the telescope stable enough to
continue monitoring distant stars in search of transiting planets.
In May, Kepler lost the second of four gyroscope-like reaction
wheels, ending new data collection for the original mission. A new mission
concept, dubbed K2, would continue Kepler's search for other worlds, and
introduce new opportunities to observe star clusters, young and old stars,
active galaxies and supernovae.
Using the sun and the two remaining reaction wheels, engineers have
devised an innovative technique to stabilize and control the spacecraft in all
three directions of motion. This technique of using the sun as the 'third wheel'
to control pointing is currently being tested on the spacecraft.
To achieve the necessary stability, the orientation of the
spacecraft must be nearly parallel to its orbital path around the sun, which is
slightly offset from the ecliptic, the orbital plane of Earth. The ecliptic
plane defines the band of sky in which lie the constellations of the zodiac.
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 K2 mission concept has been presented to NASA Headquarters. A
decision to proceed to the 2014 Senior Review – a biannual assessment of
operating missions – and propose for budget to fly K2 is expected by the end of
2013.
Image credit: NASA Ames/W
Stenzel
NASA
Guillermo Gonzalo Sánchez Achutegui
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