K2 mission gives Kepler space telescope a second chance to shine
In May 2013, the prognosis looked grim for NASA’s Kepler space telescope. The loss of a reaction wheel had deprived the planet-hunting spacecraft of its ability to stay pointed at a target without drifting off course. Over the course of that summer, engineers at Ball Aerospace devised a strategy to keep the space telescope stable using the pressure of sunlight. In late August 2013, a small group of the engineers waited nervously for telemetry data to confirm that the technique could work.
“You’re not watching it unfold in real time,” said Dustin Putnam, Ball’s attitude control lead for Kepler. “You’re watching it as it unfolded a few minutes ago, because of the time the data takes to get back from the spacecraft.”
The room broke out in cheers when the team received confirmation that the fix had worked. Kepler had been granted a new lease on life and a new role known as the K2 mission. Since that time, the space telescope has made hundreds of more discoveries and helped to usher in new opportunities for astrophysics research.
“Many of us believed that the spacecraft would be saved, but this was perhaps more blind faith than insight,” said Tom Barclay, senior research scientist and director of the Kepler and K2 guest observer office at NASA’s Ames Research Center in California’s Silicon Valley. “The Ball team devised an ingenious solution allowing the Kepler space telescope to shine again.”
Just over two years after the new stabilization technique was first tested, K2 has made a wide variety of discoveries. Continuing Kepler’s original planet-hunting mission, K2 has discovered over three dozen new confirmed exoplanets and more than 250 candidates that are awaiting confirmation. A few of these new worlds are near-Earth-sized and orbit stars that are bright and relatively nearby, which allows scientists to perform follow-up studies. These exoplanets are possible targets for future observations by the Hubble Space Telescope and its successor, the forthcoming James Webb Space Telescope (JWST), to study their atmospheres in search of signs that might indicate life.
K2’s unexpected discovery of a star with a close-in Jupiter-sized planet sandwiched between two smaller companion planets has scientists rethinking long-held theories of planetary formation and the commonly understood lonely “hot Jupiter” paradigm. Theorists are now re-working their computer models and astronomers are searching the skies for more hot Jupiter companions.
K2 has also discovered the rubble of a destroyed exoplanet orbiting a dead star known as a white dwarf. Exoplanets had long been thought to orbit these remnant stars, but not until K2 had the theory been confirmed.
Campaign 9, K2’s next observational period, will begin in April 2016. In this campaign, K2 and astronomers at ground-based observatories on five continents will simultaneously observe a region of the sky toward the center of the galaxy in search of small planets, such as the size of Earth, orbiting very far from their host star, or in some cases orbiting no star at all. For this experiment, researchers will use a phenomenon called gravitational microlensing. Microlensing occurs when the gravity of a foreground object, such as a planet, focuses and magnifies the light from a distant background star. This detection method should allow scientists to find and determine the mass of planets that orbit their stars at great distances.
Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.
Fascinating science, fantastic engineering and a first rate report!
Thanks to all who made this possible!
I have a question: why are reaction wheels so hard? Is it that we use them beyond their design life or that load-bearing bearings are difficult in space or something else?