NASA’s first planet hunting mission finally drew to a close on October 30, 2018. After spending nine years in deep space circling the Sun in an orbit somewhat wider and slower than the Earth’s and collecting data that indicated the existence of billions of undiscovered planets, the Kepler telescope has run out of the fuel it needs to execute further operations. The telescope was launched on March 6, 2009.
“As NASA’s first planet-hunting mission, Kepler has wildly exceeded all our expectations and paved the way for our exploration and search for life in the solar system and beyond,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington. “Not only did it show us how many planets could be out there, it sparked an entirely new and robust field of research that has taken the science community by storm. Its discoveries have shed a new light on our place in the universe, and illuminated the tantalizing mysteries and possibilities among the stars.”
The latest analysis of the data collected by Kepler indicated that the gravitational fields of 20 to 50 percent of the stars visible to humans could host small, rocky planets similar to Earth. Some of these planets could be located at just the right distance from their host stars to allow the presence of water in liquid form.
The most common planet size observed by the telescope does not exist in our solar system. This falls somewhere between the size of Earth and Neptune. Not much is currently known about these planets.
Kepler also found that nature often produces jam packed solar systems, with so many planets clustered so close to their host stars that our own solar system seems sparsely populated in comparison.
The Kepler space telescope used a number of cutting edge technologies to measure stellar brightness. It was outfitted with the largest ever digital camera outfitted for space observations at that time.
“The Kepler mission was based on a very innovative design. It was an extremely clever approach to doing this kind of science,” said Leslie Livesay, director for astronomy and physics at NASA’s Jet Propulsion Laboratory, who served as Kepler project manager during mission development.
New research spurred by the data collected by Kepler is currently furthering several areas of astronomy, including the history of the Milky Way and the initial stages of exploding stars (called supernovae) that are used to study the expansion rate of the universe.
Scientists were able to push the telescope to its full potential after initial warnings of low fuel, successfully completing multiple observation campaigns and downloading valuable data.
“When we started conceiving this mission 35 years ago we didn’t know of a single planet outside our solar system,” said the Kepler mission’s founding principal investigator, William Borucki, now retired from NASA’s Ames Research Center in California’s Silicon Valley. “Now that we know planets are everywhere, Kepler has set us on a new course that’s full of promise for future generations to explore our galaxy.”