Quick Facts: Kepler

Mission Introduction

Kepler spacecraft

One goal of the Kepler mission was to estimate the number of planets that exist in multiple-star systems. (Courtesy NASA/Wendy Stenzel)

The centuries-old quest for other worlds like our Earth has been rejuvenated by the intense excitement and popular interest surrounding the discovery of hundreds of planets orbiting stars beyond our solar system.

Kepler was specifically designed to survey a portion of our region of the Milky Way galaxy to discover planets in or near the habitable zone of their stars and determine how many of the billions of stars in our galaxy have such planets. Results from this mission have allowed us to place our solar system within the continuum of planetary systems in the Galaxy.

There is now clear evidence for substantial numbers of three types of exoplanets; gas giants, hot-super-Earths in short period orbits, and ice giants. Through Kepler observations, astronomers were able to discover 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. The discovery of Kepler-186f confirmed that planets the size of Earth exist in the habitable zone of stars other than our Sun and we now know that billions of these planets exist.

Kepler has collected a treasure trove of data for science that will be mined for many years to come.

The scientific objective of the Kepler Mission was to explore the structure and diversity of planetary systems. This objective was achieved by surveying a large sample of stars to:

  1. Determine the abundance of terrestrial and larger planets in or near the habitable zone of a wide variety of stars
  2. Determine the distribution of sizes and shapes of the orbits of these planets
  3. Estimate how many planets there are in multiple-star systems
  4. Determine the variety of orbit sizes and planet reflectivities, sizes, masses and densities of short-period giant planets
  5. Identify additional members of each discovered planetary system using other techniques
  6. Determine the properties of those stars that harbor planetary systems

Kepler’s loss of a second spacecraft reaction wheel in May 2013 effectively ended data collection in the original Kepler field after 4 years of continuous monitoring. However, all other Kepler assets remained intact and were used with great results for the subsequent K2 mission. The K2 mission provided an opportunity to continue Kepler’s ground-breaking discoveries in the field of exoplanets and expanded its role into new and exciting astrophysical observations.

Both missions were founded on the proven value of long-baseline, high-cadence, high-precision photometry and exploited a large field of view to simultaneously monitor many targets. On two reaction wheels, K2 was limited to pointing near the ecliptic plane, sequentially observing fields as it orbited the Sun. This observing strategy regularly brought new, well-characterized target fields into view, enabling observations of scientifically important objects across a wide range of galactic latitudes in both the northern and southern skies. K2 performed a series of 19 long, ecliptic-pointed campaigns to collect data for the astrophysical community that aided their understanding of planet formation processes, young stars, stellar activity, stellar structure and evolution, and extragalactic science.

LASP Roles

LASP managed Mission Operations for Kepler and the K2 mission.

LASP Instruments

LASP did not provide any instruments for the Kepler mission.

For more information about the Kepler and K2 missions and mission operations at LASP, see:

Kepler Field of View

Kepler originally observed just one large area of the sky in the constellations Cygnus and Lyra. (Courtesy Carter Roberts)

Quick Facts

Launch date: March 6, 2009
Launch location: Kennedy Space Center, Cape Canaveral, Florida
Launch vehicle: Delta II
Mission target: Earth-trailing orbit
Mission duration: 9 1/2 years
Other key date: October 30, 2018 – Kepler/K2 End of Flight
Other organizations involved:

  • NASA Ames Research Center
  • NASA Jet Propulsion Laboratory
  • Ball Aerospace
  • SETI Institute
  • Lawrence Hall of Science
  • Smithsonian Astrophysical Observatory
  • Space Telescope Science Institute

KeplerClick on the image to view a PDF (672 KB) of Kepler FAQs.