Donald J. Kessler

Donald J. Kessler is an American astrophysicist and former NASA scientist known for his studies regarding space debris.

Kessler worked at the Johnson Space Center in Houston, Texas, as part of NASA's Environmental Effects Project Office. While there, he developed what is now known as the Kessler syndrome, which posits that collisions between space debris become increasingly likely as the density of space debris increases in orbit around the earth, and a cascade effect results as each collision in turn creates more debris that can cause further collisions. Kessler first published his ideas in 1978, in an academic paper titled "Collision Frequency of Artificial Satellites: The Creation of a Debris Belt." The paper established Kessler's reputation, and NASA subsequently made him the head of the newly created Orbital Debris Program Office to study the issue and issue guidelines to slow the accumulation of space debris.

Kessler retired from NASA in 1996, and lives in Asheville, North Carolina. He continues to be active in the field of orbital debris. In 2009, he gave an address to the first International Conference on Orbital Debris Removal in Arlington, Virginia, co-sponsored by NASA and DARPA. In 2011, he was a key adviser in the making of the educational IMAX film Space Junk 3D and also served has chairman of a United States National Research Council committee to assess NASA's orbital debris programs. In 2013, he gave a special lecture in Tokyo to the Second International Symposium on Sustainable Space Development and Utilization for Humankind, sponsored by the Japan Space Forum.

Kessler has received numerous awards for his pioneering work, the most recent being the 2010 Dirk Brower Award for his half-century career in astrodynamics.