R. Asa Gordon is a retired NASA astrodynamicist, civil rights activist, and research historian whose career spans the Apollo era, the personal computer revolution, and decades of work preserving African American history.
Gordon studied at Hampton Institute (now Hampton University) in Virginia, coming of age during the Jim Crow era when many universities in the South were closed to him by law. He found his way to computing through physics, teaching himself FORTRAN on punch cards at Howard University before joining NASA’s Goddard Space Flight Center in Greenbelt, Maryland, where he would spend 25 years.
At Goddard he worked in orbital analysis and prediction, developing the mathematical tools used to track satellites and plan mission operations. During the Apollo program he computed the precise moment of radio signal acquisition and loss for Apollo 8 as it rounded the Moon on Christmas Eve 1968, calculating the geometry by hand with styrofoam spheres and a flashlight before writing the code. He served two terms as president of the Goddard Engineers, Scientists and Technicians Association, and his research was employed by private industry domestically and abroad for satellite tracking applications.
In 1986 Gordon developed a semi-analytical orbit theory, the “Bg theory”, compact enough to run on the Timex/Sinclair 2068 home computer in 8K of BASIC. The theory models the effects of Earth’s non-spherical gravity and atmospheric drag on satellite orbits, producing predictions comparable in accuracy to what mainframe computers of the era were generating. It was deployed operationally at NASA tracking stations before the formal paper was even published. NASA Technical Paper 2811, “An Economical Semi-Analytical Orbit Theory for Micro-Computer Applications,” appeared in March 1988. The TS2068 BASIC programs from that paper — BgORBIT, BgOBSMEAN, and BgDCseculr — are preserved and available on this site.
After retiring from NASA, Gordon became a prominent advocate for voting rights and electoral reform. He founded the Douglass Institute of Government, a Washington D.C.-based educational think tank, and serves as secretary-general of the Sons and Daughters of the United States Colored Troops, an organization chartered by the African American Civil War Memorial Freedom Foundation to honor those who served in the USCT. He is also a research historian and consulting curator of the African American Civil War Memorial Museum in Washington D.C.
Gordon attended a Timex/Sinclair Online User Group meeting in August 2025, sharing the story of his career and the physics behind his orbit theory.
