12373 Lancearmstrong, provisional designation 1994 JE9, is an asteroid from the inner regions of the asteroid belt, approximately 5 kilometers in diameter. It was discovered on 15 May 1994, by American astronomer and software engineer Charles de Saint-Aignan after examining films taken at Palomar Observatory, California.
The asteroid orbits the Sun at a distance of 2.2–2.7 AU once every 3 years and 10 months (1,402 days). Its orbit has an eccentricity of 0.11 and an inclination of 7° with respect to the ecliptic. The body's observation arc begins in 1994, as no precoveries were taken prior to its discovery.
Based on an absolute magnitude of 14.2 and an assumed albedo of 0.20, which is typical for bodies with a silicaceous composition, Lancearmstrong measures between 4 and 6 kilometers in diameter. According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid measures 3.3 kilometers in diameter due to an unusually high albedo of 0.449. As of 2016, its composition, shape and rotation period and shape remains unknown.
The minor planet was named after American Lance Armstrong (b. 1971), former professional road racing cyclist. Despite being diagnosed with metastatic testicular cancer, he recovered and returned to cycling. At the time this minor planet was named, he had won the Tour de France three times and encouraged athletes and cancer survivors worldwide. Naming citation was published on 1 November 2001 (M.P.C. 43762). In 2012, Armstrong was stripped of his Tour de France victories after a doping scandal.