The Proton (Прото́н) rocket (formal designation: UR-500, also known as D-1/ D-1e or SL-12/SL-13) is a Russian unmanned space vehicle design, first launched in 1965. It is still in use as of 2015 for both commercial and government launches. This makes it one of the most successful heavy boosters in the history of spaceflight. All Protons launch from Baikonur Cosmodrome in Kazakhstan.
The name "Proton" originates from a series of large scientific satellites, which were among the rocket's first payloads. The enormous capacity of the new rocket allowed the heavy materials used in particle detectors. Thus the Proton satellites were pioneers of high-energy astronomy. Like many Soviet boosters, the name of the recurring payloads became associated with their launchers.
Payloads can be fitted with either a Blok D or Briz-M upper stage. Launch capacity to low Earth orbit is about 22 tonnes (44,000 lbm). Interplanetary transfer capacity is about 5–6 tonnes (11,000–13,000 lbm).
An aviator with the U.S. Navy, Crippen was originally chosen to the U.S. Air Force's Manned Orbiting Laboratory program, a project involving a military space station, in 1966. When that project was canceled in 1969, Crippen was transferred to NASA. He was selected as pilot of the first Space Shuttle mission, STS-1, along with commander John Young, which he flew on April 12-14, 1981, on the orbiterColumbia.
Crippen would likewise become the first Shuttle pilot to be promoted to commander, leading the STS-7 mission on orbiter Challenger in June 1983. He would command two other missions (STS-41-C and STS-41-G) in 1984. He was training for another mission when the Challenger disaster occurred, and was re-assigned as Deputy Director of Kennedy Space Center in 1987.
Crippen would serve as the Director of Kennedy Space Center from January 1992 until January 1995, when he left NASA. He would hold executive positions at Lockheed Martin and Thiokol before retiring in 2001.
