DON'T expect to get promoted while your there...you will be a terminal O-5, O-6 ect. I'm sure the ride in space will be some small consolation...but most people retire at 20+ years and enjoy the increase in pay+military retirement as a GS astronaut.
While it's not likely if not impossible to make admiral/general in the Astronaut Corps, I can attest that many of my friends and acquaintances did get promoted while there so I don't think you can say NASA is a career ender for everyone who gets selected like this fine gent in particular:
Major General
Charles F. Bolden Jr.
Major General Charles F. Bolden, Jrs'., last billet before retirement was as the Commanding General, 3d Marine Aircraft Wing. He assumed this assignment on August 9, 2000.
Born in Columbia, S.C., Major General Bolden received a Bachelor of Science degree from the U.S. Naval Academy in 1968 and later earned a Master of Science degree in systems management from the University of Southern California in 1977.
Accepting a commission as a second lieutenant in the U.S. Marine Corps following graduation from the Naval Academy, he underwent flight training at Pensacola, Fla., Meridian, Miss., and Kingsville, Texas, before being designated a naval aviator in May 1970. Between June 1972 and June 1973 he flew more than 100 combat missions into North and South Vietnam, Laos and Cambodia in the A-6A Intruder while assigned to VMA (AW)-533 at Nam Phong, Thailand.
Upon returning to the United States, Major General Bolden began a two-year tour as a Marine Corps Officer Selection and Recruiting Officer in Los Angeles, Calif., followed by three years in various assignments at the Marine Corps Air Station, El Toro, Calif. In June 1979, he graduated from the U.S. Naval Test Pilot School at Patuxent River, Md., and was assigned to the Naval Air Test Center's Systems Engineering and Strike Aircraft Test Directorates. While there, he served as an ordnance test pilot and flew numerous test projects in the A-6E, EA-6B and A-7C/E aircraft. Throughout his career Major General Bolden has logged more than 6,000 hours of flying time in more than thirty models of fixed and rotary wing aircraft.
Selected as an astronaut candidate by NASA in 1980, Major General Bolden qualified as a space shuttle pilot astronaut in 1981 and subsequently flew four missions in space. During his first mission on board the Space Shuttle Columbia in 1986, he participated in the successful deployment of the SATCOM KU satellite and conducted experiments in astrophysics and materials processing.
As pilot of the Space Shuttle Discovery in 1990, Major General Bolden and crew successfully deployed the Hubble Space Telescope while orbiting the earth from a record setting altitude of 400 miles. Additionally, they also conducted extensive scientific experimentation and employed a variety of cameras, including both the IMAX in-cabin and cargo bay cameras for Earth observations.
On his third mission in 1992, he commanded the Space Shuttle Atlantis on the first Space Laboratory (SPACELAB) mission dedicated to NASA's "Mission to Planet Earth." During this nine-day mission, the crew operated the ATLAS-1 (Atmospheric Laboratory for Applications and Science), a system composed of twelve experiments which succeeded in making a vast amount of detailed measurements of the Earth's atmospheric chemical and physical properties. Immediately following this mission, Major General Bolden was appointed Assistant Deputy Administrator for the National Aeronautics and Space Administration.
He held this Washington, D.C. post until assigned as commander of STS-60, the 1994 flight of a six member crew on the Space Shuttle Discovery. This landmark eight day mission was the first joint U.S./Russian Space Shuttle mission, involving the participation of a Russian Cosmonaut as a mission specialist. The crew conducted a series of joint U.S./Russian science activities and carried the Space Habitation Module-2 and the Wake Shield Facility-01 into space. Upon completion of this fourth mission, Major General Bolden left the space program having logged more than 680 hours in space.
In 1995, after successfully completing a one year tour as the Deputy Commandant of the U.S. Naval Academy in Annapolis, Md., Major General Bolden served as the Assistant Wing Commander, 3rd Marine Aircraft Wing in Miramar, Calif. In July of 1997, he was assigned as the Deputy Commanding General, I MEF, Marine Forces, Pacific. From February to June 1998, he served as Commanding General, I MEF (FWD) in support of Operation Desert Thunder in Kuwait. In July 1998 he was promoted to his current rank and assumed his previous duties as the Deputy Commander, U.S. Forces, Japan.
Major General Bolden has been awarded a number of military and NASA decorations and has received Honorary Doctorates from several distinguished universities.