• launched
• numerous satellites,
• interplanetary probes, and
• the Hubble Space Telescope (HST);
• conducted science experiments in orbit; and
• participated in construction and servicing of the International Space Station.

The Shuttle fleet's total mission time was 1,322 days, 19 hours, 21 minutes and 23 seconds.

Shuttle components included the

• Orbiter Vehicle (OV) with three clustered Rocketdyne RS-25 main engines,
• a pair of recoverable solid rocket boosters (SRBs), and
• the expendable external tank (ET) containing liquid hydrogen and liquid oxygen.

The Space Shuttle was launched vertically, like a conventional rocket, with the two SRBs operating in parallel with the OV's three main engines, which were fueled from the ET. The SRBs were jettisoned before the vehicle reached orbit, and the ET was jettisoned just before orbit insertion, which used the orbiter's two Orbital Maneuvering System (OMS) engines. At the conclusion of the mission, the orbiter fired its OMS to de-orbit and re-enter the atmosphere. The orbiter then glided as a spaceplane to a runway landing, usually to the Shuttle Landing Facility at Kennedy Space Center, Florida or Rogers Dry Lake in Edwards Air Force Base, California. After landing at Edwards, the orbiter was flown back to the KSC on the Shuttle Carrier Aircraft, a specially modified version of the Boeing 747.

The first orbiter, Enterprise, was built in 1976, used in Approach and Landing Tests and had no orbital capability. Four fully operational orbiters were initially built:

1. Columbia,
2. Challenger,
3. Discovery, and
4. Atlantis.

Of these, two were lost in mission accidents:

• Challenger in 1986 and
• Columbia in 2003,

with a total of fourteen astronauts killed. A fifth operational (and sixth in total) orbiter, Endeavour, was built in 1991 to replace Challenger. The Space Shuttle was retired from service upon the conclusion of Atlantis's final flight on July 21, 2011. The U.S. has since relied primarily on the Russian Soyuz spacecraft to transport supplies and astronauts to the International Space Station.

* Note 1 - In this year, Approach and Landing Tests (ALT) were accomplished. These were atmospheric only, non-spaceflight drop-tests from a Boeing 747 Shuttle Carrier Aircraft.
** Note 2 - The durations listed count only the orbiter free-flight time, and not total time aloft along with airborne time atop of the 747 SCA.