STS Credit: NASA

The manned reusable space system which was designed to slash the cost of space transport and replace all expendable launch vehicles. It did neither, but did keep NASA in the manned space flight business for 30 years (and counting...) Redesign of the shuttle with reliability in mind after the Challenger disaster reduced maximum payload to low earth orbit from 27,850 kg to 24,400 kg. Launches: 113. Failures: 1. Success Rate: 99.12% pct. First Launch Date: 12 April 1981. Last Launch Date: 16 January 2003. Launch data is: continuing. LEO Payload: 24,400 kg. to: 204 km Orbit. at: 28.5 degrees. Payload: 12,500 kg. to a: space station orbit, 407 km, 51.6 deg inclination trajectory. Apogee: 600 km. Liftoff Thrust: 2,625,932 kgf. Liftoff Thrust: 25,751.60 kN. Total Mass: 2,029,633 kg. Core Diameter: 8.70 m. Total Length: 56.00 m. Development Cost $: 10,100.00 million. in 1977 average dollars. Launch Price $: 245.00 million. in 1988 price dollars. Total Production Built: 5. Flyaway Unit Cost $: 63.00 million. in 1988 unit dollars. Cost comments: Shuttle has high fixed costs and low marginal costs. Cost per mission dependent on rate. Flyaway cost is marginal cost for extra mission. Launch cost is cost per flight at 6 per year.

• Stage Number: 0. 2 x Shuttle SRB Gross Mass: 589,670 kg. Empty Mass: 86,183 kg. Thrust (vac): 1,174,713 kgf. Isp: 269 sec. Burn time: 124 sec. Isp(sl): 237 sec. Diameter: 3.71 m. Span: 5.10 m. Length: 38.47 m. Propellants: Solid No Engines: 1. SRB Other designations: Solid Rocket Booster. Status: Hardware.

• Stage Number: 1. 1 x Shuttle Tank Gross Mass: 750,975 kg. Empty Mass: 29,930 kg. Thrust (vac): 0.000 kgf. Isp: 455 sec. Burn time: 480 sec. Isp(sl): 363 sec. Diameter: 8.70 m. Span: 8.70 m. Length: 46.88 m. Propellants: Lox/LH2 No Engines: 0. None Other designations: External Tank. Status: Hardware.

• Stage Number: 2. 1 x Shuttle Orbiter Gross Mass: 99,318 kg. Empty Mass: 99,117 kg. Thrust (vac): 696,905 kgf. Isp: 455 sec. Burn time: 480 sec. Isp(sl): 363 sec. Diameter: 4.90 m. Span: 23.79 m. Length: 37.24 m. Propellants: Lox/LH2 No Engines: 3. SSME Other designations: Shuttle; STS (Space Transportation System). Status: Hardware.

Two major directions were identified for manned space flight in the next decade. These were further exploration of the Moon, with possibly the establishment of a lunar surface base, and the continued development of manned flight in Earth orbit, leading to a permanent manned space station supported by a low-cost shuttle system. To maintain direction, the following key milestones were proposed: 1972 - AAP operations using a Saturn V launched Workshop 1973 - Start of post-Apollo lunar exploration 1974 - Start of suborbital flight tests of Earth to orbit shuttle - Launch of a second Saturn V Workshop 1975 - Initial space station operations - Orbital shuttle flights 1976 - Lunar orbit station - Full shuttle operations 1977 - Nuclear stage flight test 1978 - Nuclear shuttle operations-orbit to orbit 1979 - Space station in synchronous orbit By 1990 - Earth orbit space base - Lunar surface base - Possible Mars landing

The countdown for Columbia's launch was halted by on-board computers at T-3 seconds following a problem with purge pressure readings in the oxidizer preburner on main engine #2 Columbia's three main engines were replaced on the launch pad, and the flight was rescheduled behind Discovery's launch on STS-56. Columbia finally launched on April 26, 1993.

The countdown for Discovery's third launch attempt ended at the T-3 second mark when on-board computers detected the failure of one of four sensors in main engine #2 which monitor the flow of hydrogen fuel to the engine. All of Discovery's main engines were ordered replaced on the launch pad, delaying the Shuttle's fourth launch attempt until September 12, 1993.

The countdown for Endeavour's first launch attempt ended 1.9 seconds before liftoff when on-board computers detected higher than acceptable readings in one channel of a sensor monitoring the discharge temperature of the high pressure oxidizer turbopump in main engine #3. A test firing of the engine at the Stennis Space Center in Mississippi on September 2nd confirmed that a slight drift in a fuel flow meter in the engine caused a slight increase in the turbopump's temperature. The test firing also confirmed a slightly slower start for main engine #3 during the pad abort, which could have contributed to the higher temperatures. After Endeavour was brought back to the Vehicle Assembly Building to be outfitted with three replacement engines, NASA managers set October 2nd as the date for Endeavour's second launch attempt.

• McDowell, Jonathan, Jonathan's Space Home Page, Harvard University, 1997-present. Web Address when accessed: http://hea-www.harvard.edu/~jcm/space/space.html.
• Isakowitz, Steven J,, International Reference to Space Launch Systems Second Edition, AIAA, Washington DC, 1991.
• Jenkins, Dennis R,, Space Shuttle: The History of Developing the National Space Transportation System, Motorbooks International, ISBN 0-9633974-4-3, 1996.
• Isakowitz, Steven J, Hopkins, Joshua B, and Hopkins, Joseph P, International Reference to Space Launch Systems Third Edition, AIAA, Washington DC, 2000.