In October 1977, Chester Lee, director of Space Transportation System (STS) Operations at NASA Headquarters, distributed the first edition of the STS Flight Assignment Baseline, a launch schedule and payload manifest for the first 16 operational Shuttle missions. The document was in keeping with NASA's stated philosophy that reusable Shuttle Orbiters would fly on-time and often, like a fleet of cargo airplanes. The STS Utilization and Operations Office at NASA's Johnson Space Center (JSC) in Houston had prepared the document, which was meant to be revised quarterly as new customers chose the Space Shuttle as their cheap and reliable ride to space.
The JSC planners assumed that six Orbital Flight Test (OFT) missions would precede the first operational Shuttle flight. The OFT flights would see two-man crews (Commander and Pilot) put Orbiter Vehicle (OV)-102 through its paces in low-Earth orbit. The planners did not include the OFT schedule in their document, but the 30 May 1980 launch date for their first operational Shuttle mission suggests that they based their flight schedule on the March 1979 first OFT launch date.
|Image credit: NASA|
|Image credit: NASA|
As for OV-101, its name was changed from Constitution to Enterprise in mid-1976 at the insistence of Star Trek fans. Enterprise flew in Approach and Landing Test (ALT) flights at Edwards Air Force Base in California beginning on 15 February 1977. ALT flights, which saw the Orbiter carried by and dropped from a modified 747, ended soon after the NASA JSC planners released their document.
The first operational Space Shuttle mission, Flight 7 (30 May-3 June 1980), would see Columbia climb to a 225-nautical-mile (n-mi) orbit inclined 28.5° relative to Earth's equator (unless otherwise stated, all orbits are inclined at 28.5°, the latitude of Kennedy Space Center in Florida). The delta-winged Orbiter would carry a three-person crew in its two-deck crew compartment and the bus-sized Long Duration Exposure Facility (LDEF) in its 15-foot-wide, 60-foot-long payload bay.
Columbia would also carry a "payload of opportunity" - that is, an unspecified payload. The presence of a payload of opportunity meant that the flight had available excess payload weight capacity. Payload mass up would total 27,925 pounds. Payload mass down after the Remote Manipulator System (RMS) arm hoisted LDEF out of Columbia's payload bay and released it into orbit would total 9080 pounds.
|A page from the STS Flight Assignment Baseline document of October 1977 shows payloads and other features of the first five operational Space Shuttle missions plus Flight 12/Flight 12 Alternate. Image: NASA|
Prior to release, the crew would spin the SBS-A satellite about its long axis on a turntable to create gyroscopic stability and raise TDRS-A on a tilt-table. After release, their respective solid-propellant stages would propel them to their assigned slots in geostationary orbit (GEO), 19,323 n mi above the equator. Payload mass up would total 51,243 pounds; mass down, 8912 pounds, most of which would comprise reusable restraint and deployment hardware for the satellites.
The TDRS system, which would include three operational satellites and an orbiting spare, was meant to trim costs and improve communications coverage by replacing most of the ground-based Manned Space Flight Network (MSFN). Previous U.S. piloted missions had relied on MSFN ground stations to relay communications to and from the Mission Control Center (MCC) in Houston. Because spacecraft in low-Earth orbit could remain in range of a given ground station for only a few minutes at a time, astronauts were frequently out of contact with the MCC.
On Flight 9 (1-6 August 1980), Columbia would climb to a 160-n-mi orbit. Three astronauts would deploy GOES-D, a National Oceanic and Atmospheric Administration (NOAA) weather satellite, and Anik-C/1, a Canadian communications satellite. Before release, the crew would raise the NOAA satellite and its SSUS-Atlas-class (SSUS-A) rocket stage on the tilt-table and spin up the Anik-C/1-SSUS-D combination on the turntable. In addition to the two named satellites, NASA JSC planners reckoned that Columbia could carry a 14,000-pound payload of opportunity. Payload mass up would total 36,017 pounds; mass down, 21,116 pounds.
Following Flight 9, NASA would withdraw Columbia from service for 12 weeks to permit conversion from OFT configuration to operational configuration. The JSC planners explained that the conversion would be deferred until after Flight 9 to ensure an on-time first operational flight and to save time by combining it with Columbia's preparations for the first Spacelab mission on Flight 11. The switch from OFT to operational configuration would entail removal of Development Flight Instrumentation (sensors for monitoring Orbiter systems and performance); replacement of Commander and Pilot ejection seats on the crew compartment upper deck (the flight deck) with fixed seats; power system upgrades; and installation of an airlock on the crew compartment lower deck (the mid-deck).
Flight 10 (14-16 November 1980) would be a near-copy of Flight 8. A three-person Columbia crew would deploy TDRS-B/IUS and SBS-B/SSUS-D into a 160-n-mi-high orbit. The rocket stages would then boost the satellites to GEO. Cargo mass up would total 53,744 pounds; mass down, 11,443 pounds.
Flight 11 (18-25 December 1980) would see the orbital debut of Spacelab. Columbia would orbit Earth 160 n mi high at 57° of inclination. NASA and the multinational European Space Research Organization (ESRO) agreed in August 1973 that Europe should develop and manufacture Spacelab pressurized modules and unpressurized pallets for use in the Space Shuttle Program. Initially dubbed the "sortie lab," Spacelab would operate only in the Orbiter's payload bay; it was not intended as an independent space station, though many hoped that it would help to demonstrate that an Earth-orbiting station could be useful.
ESRO merged with the European Launcher Development Organization in 1975 to form the European Space Agency (ESA). Columbia's five-person crew for Flight 11 would probably include scientists and at least one astronaut from an ESA member country.
Flight 12 (30 January-1 February 1981), a near-copy of Flights 8 and 10, would see Columbia's three-person crew deploy TDRS-C/IUS and Anik-C/2/SSUS-D into 160-n-mi-high orbit. Payload mass up would total 53,744 pounds; mass down, 11,443 pounds.
JSC planners inserted an optional "Flight 12 Alternate" (30 January-4 February 1981) into their schedule which, if flown, would replace Flight 12. Columbia would orbit 160 n mi above the Earth. Its three-person crew would deploy Anik-C/2 on a SSUS-D stage. The mission's main purpose, however, would be to create a backup launch opportunity for an Intelsat V-class satellite already scheduled for launch on a U.S. Atlas-Centaur or European Ariane I rocket. An SSUS-A stage would boost the Intelsat V from Shuttle orbit to GEO.
NASA JSC assumed that, besides the satellites, stages, and their support hardware, Columbia would for Flight 12 Alternate tote an attached payload of opportunity that would need to operate in space for five days to provide useful data (hence the mission's planned duration). Payload mass up would total 37,067 pounds; mass down, 17,347 pounds.
|Space Shuttle Flights 13 through 18 would include the first orbital mission of the OV-101 Enterprise (Flight 17), during which astronauts would retrieve the LDEF payload deployed during Flight 7. Image credit: NASA|
Flight 14 would last 12 days, making it the longest described in the STS Flight Assignment Baseline document. Scheduled for launch on 7 April 1981, it would carry a "train" of four unpressurized Spacelab experiment pallets and an "Igloo," a small pressurized compartment for pallet support equipment. The Igloo, though pressurized, would not be accessible to the five-person crew. OV-102 would orbit 225 n mi high at an inclination of 57°. Mass up would total 31,833 pounds; mass down, 28,450 pounds.
Flight 15 (13-15 May 1981) would be a near-copy of Flights 8, 10, and 12. OV-102 would transport to orbit a payload totaling 53,744 pounds; payload mass down would total 11,443 pounds. The JSC planners noted the possibility that none of the potential payloads for Flight 15 – TDRS-D and SBS-C or Anik-C/3 – would need to be launched as early as May 1981. TDRS-D was meant as an orbiting spare; if the first three TDRS operated as planned, its launch could be postponed. Likewise, SBS-C and Anik-C/3 were each a backup for the previously launched satellites in their series.
Flight 16 (16-23 June 1981) would be a five-person Spacelab pressurized module flight aboard OV-102 in 160-n-mi-high orbit. Payloads of opportunity totaling about 18,000 pounds might accompany the Spacelab module; for planning purposes, a satellite and SSUS-D on a turntable behind the module was assumed. Payload mass up would total 35,676 pounds; mass down, 27,995 pounds.
Flight 17, scheduled for 16-20 July 1981, would see the space debut of Enterprise and the retrieval of the LDEF released during Flight 7. OV-101 would climb to a roughly 200-n-mi-high orbit (LDEF's altitude after 13.5 months of orbital decay would determine the mission's precise altitude).
Before rendezvous with LDEF, Flight 17's three-man crew would release an Intelsat V/SSUS-A and a satellite payload of opportunity. After the satellites were sent on their way, the astronauts would pilot Enterprise to a rendezvous with LDEF, snare it with the RMS, and secure it in the payload bay. Mass up would total 26,564 pounds; mass down, 26,369 pounds.
For Flight 18 (29 July-5 August 1981), Columbia would carry to a 160-n-mi-high orbit a Spacelab pallet dedicated to materials processing in the vacuum and microgravity of space. The three-person flight might also include the first acknowledged Department of Defense (DOD) payload of the Space Shuttle Program, a U.S. Air Force pallet designated STP-P80-1. JSC called the payload "Planned" rather than "Firm" and noted somewhat cryptically that it was the Teal Ruby experiment "accommodated from OFT [Orbital Flight Test]." The presence of the Earth-directed Teal Ruby sensor payload would account for Flight 18's planned 57° orbital inclination, which would take it over most of Earth's densely populated areas. Payload mass up might total 32,548 pounds; mass down, 23,827 pounds.
Flight 20 (30 September-6 October 1981), the second Enterprise mission, would see five astronauts conduct life science and astronomy experiments in a 216-n-mi-high orbit using a Spacelab pressurized module and an unpressurized pallet. JSC planners acknowledged that the mission's down payload mass (34,248 pounds) might be "excessive," but noted that their estimate was "based on preliminary payload data." Mass up would total 37,065 pounds.
On Flight 21, scheduled for launch on 14 October 1981, Columbia would carry the first Orbital Maneuvering System (OMS) Kit at the aft end of its payload bay. The OMS Kit would carry enough supplemental propellants for the Orbiter's twin rear-mounted OMS engines to perform a velocity change of 500 feet per second. This would enable OV-102 to rendezvous with and retrieve the Solar Maximum Mission (SMM) satellite in a 300-n-mi-high orbit.
Three astronauts would fly the five-day mission, which would attain the highest orbital altitude of any flight in the STS Flight Assignment Baseline document. JSC planners noted that the Multi Mission Modular Spacecraft (MMS) support hardware meant to carry SMM back to Earth could also transport an MMS-type satellite into orbit. Payload mass up would total 37,145 pounds; mass down, 23,433 pounds.
On Flight 22 (25 November-2 December 1981), Enterprise might carry an ESA-sponsored Spacelab mission with a five-person crew, a pressurized lab module, and a pallet to a 155-to-177-n-mi orbit inclined at 57°. Payload mass up might total 34,031 pounds; mass down, 32,339 pounds.
During Flight 23 (5-6 January 1982), the last described in the STS Flight Assignment Baseline document, three astronauts would deploy into a 150-to-160-n-mi-high orbit the Jupiter Orbiter and Probe (JOP) spacecraft on a stack of three IUSs. President Jimmy Carter had requested new-start funds for JOP in his Fiscal Year 1978 NASA budget, which had taken effect on 1 October 1977. Because JOP was so new when they prepared their document, JSC planners declined to estimate up/down payload masses.
Flight 23 formed an anchor point for the Shuttle schedule because JOP had a launch window dictated by the movements of the planets. If the automated explorer did not leave for Jupiter between 2 and 12 January 1982, it would mean a 13-month delay while Earth and Jupiter moved into position for another launch attempt.
Almost nothing in the October 1977 STS Flight Assignment Baseline document occurred as planned. It was not even updated quarterly; no update had been issued as of mid-November 1978, by which time the target launch dates for the first Space Shuttle orbital mission and the first operational Shuttle flight had slipped officially to 28 September 1979 and 27 February 1981, respectively.
|The Space Shuttle Orbiter Columbia lifts off at the start of STS-1. Image credit: NASA|
The first operational flight, also using Columbia, was STS-5 (11-16 November 1982). The mission launched SBS-3 and Anik-C/3; because of Shuttle delays, the other SBS and Anik-C satellites planned for Shuttle launch had already reached space atop expendable rockets.
To the chagrin of many Star Trek fans, Enterprise never reached space. NASA decided that it would be less costly to convert Structural Test Article-099 into a flight-worthy Orbiter than to refit Enterprise for spaceflight after the ALT series. OV-099, christened Challenger, first reached space on mission STS-6 (4-9 April 1983), which saw deployment of the first TDRS satellite.
|NASA put OV-101 Enterprise to work in a variety of tests and rehearsals (such as the "fit check" shown in the image above), but did not convert it into a spaceflight-worthy Orbiter. Image credit: NASA|
The 21,500-pound LDEF reached Earth orbit on board Challenger on STS-41C, the 11th Space Shuttle mission (6-13 April 1984). During the same mission, astronauts captured, repaired, and released the SMM satellite, which had reached orbit on 14 February 1980 and malfunctioned in January 1981. Challenger reached SMM without an OMS kit; in fact, no OMS kit ever reached space.
STS Flight Assignment Baseline document assumed that 22 Shuttle flights (six OFT and 16 operational) would occur before January 1982. In fact, the 22nd Shuttle flight did not begin until October 1985, when Challenger carried eight astronauts and the West German Spacelab D1 into space (STS-61A, 30 October-6 November 1985). Three months later (28 January 1986), Challenger was destroyed at the start of STS-51L, the Shuttle Program's 25th mission.
In addition to seven astronauts – NASA’s first in-flight fatalities – Challenger took with it TDRS-B, NASA's second TDRS satellite. The Shuttle would not fly again until September 1988 (STS-26, 29 September-3 October 1988). On that mission, OV-103 Discovery deployed TDRS-C. The TDRS system would not include the three satellites necessary for global coverage until TDRS-D reached orbit on board Discovery on mission STS-29 (13-18 March 1989).
Following the Challenger accident, NASA abandoned – though not without some resistance – the pretense that it operated a fleet of cargo planes. The space agency had at one time aimed for 60 Shuttle flights per year; between 1988 and 2003, the Shuttle Program managed about six per year. The most flights the Shuttle fleet accomplished in a year was nine in 1985.
Shuttle delays meant that JOP, renamed Galileo, missed its early January 1982 launch window. It was eventually rescheduled for May 1986, but the Challenger accident intervened. Galileo finally left Earth orbit on 18 October 1989 following deployment from OV-104 Atlantis during STS-34 (18-23 October 1989).
Between the time JOP/Galileo received its first funding and the Challenger explosion, NASA, the White House, and Congress had sparred over how the Jupiter spacecraft would depart Earth orbit. Eventually, they settled on the powerful liquid-propellant Centaur-G' rocket stage.
Citing new concern for safety following Challenger, NASA canceled Centaur-G'. Galileo had to rely on the less-powerful IUS, which meant that it could not travel directly to Jupiter: it had instead to perform gravity-assist flybys of Venus and Earth to reach its exploration target. Galileo did not reach the Jupiter system until December 1995.
LDEF had been scheduled for retrieval in March 1985, less than a year after deployment, but flight delays and the Challenger accident postponed its return to Earth by nearly six years. On mission STS-32 (9-20 January 1990), astronauts on board Columbia retrieved LDEF, the orbit of which had decayed to 178 n mi. LDEF remains the largest object ever retrieved in space and returned to Earth.
During reentry at the end of mission STS-107 (16 January-1 February 2003), Columbia broke apart over northeast Texas, killing its international crew of seven astronauts. This precipitated cancellation of the Space Shuttle Program by President George W. Bush, who announced his decision on 14 January 2004.
The end of the Space Shuttle Program was originally scheduled for 2010, immediately following the planned completion of the International Space Station. In the event, STS-135, the final Space Shuttle mission, took place four years ago, in July 2011, three months after the 30th anniversary of STS-1. The Orbiter Atlantis lifted off on 8 July with a four-person crew (the smallest since STS-6), docked with the International Space Station to deliver supplies and spares, and landed in Florida 13 days later.
STS Flight Assignment Baseline, JSC-13000-0, STS Utilization and Planning Office, NASA Johnson Space Center, 15 October 1977
MSF Schedule Assessment of Major Space Shuttle Milestones (SENSITIVE), J. Yardley and M. Malkin, 31 January 1975
Where to Launch and Land the Space Shuttle? (1971-72)