Soon after President Richard Nixon gave his blessing to the Space Shuttle Program on 5 January 1972, NASA targeted its first orbital flight for 1977, then for March 1978. By early 1975, the date had slipped to March 1979. Funding shortfalls were to blame, as were the daunting technical challenges of developing the world's first reusable orbital spaceship with 1970s technology. The schedule slip was actually worse than NASA let on: as early as 31 January 1975, an internal NASA document gave a "90% probability date" for the first Shuttle launch of December 1979.

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 mission date.

Thirteen of the 16 operational flights would use OV-102 and three would use OV-101. NASA would christen OV-102 Columbia in February 1979, shortly before it rolled out of the Rockwell International plant in Palmdale, California. As for OV-101, its name had been changed from Constitution to Enterprise in mid-1976 at the insistence of Star Trek fans (image at top of post). *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 JSC planners released their document.

This page from the STS Flight Assignment Baseline document describes Shuttle flights 7 through 13. Image: NASA. This page from the STS Flight Assignment Baseline document describes Shuttle flights 7 through 12A. Image: NASA.

The first operational Space Shuttle mission, Flight 7 (30 May-3 June 1980), would see OV-102 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. It would also carry a "payload of opportunity." The presence of a payload of opportunity meant that the flight had excess payload capacity available. Payload mass up would total 27,925 pounds. Payload mass down after the Remote Manipulator System (RMS) arm had hoisted LDEF out of OV-102's payload bay and released it into orbit would total 9080 pounds.

During Flight 8 (1-3 July 1980), OV-102 would orbit 160 n mi high. Three astronauts would release two satellites and their solid-propellant rocket stages: Tracking and Data Relay Satellite-A (TDRS-A) with a two-stage Interim Upper Stage (IUS) and the Satellite Business Systems-A (SBS-A) commercial communications satellite on a Spinning Solid Upper Stage-Delta-class (SSUS-D). Prior to release, the crew would raise TDRS-A on a tilt-table and spin the SBS-A about its long axis on a turntable to create gyroscopic stability. After release, their 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, they were frequently out of contact with the MCC.

Inside the Liquid Robotic R&D lab, new sensor payloads are installed on the gliders. This is also where the team tests its umbilical tethers – connecting the floats to the submarines – for endurance. Photo: Brian Lam

On Flight 9 (1-6 August 1980), OV-102 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. Payload mass up would total 36,017 pounds; mass down, 21,116 pounds. JSC planners reckoned that OV-102 could carry a 14,000-pound payload of opportunity.

Following Flight 9, OV-102 would be withdrawn from service for 12 weeks to permit conversion from OFT to operational configuration. The JSC planners explained that conversion would be deferred until after Flight 9 to ensure an on-time first operational flight and to save time by combining it with Orbiter preparation 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. The three-person crew of OV-102 would deploy TDRS-B/IUS and SBS-B/SSUS-D into a 160-n-mi-high orbit. The rocket stages would then boost them 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. OV-102 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 Shuttle Program. Initially dubbed the "sortie lab," Spacelab would operate only in the 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). Flight 11's five-person crew 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 OV-102'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. OV-102 would orbit 160 n mi above the Earth. Its three-person crew would, like that of Flight 12, deploy Anik-C/2 on an SSUS-D, but the mission's main purpose would be to create a backup launch opportunity for an Intelsat V-class satellite scheduled for launch on a U.S. Atlas-Centaur or European Ariane I rocket. An SSUS-A stage would boost the Intelsat V to GEO. The planners assumed that, besides the satellites and stages and their support hardware, OV-102 would 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.

Shuttle flights 13 through 18, spanning the period from March through July 1981. Image: NASA.

Flight 13 (3-8 March 1981) would see three astronauts on board OV-102 release NOAA's GOES-E satellite on an SSUS-D stage into a 160-n-mi-high orbit. OV-102 would have room for two payloads of opportunity: one attached at the front of the payload bay and one deployed from a turntable aft of the GOES-E/SSUS-D combination. Payload mass up would total 38,549 pounds; mass down, 23,647 pounds.

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. Enterprise 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, the 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), OV-102 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 would also carry the first acknowledged Department of Defense (DOD) payload of the Shuttle Program, a U.S. Air Force pallet designated STP-P80-1. JSC planners noted cryptically that this was the Teal Ruby experiment "accommodated from OFT." The presence of the Earth-directed Teal Ruby sensor payload accounted 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.

Shuttle flights 19 through 23, spanning from August 1981 to January 1982. Image: NASA.

Flight 19 (2-9 September 1981) would see five Spacelab experiment pallets fill OV-102's payload bay. Five astronauts would operate the experiments, which would emphasize physics and astronomy. The Orbiter would circle Earth in a 216-n-mi-high orbit. Payload mass up would total 29,214 pounds; mass down, 27,522 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 added that their estimate was only "based on preliminary payload data." Mass up would total 37,065 pounds.

On Flight 21, scheduled for launch on 14 October 1981, OV-102 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 reach the highest altitude of any 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 their 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 January 1982 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 flight had slipped officially to 28 September 1979 and 27 February 1981, respectively. The first Shuttle flight, designated STS-1, did not in fact lift off until 12 April 1981. As in the STS Flight Assignment Baseline document, OV-102 *Columbia *performed the OFT missions; OFT concluded, however, after only four flights. After the seven-day STS-4 mission (27 June-4 July, 1982), President Ronald Reagan declared the Shuttle operational.

Space Shuttle Columbia lifts off on April 12, 1981, beginning STS-1, the first Space Shuttle mission. Image: NASA. Space Shuttle Columbia lifts off on 12 April 1981, beginning STS-1, the first Space Shuttle mission. Image: 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 Star Trek fans, Enterprise never reached space. NASA decided that it would be less costly to convert Structural Test Article-099 into a flightworthy Orbiter than to refit Enterprise. OV-099, christened Challenger, first reached space on mission STS-6 (4-9 April 1983), which saw deployment of the first TDRS satellite.

The voluminous Spacelab pressurized module first reached orbit on board Columbia on mission STS-9 (28 November-8 December 1983). The 10-day Spacelab 1 mission included two researchers from ESA and NASA scientist-astronauts Owen Garriott and Robert Parker. Garriott, selected to be an astronaut in 1965, had flown for 59 days on board the Skylab space station in 1973. Parker had been selected in 1967, but STS-9 was his first spaceflight.

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 February1980 and malfunctioned in January 1981.

The 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 the second TDRS satellite, TDRS-B. 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 at one time had 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). Citing new concern for safety following Challenger, NASA canceled the powerful liquid-propellant Centaur rocket stage upon which Galileo had become dependent. The spacecraft had to rely instead on the less-powerful IUS, which meant that it could not be launched directly to Jupiter: instead, it had to perform gravity-assist flybys of Venus and Earth. Galileo did not reach the Jupiter system until December 1995.

LDEF had been scheduled to be retrieved in March 1985, less than a year after deployment, but flight delays and the Challenger accident postponed retrieval for 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 nm. LDEF was the largest object ever retrieved from 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. This precipitated cancellation of the Space Shuttle Program by President George W. Bush, who announced his decision on 14 January 2004. The program's end 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 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.

References:

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.