Launched: 1975. Number crew: 3 .
NASA realized that after the completion of the Apollo, Skylab, and ASTP programs there would still be significant Apollo surplus hardware. This amounted to two Saturn V and three Saturn IB boosters; one Skylab space station, three Apollo CSM's and two Lunar Modules. After many iterations NASA considered use of these assets for a second Skylab station in May 1973. A range of options were considered. Saturn V SA-515 would boost the backup Skylab station into orbit somewhere between January 1975 and April 1976. It would serve as a space station for Apollo and Soyuz spacecraft in the context of the Apollo ASTP mission. The Advanced or International Skylab variants proposed use of Saturn V SA-514 to launch a second workshop module and international payloads. This station would be serviced first by Apollo and Soyuz, then by the space shuttle. Using the existing hardware, these options would cost anywhere from $ 220 to $ 650 million. But funds were not forthcoming. The decision was taken to mothball surplus hardware in August 1973. In December 1976, the boosters and spacecraft were handed over to museums. The opportunity to launch an International Space Station, at a tenth of the cost and twenty years earlier, was lost.
A study was conducted to determine the feasibility of providing an artificial gravity operating mode for a second OWS. Study results indicated there were several areas of the OWS that would require unique configuration characteristics. Among the areas of concern were antenna location and coverage; CSM/MDA docking interface strength; reaction control system characteristics, propellant consumption, and attitude control logic to maintain solar orientation in the face of gravity gradient torques; ATM mounting and deployment provisions; and the ATM solar array structure.
Definitized contract with McDonnell Douglas for two Orbital Workshops for the Apollo Applications Program. MSFC definitized the existing contract with McDonnell Douglas for two Orbital Workshops for the Apollo Applications Program, converted S IVB stages to be launched by Saturn V boosters. The contract was slated to run through July 1972, with most of the work to be performed at the company's plant at Huntington Beach, California. The first Workshop was tentatively scheduled for flight in mid-1972, with the second article initially serving as a backup vehicle if needed.
The objectives, constraints, and guidelines for a second OWS were stated in general terms along the following lines: OWS would reflect the same physical features and capabilities exhibited by the initial Workshop and would use the flight hardware to be procured as backup for the first Workshop missions. Crew complement would consist of three men (at least one scientist astronaut). Operating life would be 12 to 24 months, nominally continuously manned. Orbital altitude would be in the range of 390 to 500 km at an inclination up to 55°. Additional Details: here....
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
Definition studies for a second Orbital Workshop (Skylab II) were under study. Mission objectives would respond to the following major objectives: continued development and expansion of the ability to live, work, and operate effectively in space; exploitation of space for practical benefits through the observation of Earth and its environment; and the use of space for scientific research.
Issues discussed were whether there should be a Skylab II, and, if so, what its fundamental mission and configuration should be, how long it should stay in orbit, what its experiment payload should be, and how many manned launches should be planned for it. MSC recommended that artificial gravity and expanded Earth-survey experiments be included as major objectives of a second Skylab Program.
The feasibility of docking a second Orbital Workshop to Skylab 1 had been under consideration. However, the practical problems that would be engendered by such an operation were formidable. They included such items as docking loads, docking control, flight attitude of tandem Skylabs, consumables, and in-orbit storage of Skylab 1.
A study, which was initiated in April concerning a second Skylab Program, had generated sufficient data for planning purposes. The study indicated that a second set of Skylab missions would provide a useful and worthwhile continuation of manned space flight in the mid 1970s, even if the hardware were unchanged. It would also offer an economically feasible program option if future funding for the Space Shuttle Program fell behind the anticipated growth rate.
Objection was voiced to a proposal that the Saturn V backup launch capability and all activities associated with it be terminated immediately following the first manned mission of Skylab. Reasons for the objection were NASA would be placed in the position of retaining a backup capability for the most reliable portions of Skylab and disposing of that capability for the most immature elements such as the Workshop and solar arrays. Additional Details: here....
Second Skylab-B program between considered to fill late 1970's gap between the Apollo-Soyuz Test Project and the Space Shuttle. Consideration was being given to the feasibility of a second set of Skylab missions (designated Skylab-B) during the interval between the Apollo-Soyuz Test Project in 1975 and the start of Space Shuttle operations late in 1979. The inherent worth of a Skylab-B was recognized, but officials were reluctant to recommend it, on the premise that it would be unwise to allow it to delay or displace the development of the Space Shuttle and other programs already included in the FY 1974 budget.
Flexibility to conduct a second Skylab mission would be retained until such time as NASA planning for the FY 1976 budget was complete. To accomplish this, NASA issued the following guidelines. Launch umbilical tower 2 would be retained in its present status for possible Skylab usage until a decision was made to prepare for a Skylab launch or to begin modifications for the Shuttle Program. Action would be continued to place in storage existing hardware (including appropriate backups and spares) required for conduct of a Skylab mission. The Skylab Program would fund the activities required to place the hardware in minimum cost storage and the storage costs through June 1974.
NASA considered use of surplus Apollo/Saturn assets for a second Skylab station in May 1973. Instead the decision was taken to mothball surplus hardware in August 1973. In December 1976, the boosters and spacecraft were handed over to museums. The opportunity to launch an International Space Station, at a tenth of the cost and twenty years earlier, was lost.