Encyclopedia Astronautica
AACB Class 1

American winged orbital launch vehicle. In 1965-1966 NASA and the Department of Defense jointly studied two-stage-to-orbit reusable launch vehicles as a follow-on to existing expendable launchers. Following review of the three classes of alternative approaches, it was recommended that the immediate goal of the United States should be development of a partially reusable 'Class I' launch vehicle, which could be available by 1975 and would be competitive with existing expendable boosters. A fully reusable vehicle should only be pursued at a later date.

After the Aerospaceplane was terminated, the USAF Flight Dynamics Laboratory began study of less ambitious near-term spaceplane designs. These were dubbed the RLV (Reusable Launch Vehicle) or RSLV (Reusable Space Launch Vehicle). On the NASA side, its Committee on Hypersonic Lifting Vehicles had formally endorsed the development of a fully reusable two-stage launch vehicle in June 1964, but NASA management remained relatively uninterested. Apollo and other projects received most of their attention and resources. In the summer of 1965 NASA and the Department of Defense agreed to set up a joint Aeronautics and Astronautics Coordinating Board (AACB) Subpanel on Reusable Launch Vehicle Technology. Contractor studies were funded under the auspices of the AACB Joint Subpanel on 24 August 1965. The final report was issued in September 1966, and suggested that reusable launch vehicles be developed in a series of 'Classes'.

  • Class I would be a rudimentary reusable capability, available for space station crew transfer and resupply missions by 1974. The manned spacecraft itself would be a lifting body, with a gross mass of 7050 kg, a 900 kg payload, and crew of 4 to 6 - essentially a more-modern version of the X-20 DynaSoar cancelled a year earlier. The following booster options were considered:
    • Baseline: The spaceplane would be boosted by either a Titan 3M (825,500 kg gross mass) or Saturn IB (587,900 kg gross). Development cost was estimated at $700 million in 1965 dollars, plus $ 19 million per flight for ten years of missions atop a Titan III, or $ 36 million per flight for ten years of missions boosted by a Saturn IB.
    • Alternate I: Instead of an existing booster, a new expendable launch vehicle would be developed. Additional development cost would be $ 2 billion, but per-flight cost would be reduced to $14 million. The new booster would have a gross lift-off mass of 396,000 kg.
    • Alternate II: A partially reusable booster would be designed, with a winged flyback booster stage and an expendable second stage. Development cost was expected to be $ 2.5 billion, but per-flight cost would be $15 million, actually more than the new expendable vehicle. The vehicle would have a gross mass of 544,300 kg.
    The AACB subpanel preferred the Class I option since it would cost less to develop and the development risk would be lower than for an advanced fully reusable system. A Class I vehicle could become operational as early as 1974 for use with the Apollo Applications/Skylab Program program, and the comparatively low development cost could be amortized in only a few flights.

    LEO Payload: 8,000 kg (17,600 lb). Development Cost $: 2,000.000 million. Launch Price $: 14.000 million in 1966 dollars in 1966 dollars.

    Status: Study 1966.
    Gross mass: 395,986 kg (872,999 lb).
    Payload: 8,000 kg (17,600 lb).

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    Associated Countries
    See also
    • Winged In the beginning, nobody (except Jules Verne) thought anybody would be travelling to space and back in ballistic cannon balls. The only proper way for a space voyager to return to earth was at the controls of a real winged airplane. More...

    Associated Manufacturers and Agencies
    • USAF American agency overseeing development of rockets and spacecraft. United States Air Force, USA. More...

    • Jenkins, Dennis R,, Space Shuttle: The History of the National Space Transportation System : The First 100 Missions, Third edition, Voyageur Press, 2001.

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