Slide 15 of 100
Although NASA's Committee on Hypersonic Lifting Vehicles formally endorsed the development of a
fully reusable two-stage launch vehicle in June 1964, the military and NASA remained relatively
uninterested. Apollo and other projects received most of the attention and resources from space
planners. However, NASA and the Department of Defense did a gree to set up joint Aeronautics &
Astronautics Coordinating Board (AACB) Subpanel on Reusable Launch Vehicle Technology in August
1965. The AACB subpanel then examined various NASA and USAF candidate concepts over the next
The AACB concepts belonged to three different classes. All Class 1 designs used a small
6800-kilogram reusable lifting-body spaceplane to carry the crew and payload.
The emphasis was on manned space station crew transfer/resupply
missions with relatively small payloads of 907kg in addition to a crew of 4-6 astronauts.
The most advanced Class 1 concept (top) consisted of a horizontal launch & landing (HTHL)
winged booster plus expendable upper stage to lift the lifting-body orbiter into orbit. The
gross liftoff mass was 544,310kg, the expected development cost was $2.5 billion [1965 dollars]
and the cost per launch would have been $15 million. Alternatively, the Class 1 lifting-body
orbiter could have been launched on an existing USAF Titan IIIM expendable booster (left). This
option would have cost only $700 million to develop, plus $19 million per launch over ten years.
If the Saturn IB (center) were used, the development cost would stay the same but the cost per
mission would increase to $36 million. Finally, a new expendable low-cost booster (right) could
have been developed for $2,000 million; the marginal launch cost would have been only $14 million.
The gross liftoff weights were expected to be 825,538kg (Titan IIIM+Class I), 587,855kg
(Saturn IB+Class I) and 395,986kg (new expendable LOX/LH2 booster) respectively. The AACB
panel 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.
The AACB Class II concepts were fully reusable all-rocket TSTO vehicles. The orbiter retained
the lifting-body shape but it was much larger since it had to carry internal tanks for the
oxygen+hydrogen rocket propellant. These concepts were designed for larger payloads of 9,072kg.
The VTHL TSTO design (left) would have had a gross liftoff weight of 745,479kg. It was expected
to cost $3 billion to develop (=$15.9B at 1999 economic conditions) but only $4 million to
operate per flight. An alternative 598,742-kilogram HTHL TSTO design (right) would have cost
$4 billion (=21B in 1999 dollars) but otherwise offer similar capabilities.
These vehicles would have been available in 1978. They would have reduced the
cost per kilogram of a manned launch from Class I's $26000-$67000/kg to $2300/kg [1999 $s] but
would also have required high flight rates to compensate for the higher development cost vs.
”Space Shuttle” -- Dennis R. Jenkins, 1981, ISBN: 0963397451