Slide 24 of 125
McDonnell-Douglas (McDAC) decided not to pursue the Langley HL-10 design any further and
instead proposed a number of comparatively low-cost straight wing orbiter designs. Pictured
here is the company's “drawbridge wing” shuttle orbiter from late 1969. It would have reentered
with folded wings for high-crossrange (>2800km) military missions. The crossrange with
extended wings would have been only 400km but the reentry heat loads also would be less severe.
The gross liftoff weight of this system was 1,587.5t and McDonnell-Douglas estimated it would
cost $6.5 billion to develop in 1969 dollars (=$29.5B at 1999 rates).
McDAC 'drawbridge' orbiter rendezvouses with 12-man space station. In early 1970, the
space station was still regarded as NASA's next flagship project. E.g. McDonnell-Douglas was spending
$2.9 million on a very detailed space station study vs. only $0.25 million on space shuttle
trade studies. The roles were reversed in May 1970 when the Phase B space station contract ended
and the project was postponed into the 1980s.
Besides the primary drawbridge shuttle concept, McDonnell-Douglas proposed a smaller alternative
orbiter design derived from the 1968 ILRV concept. Its
4.57 * 18.3-meter cargo bay would contain a small propellant tank on some missions (bottom). It
could then be capable of deploying 9,072-kilogram 7.3 meter long payloads in a fully reusable
mode. 22,680-kilogram payloads occupying the entire cargo bay could still be launched if
expendable external drop tanks were used (top). The empty tanks could be returned to Earth
inside the cargo bay on some missions, or alternatively be discarded. This system actually
would have been only marginally more expensive to operate ($4-5.5M/flight vs. $3.5-4.5 million
for the drawbridge orbiter concept). The specific launch cost would be less, since the drop-tank
orbiter would carry a significantly larger payload than the drawbridge version.
The drop tank orbiter would have used a scaled-down version of the drawbridge configuration
booster. This smaller system would have cost $5.5 billion ($25B at 1999 rates) to develop.
McDAC also proposed a simpler and less expensive unmanned tow-back winged booster to further
reduce the weight and cost the booster as well as the entire system, down to $4 billion
(=$18 billion in 1999 $'s). The booster would have been snagged by a C-5A Galaxy following
reentry and then towed back to base. McDAC also investigated even simpler and cheaper interim
recoverable and expendable ballistic boosters.
McDAC drawbrigde orbiter specifications.
Development cost: $6.5 billion [1969 dollars -- $29.55B in FY 1999].
Marginal cost per mission: $3.5-4.5M [at 1969 rates; $1000-$1250/kg in 1999; 100 reuses of each vehicle].
Liftoff Thrust: . Total Mass: 1,600,727kg. Total Length: .
Payload capability: 19,958kg payload to a 555km 55 degree space station orbit.
Stage Number 1: Gross Mass: 1,330,840kg. Empty Mass 357,500kg.
Thrust: . Isp: Length: . Span: . Propellants: LOX/LH2.
Stage Number 2: 2 x SSME study. Gross Mass: 269,887kg. Empty Mass 64,115kg.
Thrust: . Isp: Length: 45.1m. Span: . Propellants: LOX/LH2.
“Shuttle to Fit the Times” -- Quest & Waganer, Astronautics & Aeronautics1970/August/p.36