Slide 7 of 100
Notes:
NASA awarded contracts to Aerojet,Space Tech Laboratories, Douglas and RAND Corp. in January 1962 to study recoverable sea-launched Nova vehicles while Martin Marietta, General Dynamics and Boeing would investigate expendable liquid-propellant configurations. Follow-on contracts were awarded to Douglas, General Dynamics and Martin in June 1963 for work on “Class III” fully reusable Nova configurations in the 450,000-kilograms-to-LEO
payload class. The concept at left is General Dynamics' fully recoverable 1.5-stage-to-orbit design. The booster
engines would have been recovered separately, and the entire tankage would be placed in orbit. The second GD “Class III” Nova concept was Krafft Ehricke's giant “Nexus” VTVL SSTO rocket which also would have been recovered at sea using parachutes and retrorockets. Martin Marietta's “Renova” design (right) featured rocket engines enclosed in an air duct equipped with adjustable inlets. The conical payload fairing would serve as an inlet spike during the
ascent through the atmosphere. The air (which is heated by the rocket exhaust) would contrubute additional thrust as it expands past the plug-shaped afterbody. The inlets would be closed after leaving the atmosphere.
Douglas Aircraft Co. engineer Phil Bono did much to promote the concept of reusable ballistic
space vehicles during the 1960s.
Bono and his team at Douglas Aircraft examined fifteen different Nova concepts during 1962-64, including the two nuclear powered vehicles depicted here. Safety considerations would however rule out the possibility of using nuclear power on vertical takeoff-&-landing SSTOs such as the RITA concept. HTHL SSTOs were also rejected as impractically large since they require a very large wing area to keep wing loading within acceptable limits; the total area will be bigger than is needed to store the liquid hydrogen fuel. Smaller wings, on the other hand, would produce prohibitive landing velocities. Consequently, the only realistic SSTO launch and landing configuration appeared to be VTVL.
Among the reusable chemical rocket concepts, winged two-stage vehicles such as ASTRO (right)
would have to be impractically large for heavy-lift missions. The preferred reusable concept
was ROOST (Recoverable One Stage Orbital Space Truck, left), which would have used an
inflatable blunt-body drag cone for recovery at sea. ROOST would have impacted the water at
33.5 meters per second so the refurbishment cost would have been high. An alternative "buoyant"
ROOST would have incorporated a buoyancy torus and ballute/balloon inflated by warm residual
hydrogen to reduce the landing speed,
but the additional mass of the recovery system naturally increased the gross liftoff weight
too. ROOST would have cost $16/lb (7-8 reuses) vs. $250/lb for the Saturn V at 1962 rates. The
equivalent costs in 1999 dollars would be $195/kg for ROOST and $3,040/kg for the Saturn V.
Bono concluded that high pressure LOX/LH2 engines and a 7-1 oxygen/hydrogen mixture ratio
would reduce the size & weight of the vehicles. Disposable tanks & parallel staging were
initially rejected since complex cross-plumbing would be required, but Douglas would rather
return to the drop tank concept in order to achieve greater weight margins for its future SSTO
designs.
"Design Objectives for Tomorrow's Big Boosters” -- Bono, AAS 1963/vol.13/p. 20
”Nova Launch Vehicle Design Studies” -- Kalitinsky, AAS 1963/vol.15/p. 107
"Spaceflight and Rocketry -- a Chronology" -- David Baker:, Facts on File Inc, 1996, ISBN 0-8160-1853-7
