Chrysler SERV
SERV looked like a greatly expanded Apollo capsule, with an empty central core able to carry 125,000 lb (57,000 kg) of cargo.
On the simpler end of the development scale were the "Class I" vehicles that placed a spaceplane on top of an existing or modified ICBM-based launcher.
The idea of a simple and inexpensive crewed launcher, a "ferry and logistics vehicle", developed out of the space station studies almost as an afterthought, the first mention of it being in the fiscal year 1967 budgets.
[1] Design of a low cost, reusable Space Transportation System (STS) started in earnest in December 1967, when George Mueller organized a one-day brainstorming session on the topic.
Like the original USAF studies, a small vehicle was envisioned, carrying replacement crews and basic supplies, with an emphasis on low cost of operations and fast turnarounds.
Unlike the USAF, however, NASA's Space Task Force quickly decided to move directly to the Class III designs.
This report described a 23 foot (7.0 m) wide cargo bay[a] Tharratt was convinced that SERV offered better flexibility than any of the winged platforms, allowing it to launch both crewed and uncrewed missions, and being much smaller overall.
[2] With most of the NASA centers backing one of the winged vehicles, and being dramatically different from any of them, SERV found no supporters within the bureaucracy and was never seriously considered for STS.
[3] Additionally, the astronaut corps was adamant that any future NASA spacecraft would have to be crewed,[4] (so the potentially uncrewed SERV won no converts there either), and the concept had high technological risk as an SSTO due to weight growth sensitivity.
This differed mostly in minor details, the major change being the reduction of the cargo bay width from 23 feet to 15 foot (4.6 m) in keeping with the rest of the Shuttle proposals.
Tilting the vehicle in relation to the direction of motion changes the pattern of the shock waves, producing lift that can be used to maneuver the spacecraft - in the case of SERV, up to about 100 NM on either side of its ballistic path.
[12] During the ascent the shields would move out from the body to adjust for decreasing air pressure, forming a large altitude compensating nozzle.
"Mode B" missions flew to a 110 nmi (200 km) low Earth orbit (LEO) inclined at 28.5 degrees, a due-east launch from the Kennedy Space Center.
[15] In the second version of the study, Chrysler also added an option that replaced MURP with a "personnel module", based on the Apollo CSM, which was 74 feet (23 m) long when combined with the same cargo container.
[18] The Extended Nosecone was a long spike with a high fineness ratio that lowered atmospheric drag by creating shock waves that cleared the vehicle body during ascent.
[19] Typically it would return after a small number of orbits brought its ground track close enough to Kennedy, and abort-once-around missions were contemplated.
The vehicle was designed to return to a location within four miles (6 km) of the touchdown point using re-entry maneuvering, the rest would be made up during the jet-powered descent.
Tilting this shape relative to the path of motion generates considerably more lift than the blunt base of SERV, but also subjects the airframe to much higher heating loads.
Like the SERV, Goddard did not need the extended crossrange capabilities of a military launcher, and returned to the simpler blunt-base re-entry profile.
