Deep Nozzle Throat
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- Registrado
- 24 de Jun, 2025
The Shuttle wasn't forced to have a high crossrange because of the military, it was the other way around. The earliest estimates for breakeven with the Shuttle (the point where it would be more cost effective to develop a fully reusable launch vehicle versus continuing the Titan family or developing a dedicated expendable vehicle that wasn't Saturn derived) assumed that a) the Shuttle would generate a tremendous amount of its own traffic (think 300+ flights a year) and b) would be the only launch vehicle operated by the US, in order to guarantee a). This was the conclusion Mathematica Corporation endorsed when tapped to assess the Shuttle program in 1971. Because it was both a genuine belief that the Shuttle should be flexible enough to encompass all US space needs, including defense, and it was seen as a safe harbor for continued funding, the DoD's needs became a design criteria.
The pullout point was post-Challenger. The Shuttle had been lagging behind from its intended earliest operational date, and the post-Challenger safety and operation concerns wound up dooming Shuttle-Centaur and polar Shuttle operations. (LC-39A had been partially converted to support Shuttle-Centaur, and the first mission was scheduled for April 1986). Titan eventually took over that role and was the primary DoD launcher from 1986 to the late 1990s, when Delta IV was conceived to support the speculative satellite internet constellation market and fill the DoD's requirements. Boy, doesn't that sound familiar.
The sidemounted Shuttle, meanwhile, was the biproduct of a cost-benefit study, following on from the Mathematica study, that argued Thrust Assisted Orbiter Shuttle (TAOS) was a reasonable compromise between development costs and operational costs. This became quickly endorsed by NASA leadership (as the external tank had evolved out of ballooning Orbiter sizes) and was ultimately adopted as part of the final design in December 1971/January 1972.
"The Space Shuttle Decision" is a labyrinthine but thorough history of the decision-making that produced the Shuttle program, and it stands with "Stages to Saturn" as a defining history. Unfortunately most of the newspace retards have only read "LEO On The Cheap," which looks embarrassingly quaint these days.
PS - grab a frosty beverage and tune in to the Apollo 11 in Real Time stream.
