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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Lockheed Star Clipper | 1/2 | https://en.wikipedia.org/wiki/Lockheed_Star_Clipper | reference | science, encyclopedia | 2026-05-05T13:22:18.631862+00:00 | kb-cron |
The Lockheed Star Clipper was a proposed Earth-to-orbit spaceplane based on a large lifting body spacecraft and a wrap-around drop tank. Originally proposed during a United States Air Force program in 1966, the basic Star Clipper concept lived on during the early years of the NASA Space Shuttle program, and as that project evolved, in a variety of new versions like the LS-200. Although the Star Clipper design did not progress far in the Space Transportation System (STS) program, it had an enormous effect on the emerging Space Shuttle design. The detailed study of the cost advantages of the drop tank design demonstrated a dramatic reduction in development risk, and as a result, development costs. When funding for STS development was cut, the drop tank was taken up as a way to meet the developmental budgets, leading to the semi-reusable Space Shuttle design.
== History ==
=== Max Hunter === Maxwell Hunter was working at Douglas Aircraft where he formalized the calculation of aircraft operation economics. His methodologies were first published in 1940, and were later applied to the Douglas DC-6 and DC-7. The methodologies were later adopted as a standard by the Air Transport Association. He later joined the Thor missile project as the chief design engineer, and this introduced him to the world of space launchers. With new upper stages, Thor became the Delta, one of the most-used launchers in the 1960s. In spite of Thor's success, Hunter was dissatisfied with the state of the launcher market and later wrote that "by the end of 1963 the state of recoverable rockets was terrible." He was convinced that as long as launchers were thrown away, access to space would never be affordable. Several companies had already completed early feasibility studies of fully reusable spacecraft, like the Martin Marietta Astrorocket and Douglas Astro. The designs used two flyback stages, one of which flew back to the launch point, while the other flew into orbit and landed after its mission. Hunter thought that any such design was tantamount to making two aircraft to do the job of one, and it was only the upper stage that was of any real use. By March 1964 he had developed a new concept, the stage-and-a-half configuration. In a two-stage rocket, one rocket fires to lift a second high into the air, and then falls off. The second then fires and travels into orbit. The advantage to this design is that the weight of the rocket decreases as it climbs, reducing the amount of mass that has to be carried all the way into orbit. The downside to this approach is that it needs two complete rockets, both expensive, and a time-consuming operation. In his stage-and-a-half configuration, Hunter had only one rocket. However, no rocket of the era had the performance needed to reach orbit on its own with a useful payload, so some sort of staging was needed. Hunter's solution was to place just the fuel tanks in the "stage", which would be ejected during the ascent. This gave the vehicle the advantages of staging, but threw away only the tankage, returning all of the expensive parts for re-use. After landing the vehicle would be refit, mated with another tank, and be ready for another mission. Hunter moved to Lockheed in the fall of 1965. On his first day he was asked if there was anything Lockheed should be looking at, and he immediately suggested development of his stage-and-a-half design. His suggestions caught the ear of Eugene Root, president of Lockheed Missiles and Space, who gave him the go-ahead to study what became known as the Star Clipper.
=== Space Transportation System ===