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Thread: Shuttle to Polar Orbit

  1. #1
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    Shuttle to Polar Orbit

    I recently read somewhere (an editorial at space.com, perhaps?) that one of the design requirements for the space shuttle was that it be able to complete one polar orbit and return to the launch site. I recall that the military had big plans for the shuttle and constructed a launch site at Vandenberg to permit launches to polar orbit, and can see how polar orbit would be useful to them. But why the requirement for return after just one orbit?

    BTW: The article claimed that this requirement forced the shuttle to have larger wings than are needed for near-equatorial orbit. As I understand it, the Earth rotated eastward under the orbit, and the shuttle would re-enter to the west of the launch site. Therefore, the shuttle had to glide further than it would for an equatorial orbit's "straight-in" landing approach.
    I may have many faults, but being wrong ain't one of them. - Jimmy Hoffa

  2. #2
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    I suspect the one orbit requirement was for an Abort-To-Orbit situation where the orbiter made one orbit and then returned to Earth. As you mentioned the Earth rotated under the shuttle's path. This required more of a "cross-range" capability so that the shuttle could get back to its launch site.

    [Edit: I just found an article here that outlines these requirements. Search for "polar orbits" in the article.]

    [Second Edit: It is actually an Abort-Once-Around (AOA) not an Abort-To-Orbit (ATO).]

  3. #3
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    Re: Shuttle to Polar Orbit

    Quote Originally Posted by Extravoice
    I recently read somewhere (an editorial at space.com, perhaps?) that one of the design requirements for the space shuttle was that it be able to complete one polar orbit and return to the launch site. I recall that the military had big plans for the shuttle and constructed a launch site at Vandenberg to permit launches to polar orbit, and can see how polar orbit would be useful to them. But why the requirement for return after just one orbit?

    BTW: The article claimed that this requirement forced the shuttle to have larger wings than are needed for near-equatorial orbit. As I understand it, the Earth rotated eastward under the orbit, and the shuttle would re-enter to the west of the launch site. Therefore, the shuttle had to glide further than it would for an equatorial orbit's "straight-in" landing approach.
    The mission requirement being discussed at the time the shuttle system was being built (as unrealistic as it sounds now) ran as follows. In a time of international tension (this was in the depths of the Cold War, after all) the US discovers the urgent need to deploy a reconnaissance satellite into polar orbit. Tensions are so high that the shuttle may be exposed to ASAT measures, being a much easier target to track than its payload. So they launch south across the Pacific, pop open the payload doors as soon as they reach orbit, deploy the satellite, close doors and hope there isn't a proble, do a deorbit burn, and angle the re-entry path hard to return to Vandenburg. As events unfolded (even aside from the geopolotical situation), the fact that a shuttle could never be prepared for launch on any kind of short notice, plus the tight timeline for such a mission and the changing economics of missions after Challenger, let this idea fade more or less gracefully from memory. The closest you'll see are some photos of an orbit (Enterprise?) at the VAFB launch complex for fit and procedure tests.

    The claim that it was this requirement by the Air Force that forced wings on the orbiter as the price of political support has been made by many writers. When the USSR wanted a similar capability, their designers suggested a long lifting body as more efficient, but someone in the Kremlin liked the cross-range idea (especially for a nation without a worldwide network of military bases) so much that they were basically instructed to match the Shuttle's crossrange (which then implied that its airframe would be pretty similar).

  4. #4
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    Re: Shuttle to Polar Orbit

    Quote Originally Posted by Extravoice
    I recently read somewhere (an editorial at space.com, perhaps?) that one of the design requirements for the space shuttle was that it be able to complete one polar orbit and return to the launch site.
    You may be thinking of this article at Space.com:

    Last Chapter Opens For Space Shuttle Born Of Compromise

  5. #5
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    The shuttle was to launch from the SLC-6 site that now has been rated for the Delta IV. When shuttle was killed for polar orbits--that was when the curse went into high gear.

    more about military shuttles here:
    www.up-ship.com

  6. #6
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    Re: Shuttle to Polar Orbit

    Quote Originally Posted by publiusr
    The shuttle was to launch from the SLC-6 site that now has been rated for the Delta IV. When shuttle was killed for polar orbits--that was when the curse went into high gear.

    more about military shuttles here:
    www.up-ship.com
    What curse?

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