djw@cci632.UUCP (David Wright) (02/04/89)
I would like to pose a few questions to all you shuttle fanatics out there regarding the payload capabilities of the 3 shuttles. Is there a difference between Columbia, Atlantis, and Discovery structural configurations? Is there any reason why Atlantis is usually the orbiter used on DoD missions (going from memory here, don't flame me if I remember incorrectly!). Also how come Columbia has been in dry dock (is that an applicable term?) for so long? Are they making modif- ications to increase the payload capacity? I thought Atlantis was the orbiter that was to launch from Vandenburg. If that is the case, was Atlantis (being the last one built if I remember correctly) assembled using metals stronger and lighter than were used in previous orbiters. I know NASA was looking at SRB's made with (I believe) carbon fiber casings to reduce the overall weight of the shuttle launch vehicle. The weight reduction was necessary to (I thought) carry more fuel to allow launches against the Earth's rotation [can you say polar orbit with a minimum of manuevers? :-) ]. If these assumptions are correct, could Columbia be undergoing a complete retrofit to make her compatible with the rest of the fleet? Dave Wright rochester!cci632!djw Computer Consoles Inc. (CCI) uunet!ccicpg!cci632!djw Rochester, NY uunet!rlgvax!cci632!djw
henry@utzoo.uucp (Henry Spencer) (02/09/89)
In article <26162@cci632.UUCP> djw@cci632.UUCP (David Wright) writes: > Is there a difference between Columbia, Atlantis, and Discovery > structural configurations? Is there any reason why Atlantis is usually > the orbiter used on DoD missions... Basically, Columbia is older and is heavier. A number of improvements were made to the later orbiters, notably Atlantis and (I think) Discovery. There is no particular preference for Atlantis for DoD missions, although Columbia is excluded from most of the weight-critical missions, and DoD missions tend to be weight-critical. > ... Also how come Columbia has been in dry > dock (is that an applicable term?) for so long? Are they making modif- > ications to increase the payload capacity? Although some mods are being made, basically Columbia got left behind in various pieces of updating work because she was a less capable orbiter. Current plans are to make her the long-duration orbiter, for Spacelab in particular. > I thought Atlantis was the orbiter that was to launch from Vandenburg. I don't remember which one was scheduled to be first for Vandenberg, but there was no plan to dedicate specific orbiters to specific launch sites that I know of. > could Columbia be undergoing a complete retrofit to make her compatible > with the rest of the fleet? I think you'd have to rebuild her completely, at almost the cost of a new orbiter, to bring her up to the same specs as the newer birds. It turned out that a slight relaxation of the initial post-Challenger weight limits made it possible to fly pretty well all Spacelab missions on Columbia, which fitted in with the idea of modifying one orbiter for longer stay time in orbit. -- Allegedly heard aboard Mir: "A | Henry Spencer at U of Toronto Zoology toast to comrade Van Allen!!" | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
kcarroll@utzoo.uucp (Kieran A. Carroll) (02/10/89)
Henry Spencer writes: >In article <26162@cci632.UUCP> djw@cci632.UUCP (David Wright) writes: > >> ...I thought Atlantis was the orbiter that was to launch from Vandenburg. > >I don't remember which one was scheduled to be first for Vandenberg, but >there was no plan to dedicate specific orbiters to specific launch sites >that I know of.... "From the moment it was approved in April 1972, America's space shuttle was intended to be a "national launch system" replacing all expendable military and civilian launch vehicles by 1980. It is unlikely that the shuttle would have been built without this goal: the famous Mathematica study "proved" that the shuttle would be economical only if it carried all of America's space traffic. "Since a majority of America's space launches have been for military purposes, it was inevitabe the the shuttle would require the participation of the US Air Force, the officiall launch agency for not only the military services, but for American intelligence agencies as well. "In exchange for its grumbling support, the Air Force demanded -- and got -- changes in the design of the vehicle to accommodate its need for improved cross-range and large payloads, among others. For its part, the Air Force was to develop an inertial upper stage and fund the construction of orbiters 105, 106 and 107. "These `blue' shuttles would have been `dedicated' to classified military missions launched (in some cases) into polar orbits from the re-designed space launch complex six at Vandenberg Air Force Base... "...(after DoD shuttle funding started to wane) a brief attempt to dedicate OV-103 `Discovery' to the DoD failed..." From "The Manned Space Fligth Engineer Programme", by Micheal Cassutt, pp.26-33, Spaceflight, Vol.31 #1, Jan. 1989 (Spaceflight is published by the British Interplanetary Society, 27/29 South Lambeth Road, London, SW8 1SZ, England). -- Kieran A. Carroll @ U of Toronto Aerospace Institute {allegra,ihnp4,decvax,utai}!utzoo!kcarroll
henry@utzoo.uucp (Henry Spencer) (02/11/89)
In article <1989Feb10.145924.6208@utzoo.uucp> kcarroll@utzoo.uucp (Kieran A. Carroll) writes: >>...there was no plan to dedicate specific orbiters to specific launch sites >>that I know of.... > >... For its part, the Air >Force was to develop an inertial upper stage and fund the >construction of orbiters 105, 106 and 107. You'll notice that that idea died very early, since 106 and 107 were dropped from shuttle planning before things got very far. >"These `blue' shuttles would have been `dedicated' to >classified military missions launched (in some cases) into >polar orbits from the re-designed space launch complex six >at Vandenberg Air Force Base... > >"...(after DoD shuttle funding started to wane) a brief attempt >to dedicate OV-103 `Discovery' to the DoD failed..." While I dislike questioning things in Spaceflight, it should be noted that mistakes do get made from time to time. As far as I know -- I could be wrong -- there has never been a definite, approved *plan* to dedicate specific orbiters as "blue shuttles". There has been lots of *talk* about it, but I don't think there has ever been an actual decision to do it. Note the word "plan", as opposed to "proposal", in my original posting. For that matter, note that the blue shuttles would have operated from KSC at times, so my original comment about dedication of orbiters to launch sites stands for another reason too! -- The Earth is our mother; | Henry Spencer at U of Toronto Zoology our nine months are up. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu