|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Cheap Realistic Space Flight
(sci.space.history added to newsgroups list)
In article , ed kyle wrote: Not correct. The reason Voyager was moved to the Saturn V was that it simply *outgrew* Saturn IB/Centaur... That was one of the stated reasons for stopping Saturn IB/Centaur, but NASA's own history, SP-4212 "On Mars: Exploration of the Red Planet, 1958-1978", ("http://history.nasa.gov/SP-4212/contents.html") makes it clear that money was the driving force behind the decision. Begin Quote (in mid 1965) NASA's "budget request for $5.26 billion yielded an appropriation of $5.175 billion for fiscal year 1966. ... Voyager, as a new start, was vulnerable, but other projects such as the adaptation of the Centaur to the Saturn IB were also at risk, since such development diverted money away from the completion of the Saturn V, Apollo's powerful booster..." And to continue that quote: "The unfavorable budget was trouble enough without the additional bad news brought by ... Mariner 4. The Martian atmosphere was much less dense than previously estimated. All proposals for landing capsules had to be thrown out... Given the 3000-kilogram launch weight for the spacecraft, much of the scientific payload would have to be sacrificed... No matter which approach to the problem was taken -- larger aeroshell, braking rockets, larger parachutes -- it would mean too much weight for the Saturn IB." While there was a lot of budget pressure weighing against continuation of Saturn IB Centaur, it might have been resisted, had Voyager stayed within that launcher's mass limits. The Mariner 4 atmosphere data was the fatal blow: Voyager's case for keeping its own launcher was wrecked when it outgrew that launcher. The advocates of Saturn IB Centaur previously had successfully defended their choice against pressure from higher up, but with Voyager unable to fly that way, they no longer had a leg to stand on, and resistance to the outside pressures collapsed. Whether a dense Martian atmosphere would have saved Saturn IB Centaur is not clear. The pressures against it were strong. But the thin Martian atmosphere was definitely what killed it. The move to Saturn V doomed Mars Voyager by nearly doubling its costs. "On Mars" again: "Considering the political climate, Voyager still might have survived, but only if NASA were very careful about how it promoted its planetary program. Unfortunately, the Manned Spacecraft Center in Houston chose the first week of August 1967 to send 28 prospective contractors a request for proposals to study a manned mission to Venus and Mars... previous exercises of this kind ... had been billed as logical extensions of the Voyager missions. This cast Voyager in the role of a 'foot in the door' for manned flights to the planets..." Voyager was on thin ice already -- don't forget that summer 1967 was a very bad time for the NASA budget in general, and that attempts to start Voyager hardware development had already been postponed once by funding shortages -- but it was political ineptitude by NASA that ultimately killed it. The greater costs of a Saturn V Voyager might someday have had an adverse effect on the project, but in the end, Voyager never got far enough for that to be a real issue. In the end, the Titan IIIE Viking orbiter/lander combination massed 3330 kg versus the original 3175 kg for the Voyager orbiter/lander. And Saturn IB Centaur's payload to Mars was 2700 kg. An overrun of nearly 500 kg is not something that could have been overcome trivially. And they were then the only definite customer for Saturn IB/Centaur, so their departure (plus NASA's strong desire to reduce the number of different launchers it was developing) doomed it. Six Saturn IB/Centaur launches were planned (2 R&D and 4 Voyager). Tentative plans called for future launches to Venus and the outer planets... All under the Voyager program. No Voyager, no customers. Yes, there were other program concepts that *might* have used it, but that counted for little in the final decision. -- MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer pointing, 10 Sept; first science, early Oct; all well. | |
#2
|
|||
|
|||
Cheap Realistic Space Flight
|
#3
|
|||
|
|||
Cheap Realistic Space Flight
In article ,
ed kyle wrote: And Saturn IB Centaur's payload to Mars was 2700 kg. An overrun of nearly 500 kg is not something that could have been overcome trivially. According to "On Mars", ("http://history.nasa.gov/SP-4212/contents.html") NASA was trying to meet a 3,000 kg spacecraft weight limit to fly on Saturn IB/Centaur. The 2700-kg number is also from "On Mars", interestingly enough. Note that the 3000-kg mass estimate increased very substantially after the true density of the Martian atmosphere became clear -- it was *not* a realistic mass for the Voyager spacecraft, as it turned out. -- MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer pointing, 10 Sept; first science, early Oct; all well. | |
#4
|
|||
|
|||
Cheap Realistic Space Flight
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
European high technology for the International Space Station | Jacques van Oene | Space Station | 0 | May 10th 04 02:40 PM |
NASA Fills Key Space Flight Positions | Jacques van Oene | Space Shuttle | 0 | March 3rd 04 05:55 PM |
NASA Names Crew Members For Shuttle Return To Flight Mission | Ron Baalke | Space Station | 1 | November 7th 03 09:44 PM |
NASA Modifies Space Flight Operations Contract | Ron Baalke | Space Station | 1 | October 11th 03 10:26 AM |
NASA Stennis Space Center employees are committed to return to flight | Jacques van Oene | Space Station | 0 | August 27th 03 10:07 AM |