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#72
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Jonathan Silverlight
wrote in : Could the system being proposed for HST be used to deorbit ISS? Probably not "as is". ISS is already 15 times more massive than HST and may be as much as 40 times more massive by the time it's deorbited. It will require much more propellant to deorbit. -- JRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. |
#73
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![]() Could the system being proposed for HST be used to deorbit ISS? Probably not "as is". ISS is already 15 times more massive than HST and may Just let ISS get low enough and one progress could bring it down. The hard part isnt bringing it down, just dont reboost wait long enough and its down..... The trouble is putting it down where you want it.... Not on top of somenes head.... Keeping it up is really the challenge. Hey this is my opinion ![]() |
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On 22 Mar 2004, "Jorge R. Frank" wrote:
"JimO" wrote in : I recall that the higher HST orbit does introduce some vulnerability to prop failures/leaks that lose you de-orbit sooner than you'd lose it from the ISS altitude, right? I believe so, but I'm not sure (in particular, I'd heard RCS deorbit was not available as a downmode). RCS Deorbit isn't necessarily a given from an ISS orbit either and neither an HST or ISS flight has "propellant fail" capability (the ability to deorbit after the loss of a single OMS propellant tank) once the final orbit is achieved. Both of these capabilities might exist early in the mission while still in a lower orbit while the orbiter is still catching up with the target while deorbit costs are low and propellant reserves are high, but once rendezvous altitude is achieved there isn't enough propellant left over to cover either of these failures. -- Dean Lenort |
#76
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![]() "Herb Schaltegger" wrote in message ... In article , "Greg D. Moore \(Strider\)" wrote: ISSS has been in the planning and construction phases since 1992. Before that we were planning Freedom for many years, but never got much done. No, it was Space Station Freedom all the way through CDR in the spring of 1993. It was briefly "Alpha" during the summer/fall timeframe during the time the Russians were climbing aboard and turned into "ISS" shortly thereafter. Thanks. I thought Clinton had announced the change in 92, not 93. And it is not a test bed to test tech for Mars. In fact, Congress in the past few years made it clear that NASA could NOT test Mars bound tech on the station (witness the fate of transhab.) SSF was supposed to be - that's what the closed-loop ECLSS was for, the on-orbit assembly/maintenance experience was to lead up to, and the planning and logistics for multinational/multiyear missions was supposed to culminate in. No argument, but the discussion was about what ISS is now, not what Freedom was supposed to be. However, once ISS scaled back the original lifetime to 15 years (rather than 30) - half of which or more is being used up in a drawn-out assembly sequence - and once the systems requirements deleted, delayed or pushed waaaay down the line all the real interesting and useful stuff (closed loop ECLSS, 8 person crew, deleting Lab "B" and both Habs, delaying the centrifuge module, delaying Columbus and Kibo labs, deletion of Nodes 3 and 4, etc), real tangible benefits for any kind of additional mission (whether to the Moon, Mars or anywhere) are hard to find. Ayup. -- Herb Schaltegger, B.S., J.D. Reformed Aerospace Engineer Columbia Loss FAQ: http://www.io.com/~o_m/columbia_loss_faq_x.html |
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Chris Bennetts wrote:
Just how much science return do you expect to get from ISS? Down here on Earth, most small science labs don't generate large returns. Given that the ISS is a pretty small science lab, it's unreasonable to expect large, publicity-generating science returns to come from it. It's the nature of scientific research. I expect a lab down on Earth that had a budget of $100 B would produce an enormous amount of science. The science that can be expected to come from ISS is, at best, pitiful. Paul |
#78
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Brian Thorn wrote:
10 years and ISS will be at end of life. No, it will have two years left, possibly much more under commercial sponsorship of the US segment. Do you actually think there's going to be any significant commercial interest in ISS? Microgravity just isn't commercially attractive given current launch technology. Paul |
#79
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Derek Lyons wrote:
(bob haller) wrote: But it shoqws the present experiments have little value or scientific return.. No. It shows the present experiments are not in line with the area or knowledge most being researched. This is a wonderful example of terminally wishful self-delusion. Past non-performance (the existing experiments being of low value) is not a problem -- the future experiments will be wonderful! True believers can excuse anything. NASA loves fools like you, Derek. Paul |
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On Sun, 28 Mar 2004 09:37:07 -0600, "Paul F. Dietz"
wrote: Brian Thorn wrote: 10 years and ISS will be at end of life. No, it will have two years left, possibly much more under commercial sponsorship of the US segment. Do you actually think there's going to be any significant commercial interest in ISS? Microgravity just isn't commercially attractive given current launch technology. By 2016, we may not be talking about "current launch technology". Brian |
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