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#11
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Don't Desert Hubble
Explorer8939 wrote:
I have to say that I am surprised how lightly everyone is taking the ISS safe haven concept for Shuttle. What if a Shuttle is stranded at ISS, and something goes wrong with the next Progress that is required to keep the 10 person crew going? Is the ISS safe haven truly 2 fault tolerant? Because, the 3 remaining shuttles are all going to be in rotation and an accelarated launch would have the next shuttle going up within a few weeks.. And, ATV and Progress gives 2 resupply vehicles possible. Brett Buck wrote in message ... Brian Gaff wrote: Hmm, I have not seen anywhere any detailed, data supported reasons for the cancellations yet. Lots of words, but no arguable reason for it. so, what is the reason? Seems perfectly simple and well-defined to me. No on-orbit repair capability because it's too expensive, no ready rescue flight because it's too expensive, so all shuttle flight go to ISS as a safe haven. What's so hard to understand about that? Brett |
#12
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Don't Desert Hubble
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#13
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Don't Desert Hubble
"Jorge R. Frank" wrote:
(Explorer8939) wrote: I have to say that I am surprised how lightly everyone is taking the ISS safe haven concept for Shuttle. What if a Shuttle is stranded at ISS, and something goes wrong with the next Progress that is required to keep the 10 person crew going? Is the ISS safe haven truly 2 fault tolerant? I have to say that I am surprised how lightly everyone is taking the LM lifeboat concept for Apollo. What if the Service Module suffers a massive systems failure, and something goes wrong with the LM that is required to land on the moon? Is Apollo truly 2 fault tolerant? The Apollo CSM/LM last flew over 30 years ago. How is that system relevant to today? -- Scott M. Kozel Highway and Transportation History Websites Virginia/Maryland/Washington, D.C. http://www.roadstothefuture.com Philadelphia and Delaware Valley http://www.pennways.com |
#14
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Don't Desert Hubble
On Fri, 13 Feb 2004 23:28:10 GMT, Brett Buck
wrote: What's so hard to understand about that? The "no ready rescue flight because it's too expensive" part. It would be inconvenient (to ISS) but not particularly expensive. Pretty expensive for a mission that was going to end relatively soon in any case. I don't follow... we've already spent a small fortune on SM-4, and the replacement equipment already exists. So SM-4 by itself doesn't present a particularly great cost to NASA. The big costs will be the RCC repair technology, and NASA has essentially said SM-4 isn't worth that cost. That puts the ball in Congress' court: they either have to tell NASA to waive the CAIB recommendation or cough up the funding for the repairs. The rescue Shuttle would simply be the next scheduled Shuttle launch, with some preparation to allow quick offloading of the ISS hardware and loading of Shuttle/Shuttle rendezvous software. NASA holds the SM-4 Shuttle until the ISS Shuttle is on the other pad a week or two away from launch. This is a scheduling inconvenience to be sure, but the history of the Shuttle is replete with scheduling problems. What's one more? Brian |
#15
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Don't Desert Hubble
"Scott M. Kozel" wrote in
: "Jorge R. Frank" wrote: (Explorer8939) wrote: I have to say that I am surprised how lightly everyone is taking the ISS safe haven concept for Shuttle. What if a Shuttle is stranded at ISS, and something goes wrong with the next Progress that is required to keep the 10 person crew going? Is the ISS safe haven truly 2 fault tolerant? I have to say that I am surprised how lightly everyone is taking the LM lifeboat concept for Apollo. What if the Service Module suffers a massive systems failure, and something goes wrong with the LM that is required to land on the moon? Is Apollo truly 2 fault tolerant? The Apollo CSM/LM last flew over 30 years ago. How is that system relevant to today? Because no manned spacecraft, past or present, is fully two fault tolerant. Oh sure, they may be two fault tolerant in some systems, but not in all. It's simply impractical. I believe no manned spacecraft will be *fully* two fault tolerant in my lifetime. If Explorer8939 wishes to see a fully two fault tolerant spacecraft, I suggest he take some sleeping pills, lie down, and dream about them. That's the only place he'll see them in *his* lifetime, either. -- JRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. |
#16
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Don't Desert Hubble
Scott M. Kozel wrote:
The Apollo CSM/LM last flew over 30 years ago. How is that system relevant to today? No currently flying system is going to evolve into the future US manned spaceflight system. As such, the age of anything is irrelevant to the discussion. Any feature from any past vehicle which appears to support the new mission requirements is valid for consideration. As are unflown but previously or newly proposed features. -george william herbert |
#17
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Don't Desert Hubble
Brian Thorn wrote:
On Fri, 13 Feb 2004 23:28:10 GMT, Brett Buck wrote: What's so hard to understand about that? The "no ready rescue flight because it's too expensive" part. It would be inconvenient (to ISS) but not particularly expensive. Pretty expensive for a mission that was going to end relatively soon in any case. I don't follow... we've already spent a small fortune on SM-4, and the replacement equipment already exists. So SM-4 by itself doesn't present a particularly great cost to NASA. The big costs will be the RCC repair technology, and NASA has essentially said SM-4 isn't worth that cost. That puts the ball in Congress' court: they either have to tell NASA to waive the CAIB recommendation or cough up the funding for the repairs. The ET tanks alone costs more than the replacement equipment for Hubble. Throw in all the associated non-recoverable launch costs and an additional 2-3 months of Shuttle workforce and their associated salaries.. If they don't fly SM-4, they can close shop on the entire Shuttle infrastructure 2-3 months earlier than otherwise. You are seriously looking at a mission that represents potentially billions of dollars when you look at it as extending the life of a program beyond a certain date. If they can close shop on Dec 31 2009 without flying SM-4, but Mar 31 2010 with SM-4, what are the associated costs of SM-4? It's about 1 billion dollars. The last sentence you stated is the important one. This is a political,not technical decision and NASA is putting it back onto Congress to be *consistant*. NASA just got crucified for not following basic safety requirements and now they are getting flamed for not waiving those requirements when something "important" comes along. The rescue Shuttle would simply be the next scheduled Shuttle launch, with some preparation to allow quick offloading of the ISS hardware and loading of Shuttle/Shuttle rendezvous software. NASA holds the SM-4 Shuttle until the ISS Shuttle is on the other pad a week or two away from launch. This is a scheduling inconvenience to be sure, but the history of the Shuttle is replete with scheduling problems. What's one more? The drop-dead date for Shuttle is 2010. They don't really have any room for slippage. |
#18
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ISS Safe Haven (WAS: Don't Desert Hubble)
There is no question that the NASA of today is less risk tolerant than
the NASA of the Apollo era. "Jorge R. Frank" wrote in message ... (Explorer8939) wrote in om: I have to say that I am surprised how lightly everyone is taking the ISS safe haven concept for Shuttle. What if a Shuttle is stranded at ISS, and something goes wrong with the next Progress that is required to keep the 10 person crew going? Is the ISS safe haven truly 2 fault tolerant? I have to say that I am surprised how lightly everyone is taking the LM lifeboat concept for Apollo. What if the Service Module suffers a massive systems failure, and something goes wrong with the LM that is required to land on the moon? Is Apollo truly 2 fault tolerant? |
#19
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ISS Safe Haven (WAS: Don't Desert Hubble)
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#20
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Don't Desert Hubble
Charles Buckley wrote in
: The ET tanks alone costs more than the replacement equipment for Hubble. Hmm? I'd sure like to see some sources for that. I've seen quotes of $200 million for the instruments alone on SM-4, let alone the gyros. That's at least three ETs right there. And most of that $200 million has *already* been spent. The last sentence you stated is the important one. This is a political,not technical decision and NASA is putting it back onto Congress to be *consistant*. You might want to tell O'Keefe that. He's certainly painting this as a technical (specifically, crew safety) decision. Congress has every right to override a political decision, but they would be understandably reluctant to override a technical decision. NASA just got crucified for not following basic safety requirements and now they are getting flamed for not waiving those requirements when something "important" comes along. No waiving of requirements is necessary. The CAIB certainly had no intention of painting NASA into a corner such that they couldn't service HST. Dr. Osheroff has already spoken up on that particular issue. (Hint: Read chapter 10 of the CAIB report. There is *no* requirement for ISS safe haven, nor a rescue shuttle for non-ISS missions.) The drop-dead date for Shuttle is 2010. They don't really have any room for slippage. They have about 18 months, actually, based on the last manifest published before the new space policy was announced. -- JRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. |
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