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#40 by Danderman on 29 Sep, 2009 16:12
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And how exactly do you propose doing that? Where are the suitable attach points?
This is a very good question. At this point, I am hoping that the experts here will come up with something.
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#41 by Jim on 29 Sep, 2009 16:13
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And how exactly do you propose doing that? Where are the suitable attach points?
This is a very good question. At this point, I am hoping that the experts here will come up with something.
cradle -
#42 by Danderman on 29 Sep, 2009 16:17
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What else was in the payload bay with Shuttle Mir Docking Module?
nothing. That is my point
If your point was that somehow the 4 ton Shuttle Mir Docking Module obviated any other payloads for STS-74, I would respond that you are incorrect. Moreover, STS-132 will fly both MRM-1, which is similar to the Docking Module and Pirs, but much, much heaver PLUS STS-132 will fly an ICC filled with batteries.
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#43 by Danderman on 29 Sep, 2009 16:18
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Directly attaching anything to PIRS is not viable.
What is the technical basis for this assertion?
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#44 by Jim on 29 Sep, 2009 16:35
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Directly attaching anything to PIRS is not viable.
What is the technical basis for this assertion?
there are many.
You came up with this idea, don't you have a way to do it? -
#45 by Jim on 29 Sep, 2009 16:38
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What else was in the payload bay with Shuttle Mir Docking Module?
nothing. That is my point
If your point was that somehow the 4 ton Shuttle Mir Docking Module obviated any other payloads for STS-74, I would respond that you are incorrect. Moreover, STS-132 will fly both MRM-1, which is similar to the Docking Module and Pirs, but much, much heaver PLUS STS-132 will fly an ICC filled with batteries.
Which means only an empty cradle and alone ICC are going to the ISS. There isn't a MRM-1 or Docking module to exchange with PIRS.
The ICC is not sufficient justification for a flight to the ISS.
It is not worth going through the technical exercise because there are too many programmatic, schedule, and cost issues. -
#46 by seanpg71 on 29 Sep, 2009 17:00
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...
It is not worth going through the technical exercise because there are too many programmatic, schedule, and cost issues.
So don't go through the technical exercise if it's not worth it to you to do so. You've made your point that it's not something that is likely to happen. That does not mean it's not possible or that there aren't circumstances under which it might be worth it. There were probably too many programmatic, schedule, and cost issues associated with using the LM as a lifeboat or replacing a pitted SARJ race ring, but that doesn't mean it's not interesting to think about what you could do if you really needed to for some reason.
So you're going to have to build a cradle to bring it down. Building that cradle is going to require time. Would it take 3 years to design? One year? What if we needed it down ASAP?
Bringing the cradle up will cost upmass. Fair enough. Is volume also an an issue? If so, what does a cradle entail? Could you build a foldable one that is then deployed on orbit? -
#47 by bodge on 29 Sep, 2009 17:05
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What else was in the payload bay with Shuttle Mir Docking Module?
nothing. That is my point
If your point was that somehow the 4 ton Shuttle Mir Docking Module obviated any other payloads for STS-74, I would respond that you are incorrect. Moreover, STS-132 will fly both MRM-1, which is similar to the Docking Module and Pirs, but much, much heaver PLUS STS-132 will fly an ICC filled with batteries.
Which means only an empty cradle and alone ICC are going to the ISS. There isn't a MRM-1 or Docking module to exchange with PIRS.
The ICC is not sufficient justification for a flight to the ISS.
It is not worth going through the technical exercise because there are too many programmatic, schedule, and cost issues.
There IS an MRM-1 and it is going to launch on STS-132, Jim.
It may not be delivered to KSC per the original baseline, but it will get to KSC. There are plans out there to make up for any lost time.
In the event it continues to be delayed, you will probably see the final flight of Atlantis slip out to after STS-134.
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#48 by Jim on 29 Sep, 2009 17:08
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1. That does not mean it's not possible or that there aren't circumstances under which it might be worth it.
2. There were probably too many programmatic, schedule, and cost issues associated with using the LM as a lifeboat or replacing a pitted SARJ race ring,
3. So you're going to have to build a cradle to bring it down. Building that cradle is going to require time. Would it take 3 years to design? One year? What if we needed it down ASAP?
4. Bringing the cradle up will cost upmass. Fair enough. Is volume also an an issue? If so, what does a cradle entail? Could you build a foldable one that is then deployed on orbit?
1. Not viable means there are no circumstances that are worth it
2. Wrong analogies. This is returning a module for a museum, a frivolous endeavor, it is not an exercise to save lives or return functionality to a broken item. Also, show me where using the LM as a lifeboat is a programmatic issue over saving a crew
3. There would be no reason to return it ASAP. The 3 years is for design, build and integration.
4. Volume is the main constraint, mass isn't one. Folding is highly unlikely. -
#49 by Jim on 29 Sep, 2009 17:10
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There IS an MRM-1 and it is going to launch on STS-132, Jim.?? Read my post.
I know that and it isn't my point. My point is because of the cradle, there isn't a payload going to the ISS. -
#50 by Danderman on 29 Sep, 2009 17:50
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Which means only an empty cradle and alone ICC are going to the ISS. There isn't a MRM-1 or Docking module to exchange with PIRS.
The ICC is not sufficient justification for a flight to the ISS.
It is not worth going through the technical exercise because there are too many programmatic, schedule, and cost issues.
Let me try it this way, let us assume for a moment that STS-134 is delayed from late 2010 until, say, late 2011 or thereabouts. Could Pirs be swapped out with AMS-02 on the way home? Of course, there is the problem that STS-134 has zero mass margin uphill at this time, AFAIK, which brings us back to devising a way to incorporate trunnions and a keel with Pirs without carrying this stuff on STS-134 uphill.
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#51 by Danderman on 29 Sep, 2009 17:52
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2. Wrong analogies. This is returning a module for a museum, a frivolous endeavor, it is not an exercise to save lives or return functionality to a broken item. Also, show me where using the LM as a lifeboat is a programmatic issue over saving a crew
Actually, the rationale I have laid out is to return Pirs for ground inspection, so that when and if a decision is made to extend ISS lifetime, that there is good data on one of the oldest modules on hand when that decision is made.
This would also inform NASA and Roskosmos on actual MMOD experience over the long term.
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#52 by seanpg71 on 29 Sep, 2009 17:56
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1) The original post asked two questions. Why might you want to return Pirs, and how would you go about doing it.1. That does not mean it's not possible or that there aren't circumstances under which it might be worth it.
2. There were probably too many programmatic, schedule, and cost issues associated with using the LM as a lifeboat or replacing a pitted SARJ race ring,
3. So you're going to have to build a cradle to bring it down. Building that cradle is going to require time. Would it take 3 years to design? One year? What if we needed it down ASAP?
4. Bringing the cradle up will cost upmass. Fair enough. Is volume also an an issue? If so, what does a cradle entail? Could you build a foldable one that is then deployed on orbit?
1. Not viable means there are no circumstances that are worth it
2. Wrong analogies. This is returning a module for a museum, a frivolous endeavor, it is not an exercise to save lives or return functionality to a broken item. Also, show me where using the LM as a lifeboat is a programmatic issue over saving a crew
3. There would be no reason to return it ASAP. The 3 years is for design, build and integration.
4. Volume is the main constraint, mass isn't one. Folding is highly unlikely.
You're bunching them together and saying, "The only reason you'd want to bring it back is for a museum, and it's sufficiently hard to do, that it's not viable."
So, assume that it's free to bring back. What would we do with it? There is clearly *some* value in bringing it back. It would be neat in a museum. Is there any science/engineering value in looking at the thing? Probably not much, probably more than a banana peel.
Then, assume that we need it back for some reason, how would we go about doing it and what are the costs and risks? We'd have to build a cradle. It would take time and money and payload bay volume. There are some tradeoffs that could be made to lessen the volume or time, but that would just increase the cost.
When those are combined, we come to the same assesment you did in your head. Your experience allows you to skip a few steps and we appreciate that. But, that doesn't mean that we're not interested in doing the exercise to come to that conclusion ourselves.
2) The analogies were meant to point out things that were non viable thought experiments at one point, and then suddenly became very real problems that needed to be solved. Just because it's currently not worth it does not make it impossible. You claimed that attaching something directly to PIRS is not viable. This is likely true in the same way that cutting through the insulation on a soyuz to pull out a pyrobolt isn't viable. Doesn't mean you can't do it.
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#53 by Danderman on 29 Sep, 2009 17:59
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Bringing the cradle up will cost upmass. Fair enough. Is volume also an an issue? If so, what does a cradle entail? Could you build a foldable one that is then deployed on orbit?
I would assign about 5% of total mass to the Shuttle-Pirs adapter whether it be a cradle or some sort of other adapter. Since Pirs has an empty mass of about 3 tons max and maybe 4 tons if stuff with downmass, I would expect the adapter or cradle to have a mass of 150 to 200 kg, if my math is correct.
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#54 by Jim on 29 Sep, 2009 17:59
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Let me try it this way, let us assume for a moment that STS-134 is delayed from late 2010 until, say, late 2011 or thereabouts. Could Pirs be swapped out with AMS-02 on the way home? Of course, there is the problem that STS-134 has zero mass margin uphill at this time, AFAIK, which brings us back to devising a way to incorporate trunnions and a keel with Pirs without carrying this stuff on STS-134 uphill.
No, it is not viable. The cradle needs to fly uphill.
There is no way to attach trunnions and a keel to PIRS without welding or drilling, hence the need for a cradle. trunnions have very specific dimensional critieria. Something that can't be done EVA. -
#55 by Jim on 29 Sep, 2009 18:00
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I would assign about 5% of total mass to the Shuttle-Pirs adapter whether it be a cradle or some sort of other adapter.
Way too low. 50% would be more like it. It would be in the 2000 to 4000 lb range. -
#56 by Jim on 29 Sep, 2009 18:01
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Actually, the rationale I have laid out is to return Pirs for ground inspection, so that when and if a decision is made to extend ISS lifetime, that there is good data on one of the oldest modules on hand when that decision is made.
This would also inform NASA and Roskosmos on actual MMOD experience over the long term.
That isn't enough of a reason. -
#57 by Danderman on 29 Sep, 2009 18:03
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2) The analogies were meant to point out things that were non viable thought experiments at one point, and then suddenly became very real problems that needed to be solved. Just because it's currently not worth it does not make it impossible. You claimed that attaching something directly to PIRS is not viable. This is likely true in the same way that cutting through the insulation on a soyuz to pull out a pyrobolt isn't viable. Doesn't mean you can't do it.
Jim has also informed us that MPLMs absolutely cannot be parked at ISS for long periods, nor that the ISS RMS can berth a module to ISS using the probe and cone docking system.
Its easy to say "it can't be done", but without a technical rationale, simply saying so don't make it so. If there is a technical reason why Pirs cannot be return in the Shuttle, so be it. But so far, I haven't seen one.
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#58 by Jim on 29 Sep, 2009 18:04
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This is likely true in the same way that cutting through the insulation on a soyuz to pull out a pyrobolt isn't viable. Doesn't mean you can't do it.
No where near the same thing, Cutting insulation has happened many times in flight over the years. -
#59 by Jim on 29 Sep, 2009 18:06
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If there is a technical reason why Pirs cannot be return in the Shuttle, so be it. But so far, I haven't seen one.
Anything can happen with time and money. There isn't any of that available for PIRS.
The issue is the "dedicated" shuttle flight with a cradle and the associated EVA crew time.
