NASASpaceFlight.com Forum
International Space Station (ISS) => ISS Section => Topic started by: Danderman on 09/28/2009 02:29 pm
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Rather than have Pirs disposed of by having a Progress dock with it, and then at end of mission, dump Pirs into a destructive de-orbit, why not return Pirs on the Shuttle? Clearly, it would be difficult to return Pirs on the shuttle under the current manifest, but if the Shuttle program were stretched out, or additional flights were authorized, one of those later missions could probably return Pirs to Earth.
The questions are: why return Pirs, and how to do it?
???
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Why would you want to return Pirs in the first place?
(PS Tags are for L2 posts)
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Let me ask a counter-question: Is there any reason why Pirs should be removed from the ISS prior to retirement in ~2020? AFAIK, none of the other Russian modules are going to get in its way.
If it isn't removed before 2020, then the shuttle isn't going to be able to recover it. Shuttle retirement is no later than 2015 and would more likely be 2011.
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Let me ask a counter-question: Is there any reason why Pirs should be removed from the ISS prior to retirement in ~2020? AFAIK, none of the other Russian modules are going to get in its way.
If it isn't removed before 2020, then the shuttle isn't going to be able to recover it. Shuttle retirement is no later than 2015 and would more likely be 2011.
Well, there IS a russian lab module (still on the manifest AFAIK) that is supposed to be docked where Pirs is right now, for starters. It cannot simply dock beneath Pirs because Pirs does not have the passive Hybrid Berthing interface it needs to dock to the SM.
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Why would you want to return Pirs in the first place?
(PS Tags are for L2 posts)
A couple of reasons:
1) AFAIK, no space station module that has been in operation for 10+ years has even been examined on the ground. To do so with Pirs would help significantly in extending (or not) the certified life of the rest of the Russian segment.
2) The Shuttle often returns to earth with an empty cargo bay. To return with a cargo module filled with downmass would be a very good thing for a mission that would not otherwise return a module.
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2) The Shuttle often returns to earth with an empty cargo bay. To return with a cargo module filled with downmass would be a very good thing for a mission that would not otherwise return a module.
Other than the PLM, there are no other missions with an empty payload bay
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Since the PIRS was not designed for launch by the shuttle, it has none of the necessary attach hardware to fit in the payload bay. This will require a cradle to return the module which negate the use of the payload bay for an up payload. Hence returning PIRS is a bad idea.
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2) The Shuttle often returns to earth with an empty cargo bay. To return with a cargo module filled with downmass would be a very good thing for a mission that would not otherwise return a module.
Other than the PLM, there are no other missions with an empty payload bay
And if they launch the PLM as planned on STS-133 even with a shuttle extension MLM will not have been launched get.
And where would they stove the Pirs in between MLM launch and Shuttle launch?
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2) The Shuttle often returns to earth with an empty cargo bay. To return with a cargo module filled with downmass would be a very good thing for a mission that would not otherwise return a module.
Other than the PLM, there are no other missions with an empty payload bay
And if they launch the PLM as planned on STS-133 even with a shuttle extension MLM will not have been launched get.
And where would they (store) the Pirs in between MLM launch and Shuttle launch?
Pirs will be undocked right before MLM is launched, the port will just not be used for a little while.
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Pirs will be undocked right before MLM is launched, the port will just not be used for a little while.
Is was talking about if they would bring it down on a shuttle. How big is the chance that a shuttle will be at the station around the time of undocking of Pirs? They could of course bring it down earlier but don't they need that port as much as possible?
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Is was talking about if they would bring it down on a shuttle.
a) How big is the chance that a shuttle will be at the station around the time of undocking of Pirs? b)They could of course bring it down earlier but don't they need that port as much as possible?
a) none - no docking/undocking allowed while the Shuttle is docked to ISS
b) The Progress docked to PIRS will be used to deorbit it - PIRS will be undocked from the ISS while still attached to the Progress. It has to be planned for a specific Progress flight to ensure the Progress has enough propellant remaining to deorbit both total masses.
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Pirs will be undocked right before MLM is launched, the port will just not be used for a little while.
Is was talking about if they would bring it down on a shuttle. How big is the chance that a shuttle will be at the station around the time of undocking of Pirs? They could of course bring it down earlier but don't they need that port as much as possible?
Read what Jim wrote. Pirs cannot come back on a shuttle. It lacks the proper attach fittings.
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First off, if the 9th floor decides to do something, the technical issues that previously could not be overcome suddenly become doable, if you have any doubts, please read the "Why can't an MPLM be left at ISS?" thread. I should therefore rephrase my question as "IF you were tasked with figuring out a way to return Pirs in the Shuttle, what would you recommend?". Pushing back on the requirement is NOT a legitimate response.
As for there being no missions apart from PLM that would return an empty payload bay, the original post here specified that either the shuttle manifest would have to be stretched out OR additional missions added for the Pirs return to be possible. Please, please, please read the question before answering!
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Pirs will be undocked right before MLM is launched, the port will just not be used for a little while.
Is was talking about if they would bring it down on a shuttle. How big is the chance that a shuttle will be at the station around the time of undocking of Pirs? They could of course bring it down earlier but don't they need that port as much as possible?
You are assuming that there is a requirement for Pirs to be replaced by MLM immediately.
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Since the PIRS was not designed for launch by the shuttle, it has none of the necessary attach hardware to fit in the payload bay. This will require a cradle to return the module which negate the use of the payload bay for an up payload. Hence returning PIRS is a bad idea.
Everything in your post was okay until you got to the point where you assuming that a cradle would take up the whole payload bay.
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First off, if the 9th floor decides to do something, the technical issues that previously could not be overcome suddenly become doable, if you have any doubts, please read the "Why can't an MPLM be left at ISS?" thread. I should therefore rephrase my question as "IF you were tasked with figuring out a way to return Pirs in the Shuttle, what would you recommend?". Pushing back on the requirement is NOT a legitimate response.
OK, here's what I would recommend:
1) Shuttle program would have to be stretched at least three years.
2) The organization that wants Pirs returned pays for the mission, and at the annual program cost, not the marginal cost.
3) The Pirs PLB cradle will be provided by the Russians at the expense of the organization that wants Pirs returned.
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I personally think you have a better chance of another HST mission than a Pirs Return mission. ;)
My recommendation, undock and deorbit it it or place it to the forward end of the MLM once it gets there.
Orbiter
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Everything in your post was okay until you got to the point where you assuming that a cradle would take up the whole payload bay.
It takes up enough of the bay to negate carrying an MPLM
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The only reason for doing this would be to put it in a museum - like the thought of bringing the Hubble down to put in the Smithsonian / Air & Space Museum.
Why? The Russians surely aren't sentimental about a docking compartment. And certainly aren't going to go for $125M for it.
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Everything in your post was okay until you got to the point where you assuming that a cradle would take up the whole payload bay.
It takes up enough of the bay to negate carrying an MPLM
The numbers that I came up with also suggest that the Pirs compartment has too large a diameter to fit in the payload bay.
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Where did the concept of putting Pirs into an empty payload bay transmogrify into somehow needing to fly an extra mission simply to return Pirs?
And why would it take 3 years to return Pirs????
Let's say that the current manifest is extended out until 2012 or so. Aren't there missions at the tail end of the manifest that will return with at least partially empty payload bays?
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If it's too large to fit in the payload bay, does it matter which missions have empty bays on the way home?
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The numbers that I came up with also suggest that the Pirs compartment has too large a diameter to fit in the payload bay.
I don't see how. Aside from the Strela and a couple other removable appendages it's only slightly fatter than a Soyuz and Progress (<3 meter diameter) See http://spaceflight.nasa.gov/gallery/images/station/pirs/hires/jsc2001e26682.jpg
Anyway, even if you are right, that's doesn't mean it's impossible, you just convert one of the orbiters into a wide body special... STS Super Guppy ;D
^ approximately as realistic as the rest of the plan.
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If it's too large to fit in the payload bay, does it matter which missions have empty bays on the way home?
Pirs is tiny compared to, say, an MPLM. For a good comparison, look at the similarly sized Shuttle Mir Docking Module in the Shuttle payload bay (only the orange structure was the module, the rest of the stuff was additional cargo or trusses):
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The numbers that I came up with also suggest that the Pirs compartment has too large a diameter to fit in the payload bay.
You ARE kidding, aren't you? With the male docking adapter removed, Pirs could fit in the Shuttle payload bay sideways. Otherwise, the max diameter of Pirs is 2.55 meters, and with judicial placement, you could put two of them side by side in the payload bay.
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I don't see how. Aside from the Strela and a couple other removable appendages it's only slightly fatter than a Soyuz and Progress (<3 meter diameter) See http://spaceflight.nasa.gov/gallery/images/station/pirs/hires/jsc2001e26682.jpg
Note that the image in that links shows Pirs with the Progress-M service module still attached. That particular hardware was jettisoned in 2001.
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The Mir docking module was equipped for a mounting in the Shuttle cargo bay, Pirs is not - i.e. Pirs can not be put into an empty space, because it can not be fixated in the cargo bay.
It would require a mounting cradle, which would occupy space and mass on the way up, so it would be a very bad deal to sacrifice upmass to bring back an old module.
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Shuttle landing is pretty smooth, is it? At least I have heard that it is more or less comparable to normal commercial aircraft landing.
If we think that the return flight would be the last flight for that orbiter, then why not using some cargo bands to tie up the Pirs to the cargo bay? Of course it would move and shake more or (hopefully) less during the landing, but by this way it won't require that much upmass penalties... And of course this would be pretty ugly way to treat space hardware, but might do the trick.
This is my 10 cents worth for this discussion... I know NASA wouldn't return Pirs like this because of safety issues etc. but at least I have given my thoughts. :)
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1. And why would it take 3 years to return Pirs????
2. Let's say that the current manifest is extended out until 2012 or so. Aren't there missions at the tail end of the manifest that will return with at least partially empty payload bays?
1. to build the cradle
2. No, because there are no more construction missions. The remaining missions are resupply which bring up and down the same hardware. There is no empty payload bays. Because the empty cradle going up will negate bringing up hardware like MPLM
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If we think that the return flight would be the last flight for that orbiter, then why not using some cargo bands to tie up the Pirs to the cargo bay?
The payload bay is not a container (it does not have rigid surfaces) , it is an enclosed mounting frame, and hence cargo can not rest on the bottom and be tied down
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Pirs is tiny compared to, say, an MPLM. For a good comparison, look at the similarly sized Shuttle Mir Docking Module in the Shuttle payload bay (only the orange structure was the module, the rest of the stuff was additional cargo or trusses):
Here is a hint, what else was in the payload bay with it
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Pirs is tiny compared to, say, an MPLM. For a good comparison, look at the similarly sized Shuttle Mir Docking Module in the Shuttle payload bay (only the orange structure was the module, the rest of the stuff was additional cargo or trusses):
Here is a hint, what else was in the payload bay with it
A SpaceLAB module, along with the External Airlock/ODS. And let's not forget that Atlantis still had her original internal airlock as well at the time of the Shuttle/Mir missions. The first OV-104 mission to fly without the internal airlock was STS-101 in May 2000.
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Here is a hint, what else was in the payload bay with it
A SpaceLAB module, along with the External Airlock/ODS. And let's not forget that Atlantis still had her original internal airlock as well at the time of the Shuttle/Mir missions. The first OV-104 mission to fly without the internal airlock was STS-101 in May 2000.
No Spacelab or Spacehab on STS-74. Besides the external airlock/ODS, the Docking Module flew in an otherwise empty payload bay.
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If we think that the return flight would be the last flight for that orbiter, then why not using some cargo bands to tie up the Pirs to the cargo bay?
The payload bay is not a container (it does not have rigid surfaces) , it is an enclosed mounting frame, and hence cargo can not rest on the bottom and be tied down
The question is how to attach trunnion pins and a keel to Pirs.
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Pirs is tiny compared to, say, an MPLM. For a good comparison, look at the similarly sized Shuttle Mir Docking Module in the Shuttle payload bay (only the orange structure was the module, the rest of the stuff was additional cargo or trusses):
Here is a hint, what else was in the payload bay with it
What else was in the payload bay with Shuttle Mir Docking Module?
:o ???
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If we think that the return flight would be the last flight for that orbiter, then why not using some cargo bands to tie up the Pirs to the cargo bay? Of course it would move and shake more or (hopefully) less during the landing, but by this way it won't require that much upmass penalties... And of course this would be pretty ugly way to treat space hardware, but might do the trick.
Surely you're not serious! A module sliding all over the payload bay can do all kinds of damage to every single system needed for re-entry and landing! You're talking about a sizeable piece of free-flying hardware that can detroy the APUs, or smash into the cabin from behind. I don't think there would be enough lucky rabbits feet to keep that landing from being a bad day.
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The Mir docking module was equipped for a mounting in the Shuttle cargo bay, Pirs is not - i.e. Pirs can not be put into an empty space, because it can not be fixated in the cargo bay.
It would require a mounting cradle, which would occupy space and mass on the way up, so it would be a very bad deal to sacrifice upmass to bring back an old module.
The alternative would be to affix trunnion pins and a keel to Pirs.
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And how exactly do you propose doing that? Where are the suitable attach points?
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The Mir docking module was equipped for a mounting in the Shuttle cargo bay, Pirs is not - i.e. Pirs can not be put into an empty space, because it can not be fixated in the cargo bay.
It would require a mounting cradle, which would occupy space and mass on the way up, so it would be a very bad deal to sacrifice upmass to bring back an old module.
The alternative would be to affix trunnion pins and a keel to Pirs.
That is the way to affix trunnion pins and a keel to Pirs. Via a cradle. Directly attaching anything to PIRS is not viable.
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What else was in the payload bay with Shuttle Mir Docking Module?
:o ???
nothing. That is my point
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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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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
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What else was in the payload bay with Shuttle Mir Docking Module?
:o ???
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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Directly attaching anything to PIRS is not viable.
What is the technical basis for this assertion?
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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?
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What else was in the payload bay with Shuttle Mir Docking Module?
:o ???
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.
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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?
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What else was in the payload bay with Shuttle Mir Docking Module?
:o ???
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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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.
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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.
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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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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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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.
1) The original post asked two questions. Why might you want to return Pirs, and how would you go about doing it.
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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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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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.
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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.
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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.
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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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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.
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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.
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If the ISS Program really wanted to bring Pirs back (something I question the need for), then why not design a trunnion & keel cradle, with an integrated Russian Probe assembly at the rear, that can swivel up to project out of the Payload Bay.
Then, attach a grapple fixture to Pirs somewhere (shouldn't be too hard to do), grapple Pirs with the SSRMS, move it to the cradle, and bring it's drogue down over the protruding probe. Then, latch the probe to the drogue, just like any normal Russian docking, and swivel the probe back down into the Payload Bay, and latch it in place.
One possible issue I see is that the SSRMS might not have the reach to grapple Pirs (it may have when Node 3 is in place).
What does everyone think - is this feasible/viable?
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If NASA really wanted to bring Pirs back (something I question the need for), then why not design a trunnion & keel cradle, with an integrated Russian Probe assembly at the rear, that can swivel up to project out of the Payload Bay.
Then, attach a grapple fixture to Pirs somewhere (shouldn't be too hard to do), grapple Pirs with the SSRMS, move it to the cradle, and bring it's drogue down over the protruding probe. Then, latch the probe to the drogue, just like any normal Russian docking, and swivel the probe back down into the Payload Bay, and latch it in place.
One possible issue I see is that the SSRMS might not have the reach to grapple Pirs (it may have when Node 3 is in place).
What does everyone think - is this feasible/viable?
nope. Russian docking system needs a high impulse to engage. Attaching a grapple fixture is not a simple thing.
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One possible issue I see is that the SSRMS might not have the reach to grapple Pirs (it may have when Node 3 is in place).
A PDGF on Zarya would do the trick, I know that there was talk of taking the extra one on P6 and relocating it to Zarya.
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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.
LM lifeboat was never non viable.
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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.
LM lifeboat was never non viable.
I would argue that returning PIRS was also never non viable. We just don't have a pressing reason to do it at the moment.
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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.
LM lifeboat was never non viable.
I would argue that returning PIRS was also never non viable. We just don't have a pressing reason to do it at the moment.
There will never be one, hence it is non viable.
There isn't reason to overcome the billion plus dollar cost of a shuttle mission to do it.
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nope. Russian docking system needs a high impulse to engage.
Maybe the Shuttle could fire it's RCS (although doing so probably wouldn't create much relative velocity while the Shuttle was docked to ISS).
Or else, maybe a new type of latching system for the probe could be developed.
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Russian docking system needs a high impulse to engage.
And how is MRM-1 engaged ? what will provide the impulse ?
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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.
I completely agree that if a dedicated Shuttle flight were required for return of Pirs, based on the assumption that a cradle would take up much or most of the payload bay, then this would be a non-starter.
Could someone explain why the HST cradle, which is very large, also allows many, many tons of other payload to be carried by the Shuttle to 600 km altitude?
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One possible issue I see is that the SSRMS might not have the reach to grapple Pirs (it may have when Node 3 is in place).
What does everyone think - is this feasible/viable?
Bingo, you are the first to address a major issue, how to get Pirs into the Shuttle payload bay. If a PDGF were fitted onto FGB, this would be a difficult, but possible RMS maneuver.
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Could someone explain why the HST cradle, which is very large, also allows many, many tons of other payload to be carried by the Shuttle to 600 km altitude?
There isn't an HST cradle. HST has the trunnions and keel on it. When HST was first deployed by the shuttle there was nothing else in the payload bay
What was used for the repair missions was servicing cradle which attached to the aft of HST. It only held HST while on orbit. There other cradles that held the instruments and other hardware. HST could not have returned on a repair mission. A dedicated mission would be required.
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Russian docking system needs a high impulse to engage.
And how is MRM-1 engaged ? what will provide the impulse ?
AFAIK, the ISS RMS would provide the "impulse", but I could be wrong. One option not feasible is to have the RMS provide soft dock, and then to have a Progress or Soyuz dock with MRM-1 to then provide hard dock to ISS.
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Could someone explain why the HST cradle, which is very large, also allows many, many tons of other payload to be carried by the Shuttle to 600 km altitude?
There isn't an HST cradle. HST has the trunnions and keel on it. When HST was first deployed by the shuttle there was nothing else in the payload bay
What was used for the repair missions was servicing cradle which attached to the aft of HST. It only held HST while on orbit. There other cradles that held the instruments and other hardware. HST could not have returned on a repair mission. A dedicated mission would be required.
I was suggesting that the HST "Servicing cradle" was probably larger in volume and mass than any Pirs cradle, yet STS-125 was able to manifest both the HST Servicing Cradle plus many tons of extra equipment.
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One possible issue I see is that the SSRMS might not have the reach to grapple Pirs (it may have when Node 3 is in place).
A PDGF on Zarya would do the trick, I know that there was talk of taking the extra one on P6 and relocating it to Zarya.
My understanding is that placement of this PGDF on FGB is a requirement for the MRM-1 airlock to be transferred to MLM. However, given the slippage of MLM launch, the requirement to move the PGDF from P6 to FGB is not pressing.
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One possible issue I see is that the SSRMS might not have the reach to grapple Pirs (it may have when Node 3 is in place).
What does everyone think - is this feasible/viable?
Bingo, you are the first to address a major issue, how to get Pirs into the Shuttle payload bay. If a PDGF were fitted onto FGB, this would be a difficult, but possible RMS maneuver.
But, if the SSRMS were based from Zarya, then it probably wouldn't be able to reach the Shuttle's Payload Bay.
So, Pirs would probably have to be handed-off to the SRMS (but then you'd need two FRGF's on Pirs).
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Other than the PLM, there are no other missions with an empty payload bay
Is this actually true? If so, are there missions that will return with a partially empty payload bay?
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And if they launch the PLM as planned on STS-133 even with a shuttle extension MLM will not have been launched get.
I don't understand this assertion. What if the Administration chooses to stretch out the Shuttle program until November 6, 2012? Would the statement above still be true?
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Pirs will be undocked right before MLM is launched, the port will just not be used for a little while.
Note that Pirs can be removed long before MLM is launched; its simply a matter of fitting a hybrid docking adapter on any visiting vehicle programmed to dock with Zvezda nadir. Soyuzes have already docked with space stations using a similar adapter, its just a matter of accepting the additional 100 kg or so mass hit, and in the next few years, we will see Soyuzes and Progresses launched on Soyuz 2, which will provide the additional mass margin.
One concern that would arise from an early departure of Pirs from ISS is the possibility that MLM would have a bad day between its launch and docking with ISS (I do not believe that Pirs would be removed if it appeared that MLM launch was not perceived to be really happening in the relatively near future). In that even, if Pirs were returned to Earth by Shuttle, Pirs itself could serve as the MLM backup, if the MLM were to fail, as a refurbished Pirs could be launched on a Progress bus back to ISS.
Which gives us another rationale for returning Pirs on Shuttle, since the current baseline is to remove and destroy Pirs, and then hope that MLM works, and if not, Zvedza nadir port remains hybrid forever.
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Other than the PLM, there are no other missions with an empty payload bay
Is this actually true? If not, are there missions that will return with a partially empty payload bay?
I'm under the impression that 129 will land with an emptly PLB, so will 130, 134, 133
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Other than the PLM, there are no other missions with an empty payload bay
Is this actually true? If not, are there missions that will return with a partially empty payload bay?
There are no more assembly missions, no more items to be left at the ISS. The "additional" missions will just be resupply, MPLMs and ELC's
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Which gives us another rationale for returning Pirs on Shuttle, since the current baseline is to remove and destroy Pirs, and then hope that MLM works, and if not, Zvedza zenith port remains hybrid forever.
That is not a viable reason. A new Pirs would be easier.
I can provide many other what ifs. Don't undock ATV's, the next one might not dock.
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Other than the PLM, there are no other missions with an empty payload bay
Is this actually true? If not, are there missions that will return with a partially empty payload bay?
I'm under the impression that 129 will land with an emptly PLB, so will 130, 134, 133
Still forgetting the Pirs cradle.
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There are no more assembly missions, no more items to be left at the ISS. The "additional" missions will just be resupply, MPLMs and ELC's
I think that ELC's + Node 3 count as assembly missions.
Which gives us another rationale for returning Pirs on Shuttle, since the current baseline is to remove and destroy Pirs, and then hope that MLM works, and if not, Zvedza zenith port remains hybrid forever.
Unless of course you put some kind of Hybrid-to-Probe & Drogue adapter hatch in Zvezda's zenith port, much like this style of hatch (obviously the hatch would need to include all the necessary hardware to latch spacecraft in place):
(http://www.nasa.gov/images/content/356102main_korth_exp20_sm_covers.jpg)
Also, I'm under the impression that MLM will dock at Zvezda's nadir.
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Other than the PLM, there are no other missions with an empty payload bay
Is this actually true? If not, are there missions that will return with a partially empty payload bay?
I'm under the impression that 129 will land with an emptly PLB, so will 130, 134, 133
Still forgetting the Pirs cradle.
No one can possibly forget your assumed Pirs cradle, but it would be nice to separate urban legends from actual facts. It appears that many Shuttle missions will land with an empty payload bay, despite your earlier assertion.
There is also an assertion that a Pirs cradle would have a large volume, which is something to be examined.
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I think that ELC's + Node 3 count as assembly missions.
We are talking the extension missions.
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No one can possibly forget your assumed Pirs cradle, but it would be nice to separate urban legends from actual facts. It appears that many Shuttle missions will land with an empty payload bay, despite your earlier assertion.
What urban legends? What are you calling me out on?
You are trying to look at something that is not viable, Can't you take a hint.
Which missions ? We are talking extension missions, not the ones on the current manifest.
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Unless of course you put some kind of Hybrid-to-Probe & Drogue adapter hatch in Zvezda's zenith port, much like this style of hatch (obviously the hatch would need to include all the necessary hardware to latch spacecraft in place):
Also, I'm under the impression that MLM will dock at Zvezda's nadir.
I screwed up and confused Zvezda Nadir with Zenith. MLM and Pirs operate at Zvezda Nadir. Sorry.
As for your adapter hatch for Zvezda NADIR in case MLM has a bad day, sure, it could be done, in theory a Progress could deliver it on its nose, subject to control-ability issues, or it could be carried up by Shuttle, although Jim will tell us that's not possible because its cradle would take up the whole payload bay. ;D
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There is also an assertion that a Pirs cradle would have a large volume, which is something to be examined.
It would be as long or longer than the PIRS and then add the clearance for placing it in the bay, which will negate room for a MPLM.
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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.
SO this was a slam.
The MPLM is not going to be parked at the ISS. It is a PLM, a big difference.
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We are talking the extension missions.
Ah, OK. I just got confused when you mentioned ELC's - all ELC's are currently planned to be launched on currently manifested missions.
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And also, maybe a cradle for Pirs could be, at least partially, constructed on orbit - there are already some unused keel assembly's on the ISS, that were used when the S0, S1 & P1 Trusses were launched.
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What urban legends? What are you calling me out on?
You are trying to look at something that is not viable, Can't you take a hint.
Which missions ? We are talking extension missions, not the ones on the current manifest.
My original post suggested that we look at the possibility of extending or stretching out the Shuttle manifest, and if this happened, could Pirs be retrieved by Shuttle from ISS. I suggested that there may be missions that return to Earth with an empty payload bay, to which you responded:
Quote from: Jim on 09/28/2009 03:46 PM
Other than the PLM, there are no other missions with an empty payload bay
which does not appear to be accurate, thus the comment "urban legend". There have been other urban legends in this thread also, such as the "Pirs will not fit in the Shuttle payload bay", although its only 2.55 meters in diameter.
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And also, maybe a cradle for Pirs could be, at least partially, constructed on orbit - there are already some unused keel assembly's on the ISS, that were used when the S0, S1 & P1 Trusses were launched.
I had no idea about this. Where are those keels now, and what is being done with them?
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And also, maybe a cradle for Pirs could be, at least partially, constructed on orbit - there are already some unused keel assembly's on the ISS, that were used when the S0, S1 & P1 Trusses were launched.
I had no idea about this. Where are those keels now, and what is being done with them?
Keels are not a generic item, that is swapped between spacecraft. The keel is another trunnion but in a different plane than the others. What holds the keel trunnion varies greatly between spacecraft. The truss keel assembly's are not viable for this.
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And also, maybe a cradle for Pirs could be, at least partially, constructed on orbit - there are already some unused keel assembly's on the ISS, that were used when the S0, S1 & P1 Trusses were launched.
I had no idea about this. Where are those keels now, and what is being done with them?
They are currently being stored inside the Truss.
Here's a photo of one of them.
I'll look for some more.
(http://www.spaceflight.nasa.gov/gallery/images/shuttle/sts-110/lores/sts110-304-010.jpg)
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Keels are not a generic item, that is swapped between spacecraft. The keel is another trunnion but in a different plane than the others. What holds the keel trunnion varies greatly between spacecraft. The truss keel assembly's are not viable for this.
The keel's in question were designed to support the S0/S1/P1 Truss segments, which weighed 13,132 Kg, 12,572 Kg, & 12,500 Kg respectively. Pirs weighs a comparatively small 3,580 Kg, so I would think that they would structurally be able to support Pirs.
Also, they will not be needed for the Truss segments ever again, so I see no problem with removing them - it would be a fairly simple EVA task.
I'm just trying to establish the feasibility of launching a "flat-packed" cradle for Pirs.
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Just for the record, here's some photo's of the keel assembly's in question:
Here they are attached to the S0 Truss (they needed to be removed once on orbit, as they would have prevented the MT from moving along the S0's rails):
(http://www.spaceflight.nasa.gov/gallery/images/shuttle/sts-110/lores/sts110-341-002.jpg)
Here's a couple of shots of them once they were removed on orbit:
(http://www.spaceflight.nasa.gov/gallery/images/shuttle/sts-110/lores/sts110-716-026.jpg)
(http://www.spaceflight.nasa.gov/gallery/images/shuttle/sts-110/lores/s110e5537.jpg)
You can see the keels installed inside the truss at the very right of this photo:
(http://www.spaceflight.nasa.gov/gallery/images/shuttle/sts-126/lores/s126e013902.jpg)
Hi-res version: http://www.spaceflight.nasa.gov/gallery/images/shuttle/sts-126/hires/s126e013902.jpg
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I'll get into the discussion. I too find this question interesting, even though it most probably won't ever need to be considered. But as a hypothetical question, it seems appealing.
So the main showstoppers you've talked about so far are volume, how to get a cradle up, how to attach it to Pirs, how to maneuver it to the payload bay and which mission can bring it down.
The volume issue is settled, because it would easily fit in the payload bay even with a cradle. There are also flights coming down with an empty payload bay (you forgot to mention 132, which will only bring the ICC back. That makes a total of 5 downmass-empty flights. Excluding extension, the only viable flights to bring it down would be 132, 133 and 134, because of the time needed for planning the operation. Of course, as it's not a pressing issue, it's probable it wouldn't be ready even for 133, but just talking from a technical standpoint.
How to transport it to ISS? If it's somehow made foldable and takes advantage of the existing keels (assuming some clever way to mount them with the cradle structure was devised), it could be delivered on an ELC. That would of course mean few to no ORUs in that ELC, which isn't a good tradeoff if there's no extension. The only other mission that may have the volume to hold a foldable/unfoldable cradle would be 130, but its APM is too low. So no extension = no Pirs cradle even if they really wanted it done.
The attachment to Pirs seems easier to me (from my untrained perspective) because you could build a sort of double ring structure that would hold the module from its two docking ends, keeping it in place. The cradle could even be fitted with a PDGF (or two) so that it could be maneuvered to/from Pirs instead of the other way round. That plan would probably mean a Zarya PDGF or using MRM-1 as a base (but I think this isn't possible because MRM-1 will have a FRGF?)
So, if they suddenly wanted Pirs down for some very pressing reason, it couldn't be done unless a Shuttle extension was approved? Could the cradle I proposed be concievably (and with a reasonable budget) be built?
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Let me attack the cradle issue from a different perspective. First off, the most important decision is the orientation of Pirs in the Shuttle payload bay. The standard orientation would be lengthwise down the payload bay, similar to MRM-1 or the Docking Module. However, transverse mount (ie sideways) should also be considered, as well as the unfamiliar vertical mount.
In particular, vertical mounting would have advantages that don't seem to be obvious at first, but such an attitude would mostly obviate the cradle issue. Instead of a cradle, a "sort of" Russian male docking adapter could be flown in the Shuttle, locked into a keel pin socket. Then, Pirs would be moved by the RMS to be mated (via the Pirs passive docking adapter), hard docked in the vertical position, with 2 trunions attached to its sides (that part is still magic, although its possible that the truss keel pins mentioned above could be used as trunnions. Once hard docked to a keel fixture fixed to the floor of the payload bay, and assuming that this keel fixture (based on a Russian docking adapter), I suspect that Pirs would be very securely attached to the payload bay.
This "sort of" Russian docking adapter would have a mass about 200 kg, and be small enough to fit under an ICC, ELC and maybe even AMS-02, so it would not "fill the payload bay" as suggested above.
What I don't know is if there is a way to use the truss keel pins as trunnions for Pirs. With a max diameter of 2.55, and assuming a Shuttle payload bay diameter of (geez, I forgot what it is) around 4.5 meters, each keel pin must extend about 1 meter laterally, which from the photos is about their length. How the keel pins or any trunnion, would attach to Pirs is TBD at the moment.
This is a hand wave explanation for one orientation, I am sure that there are others for the other orientations, as well.
The trick is to minimize the mass and volume of the cradle. How that would be done would very interesting.
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so I would think that they would structurally be able to support Pirs.
That is a minor consideration. The dimensions are more critical.
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In particular, vertical mounting would have advantages that don't seem to be obvious at first, but such an attitude would mostly obviate the cradle issue. Instead of a cradle, a "sort of" Russian male docking adapter could be flown in the Shuttle, locked into a keel pin socket.
A. What says the russian docking adapter can take shuttle landing loads? docking loads are much less
B. The keel can not handle a free standing object. That is reason for the cradle.
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How the keel pins or any trunnion, would attach to Pirs is TBD at the moment.
That is the whole issue.
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A. What says the russian docking adapter can take shuttle landing loads? docking loads are much less
This is a very good question. However, the question assumes that the object under consideration is a standard probe and cone system, although it may turn out to be similar but more robust.
To be fair, I should try to answer the question, though. There really are two different kinds of loads to consider during the Shuttle return, continuous and transitory, where the latter are the sharp loads caused by, say, landing on the ground, and the former are the G-loads that are incurred during the actual re-entry itself, plus the 1g vertical load from the 4 ton mass of Pirs.
I am fairly certain that even the standard Russian docking adapter can handle the 1g vertical load, since Progress often maintains ISS on its nose (so to speak) during orbital adjustments - although the Progress engines only generate a fraction of 1g acceleration, ISS has a very large mass; since ISS is not a point mass, and has large dispersions from its c/g (especially with Kibo and Columbus hanging off the sides plus the truss), there are large axial loads on the docking adapter, during these burns, as well. I should mention that the docking hooks and latches are supplemented by clamps during these operations, which help with the loads a bit.
Even more significant are the loads imparted on the Zvezda-Zarya docking adapter when the 2 Zvezda engines provide an orbital correction; although in this case, its a hybrid port handling the loads, the 2 Zvezda engines provide > 600 kg of thrust, which apparently provides noticeable acceleration.
I cannot do the math to calculate the loads with any precision, but its fairly obvious that the loads on the docking adapter are fairly high during these prolonged operations.
As far as the transitory loads, these are precisely what the docking adapter is designed to mitigate. However, once again to be fair, the adapter was not designed to handle axial transitory loads that would be incurred during landing; its good that there would be trunnions to help with those loads.
Note that all of this discussion relates to a hypothetical carrying of Pirs in an upright attitude in the Shuttle cargo bay. There are other attitudes that probably can handle the loads much better.
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How the keel pins or any trunnion, would attach to Pirs is TBD at the moment.
That is the whole issue.
So, at least we are near the point that if someone figures out how to attach trunnions and a keel pin to Pirs, we are home free. Hopefully, someone here is sharp enough to figure that one out. :-\
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Here they are attached to the S0 Truss (they needed to be removed once on orbit, as they would have prevented the MT from moving along the S0's rails)
It looks like they have little bolt thingies on the ends that were probably used to connect to the truss elements. If these bolts could be removed on orbit, there is probably a way to use them to connect to Pirs on orbit, as well, as long as are suitable hard points on Pirs.
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How the keel pins or any trunnion, would attach to Pirs is TBD at the moment.
That is the whole issue.
So, at least we are near the point that if someone figures out how to attach trunnions and a keel pin to Pirs, we are home free. Hopefully, someone here is sharp enough to figure that one out. :-\
This was the purpose of my idea: avoid attaching anything to Pirs transferring the loads to the docking rings at both ends. A pair wider, clamshell-opening rings that would hold Pirs' rings could be included at both ends of the hypothetical cradle. Each one of them would need a keel pin to hold them to the bottom of the payload bay.
A cage-like structure over and below the main body of Pirs would rigidize the system and avoid misalingments/shiftings, and possibly incorporate (or allow for them to be added on-orbit) the trunnions. This could be the concievably foldable structure, or at least disassemblable, so that it wouldn't take up as much volume at launch. The rings could even be launched separately from the main structure.
All this is absolutely armchair speculation, of course, perhaps a structure assembled this way couldn't carry the loads or even be feasibly constructed in space.
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Remember that any folds must be able to handle loads of 5 tons + at any particular moment. I am not suggesting that this is easy concept to implement, I simply object to arm waving assertions that its "not viable" without looking at the options.
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Just a few thoughts and please remember that I don't have a dog in this fight.
1) The Pirs module was launched by a Soyuz/R7 rocket, so we know that it is engineered to take a Soyuz launch's g-loads along its vertical (SM-to-Soyuz) axis. I will leave it to those more engineering-savvy than me to say upon which axis the maximum g-loads would be during a shuttle's re-entry, descent and landing.
2) If Pirs is being replaced by MLM-1, is is possible to modify the MLM cradle so that it can support Pirs on the way down?
This is an intreguing thought experiment but I have to agree that the benefits of examining Pirs on the ground would be more than outweighed by the cost of developing the tools and proceedures needed to return it. The problem is, unlike those items regularly returend from the ISS, it was never intended for return. Because of this, doing it is that much more difficult and cotostly. Ultimately, if there was no overwhelming pressing reason for doing so, I can't see either NASA or Roscosmos being interested in it.
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MLM (I assume you mean the Russian module to be launched on STS-132) is not launched in a craddle. It is supported in the payload by its own trunnions.
I still don't see much value in the whole exercise: You can inspect LDEF, EURECA, MISSE or HST elements / experiments if you want to learn about long duration LEO exposure - from months up to more than a decade.
The best solution I see is something like a spacelab pallet on which PIRS would be mounted: Think of HS376 during STS-51A. But I don't see the value.
Analyst
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I am fairly certain that even the standard Russian docking adapter can handle the 1g vertical load, since Progress often maintains ISS on its nose (so to speak) during orbital adjustments - although the Progress engines only generate a fraction of 1g acceleration,
That is not proof and actually means the loads are small. The loads are produced by the thrusters which are low thrust.
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since ISS is not a point mass, and has large dispersions from its c/g (especially with Kibo and Columbus hanging off the sides plus the truss), there are large axial loads on the docking adapter, during these burns, as well. I should mention that the docking hooks and latches are supplemented by clamps during these operations, which help with the loads a bit
No, those loads are not seen at the Progress interface. The Progress only sees the small axial load that the thrusters are causing. It isn't firing side thrusters. Kibo and Columbus interfaces are the ones that see the loads from the offset CG.
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I simply object to arm waving assertions that its "not viable" without looking at the options.
What arm waving? I have not done any of that. You are the one making the gross inaccurate assumptions.
I know it is not feasible.
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MLM (I assume you mean the Russian module to be launched on STS-132) is not launched in a craddle. It is supported in the payload by its own trunnions.
I still don't see much value in the whole exercise: You can inspect LDEF, EURECA, MISSE or HST elements / experiments if you want to learn about long duration LEO exposure - from months up to more than a decade.
The best solution I see is something like a spacelab pallet on which PIRS would be mounted: Think of HS376 during STS-51A. But I don't see the value.
Analyst
Bingo
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Here they are attached to the S0 Truss (they needed to be removed once on orbit, as they would have prevented the MT from moving along the S0's rails)
It looks like they have little bolt thingies on the ends that were probably used to connect to the truss elements. If these bolts could be removed on orbit, there is probably a way to use them to connect to Pirs on orbit, as well, as long as are suitable hard points on Pirs.
What hard points and if there were, what are the chances that they are in the right place?
Drill holes and bolt on or weld on the trunnions and a keel pin. Two things that are not going to happen. Also what fixture is going to provide the precise measurements for aligning the hardware.
It needs a cradle that would "strap" it down or have interfaces with the rings at the ends.
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How the keel pins or any trunnion, would attach to Pirs is TBD at the moment.
That is the whole issue.
So, at least we are near the point that if someone figures out how to attach trunnions and a keel pin to Pirs, we are home free. Hopefully, someone here is sharp enough to figure that one out. :-\
there isn't a way
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The best solution I see is something like a spacelab pallet on which PIRS would be mounted: Think of HS376 during STS-51A. But I don't see the value.
Analyst
The question is how would Pirs be mounted to the Spacelab Pallet? A Pirs to pallet adapter would have to be created, and someone would raise the following issues:
a) Pirs was not intended to fly on a SpaceLab pallet;
b) The attachments between Pirs and the pallet would have to be installed in space without a system for finely determining the measurements;
in short, all the problems with emplacing Pirs in the shuttle payload bay exist for emplacing Pirs in a SpaceLab pallet.
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I still don't see much value in the whole exercise: You can inspect LDEF, EURECA, MISSE or HST elements / experiments if you want to learn about long duration LEO exposure - from months up to more than a decade.
This ignores the long debate about prolonging the life of Mir space station; the data from the systems above were not germane to that debate.
I guarantee you at the end of this decade that some will want to end ISS precisely because the condition of the Russian segment will be unknown, and therefore maintaining humans at ISS will be declared risky. We don't have a good baseline for understanding the long term condition of the Russian segment.
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The question is how would Pirs be mounted to the Spacelab Pallet? A Pirs to pallet adapter would have to be created,
Easier than a making a dedicated cradle
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I guarantee you at the end of this decade that some will want to end ISS precisely because the condition of the Russian segment will be unknown, and therefore maintaining humans at ISS will be declared risky. We don't have a good baseline for understanding the long term condition of the Russian segment.
Incorrect. It can be analyzed without inspection. This is done all the time. But there is a baseline, it was called MIR. Also the USOS has elements that are just as old. What is going to be done for it?
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What hard points and if there were, what are the chances that they are in the right place?
Drill holes and bolt on or weld on the trunnions and a keel pin. Two things that are not going to happen. Also what fixture is going to provide the precise measurements for aligning the hardware.
It needs a cradle that would "strap" it down or have interfaces with the rings at the ends.
In some sense this is a semantic issue, since whatever interface between the Shuttle and Pirs were developed, Jim would claim that this is his "cradle", and therefore he was right, just as with the earlier "why can't they leave an MPLM at ISS" thread, at the end of the day, after months of claiming that "it couldn't be done", when NASA decided it COULD be done, Jim was able to conclude that the modifications to make an MPLM a PLM meant that a MPLM couldn't be left at ISS, so he was right.
In short, if some sort of light and compact cradle, or an alternative set of trunnions and a keel pin were developed, and Pirs were returned, Jim would tell us: "see, you needed a cradle". I am not interested, however, in that semantic argument, what I am interested in are ways to make the return hardware as light as possible and as simple as possible, without sacrificing Shuttle safety requirements.
The major programmatic and technical issues at the moment in returning Pirs are:
1) The Shuttle program has not been extended or stretched yet, so there is no manifest in 2011 or 2012 to return Pirs;
2) There is no base point for the ISS RMS to be located so that it could interface with Pirs;
3) There is no grapple fixture on Pirs.
4) Pirs does not currently have interface hardware for Shuttle return, ie the trunnions and keel pin.
Suggestions on how to address the last three points would be welcome. More posts in the vein of "it can't be done" are not.
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There have a few videos from Roskosmos on this site lately, related to transport of MRM-2 to and from the vacuum chamber. What is relevant to this thread is that the module, which is virtually identical to Pirs, is transported via 2 large hubs that are somehow attached to the Docking Compartment, ie there are hard points on the exterior of the Docking Compartment which are capable of extremely high loading.
A close look at those hard points indicates that the hubs are attached to the Docking Compartment via a small number of bolts, which is amazing to me - that maybe 8 bolts can handle all of the mass of the Docking Compartment. Of course, getting back to this thread, if a way to connect those hard points to trunnions could be developed, then transport of Pirs in the Shuttle payload bay may be possible.
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, ie there are hard points on the exterior of the Docking Compartment which are capable of extremely high loading.
You have no proof of that
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if a way to connect those hard points to trunnions could be developed, then transport of Pirs in the Shuttle payload bay may be possible.
That has been the main issue all along. No possible without welding or drilling. The cradle is needed that has large circular clamps to hold it in place.
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, ie there are hard points on the exterior of the Docking Compartment which are capable of extremely high loading.
You have no proof of that
I have some detailed shots better showing the hard points, which apparently use bolts to handle the loads.
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if a way to connect those hard points to trunnions could be developed, then transport of Pirs in the Shuttle payload bay may be possible.
That has been the main issue all along. No possible without welding or drilling. The cradle is needed that has large circular clamps to hold it in place.
Identification of hard points on MRM-2 would obviate this concern.
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, ie there are hard points on the exterior of the Docking Compartment which are capable of extremely high loading.
You have no proof of that
I have some detailed shots better showing the hard points, which apparently use bolts to handle the loads.
All the items that are red are removed before flight. There are no flight hard points. The red rings are what clamps in a cradle would replicate
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, ie there are hard points on the exterior of the Docking Compartment which are capable of extremely high loading.
You have no proof of that
I have some detailed shots better showing the hard points, which apparently use bolts to handle the loads.
All the items that are red are removed before flight. There are no flight hard points. The red rings are what clamps in a cradle would replicate
What do the red rings attach to? Actually, this is a rhetorical question - the red rings attach to hard points on Pirs.
The lower of the two red "rings" attach to hard points on the base of the Progress M PAO which are also on the separation plane of the spacecraft and the adapter section for Soyuz. Unfortunately, this PAO is detached from Pirs on orbit, so those hard points no longer exist. Fortunately, there is also a separation plane between Pirs and the PAO with hard points, for which I do not have a good photo, but I have seen images showing the hard points on the lower portion of Pirs.
I believe that I have identified a candidate location for placement of a Shuttle grapple fixture, as well.
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All the items that are red are removed before flight. There are no flight hard points. The red rings are what clamps in a cradle would replicate
A point of information here: for return aboard Shuttle, Pirs would not require rings, as used on Earth, but, at the most, "half rings" since, AFAIK, there are no significant loads in the -Y axis for return to Earth. Obviously, given that at Baikonur, Pirs (and Progress) are transported via 360 degree rings, there are hard points around the entire circumference of the spacecraft.
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A point of information here: for return aboard Shuttle, Pirs would not require rings, as used on Earth, but, at the most, "half rings" since, AFAIK, there are no significant loads in the -Y axis for return to Earth.
Incorrect. There are the landing loads.
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What do the red rings attach to?
Not "hard points", that is why there are rings. They distribute the loads around the circumference of the vehicle.
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Taking a step back...
Just for a moment, let's presume a way exists to safely return this module and we do so.
Now what? The OP posits that we could "examine it on the ground". _Exactly_ what 'examinations' are proposed? What do we expect to find?
'We won't know until we get it back' is not a good answer - you'd need to do a lot better than that if you were asking me for the money. Even in basic research science, the principal investigators are required to come up with a pretty detailed description of what they are looking for and what they think they'll find before they get funding.
In particular, what would you do on the ground that you couldn't do on orbit, by taking samples, pictures, etc. on orbit and returning them? What new data would you gather that you couldn't get by analyzing data about similar materials gathered via MISSE or other space experiments?
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This is a very good question, so I should probably answer it.
In a few years, there will be a great debate about the future of ISS. If you think there's a debate now about ending ISS in 2015-16, wait until 2014 or so when the money needs to found to keep ISS flying. Although few Americans will doubt whether Node 1 is flightworthy, just as the "aging Mir space station" (aging when it was less than 10 years old) caused many to question whether that platform was viable as early as 1995, some in Congress and NASA will call for the ending of ISS due to the age of Russian modules. This debate ultimately will rest on the technical decision about whether some of the older modules are still flightworthy.
We saw during the debate about the future of the Mir station that the amount of data considered during the debate was small - those who opposed Mir simply declared that the station was old, and therefore should be abandoned. A handful of anecdotes about failing components served to make the case that Mir should be de-orbited.
ISS is an extraordinarily expensive asset, and it would be unfortunate if its future were likewise debated and decided on the basis of anecdotes. Since the debate will likely focus on Zarya and Zvezda; however, due to difficulty of on-orbit examination of their structure and subsystems, a reasonable substitute would be to inspect Pirs, which shares many subsystems, and structural components, with the two larger Russian modules.
One major concern expressed during the Mir debate was the condition of the internal cooling loop. Since Pirs has a similar cooling loop, inspection of this subsystem. including the interface with Zvezda, would indicate the likelihood of potential future failures in the rest of the Russian segment. The ISS crew cannot access much of the cooling loop on Pirs, or the rest of the Russian segment. De-assembly of the Pirs hybrid docking adapter and its Triol lines will likely be required for accurate inspection.
Another area to inspect would be the Pirs nadir docking port, as well as the hybrid port; AFAIK, no probe and cone system exposed to space and multiple dockings over 10 years has ever been inspected to verify that it meets its certified lifetime.
The last major area to examine (that cannot be inspected by the crew) is the primary structure. It would be useful to determine whether the structure has been impacted by orbital debris - the only way to do this is to remove all the MLI and take a look, which is not practical on orbit.
Since safe return of Pirs would allow the debate over the future of ISS to be conducted on the basis of rigorous science and not anecdotes, the return is probably justified on that basis (assuming that empty Shuttle payload bays would be available in the outyears and that the return is technically feasible). However, the return of Pirs would also provide for additional downmass of some 2 tons, which could also be useful, plus Pirs may be refurbished and flown as a replacement for MRM-2 down the road, when that module reaches the end of its 5 year lifetime; alternatively, a refurbished Pirs could serve as a substitute for MLM, if that module never makes it to ISS.
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The best solution I see is something like a spacelab pallet on which PIRS would be mounted: Think of HS376 during STS-51A. But I don't see the value.
Analyst
Well, the dimensions I found quote a length of 16 feet, making it too large to stand vertically in a spacelab pallet. Something like the arrangement for PMA-3 on STS-92 using the handling rings from the 2nd photo might work if the loads are acceptable. An alternative may be to capture both docking mechanisms if the handling ring hard points aren't up to the task.
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Putting Pirs on a Spacelab Pallet simply adds mass, but does not solve the problem of attachment of Pirs to the Shuttle. Whatever bolts would attach Pirs to SLP could also be used to attach Pirs to trunnions and a keel pin, obviating the mass of the SLP.
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Whatever bolts would attach Pirs to SLP could also be used to attach Pirs to trunnions and a keel pin, obviating the mass of the SLP.
The SLP has the trunnions and a keel pin. It has many attach points that would be easier to hold fittings to the PIRS.
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Rather than have Pirs disposed of by having a Progress dock with it, and then at end of mission, dump Pirs into a destructive de-orbit, why not return Pirs on the Shuttle? Clearly, it would be difficult to return Pirs on the shuttle under the current manifest, but if the Shuttle program were stretched out, or additional flights were authorized, one of those later missions could probably return Pirs to Earth.
The questions are: why return Pirs, and how to do it?
???
Get Lavochkin to use one of their inflatable re-entry devices!
http://www.spaceflight.esa.int/irdt/factsheet.pdf
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I think I have "solved" the cradle issue.
Looking at the attached photo of the Shuttle Mir Docking Module, I noticed that this is described as Energia technicians fitting trunnions to the module. This work was done at KSC. The question is whether there are special interfaces on the module to accept the trunnions, but I realized that interfaces seem to be the same as used to accept the loading rings used to transport the module.
Since Pirs uses the same loading rings, it appears that Pirs could be adapted to interface with a set of trunnions, as well, assuming the trunnions were similar to those fitted on MRM-1 (Rassvet) - which leads to the question as to whether the MRM-1 trunnions could be removed in situ (after docking with ISS) and transferred over to Pirs. Of course, this is hypothetical, since its not likely the Shuttle will around to return Pirs in a couple of years.
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I think I have "solved" the cradle issue.
Looking at this photo of the Shuttle Mir Docking Module:
http://science.ksc.nasa.gov/shuttle/missions/sts-74/images/high/KSC-95EC-1084.jpg
I noticed that this is described as Energia technicians fitting trunnions to the module. This work was done at KSC. The question is whether there are special interfaces on the module to accept the trunnions, but I realized that interfaces are the exact same as used to accept the loading rings used to transport the module.
Since Pirs uses the same loading rings, it appears that Pirs could be adapted to interface with a set of trunnions, as well, assuming the trunnions were similar to those fitted on MRM-2 - which leads to the question as to whether the MRM-2 trunnions could be removed in situ and transferred over to Pirs. Of course, this is hypothetical, since its not likely the Shuttle will around to return Pirs in a couple of years.
No, because there is nothing on orbit to align the trunnions. The orbiter requires the trunnions to be in very specific locations. They are optically aligned on the ground
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It appears that the MRM-1 trunnions are welded on. They don't match up with the standard mounting locations (where the hemispheres meet the cylindrical section), for reasons that I won't go into here.
However, I haven't seen a good image of the keel pin yet, it may not have been installed yet, so this may be transferable to Pirs in the future.
Looking at the attached image, the red "transfer rings" that are bolted to Rassvet are attached in the following way:
Front ring: Attached to front hemisphere, apparently at the standard location (Pirs and Poisk rings were attached where the hemisphere meets the central section, whereas Rassvet's front transfer ring attaches to the same location, except that the ring itself is not located over this point, but is offset to the front, and special connectors carry the loads).
Rear ring: Attaches in the same manner as Pirs and Poisk, to the junction of the 2.2 meter cylindrical section and the frustrum that contains the rear docking adapter.
Transport:
If Rassvet followed the pattern of the Shuttle Mir Docking Module, the trunnions would not be attached until after shipment to Florida, and in the meantime, the transfer rings would be attached where the trunnions are today. However, Rassvet's trunnions were attached in Moscow prior to transport to the USA, as indicated below. This necessitated the "rear" transport ring to be offset from the real trunnion. This does not explain, however, why the front transfer ring is located in a non-standard position, but my guess is that the tiny airlock module, located on top of the main Rassvet body, is so close to the juncture of the front hemisphere and the 2.2 meter cylindrical section, ie the "normal" location for the transfer ring, that the ring is offset to avoid contact with the airlock module.
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No, because there is nothing on orbit to align the trunnions. The orbiter requires the trunnions to be in very specific locations. They are optically aligned on the ground
This is a constraint, not a show stopper. The trunnion locations cannot be as precise as is implied above, since objects are removed from the shuttle on orbit, heated and cooled, and replaced back in the shuttle - thermal expansion should misalign the trunnion pins to some degree, but apparently the trunnion locations have enough "play" in them to accommodate any thermal expansion. LDEF comes to mind as a payload left in orbit for years, and then reinserted into the shuttle with no problem.
However, this constraint is significant. First off, the engineering of the trunnions for Pirs would have to be very precise. Secondly, its probable that the keel pin should be designed to have a little play, to allow the trunnions to be inserted before everything is locked down.
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This is a constraint, not a show stopper.
It is a showstopper.
Because the payloads go back to their original "thermo" condition, once in the benign environment of the payload bay and there is no residual stress being put in the orbiter by the trunnions.
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Transport:
If Rassvet followed the pattern of the Shuttle Mir Docking Module, the trunnions would not be attached until after shipment to Florida, and in the meantime, the transfer rings would be attached where the trunnions are today. However, Rassvet's trunnions were attached in Moscow prior to transport to the USA, as indicated below. This necessitated the "rear" transport ring to be offset from the real trunnion. This does not explain, however, why the front transfer ring is located in a non-standard position, but my guess is that the tiny airlock module, located on top of the main Rassvet body, is so close to the juncture of the front hemisphere and the 2.2 meter cylindrical section, ie the "normal" location for the transfer ring, that the ring is offset to avoid contact with the airlock module.
This picture demonstrates how it could be returned on the shuttle. The shipping container is like a pallet for the shuttle. It has the trunnions to interface with the shuttle. The module sits on the pallet and it clamped down with something similar to the rings. Any misalignments and residual stress are taken care by the pallet hardware and not the shuttle.
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Just taking a look back on this. Some of you think it is a good idea to bring Pirs home on a shuttle correct? I think thats nearly impossible, first of all many of you are forgetting Pirs doesn't have a grappling fixture either, how would the SSRMS or the SRMS grapple onto Pirs? And on the note of a 'cradle' a cradle would take up enough room in the PLB so that maybe only a ELC might go up, but unlikely. Also, in the terms of money, the cost of training, getting ready, prepping, launching, and landing (+ some more if it lands at EDW) it would most likely be cheaper to launch another MRM up to ISS than to launch a shuttle up to rescue it, and much less complex.
Orbiter
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Just taking a look back on this. Some of you think it is a good idea to bring Pirs home on a shuttle correct? I think thats nearly impossible, first of all many of you are forgetting Pirs doesn't have a grappling fixture either, how would the SSRMS or the SRMS grapple onto Pirs? And on the note of a 'cradle' a cradle would take up enough room in the PLB so that maybe only a ELC might go up, but unlikely. Also, in the terms of money, the cost of training, getting ready, prepping, launching, and landing (+ some more if it lands at EDW) it would most likely be cheaper to launch another MRM up to ISS than to launch a shuttle up to rescue it, and much less complex.
First off, no one but me thinks this is a good idea (to bring back Pirs on Shuttle).
#2, the grapple fixture issue is not a big deal, I will get to that later.
#3, no one is suggesting that a Shuttle be launched up to get Pirs, this concept would only work in that world in which the Shuttle were still flying in 2011-12 AND there were a mission that would return with an empty payload bay.
#4, Jim insists that a cradle would be necessary for return of Pirs, but Jim is occasionally wrong about such stuff, he is the guy who told us that an MPLM could not be stationed at ISS permanently, or that Rassvet could be not docked with ISS using the RMS. This is a common behavior in aerospace today - as long as NASA (or the customer) doesn't have a requirement to do "X", then "X" is impossible. Once NASA says that "X" is necessary, solutions come out of the woodwork. In this case, I am searching the woodwork now, in the unlikely event that Shuttle is extended.
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he is the guy who told us that an MPLM could not be stationed at ISS permanently,
I said it couldn't as is and there was no plans for it at the time. I said it needed mods. Anything is possible with more money.
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This is a common behavior in aerospace today - as long as NASA (or the customer) doesn't have a requirement to do "X", then "X" is impossible. Once NASA says that "X" is necessary, solutions come out of the woodwork.
I am not saying that PIRS can't be retrieved. I am saying that it is not feasible to bolt trunnions on it.
The solution out of the woodwork is a cradle like the DM shipping container.
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I am not saying that PIRS can't be retrieved. I am saying that it is not feasible to bolt trunnions on it.
Below is a photo of a module very similar to Pirs having trunnions bolted on.
At this point, Jim's position is that putting spacesuits on technicians makes them incapable of doing their jobs.
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This picture demonstrates how it could be returned on the shuttle. The shipping container is like a pallet for the shuttle. It has the trunnions to interface with the shuttle. The module sits on the pallet and it clamped down with something similar to the rings. Any misalignments and residual stress are taken care by the pallet hardware and not the shuttle.
The only way to interface Pirs with such a pallet would be to bolt the rings onto the appropriate hard points on the hemispheric interface. It would be just as easy to bolt trunnions on, and leave the cradle on Earth.
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At this point, Jim's position is that putting spacesuits on technicians makes them incapable of doing their jobs.
True. Technicians don't fly into space.
The issue isn't the people, it is lack of alignment fixtures or the ability to align them.
My position is that you don't understand the trunnion interface and the requirements associated with them.
Have you worked one of this payloads and seen what it takes for trunnion alignment?
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The only way to interface Pirs with such a pallet would be to bolt the rings onto the appropriate hard points on the hemispheric interface. It would be just as easy to bolt trunnions on, and leave the cradle on Earth.
Wrong.
A. I said clamp and not bolt
B. No, it wouldn't be easier. the ring to cradle interface can be adjustable and more robust.
C. You don't understand how finicky NASA is about the trunnion interface and the requirements they impose on the payloads. They don't want unknown loads put into the orbiter.
D. There is no guarantee that the bolt holes on the module are known (as built) to enable the trunnions to be fixed without adjustability.
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A. I said clamp and not bolt
B. No, it wouldn't be easier. the ring to cradle interface can be adjustable and more robust.
C. You don't understand how finicky NASA is about the trunnion interface and the requirements they impose on the payloads. They don't want unknown loads put into the orbiter.
D. There is no guarantee that the bolt holes on the module are known (as built) to enable the trunnions to be fixed without adjustability.
The last point is indeed a good one. The trunnions would have to be developed, keeping in mind the existing hard points on Pirs and the appropriate locations on the Shuttle. Fortunately, Energia has demonstrated that its possible to support Pirs-type modules by offsets from the hardpoint, as shown in the photos above.
BTW, Pirs does not have to provide "unknown loads", RSC Energia would be happy to provide similar data as they did for Rassvet to allow loads to be appropriately analyzed.
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1. The trunnions would have to be developed, keeping in mind the existing hard points on Pirs and the appropriate locations on the Shuttle.
2. BTW, Pirs does not have to provide "unknown loads", RSC Energia would be happy to provide similar data as they did for Rassvet to allow loads to be appropriately analyzed.
You don't get it.
1. That is the problem, the "unknown" location of the attach points means trunnions and their supports can't be adequately defined for the following.
2. Misaligned trunnions cause the "unknown" loads. That is the issue. It has nothing to do with Rassvet
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First off, no one but me thinks this is a good idea (to bring back Pirs on Shuttle).
#2, the grapple fixture issue is not a big deal, I will get to that later.
#3, no one is suggesting that a Shuttle be launched up to get Pirs, this concept would only work in that world in which the Shuttle were still flying in 2011-12 AND there were a mission that would return with an empty payload bay.
#4, Jim insists that a cradle would be necessary for return of Pirs, but Jim is occasionally wrong about such stuff, he is the guy who told us that an MPLM could not be stationed at ISS permanently, or that Rassvet could be not docked with ISS using the RMS. This is a common behavior in aerospace today - as long as NASA (or the customer) doesn't have a requirement to do "X", then "X" is impossible. Once NASA says that "X" is necessary, solutions come out of the woodwork. In this case, I am searching the woodwork now, in the unlikely event that Shuttle is extended.
3# No planned shuttle missions upcoming will have any room for Pirs.
4# But Jim is also often correct with his facts, and he was right an MPLM cannot be permanently attached to the space station, it lacks the micro-meteorite shield used on Modules. However a PMM, a highly modified MPLM, will be able to be permanently attached to ISS.
Also what purpose would a Pirs-return mission serve? What use would it provide on the ground? How about you take a progress in 2011 dock it to Pirs before MLM arrives, and take Pirs a few hundred miles out, and re-dock it to MLM. Only problem with that is that a Progress might not have enough fuel to rendezvous and re-dock.
Orbiter
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You don't get it.
1. That is the problem, the "unknown" location of the attach points means trunnions and their supports can't be adequately defined for the following.
2. Misaligned trunnions cause the "unknown" loads. That is the issue. It has nothing to do with Rassvet
The trunnions would be attached to Pirs exactly as they were to Shuttle Mir Docking Module (for the front set), and in the same location as for the rear Rassvet trunnions. The same trunnions can be used in both cases. This is nothing new, except for the installation on-orbit.
Misalignment of trunnions has been resolved in the past for Russian modules flying on Shuttle.
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3# No planned shuttle missions upcoming will have any room for Pirs.
4# But Jim is also often correct with his facts, and he was right an MPLM cannot be permanently attached to the space station, it lacks the micro-meteorite shield used on Modules. However a PMM, a highly modified MPLM, will be able to be permanently attached to ISS.
Also what purpose would a Pirs-return mission serve? What use would it provide on the ground? How about you take a progress in 2011 dock it to Pirs before MLM arrives, and take Pirs a few hundred miles out, and re-dock it to MLM. Only problem with that is that a Progress might not have enough fuel to rendezvous and re-dock.
Orbiter
This entire thread is based on the hypothetical assumption that Shuttle may be extended into early 2012. Its an assumption, not an assertion, its a "what if?". However, your assertion that no planned missions have room for Pirs has been dispelled earlier in this thread.
As for the question of what are the benefits of saving Pirs, they are explained in detail earlier in the thread.
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1. The trunnions would be attached to Pirs exactly as they were to Shuttle Mir Docking Module (for the front set), and in the same location as for the rear Rassvet trunnions. The same trunnions can be used in both cases.
2. This is nothing new, except for the installation on-orbit.
3. Misalignment of trunnions has been resolved in the past for Russian modules flying on Shuttle.
You still don't get it.
1. It is not the "same", there are always manufacturing differences and tolerance build up. There has to be the ability for adjustment and the ability to know the adjustment*. Even two exactly the same modules would have some differences@.
2, Which is very new, never been done.
3. There was nothing to "resolved" because they were aligned on the ground, using theodolites and optical reference points
* That is the problem, the ability to measure the alignment.
@ this even applied to Spacehab modules. There were differences in the shimming of the trunnions. This was not known until the modules were assembly and optical measurements were taken.
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This is a very interesting discussion. I will check with some shuttle experts and get back with this.
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This is a very interesting discussion. I will check with some shuttle experts and get back with this.
So who am I? Just someone that has been blowing smoke up your a$$?
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This is a very interesting discussion. I will check with some shuttle experts and get back with this.
So who am I? Just someone that has been blowing smoke up your a$$?
I am referring to shuttle designers.
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This is a very interesting discussion. I will check with some shuttle experts and get back with this.
So who am I? Just someone that has been blowing smoke up your a$$?
I am referring to shuttle designers.
They won't have the answers. NASA JSC Shuttle payload integration sets the requirements.
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This is a very interesting discussion. I will check with some shuttle experts and get back with this.
So who am I? Just someone that has been blowing smoke up your a$$?
I am referring to shuttle designers.
I think because of the permanent MPLM comments from Jim long ago, it put a bad taste in your mouth on trusting his insight.
I'm a designer for hydraulics, but I always go to the guys in the shop who put my stuff together. How they built it & had to work on it, is more important than when it was designed months or years ago.
The technician knows best: it's called real world / life experiences. You know by doing.
You want to bring stuff back from ISS, make it useful cargo: science experiments, CMGs...maybe even the radiator (if it were possible, which it isn't due to safety IIRC), or a solar array.
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Also what purpose would a Pirs-return mission serve? What use would it provide on the ground? How about you take a progress in 2011 dock it to Pirs before MLM arrives, and take Pirs a few hundred miles out, and re-dock it to MLM. Only problem with that is that a Progress might not have enough fuel to rendezvous and re-dock.
Orbiter
Questions:
Would it be easier (or possible) to temporarily move Pirs from Zvezda nadir to Zvezda aft until Nauka arrives? I don't know if the interfaces are much different, but, assuming that there is no Progress or ATV during that period, would it be doable?
If so, would you even need a Progress to move it, or could you use assets already on station to do it?
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A quick no. Pirs' active docking port is hybrid, whereas Zvezda aft is probe and cone. They don't fit together.
In theory, the Pirs passive port, which is probe and cone, could be converted to an active port, via IVA, but then a Progress could no longer dock with Pirs. Since only a Progress could even in theory move Pirs around where the ISS RMS cannot reach. the whole concept falls apart.
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A quick no. Pirs' active docking port is hybrid, whereas Zvezda aft is probe and cone. They don't fit together.
In theory, the Pirs passive port, which is probe and cone, could be converted to an active port, via IVA, but then a Progress could no longer dock with Pirs. Since only a Progress could even in theory move Pirs around where the ISS RMS cannot reach. the whole concept falls apart.
So I take it that even in order to dock to the MLM, Pirs would have to be modified considerably, am I right?
Are there really no other ways to move Pirs, even without docking with a Progress? Understood, there aren't many grapples on Pirs or the Russian Segment for that matter, but hypothetically, could Pirs be "grabbed" by Dextre, which would be grappled by the OBSS, which would be grappled by Canadarm2 from the US segment? Or, barring that, Could the Strella cranes be a) moved to either Zarya or Zvezda, and used to "pluck" Pirs off until MLM arrives, or b) left on Pirs, but used remotely to "walk" Pirs across the station.
It just seems like a waste to me, to deorbit a perfectly good pressurized module, storage compartment, as well as an auxiliary airlock, after so much was spent getting it up there.
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but hypothetically, could Pirs be "grabbed" by Dextre, which would be grappled by the OBSS, which would be grappled by Canadarm2 from the US segment?
There is nothing for Dextre to grab on to. It does not have generic grapples. Everything, it is to grab has special fixtures. Also, the OBSS has no electrical interface for Dextre nor end effectors. There is nothing for Dextre to grab on to.
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So I take it that even in order to dock to the MLM, Pirs would have to be modified considerably, am I right?
Are there really no other ways to move Pirs, even without docking with a Progress? Understood, there aren't many grapples on Pirs or the Russian Segment for that matter, but hypothetically, could Pirs be "grabbed" by Dextre, which would be grappled by the OBSS, which would be grappled by Canadarm2 from the US segment? Or, barring that, Could the Strella cranes be a) moved to either Zarya or Zvezda, and used to "pluck" Pirs off until MLM arrives, or b) left on Pirs, but used remotely to "walk" Pirs across the station.
It just seems like a waste to me, to deorbit a perfectly good pressurized module, storage compartment, as well as an auxiliary airlock, after so much was spent getting it up there.
I can't remember if the 3 ton mass of Pirs is over Dextre load limits, so I cannot answer that question.
Also, your original question dealt with moving Pirs to Service Module aft, which is out of the question.
Last point: could the ISS RMS access and move Pirs. The answer is: probably, especially if the PGDF is installed on FGB (I believe this is a requirement for some MRM-1 operations). There are hard points on Pirs that could be fitted with grapple fixtures via EVA, or the Strela base points could be used.
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Also, your original question dealt with moving Pirs to Service Module aft, which is out of the question.
I was just trying to think of a place to put it until MRM arrives, and only for a few days. For all it matters, you could strap it to the side of the FGB. Once it arrives with the ERA, that could be used to rettach Pirs.
Last point: could the ISS RMS access and move Pirs. The answer is: probably, especially if the PGDF is installed on FGB (I believe this is a requirement for some MRM-1 operations). There are hard points on Pirs that could be fitted with grapple fixtures via EVA, or the Strela base points could be used.
So is using the Strela themselves out of the question?
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I think because of the permanent MPLM comments from Jim long ago, it put a bad taste in your mouth on trusting his insight.
FYI
http://forum.nasaspaceflight.com/index.php?topic=5978.msg101937#msg101937
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I was just trying to think of a place to put it until MRM arrives, and only for a few days. For all it matters, you could strap it to the side of the FGB. Once it arrives with the ERA, that could be used to rettach Pirs.
Would not want a module potentially loose when a docking is occurring! It seems to me there is no way, short of docking a Progress to Pirs, getting it safely out of the way, and then re-docking it (where? to MRM that just arrived? does it not take some EVA to outfit the port and enable docking?) I am not sure if that is feasible and at what cost. I am also not sure if there are good enough reasons to go through the trouble.
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I was just trying to think of a place to put it until MRM arrives, and only for a few days. For all it matters, you could strap it to the side of the FGB. Once it arrives with the ERA, that could be used to rettach Pirs.
:o
Please don't try that.
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Would not want a module potentially loose when a docking is occurring! It seems to me there is no way, short of docking a Progress to Pirs, getting it safely out of the way, and then re-docking it (where? to MRM that just arrived? does it not take some EVA to outfit the port and enable docking?) I am not sure if that is feasible and at what cost. I am also not sure if there are good enough reasons to go through the trouble.
Let's just agree that when MLM arrives, Pirs needs to be far away from ISS.
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Would not want a module potentially loose when a docking is occurring! It seems to me there is no way, short of docking a Progress to Pirs, getting it safely out of the way, and then re-docking it (where? to MRM that just arrived? does it not take some EVA to outfit the port and enable docking?) I am not sure if that is feasible and at what cost. I am also not sure if there are good enough reasons to go through the trouble.
Let's just agree that when MLM arrives, Pirs needs to be far away from ISS.
Oooo! What if you used the Progress to put Pirs on MLM BEFORE it got to ISS!
Agreed. ;D
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Not sure why you crossed out your words, perhaps because you think they are not feasible? I think the same. Sure one can rendezvous a Soyuz with Pirs and a Soyuz with the new module; then what? Would you trust docking that "thing" to ISS, with Kurs or even manually? Especially at the speed / impulse that is necessary for Russian docking?
I think one could dock the new module to Pirs, if one really wanted to. Would there be advantages to that? Yes it's some extra space, but carries a risk if Pirs would have problems before EOL of ISS, which it may.
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Not sure why you crossed out your words, perhaps because you think they are not feasible? I think the same. Sure one can rendezvous a Soyuz with Pirs and a Soyuz with the new module; then what? Would you trust docking that "thing" to ISS, with Kurs or even manually? Especially at the speed / impulse that is necessary for Russian docking?
I think one could dock the new module to Pirs, if one really wanted to. Would there be advantages to that? Yes it's some extra space, but carries a risk if Pirs would have problems before EOL of ISS, which it may.
Pretty much, yes.
At first I thought it was worth keeping Pirs at the station, even if as nothing more than a storeroom. This was because I assumed that it was a simple matter of moving it out of the way until it MLM docks. I see now that this is not the case.
I just noticed that to keep Pirs at ISS began requiring progressively more and more elaborate plans, and when I caught myself thinking the whole "Pirs to MLM and then to ISS" line of thought, I realized that I was investing more emotion than logic.
Yes, I do see the values in either keeping Pirs at ISS, or returning it to Earth. Unfortunatly, it would seem that keeping it at ISS is prohibitivly dangerous/difficult, and it does not appear that NASA plans to return it on any of the shuttle missions. Although, I am not yet convinced that if someone wanted it badly enough, NASA couldn't engineer a way to fit it in the payload bay of a returning shuttle. The issue, however, seems to be that nobody (at least to my knowledge) DOES want it that badly. It doesn't matter whether or not we see the value. It only matters if someone who sees that value is willing to pay for it.
As much as it pains me to say so, unless somebody flies a vehicle with COTS-C capability to ISS big enough to carry Pirs before December 2011, the best plan seems to be to deorbit it.
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I am unsure why would it be interesting to return it on earth, it seems to me that whatever value and usefulness it has, it is in orbit. We have had ample opportunities to study hardware that was exposed to long periods in space. In regards to talks of deorbiting ISS because of the aging of the Russians segment, the Russian partners say that, if it should come to that, they are prepared to detach their segment and keep it functional; it is the USA partners that are / were considering deorbiting ISS because of operational costs. But, it appears that Obama will not be walking that path and will keep ISS operational to 2020 and likely beyond.
It would probably be possible to design adaptors to mate MLM and Pirs, then again one needs to come up with good reasons to do so and go through the bother and the expense. Yes a storeroom is always useful, but just how much are we prepared to spend for it? Also, we are talking here of permanent docking, it's not that the hybrid ring must allow MLM and Pirs to connect for a few days. It must be certified to last for expected ISS life (or should I say, Russian segment expected life), with very stringent bounds on leak rates and all other parameters. I don't see how this can be done relatively quickly, that is to say, before the MLM is launched.
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well, well, well, now that the idea of a Shuttle extension is back on the table, this thread might not be moot anymore.
:P :P :P :P :P :P
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Just throwing an idea out there:
Assuming that putting Pirs on the Shuttle can't/doesn't happen, wouldn't this be a wonderful opportunity to test inflatable heat shield technology? Could something like a balute be attached to to Pirs via a modified Progress and deorbited?
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But do you want to test that technology over an populated area? What if it fails? Most likely it will be tested over an ocean and then Pirs will be lost anyway.
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Assuming that putting Pirs on the Shuttle can't/doesn't happen, wouldn't this be a wonderful opportunity to test inflatable heat shield technology? Could something like a balute be attached to to Pirs via a modified Progress and deorbited?
If you really want it back, you aren't going to want to rely on an untested technology to do the job.
If you just want to do the technology test, it will be much easier and cheaper to do it with a smaller, purpose built test article. Adding everything need to land Pirs intact would be difficult and expensive. For the price of returning Pirs, you could fly many smaller missions (starting with sub-orbital shots, moving up to something like Raduga that acutally returns useful cargo) until you got it right. Then you can think about returning module sized objects, although realistically you'd probably only do it with ones that were designed from the start to be returned this way.
Of course the reality is that Pirs is just 3 tons of trash once it's mission is over, and the idea that anyone would pay the hundreds of millions required to bring it back is completely absurd.
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But do you want to test that technology over an populated area? What if it fails? Most likely it will be tested over an ocean and then Pirs will be lost anyway.
Well, it's not as if Soyuz vehicles don't touch down on land. Not to mention that the space agencies of the world haven't shown a whole lot of concern where or on what their boosters land, anyway. But, let's say that you wanted to be extra careful. I'm guessing that a ballute reentry system might have different flight path than a soyuz, so you might not choose to land it on the steppes of Kazakhstan for fear of miscalculating and putting it in a suburb or Moscow or Tehran. So the Oceans it is.
Why would it be lost? Pirs would be nestled at the center of a large, inflatable balute. A recovery vessel could just pick it up. But, of course, what if it deflates when it hits the surface of the ocean? Well, according to astronautix, Pirs weighs 3600 kilograms, is 4.1 meters long and 2.6 meters wide. It is, of course, an ovoid, so that it is only that wide at its middle. Let's say that that the average width rounds down to about 2m, and the length is 4m.
(πr2)*L
3.14*12 * 4m = 12.57m3
Density = Mass/Volume
3600kg/12.57m3 = 286.40kg/m3= The density of Pirs
The density of fresh water is 1000kg/m3, and sea water is even denser. Pirs should be able to float, so long as it doesn't take on water. Slap a radio beacon onto it, and recovering it should be a cinch.
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I'm not that involved in how the inflatable heat shield work. But as you sad it would be a good way to test the technology which means extra precautions need to be taken that's why I suggested an ocean landing, maybe there are large uninhabited areas on land where it can land. Soyuz is a reliable return vehicle and can't be compared to the test of a new system.
You have to remember the equipment inside Pirs when calculating it's weight. I'm sure there are equipment which they plan to stay in Pirs as they de-orbit it.
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I'm not that involved in how the inflatable heat shield work. But as you sad it would be a good way to test the technology which means extra precautions need to be taken that's why I suggested an ocean landing, maybe there are large uninhabited areas on land where it can land. Soyuz is a reliable return vehicle and can't be compared to the test of a new system.
I agree.
You have to remember the equipment inside Pirs when calculating it's weight. I'm sure there are equipment which they plan to stay in Pirs as they de-orbit it.
How much are we talking?
6000kg/12.57m3 = 477.33kg/m3
9000kg/12.57m3 = 715.57kg/m3
12000kg/12.57m3 = 954.65kg/m3
9000kg-3600kg = 5400kg
12000kg-3600kg = 8400kg
By my calculations, Pirs could carry 2 1/3 times it's own weight in equipment and down-cargo, and still just manage to float. (and I'm basing that on fresh water. Sea water will give it even more buoyancy.)
I wonder how much collectors or museums would be willing to pay for ISS jetsam?
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I wonder how much collectors or museums would be willing to pay for ISS jetsam?
A tiny fraction of the hundreds of millions that designing and implementing this plan would cost.
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I wonder how much collectors or museums would be willing to pay for ISS jetsam?
A tiny fraction of the hundreds of millions that designing and implementing this plan would cost.
Hundreds of Millions would be worth it if it gave ISS reliable down-cargo capabitity as a result.
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I wonder how much collectors or museums would be willing to pay for ISS jetsam?
A tiny fraction of the hundreds of millions that designing and implementing this plan would cost.
Hundreds of Millions would be worth it if it gave ISS reliable down-cargo capabitity as a result.
The only plan that could be implemented for hundreds of millions would be return by the shuttle. Since the shuttle is soon to be retired, that is not a long-term down-cargo capability.
Implementing a new down-cargo capability that could return Pirs would cost billions, not hundreds of millions.
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The way I see it, Pirs is going to burn up anyway.
I don't see the harm in doing this on the cheap, provided, A) it can be reasonably established that it will not interfere with the operation of Progress, and B) it can reasonably be determined that unintended destructive reentry won't rain debris over a populated area.
Few million dollars to add a jerry-rigged system onto a Progess, and a ship to pull it out of the ocean if this hairbrained sceme works. If it doesn't, chalk up the expenses to R&D. That's all.
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Few million dollars to add a jerry-rigged system onto a Progess, and a ship to pull it out of the ocean if this hairbrained sceme works. If it doesn't, chalk up the expenses to R&D. That's all.
You won't fly anything for a "few million".
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Given that Shuttle won't be around too much longer, most of this thread is moot, so I would like to discuss an alternative - saving Pirs.
As you know, Pirs has to be removed from SM Nadir to make way for MLM. This is to be accomplished by having a Progress dock with Pirs, and after cargo unloading operations, the Progress would depart ISS, taking Pirs with it. Subsequently, MLM would dock with the now uncovered docking port.
It should be noted that MLM has a nadir docking port compatible with Pirs' docking system, and that MLM has a lateral docking port also compatible with Pirs. So .... it may be possible for the Progress that is taking Pirs away to return Pirs to dock with MLM nadir. Subsequently, the European Robotic Arm could translate Pirs to the MLM lateral port. This would leave the MRM small airlock module without a port, but the Node Module will be coming within a year and that does have a open port for the small airlock module.
Why position Pirs at MLM? Because this would give the Russian segment an airlock that does not have a crew vehicle attached to it. Therefore, no Soyuz would be cut off from ISS by an airlock module exposed to vacuum. This may be a significant new capability for ISS.
Can a Progress return Pirs to MLM Nadir? That is an open question. Can the ERA berth Pirs to the MLM lateral port? Probably not without some modifications.
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Will there be an issue with Pirs on the MLM lateral port interfering with clearance for MRM-1 docking?
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Will there be an issue with Pirs on the MLM lateral port interfering with clearance for MRM-1 docking?
Possibly. However, the constraint is merely to allow a 45 degree abort cone from MRM-1 nadir, so Pirs probably wouldn't enter into that prohibited zone. Pirs wouldn't extend any further out than the MLM radiator, which would located above it.
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Didn't think about the radiator!
Can a regular Progress with Pirs re-dock with ISS? Previously it has just the service model of the progress who have docked Pirs and MRM-2 to the station. Or did that just have to do with launch-mass?
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Didn't think about the radiator!
Can a regular Progress with Pirs re-dock with ISS? Previously it has just the service model of the progress who have docked Pirs and MRM-2 to the station. Or did that just have to do with launch-mass?
There is no practical way to connect a "service module" to Pirs. Instead, the baseline plan to remove Pirs is by docking a "used" Progress to Pirs nadir.
It would be challenging to return Pirs via that same Progress. If it were easy, this thread would not exist.
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OK, although my initial post in this thread was pretty clear in stating that return of Pirs in the Shuttle would only be possible IF the Shuttle program were extended, just about everyone told me that it was impossible to return Pirs in the Shuttle program since the Shuttle program was ending. So, let me address the issue of saving Pirs in the current environment where there is no Shuttle.
I am not going to address at the moment WHY saving Pirs is a good idea, we can assume for the moment that throwing away perfectly good space hardware is not an optimal solution.
There are 2 different approaches to saving Pirs that I can think of, but I am sure there are more. Both approaches require that a grapple fixture be attached to Pirs, either at a Strela base point, or at one of the hard points used to transport Pirs on the ground. Whatever adapter is developed for the grapple fixture should also support cabling to an external power port on Pirs, so that the module has power while being moved by the station RMS. And, in all cases, the station SSRMS will use the newly installed PGDF on FGB as a base, and, of course, the Progress docked with Pirs nadir would have to depart prior to the operation.
Scenario 1: around the time of launch of MLM, the station crew would replace the forward hybrid docking adapter on Pirs with APAS. Field replacement of hybrid with APAS is indeed a feature of the system.
After APAS is installed, the station arm would remove Pirs from the Service Module, and translate it to a PMA located at Node 3 nadir. During this time, Pirs would be powered via SSRMS. The arm would berth Pirs to the PMA. The unit used to power Shuttle from ISS would be installed in the PMA to allow for power to flow to Pirs.
Scenario 2: more complicated! Here, the female cone adapter on Pirs nadir would be replaced by a male adapter, prior to the departure of Progress (the male adapter could be removed from a Progress, and the Pirs cone could be mounted on Progress, so everything would fit as usual, except reversed. After the Progress on Pirs nadir departs, the station arm could translate Pirs to Rassvet nadir (assuming the Soyuz on Rassvet nadir magically disappears, which does happen under certain circumstances), and the male adapter on Pirs nadir would mate with the female adapter on Rassvet nadir. This would leave a male hybrid adapter exposed at the bottom of Pirs.
In both scenarios, Pirs would be temporarily stowed at ports that are planned to be occupied by other vehicles, so a more permanent location is required; in this case, the quasi-permanent location would be the radial MLM hybrid port. The station RMS would translate Pirs a second time and dock the male hybrid adapter with MLM's lateral port. Pirs would remain on MLM until the Node module were in place, after which Pirs would be moved down by ERA to an axial hybrid port on the Node Module.
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OK, although my initial post in this thread was pretty clear in stating that return of Pirs in the Shuttle would only be possible IF the Shuttle program were extended, just about everyone told me that it was impossible to return Pirs in the Shuttle program since the Shuttle program was ending. So, let me address the issue of saving Pirs in the current environment where there is no Shuttle.
I am not going to address at the moment WHY saving Pirs is a good idea, we can assume for the moment that throwing away perfectly good space hardware is not an optimal solution.
There are 2 different approaches to saving Pirs that I can think of, but I am sure there are more. Both approaches require that a grapple fixture be attached to Pirs, either at a Strela base point, or at one of the hard points used to transport Pirs on the ground. Whatever adapter is developed for the grapple fixture should also support cabling to an external power port on Pirs, so that the module has power while being moved by the station RMS. And, in all cases, the station SSRMS will use the newly installed PGDF on FGB as a base, and, of course, the Progress docked with Pirs nadir would have to depart prior to the operation.
Scenario 1: around the time of launch of MLM, the station crew would replace the forward hybrid docking adapter on Pirs with APAS. Field replacement of hybrid with APAS is indeed a feature of the system.
After APAS is installed, the station arm would remove Pirs from the Service Module, and translate it to a PMA located at Node 3 nadir. During this time, Pirs would be powered via SSRMS. The arm would berth Pirs to the PMA.
I believe the two open PMAs are being used for Commercial Crew.
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So you reopen this thread so you can once again ignore facts provided to you and slander people in the process?
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So you reopen this thread so you can once again ignore facts provided to you and slander people in the process?
You bet! ;D
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I believe the two open PMAs are being used for Commercial Crew.
Re-read Danderman's post