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#140
by
Jim
on 27 Dec, 2009 15:06
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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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#141
by
Orbiter
on 27 Dec, 2009 15:08
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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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#142
by
Danderman
on 27 Dec, 2009 21:29
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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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#143
by
Jim
on 27 Dec, 2009 21:37
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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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#144
by
Jim
on 27 Dec, 2009 21:45
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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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#145
by
Danderman
on 27 Dec, 2009 22:10
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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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#146
by
Danderman
on 27 Dec, 2009 22:12
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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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#147
by
Jim
on 27 Dec, 2009 22:26
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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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#148
by
Jim
on 27 Dec, 2009 22:31
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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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#149
by
Danderman
on 27 Dec, 2009 23:24
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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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#150
by
Jim
on 28 Dec, 2009 00:15
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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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#151
by
Orbiter
on 28 Dec, 2009 13:15
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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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#152
by
Danderman
on 28 Dec, 2009 15:02
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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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#153
by
Danderman
on 28 Dec, 2009 15:05
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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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#154
by
Jim
on 28 Dec, 2009 15:46
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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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#155
by
Danderman
on 29 Dec, 2009 19:26
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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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#156
by
Jim
on 29 Dec, 2009 19:38
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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$$?
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#157
by
Danderman
on 29 Dec, 2009 20:49
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This is a very interesting discussion. I will check with some shuttle experts and get back with this.
So who am I? Just someone that has been blowing smoke up your a$$?
I am referring to shuttle designers.
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#158
by
Jim
on 29 Dec, 2009 21:41
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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$$?
I am referring to shuttle designers.
They won't have the answers. NASA JSC Shuttle payload integration sets the requirements.
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#159
by
robertross
on 07 Jan, 2010 02:33
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This is a very interesting discussion. I will check with some shuttle experts and get back with this.
So who am I? Just someone that has been blowing smoke up your a$$?
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.