Author Topic: ISS considering the permanent attachment MPLM, advancement of STS-134  (Read 64820 times)

Offline kch

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Why not fly with only a crew of two, pilot and commander?  The Station crew could do any EVAs.  If there is a problem with the Shuttle from launch they could come back down on a Soyuz.

IIRC, don't flight rules require a minimum of 4 people on the flight deck for launches?

They didn't for the first four flights, did they?

Offline MKremer

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Adding a second port to an MPLM will not happen, you are essentially building a new module at that point.

What kind of costs would you be talking about? Don't ATVs cost something like 200M-300M euros? And an ATV is like half an MPLM + SM. Shouldn't adding a second docking port to an existing MPLM be less expensive than building an ATV from scratch? And since the components and tooling exist and ESA wants to do something similar anyway, don't you think something could be arranged? ESA has a vested interest in keeping the ISS around, since without it they have no manned space program.

How intercompatible are the various MPLMs? Could you dismantle (or rather, cut up) two single-ended MPLMs and weld appropriate pieces back together as a double-ended MPLM? (I realize that's a *much* bigger job than it sounds like. Just wondering.)

Yes, it is a good question, but I don't think it's very cost-effective, either. For one, all the structural engineering work would have to be redone from scratch (the same as if they were building a new module, which in effect they are).

The station would be mounting a new module mass that has never been planned for or figured into any of the existing CG and load forces calculations and safety factors. All of these new studies would probably need to at least have the Russians involved, and the results then reviewed and approved by all the ISS partners.

« Last Edit: 05/06/2009 03:40 pm by MKremer »

Offline MKremer

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Why not fly with only a crew of two, pilot and commander?  The Station crew could do any EVAs.  If there is a problem with the Shuttle from launch they could come back down on a Soyuz.

IIRC, don't flight rules require a minimum of 4 people on the flight deck for launches?

They didn't for the first four flights, did they?

They were the test missions. The first operational mission was STS-5.

Offline mmeijeri

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Yes, it is a good question, but I don't think it's very cost-effective, either. For one, all the structural engineering work would have to be redone from scratch (the same as if they were building a new module, which in effect they are).

The station would be mounting a new module mass that has never been planned for or figured into any of the existing CG and load forces calculations and safety factors. All of these new studies would probably need to at least have the Russians involved, and the results then reviewed and approved by all the ISS partners.

Ah, so it would be a lot of design and validation work, not so much construction work? Or would there be a lot of that too?
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Offline Chris Bergin

This may come across as very wrong, so forgive me, but it's a serious question.

I would assume it's the total weight of the crew they are looking at, so can they trade two Robert Curbeam type big guys for three Charles Camarda types? You know where I'm going with this. If upmass is *that* important, to the point of losing a crew member, then total crew 'mass' must be at play.
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Offline Tergenev

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All I remember is that a couple years back, a bunch of space fans on this site suggested just this. Why not leave an MPLM in place after its last use? We were scoffed at and denigrated by a couple of the NASA insiders on here as having no concept of what we were talking about and being completely disconnected from reality. (You know of whom I speak.)

So I guess Italy can afford the costs to modify an MPLM, but the concept that NASA might have done so was ludicrous? Interesting.

In any case, I'm glad to see that this is being discussed, if for no other reason than simply throwing away all of these modules after they were only used once or twice (or never!) seemed like the ultimate in wasted energy, effort and resources.

Offline MKremer

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Yes, it is a good question, but I don't think it's very cost-effective, either. For one, all the structural engineering work would have to be redone from scratch (the same as if they were building a new module, which in effect they are).

The station would be mounting a new module mass that has never been planned for or figured into any of the existing CG and load forces calculations and safety factors. All of these new studies would probably need to at least have the Russians involved, and the results then reviewed and approved by all the ISS partners.

Ah, so it would be a lot of design and validation work, not so much construction work? Or would there be a lot of that too?

Oh, yes, lots of that. One question would be if the structural panel design was optimized at all for friction-stir welding. That would be a stumbling block time- and cost-wise for reassembly.

Probably all new certification testing, too - pressure (maybe with a duration vacuum chamber test), thermal tests and assessments, power requirements. (And maybe more if any active racks would be included.)

Offline mmeijeri

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A couple of questions since you seem knowledgeable about this sort of thing:

Could any savings in construction costs be obtained from modifying an existing MPLM with existing ATV tooling as opposed to building a new Columbus from scratch?

How much of the engineering tools and analysis (software, modelling) used for Nodes 2&3, Columbus, MPLM, ATV and probably Spacelab before that could be reused?

How much of the effort to redesign/convert an MPLM could be reused by ESA later if they want to build a dual port ATV?
« Last Edit: 05/06/2009 04:21 pm by mmeijeri »
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Offline William Barton

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This may come across as very wrong, so forgive me, but it's a serious question.

I would assume it's the total weight of the crew they are looking at, so can they trade two Robert Curbeam type big guys for three Charles Camarda types? You know where I'm going with this. If upmass is *that* important, to the point of losing a crew member, then total crew 'mass' must be at play.

You probably have to count the seats as upmass too, so two big guys in two standard seats may weigh less than three little guys in three standard seats...

Offline William Barton

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How intercompatible are the various MPLMs? Could you dismantle (or rather, cut up) two single-ended MPLMs and weld appropriate pieces back together as a double-ended MPLM? (I realize that's a *much* bigger job than it sounds like. Just wondering.)

Good question. Your guess is as good as mine - or better. But isn't the Russian docking system asymmetrical? In that case you would need one male and one female connector, so cutting up MPLMs or ATVs wouldn't be of much use. If ESA/Astrium has the infrastructure to produce a female docking adapter (and I suspect they do), then building a new one might be the simplest thing to do.

Any experts want to chime in?

I thought the idea was to have a berthing mechanism on each end, not a docking system (so it would be compatible with HTV, Dragon, and Cygnus, but not ATV or Progress). But I think the berthing adapter is not androgynous either (I think), so it'd still have to be two different pieces of hardware (I think). Still, if they can make "outside" berthing mechanisms for HTV, Dragon, Cygnus and incoming modules, I'm sure they can find one for an MPLM.

Offline MKremer

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A couple of questions since you seem knowledgeable about this sort of thing:

Knowledgeable only as far as available ISS documentation and following module and segment manufacturing as an interested spectator.

Quote
Could any savings in construction costs be obtained from modifying an existing MPLM with existing ATV tooling as opposed to building a new Columbus from scratch?

Not knowing much about ATV manufacturing details, I couldn't even guess.
A better idea might be to see if there are any of the special manufacturing equipment that Boeing or Thales Alenia Space used for assembling and welding the Nodes or MPLMs.

Quote
How much of the engineering tools and analysis (software, modelling) used for Nodes 2&3, Columbus, MPLM, ATV and probably Spacelab before that could be reused?

Couldn't say. Shouldn't be much different than the studies and analysis done for any of the pressurized modules using those particular panel fabrications and assembly, just a module with new dimensions and mass.

Quote
How much of the effort to redesign/convert an MPLM could be reused by ESA later if they want to build a dual port ATV?

Haven't the foggiest idea.  :)

Offline MKremer

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This may come across as very wrong, so forgive me, but it's a serious question.

I would assume it's the total weight of the crew they are looking at, so can they trade two Robert Curbeam type big guys for three Charles Camarda types? You know where I'm going with this. If upmass is *that* important, to the point of losing a crew member, then total crew 'mass' must be at play.

You probably have to count the seats as upmass too, so two big guys in two standard seats may weigh less than three little guys in three standard seats...

The seats are pretty lightweight (10-15kg?). Much less than 1/3 to 1/2 the mass of a person.

Offline Jorge

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How intercompatible are the various MPLMs? Could you dismantle (or rather, cut up) two single-ended MPLMs and weld appropriate pieces back together as a double-ended MPLM? (I realize that's a *much* bigger job than it sounds like. Just wondering.)

Good question. Your guess is as good as mine - or better. But isn't the Russian docking system asymmetrical? In that case you would need one male and one female connector, so cutting up MPLMs or ATVs wouldn't be of much use. If ESA/Astrium has the infrastructure to produce a female docking adapter (and I suspect they do), then building a new one might be the simplest thing to do.

Any experts want to chime in?

I thought the idea was to have a berthing mechanism on each end, not a docking system (so it would be compatible with HTV, Dragon, and Cygnus, but not ATV or Progress). But I think the berthing adapter is not androgynous either (I think), so it'd still have to be two different pieces of hardware (I think).

That is correct. CBM has both active and passive sides. MPLM currently just has the passive side. To extend onto an MPLM, the other CBM must be active, and there must be power/command lines through the MPLM to allow the CBM to be operated.
JRF

Offline William Barton

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This may come across as very wrong, so forgive me, but it's a serious question.

I would assume it's the total weight of the crew they are looking at, so can they trade two Robert Curbeam type big guys for three Charles Camarda types? You know where I'm going with this. If upmass is *that* important, to the point of losing a crew member, then total crew 'mass' must be at play.

You probably have to count the seats as upmass too, so two big guys in two standard seats may weigh less than three little guys in three standard seats...

The seats are pretty lightweight (10-15kg?). Much less than 1/3 to 1/2 the mass of a person.


So two 100kg guys with two 15kg seats = 230kg and
three 50kg guys with three 15 kg seats = 195kg?

Of course 50kg is a pretty small guy. Most likely you'd have to find female "guys" to get the weight down that far. Even then, we're talking "petite."

Offline MKremer

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Of course 50kg is a pretty small guy. Most likely you'd have to find female "guys" to get the weight down that far. Even then, we're talking "petite."

New astronaut candidate applicants limited to former female gymnastic competitors.  ;D

Offline Jim

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No. As you say, big problems with docking and many other things. Shuttle is a manned spacecraft, humans are needed to fly.

Much more likely they drop LON for the last Shuttle mission, whichever it will be. Case 1 in the extension study assumes just this.

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Why not fly with only a crew of two, pilot and commander?  The Station crew could do any EVAs.  If there is a problem with the Shuttle from launch they could come back down on a Soyuz.

Minimum of four required for docking

Offline Jim

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Why not fly with only a crew of two, pilot and commander?  The Station crew could do any EVAs.  If there is a problem with the Shuttle from launch they could come back down on a Soyuz.

IIRC, don't flight rules require a minimum of 4 people on the flight deck for launches?

They didn't for the first four flights, did they?

Onorbit ops were not intensive and SAS not well known

Offline Jim

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1.  All I remember is that a couple years back, a bunch of space fans on this site suggested just this. Why not leave an MPLM in place after its last use? We were scoffed at and denigrated by a couple of the NASA insiders on here as having no concept of what we were talking about and being completely disconnected from reality. (You know of whom I speak.)

2.  So I guess Italy can afford the costs to modify an MPLM, but the concept that NASA might have done so was ludicrous? Interesting.


1.  If you have a problem say it and don't use selective memory.  The issue was that a standard MPLM couldn't be left at the ISS and NASA didn't have the money for the mods.  It was never said that it could "never" be done.

2.  Whether this goes forward and who pays for the costs has yet to determine

Offline Kaputnik

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Once Shuttle is retired, can't the PMAs be discarded? That would free up a spot for an MPLM. Unless I've got the wrong idea about how this works.
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Offline eeergo

Once Shuttle is retired, can't the PMAs be discarded? That would free up a spot for an MPLM. Unless I've got the wrong idea about how this works.

Orion, as currently envisioned, would dock to the Station (through an LIDS-to-APAS adapter) at Harmony's PMA. If it failed, they would need PMA-3 as a spare, or just relocate the adapter to Unity nadir.
-DaviD-

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