Quote from: KSC Sage on 05/06/2009 02:17 pmWhy 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?
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.
Quote from: mmeijeri on 05/06/2009 01:31 pmQuote from: Ronsmytheiii on 05/06/2009 01:20 pmAdding 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.)
Quote from: Ronsmytheiii on 05/06/2009 01:20 pmAdding 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.
Adding a second port to an MPLM will not happen, you are essentially building a new module at that point.
Quote from: MKremer on 05/06/2009 03:08 pmQuote from: KSC Sage on 05/06/2009 02:17 pmWhy 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?
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.
Quote from: MKremer on 05/06/2009 03:32 pmYes, 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?
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.
Quote from: William Barton on 05/06/2009 02:08 pmHow 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?
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.)
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?
Quote from: Chris Bergin on 05/06/2009 03:58 pmThis 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...
Quote from: mmeijeri on 05/06/2009 02:23 pmQuote from: William Barton on 05/06/2009 02:08 pmHow 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).
Quote from: William Barton on 05/06/2009 04:29 pmQuote from: Chris Bergin on 05/06/2009 03:58 pmThis 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.
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."
Quote from: Analyst on 05/06/2009 12:51 pmNo. 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.AnalystWhy 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.
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.Analyst
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.
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.