Author Topic: Crew limitations for ISS  (Read 19078 times)

Offline Space Pete

Re: Crew limitations for ISS
« Reply #20 on: 03/19/2011 10:56 PM »
I understand that there's supposed to be a third Russian CQ in MLM when it launches.

A-ha! Yes, of course.

That would mean that all Russian crewmembers could sleep in the RS (two Kayutas in the SM, plus one in the MLM), which would leave four CQs in the USOS.
NASASpaceflight ISS Editor

Offline Dapholine

  • Member
  • Posts: 39
  • Liked: 5
  • Likes Given: 13
Re: Crew limitations for ISS
« Reply #21 on: 03/19/2011 11:51 PM »
Nope still the plan.  Not sure of the timescale but that is our next major milestone.
Well of course. That is the long-term-plan, but as long as there is no 4+-person CRV, that plan is dead in the water.

Woo! That will certainly enable more science to get done.

We need another Crew Quarters! :)
Yes, I read that as: once we finally get a 7th (or 8th) crew member, the shuffling-bags-or-doing-repair-work to actual-time-spend-on-science ratio will finally be useful. Remember we have Columbus, Destiny and KIBO on the USOS. That is one lab per crew member! Compare that to the Spacelab missions...
The ISS is designed to be useful with 7 (and probably more!!) crew members and we need them ASAP. Somehow, in these past 10 years, policy makers have failed to notice that a large space station is only useful when it's packed with astronauts doing actual science (tm). *sigh*


« Last Edit: 03/19/2011 11:52 PM by Dapholine »

Offline Jason1701

  • Senior Member
  • *****
  • Posts: 2238
  • Liked: 70
  • Likes Given: 39
Re: Crew limitations for ISS
« Reply #22 on: 03/20/2011 01:57 AM »
Nope still the plan.  Not sure of the timescale but that is our next major milestone.
Well of course. That is the long-term-plan, but as long as there is no 4+-person CRV, that plan is dead in the water.

Woo! That will certainly enable more science to get done.

We need another Crew Quarters! :)
Yes, I read that as: once we finally get a 7th (or 8th) crew member, the shuffling-bags-or-doing-repair-work to actual-time-spend-on-science ratio will finally be useful. Remember we have Columbus, Destiny and KIBO on the USOS. That is one lab per crew member! Compare that to the Spacelab missions...
The ISS is designed to be useful with 7 (and probably more!!) crew members and we need them ASAP. Somehow, in these past 10 years, policy makers have failed to notice that a large space station is only useful when it's packed with astronauts doing actual science (tm). *sigh*




Maybe in the future we can add a small sleep module to the USOS (perhaps Cygnus-delivered) and then use the commercial crew vehicles to have a crew of seven astronauts. Russians can maintain one Soyuz for a total crew of ten.

Offline arkaska

  • Senior Member
  • *****
  • Posts: 3041
  • Sweden
  • Liked: 0
  • Likes Given: 0
Re: Crew limitations for ISS
« Reply #23 on: 03/20/2011 10:17 AM »
There is also a limit to how many science-racks can be powered at the same time.

Offline CitabriaFlyer

  • Full Member
  • ***
  • Posts: 307
  • Liked: 14
  • Likes Given: 0
Re: Crew limitations for ISS
« Reply #24 on: 03/20/2011 11:26 AM »
Maybe once commercial space is operating competition between Dragon, CST and Souyz will make it feasible to send short term science crews to ISS to give it a science surge capability.  The crew would consist of a pilot, an engineer, and five scientists.  The pilot and engineer could assist in maintenance tasks and EVAs.  The scientists could work in the labs, split into teams for 24 hour ops which would perhaps relive some of the concern regarding number of racks powered up at any given time.  I would think that you would need two commercial launches to support this.  Once to bring up basic science materials and supplies and return processed samples to earth.  Another launch to bring the crew to and from space.

Offline Space Pete

Re: Crew limitations for ISS
« Reply #25 on: 03/20/2011 11:49 AM »
Maybe once commercial space is operating competition between Dragon, CST and Souyz will make it feasible to send short term science crews to ISS to give it a science surge capability.  The crew would consist of a pilot, an engineer, and five scientists.  The pilot and engineer could assist in maintenance tasks and EVAs.  The scientists could work in the labs, split into teams for 24 hour ops which would perhaps relive some of the concern regarding number of racks powered up at any given time.  I would think that you would need two commercial launches to support this.  Once to bring up basic science materials and supplies and return processed samples to earth.  Another launch to bring the crew to and from space.

I had the same idea, but for logistics, not science.

Assume you timed everything so that Dragon & Cygnus, or HTV & ATV, were present at ISS at the same time. You could then send up a commercial crew vehicle with a "logistics crew" to spend two weeks unloading these vehicles and filling them with trash, in addition to performing maintenance tasks.

It would be just like a Shuttle mission, in the sense that you'd have six people concentrating solely on fast-paced operations, which would in turn free up the Expedition crewmembers to concentrate on science.
« Last Edit: 03/20/2011 11:51 AM by Space Pete »
NASASpaceflight ISS Editor

Offline DARPA-86

  • Full Member
  • *
  • Posts: 137
  • Pig farmer from Ryan, Iowa
  • Liked: 0
  • Likes Given: 1
Re: Crew limitations for ISS
« Reply #26 on: 03/20/2011 12:25 PM »
Maybe once commercial space is operating competition between Dragon, CST and Souyz will make it feasible to send short term science crews to ISS to give it a science surge capability.  The crew would consist of a pilot, an engineer, and five scientists.  The pilot and engineer could assist in maintenance tasks and EVAs.  The scientists could work in the labs, split into teams for 24 hour ops which would perhaps relive some of the concern regarding number of racks powered up at any given time.  I would think that you would need two commercial launches to support this.  Once to bring up basic science materials and supplies and return processed samples to earth.  Another launch to bring the crew to and from space.

I had the same idea, but for logistics, not science.

Assume you timed everything so that Dragon & Cygnus, or HTV & ATV, were present at ISS at the same time. You could then send up a commercial crew vehicle with a "logistics crew" to spend two weeks unloading these vehicles and filling them with trash, in addition to performing maintenance tasks.

It would be just like a Shuttle mission, in the sense that you'd have six people concentrating solely on fast-paced operations, which would in turn free up the Expedition crewmembers to concentrate on science.
This is the metric by which we need to start to measure what is 'full utilization".  Number of man days over the course of a full year, example 365 X 6 = 2190 days per year.  Within that you also have the schedule requirements for long term residents vs. short term stays.  For instance Astronaut health requirements push for up to 2 and half hours a day of exercise to prevent bone and muscle tissue loss for long term space fliers, i.e. six months along with other rest and health related tasks that take time off the schedule.  For short term fliers, 15 days or less, those tasks are usually waived, thus freeing up for time on task.

As an aside, the original design reference - Space Station Freedom called for ten person crews.  I personally believe the "permanment crew" number has shifted based upon the availability of CRV "lifeboats.  The key is the on-orbit loiter time of those lifeboats.

Offline clongton

  • Expert
  • Senior Member
  • *****
  • Posts: 10419
  • Connecticut
    • Direct Launcher
  • Liked: 2372
  • Likes Given: 797
Re: Crew limitations for ISS
« Reply #27 on: 03/20/2011 12:37 PM »
Maybe in the future we can add a small sleep module to the USOS

Bigelow can supply the module. That was the original purpose of TransHab, from which all Bigelow designs are derived. The crew quarters area was designed for 6 as you can see from both the link and image below.

http://en.wikipedia.org/wiki/TransHab
« Last Edit: 03/20/2011 01:13 PM by clongton »
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Space Pete

Re: Crew limitations for ISS
« Reply #28 on: 03/20/2011 01:03 PM »
Maybe in the future we can add a small sleep module to the USOS

Bigelow can supply the module. That was the original purpose of TransHab, from which all Bigelow designs are derived.

Probably the easiest thing to do would be to install four CQ (Crew Quarters) racks in Node 4/DHS, if it flies. This would mean that the visiting crewmembers would be sleeping near to their vehicle, in case an emergency suddenly occurred. The remaining two of the six visiting crewmembers could sleep in the vehicle itself.
« Last Edit: 03/20/2011 01:04 PM by Space Pete »
NASASpaceflight ISS Editor

Offline Danderman

  • Extreme Veteran
  • Senior Member
  • *****
  • Posts: 9597
  • Liked: 354
  • Likes Given: 460
Re: Crew limitations for ISS
« Reply #29 on: 03/20/2011 03:47 PM »
In general, its hard to imagine a situation where we have a commercial crew vehicle and the ability to launch Node 4 to ISS and there still being technical limitations at ISS restricting the crew size to 6. Its kind of like asking if we had Warp drive, could we go to Mars.

Offline hop

  • Senior Member
  • *****
  • Posts: 3277
  • Liked: 429
  • Likes Given: 776
Re: Crew limitations for ISS
« Reply #30 on: 03/20/2011 07:02 PM »
Well I understand about the limitations of the Soyuz, but future planned vehicles including the Dragon, the Dreamchaster, and the Boeing CST-100 all are designed for 7 people. 
At least initially, I don't think any of these are planned to be able to stay at the station for a long time. "Orion CRV" is.

Really?

What aspects of a crewed Dragon would preclude lengthy stays at ISS?
Given that Cargo dragon is expected to spend significant time at the station it's seems unlikely there would be major roadblocks to doing the same with the crew version. Of course there would additional work to certify it, but it would be surprising if there were really major problems.

Hmm, my impression was that one of justification for "Orion CRV" was that commercial would at least initially just be taxi service. But thinking back I'm not really sure where I got that and it doesn't make a whole lot of sense ;)


Offline robertross

  • Canadian Member
  • Senior Member
  • *****
  • Posts: 17795
  • Westphal, Nova Scotia
  • Liked: 461
  • Likes Given: 3851
Re: Crew limitations for ISS
« Reply #31 on: 03/20/2011 07:11 PM »
Well I understand about the limitations of the Soyuz, but future planned vehicles including the Dragon, the Dreamchaster, and the Boeing CST-100 all are designed for 7 people. 
At least initially, I don't think any of these are planned to be able to stay at the station for a long time. "Orion CRV" is.

Really?

What aspects of a crewed Dragon would preclude lengthy stays at ISS?
Given that Cargo dragon is expected to spend significant time at the station it's seems unlikely there would be major roadblocks to doing the same with the crew version. Of course there would additional work to certify it, but it would be surprising if there were really major problems.

Hmm, my impression was that one of justification for "Orion CRV" was that commercial would at least initially just be taxi service. But thinking back I'm not really sure where I got that and it doesn't make a whole lot of sense ;)

Remember: commodities to sustain a crew of 7 means that service must be available for the entire trip. Now the food & water can come from ISS, but O2 is a different matter. The services must be able to be reliable over those months on orbit. I'm not saying they can't do it, but it has to be certified to last that long.

One good way would be to find mass savings in a cargo variant (which it seems they could) and fly the ECLSS on that flight and have it stay up there for that period of time.
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Offline pathfinder_01

  • Full Member
  • ****
  • Posts: 1887
  • Liked: 49
  • Likes Given: 0
Re: Crew limitations for ISS
« Reply #32 on: 03/20/2011 08:11 PM »

Remember: commodities to sustain a crew of 7 means that service must be available for the entire trip. Now the food & water can come from ISS, but O2 is a different matter. The services must be able to be reliable over those months on orbit. I'm not saying they can't do it, but it has to be certified to last that long.


err sorry, misunderstood your message.

Food: If I remember correctly food for the space shuttle has to have a 1 year shelf life. So that is no problem.

Water:In bottle form is storeable indefinitely. Most bottle watter on the market has a 1 year shelf life but can be kept longer. Not to mention purification systems.

Oxygen:Liquid oxygen tanks have been used to keep oxygen for years. Oxygen is rather unique in that the more you cool it the less volume it takes up. Not to mention other chemical reactions that can generate oxygen.

Plus the CRV would only need 2-4 days worth of it.
« Last Edit: 03/20/2011 08:47 PM by pathfinder_01 »

Offline Jorge

  • Senior Member
  • *****
  • Posts: 6180
  • Liked: 32
  • Likes Given: 0
Re: Crew limitations for ISS
« Reply #33 on: 03/21/2011 01:41 AM »

Oxygen is rather unique in that the more you cool it the less volume it takes up.

Umm, no, incorrect. *Most* compounds decrease in volume with decreasing temperature - there is *nothing* unique about oxygen in that regard. *Water* is anomalous in that it expands when it freezes, but that is the compound humans have the most experience with in multiple phases.
JRF

Offline Cherokee43v6

  • Full Member
  • ****
  • Posts: 658
  • Garner, NC
  • Liked: 230
  • Likes Given: 96
Re: Crew limitations for ISS
« Reply #34 on: 03/21/2011 02:26 AM »
Well I understand about the limitations of the Soyuz, but future planned vehicles including the Dragon, the Dreamchaster, and the Boeing CST-100 all are designed for 7 people. 
At least initially, I don't think any of these are planned to be able to stay at the station for a long time. "Orion CRV" is.

Really?

What aspects of a crewed Dragon would preclude lengthy stays at ISS?
Given that Cargo dragon is expected to spend significant time at the station it's seems unlikely there would be major roadblocks to doing the same with the crew version. Of course there would additional work to certify it, but it would be surprising if there were really major problems.

Hmm, my impression was that one of justification for "Orion CRV" was that commercial would at least initially just be taxi service. But thinking back I'm not really sure where I got that and it doesn't make a whole lot of sense ;)

Remember: commodities to sustain a crew of 7 means that service must be available for the entire trip. Now the food & water can come from ISS, but O2 is a different matter. The services must be able to be reliable over those months on orbit. I'm not saying they can't do it, but it has to be certified to last that long.

One good way would be to find mass savings in a cargo variant (which it seems they could) and fly the ECLSS on that flight and have it stay up there for that period of time.

An interesting angle to consider on that regarding Dragon.  7 people a life support system and pressurized supplies are surely much less in mass than the maximum capacity that a Cargo Dragon can carry to the station.  However, what is in the Crew Dragon's external trunk?  Shouldn't it be fairly easy for it be configured to carry a supply of compressed consumable gasses to support a 2 - 4 week science surge to the station?
"I didn't open the can of worms...
        ...I just pointed at it and laughed a little too loudly."

Offline robertross

  • Canadian Member
  • Senior Member
  • *****
  • Posts: 17795
  • Westphal, Nova Scotia
  • Liked: 461
  • Likes Given: 3851
Re: Crew limitations for ISS
« Reply #35 on: 03/21/2011 12:08 PM »
The consumables on station, or that can be made available on station, are a fairly minor point for a surge crew. Extending more than one month, it could be a bit more challenging - but we're not there yet, and the commercial providers could fill that need, or Dragon itself.

The issue is the spacecraft itself. It takes time to qualify a system. Look at all the life support systems on the station that have had issues since we started all this. Obviously we are improving, but these are systems held by specific manufacturers. If we now bring in a new system, from a new manufacturer, there is a learning curve there, from all aspects, despite all processing steps. But this is how we learn, how the strong survive, and how a system becomes more robust.

Companies will eventually 'get there', but in some cases, ISS can't wait for that to happen. At least we have Progress, ATV & HTV to help the station out with logistics. What we lack is a Soyuz alternative that is up and running.
Remembering those who made the ultimate sacrifice for our rights & freedoms, and for those injured, visible or otherwise, in that fight.

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 27787
  • Minnesota
  • Liked: 7669
  • Likes Given: 5110
Re: Crew limitations for ISS
« Reply #36 on: 03/21/2011 02:39 PM »
The consumables on station, or that can be made available on station, are a fairly minor point for a surge crew. Extending more than one month, it could be a bit more challenging - but we're not there yet, and the commercial providers could fill that need, or Dragon itself.

The issue is the spacecraft itself. It takes time to qualify a system. Look at all the life support systems on the station that have had issues since we started all this. Obviously we are improving, but these are systems held by specific manufacturers. If we now bring in a new system, from a new manufacturer, there is a learning curve there, from all aspects, despite all processing steps. But this is how we learn, how the strong survive, and how a system becomes more robust.

Companies will eventually 'get there', but in some cases, ISS can't wait for that to happen. At least we have Progress, ATV & HTV to help the station out with logistics. What we lack is a Soyuz alternative that is up and running.
Life support systems (non-regenerative) are not that new. The problems were, I believe, mainly with the more closed-loop systems.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline erioladastra

  • Full Member
  • ****
  • Posts: 1257
  • Liked: 75
  • Likes Given: 0
Re: Crew limitations for ISS
« Reply #37 on: 03/21/2011 04:02 PM »
Nope still the plan.  Not sure of the timescale but that is our next major milestone.
Well of course. That is the long-term-plan, but as long as there is no 4+-person CRV, that plan is dead in the water.

Woo! That will certainly enable more science to get done.

We need another Crew Quarters! :)
Yes, I read that as: once we finally get a 7th (or 8th) crew member, the shuffling-bags-or-doing-repair-work to actual-time-spend-on-science ratio will finally be useful. Remember we have Columbus, Destiny and KIBO on the USOS. That is one lab per crew member! Compare that to the Spacelab missions...
The ISS is designed to be useful with 7 (and probably more!!) crew members and we need them ASAP. Somehow, in these past 10 years, policy makers have failed to notice that a large space station is only useful when it's packed with astronauts doing actual science (tm). *sigh*




That is not a reasonable comparison.  The USOS science labs are designed to have much less crew interactions.  So 2-3 people for 3 labs is not as big an issue as you think it is.  Actually ISS power, thermal and most critically the up/down mass are the real limiters.  Obviously an extra person would help with more time but unlesswe have enough upmass (which I assume will go with the increase to 7) it is only part of the issue.

Offline manboy

  • Senior Member
  • *****
  • Posts: 2082
  • Texas, USA, Earth
  • Liked: 127
  • Likes Given: 539
Re: Crew limitations for ISS
« Reply #38 on: 04/26/2011 12:18 AM »
ISS has been designed to support 6 crewmembers.

A & S: Will the size of the crew come down?

Suffredini:
No. In fact, weíre designed on the U.S. side to take four crew. The ISS design is actually for seven. We operate with six because first, we can get all our work done with six, and second, we donít have a vehicle that allows us to fly a seventh crew member. Our requirement for the new vehicles being designed is for four seats. So I donít expect us to go down in crew size. I would expect us to increase it.

http://www.airspacemag.com/space-exploration/AS-Interview-Mike-Suffredini.html
« Last Edit: 04/26/2011 12:20 AM by manboy »
"Cheese has been sent into space before. But the same cheese has never been sent into space twice." - StephenB

Offline arkaska

  • Senior Member
  • *****
  • Posts: 3041
  • Sweden
  • Liked: 0
  • Likes Given: 0
Re: Crew limitations for ISS
« Reply #39 on: 04/26/2011 09:58 AM »
A & S: Will the size of the crew come down?

Suffredini:
No. In fact, weíre designed on the U.S. side to take four crew. The ISS design is actually for seven. We operate with six because first, we can get all our work done with six, and second, we donít have a vehicle that allows us to fly a seventh crew member. Our requirement for the new vehicles being designed is for four seats. So I donít expect us to go down in crew size. I would expect us to increase it.

http://www.airspacemag.com/space-exploration/AS-Interview-Mike-Suffredini.html

That's a strange statement by Suffredini since in a recent L2 document we can see that they have trouble getting enough science in since all other activities take to much of the crews time.

Tags: