This is not a NASA Website. You might learn something. It's YOUR space agency. Get involved. Take it back. Make it work - for YOU.
Astronauts

Does ISS Need A Larger Crew?

By Keith Cowing
NASA Watch
July 2, 2012
Filed under , ,

Astronauts support expansion of space station crew size, Houston Chronicle
“Astronauts aboard the International Space Station said this week they would welcome NASA’s proposals to expand the lab’s crew size from six to seven. “It would certainly help,” said Don Pettit, a flight engineer and one of three crew members working in the U.S. half of the station. NASA senior leaders have begun talking about expanding the lab’s crew size to seven when vehicles built by private contractors, such as SpaceX, come online as expected later this decade.”

NASA Watch founder, Explorers Club Fellow, ex-NASA, Away Teams, Journalist, Space & Astrobiology, Lapsed climber.

41 responses to “Does ISS Need A Larger Crew?”

  1. Jim Oberg says:
    0
    0

    It would be nice to break out from the 3:2 Russians:Americans crew slots ratio that we’ve gotten locked into through our clever international partnership negotiations.

    Has there been any theoretical calculations of the hardware limits regarding a MAXIMUM crew size that could be sustained with enough logistics flow? Certainly you’d pay for it in wear-and-tear on regenerative equipment, and sleeping quarters luxury, but there might be a ‘sweet spot’ where it’s worth the price, and maybe somewhere above 7… maybe WELL above 7. 

    • DTARS says:
      0
      0

      Isn’t the ISS size determined by escape vehicle size? Seven crew means one dragon escape docked right?

      In an old thread I made a dream case of building X-37 E or D and was told no place to go with that many people????

      Seems they are content with a 6 or 7 man ISS.

      I know add a few of those old shuttle tanks to ISS and start doing tons of stuff at ISS with lots of these cheaper capsules.

      Is the 150 shuttle external  tank depot in the same orbit as ISS??

      Mr. Chicken and Mr. Egg

      • pathfinder_01 says:
        0
        0

        ISS was built for 7. It can accommodate up to 14 in a surge manner
        (i.e. using consumables) but 7 is the norm. The limit was always the Soyuz
        since it could only hold 3.

        ah Marcel the reason why there is one space station is becuase having mulitple ones increases the costs on NASA. If some other organization could fund a station(hint bigleow) and there was a means of getting there cheaply(commercail crew) and a need(something that can’t be done at the ISS–not likely) then they might do so. Also emergany return can occur for medical reasons not techical ones(Astronaut gets ill in orbit or injures self and needs to see a doctor).  

      • Joseph Cooper says:
        0
        0

        Whereas the Shuttles are now on museum duty, there’s no lifting shuttle tanks to orbit now.

        The ISS has multiple docking ports so if you had (for example) a pair of Soyuz spacecrafts, than the “let six people bail from ISS” market is fulfilled.

        But in any case it will be a small market; a seven seat Dragon with a seven seat ISS crew would have one flight a year to do – and then what with the Russians do?

        This would become untrue if there was more for humans to do in orbit. A study done on this ten years ago suggested one could find 50 or so paying space fliers every year even without a space station (just in something like a Soyuz) as “space tourists”.

        If that were to be true, than this could subsidize the cost of manned spaceflight for scientific purposes or (for example) lifting people to a hypothetical Mars bound space ship.

        A little imagination can turn this opportunity into a new space age, but..! A little imagination can also shown ten dozen ways it can go terribly, terribly wrong.

        Or even just minorly wrong; maybe it turns out there’s only 200 people in the world who’ll pay 10 million to go in space and we burn through them; perhaps there’s success in lowering space flight cost by say 90% but it’s not enough to create much new activity in space. Maybe high altitude aircraft and other technologies take satellite jobs and actually reduce demand for space launches.

        These are exciting times, but not predictable ones.

    • Todd Austin says:
      0
      0

      This hits the nail on the head for me

      It seems to me I’ve read that the current 6-person crew is nearly entirely consumed with keeping the station functional. If we’re to get a return on our 100-billion-dollar investment, then shouldn’t crew brought up by Dragon be added to the existing cohort, not substituted?

      Just 7? Why not 10? Or more? Surely we’re learned enough after operating ISS, Mir, Skylab, and Salyut over so many years to be able to work out the logistics.

      If more sleeping quarters and life support are needed, are we in a position to construct those segments, deliver, and attach them without the services of the shuttle? (leaving considerations of political will aside)

      • DTARS says:
        0
        0

        It doesn’t seem like the goal is to be productive, does it???????

      • Mark_Flagler says:
        0
        0

        Serious consideration should be given to expanding the usable volume of the station using something like a Bigelow inflatable.

      • ex_navy says:
        0
        0

        You are mixing up comments reagarding 3 person crew.  6 person crew is doing lots of utlization.  Don’t remeber the exact number but it is in the 50% range.

    • Daniel Woodard says:
      0
      0

      With five completely separate logistics vehicles (Dragon, Cygnus, HTV, ATV, and Progress) the logistics stream depends only on funding and crew time for berthing and unloading. Additional crew will require man-rated Dragon or CST for escape; timeline commercial crew capability is available depends, like logistics, on how much funding is made available in the near term; right now this is the long pole. For emergency crew return use Dragon and CST would also need to verify that a berthed vehicle can unberth and depart without RMS assistance, or install docking ports. Using berthing ports two vehicles could be kept attached simultaneously providing return capability for 14. Main constraint would then be sleeping space, CO2 removal, O2 generation, water, food, hygene facilities and other life support hardware on the ISS.

      • Mary Lynne Dittmar says:
        0
        0

        Copy all and agree – in addition there are psychosocial corollaries to increased “crowding” (particularly given impacts to stowage volume that would occur with additional consumables onboard) that need a look, together with impacts to workflow, space-to-ground-to-space traffic (psychological support, family interaction, internet, ‘job jar’ management) – impacts on the ground to training, flight medicine, operations…all of this representing a plusup to cost…not saying it’s a bad idea just saying that once we get beyond the hard constraints and into ops, there are complexities there too.

  2. Jerry_Browner says:
    0
    0

    The original station requirement had been for 8 crew. It was later reduced to 7 for a couple reasons including emergency return vehicle capacity. Subsequently it was reduced to 6 which is all that can be handled with 2 Soyuz. If Dragon can seat 7, then that is still good rationale. If the Russians continue to provide for 3, then the US-side return vehicle need only handle 4. We already have the design of a modular crew compartment for sleeping and there are plenty of rack bays for its future installation. I don’t see the addition of a single crew member to be much of an impact on that ‘luxury’. Once the regenerative ECLS is fully functional, and the US system did need some redesign after the initial tests in orbit, then a 15% increase, adding one crew member, is probably not a big hit.  This is a change that is pretty far off since it requires the addition of a new US provided crew launch and return capability, probably another 5 years away.

    • rachorg says:
      0
      0

      I know the Soyuz lifetime in orbit is finite.  Would the Dragon be any better?

      • John Gardi says:
        0
        0

        rachorg:

        Many folks think that the Soyuz ‘best before’ time of six months is based on the lifespan of reaction control system, but I don’t think that’s the case.

        Zarya and Zvezda have been on orbit for more than a dozen years and they use the same propulsion system. They even take fuel from visiting Progress freighters and store it in on-board tanks. The Air Force X37b stayed on orbit for over a year. Spacex’s Dragon Lab plans are for a two year mission.

        Long term on orbit storage of Dragon would be a game changer for Station. A crew of twelve would be possible. Make a Dragon lifeboat for a crew of six. Once Dragon L is docked, the Russians can send a Soyuz down with just cargo. Send up a Soyuz to bring the ISS crew to nine. Repeat the process to get a crew of twelve. Six can go home in Dragon, the others on the two Soyuz. Crew rotation then happens as normal, three at a time, by swapping out the Soyuz every six months.
        Regular Dragon cargo flights could take up the logistics slack for the extra bodies. The Dragon lifeboat could be replaced every two years. They could even take down-cargo home (waste nothing! ).

        This could be done now.

        tinker

        • Jeff2Space says:
          0
          0

           I believe the propulsion limit is due to the descent module, which uses hydrogen peroxide for propellant.  Hydrogen peroxide slowly decomposes over time, slowly reducing its potency.

          • John Gardi says:
            0
            0

             Jeffrey:

            Thank you for that. I guess since the Russians never considered missions over six months, it wasn’t worth changing. Not an issue with Dragon or any of the upcoming spacecraft that use hydrazine.

            tinker

          • DTARS says:
            0
            0

            Tinker I remember Griffin turning down methane for his moon lander on the grounds that it was hard to light. Well if dragon is going to be a Mars lander shouldn’t Spacex be making it Draco thrusters using methane as well???
            The advantage of methane is ease to process on mars right?? What about hydrazine?

            Anyway is there methane draco’s thrusters in dragons future?

            If not why not??

            Thanks

            Curious George

            Lol 

  3. newpapyrus says:
    0
    0

    That’s the problem of having one huge centralized space station instead of having multiple space stations clustered together in a particular orbit. You’re putting all of your eggs in just one basket!

    If the same amount of ISS mass had been placed into orbit into two or more smaller space stations then much larger scientific teams could be safely accommodated with each station having their own return vehicles. Astronauts could also be accommodated at one of the other nearby spaces stations in an emergency as an alternative to immediately returning to the Earth.

    Marcel F. Williams

    • DTARS says:
      0
      0

      Why should we do more stuff on ISS??
      We get 3 billion to run it as is. Does putting more people up there get us/NASA more money???

      What is the incentive to do anymore than the bare 
      Minimum with our 3 billion???

      Lol 3 billion lol that’s a lot of money Marcel lol, if we canceled ISS and gave that to Elon we could. Have your HLV vehicle AND 1/2 a billion to build a fleet of dragon moon landers.

      But you want to throw it down the SLS rat hole.

      • newpapyrus says:
        0
        0

        Why should the tax payers give a billionaire any money at all– especially when Elon’s buddies are sitting on $2 trillion of potential investment money.

         I’ve never been a big fan of the ISS program. But my point was that if you have such a program, you can get a lot more scientific research done with a lot more scientist.

        An efficiently run space station program should have deployed two or more small space stations in one orbital area, maybe even including one rotating space station with artificial gravity so that scientist could remain in orbit for several years instead of for only a few months. That would have saved a ton of money in manned space launches.

        Marcel F. Williams

      • Ralphy999 says:
        0
        0

        It is not automatic that if we cancel the ISS the US government will give that money to NASA for other projects. Look what happened with the shuttle cancellation. The money for that left NASA I believe to increase the Dept of Education budget. There are no guarantees of money.

    • no one of consequence says:
      0
      0

       I’ll try once on this.

      Nested multiple concurrent “chicken and egg” situations here.

      Idea behind having first permanent station was, like Shuttle, to bootstrap a greater future. Like Shuttle, space station attempt to “create the future” has been detoured by events and certain interests.

      My fear with the “hate ISS, do mindless ‘beyond earth’ types”  is that .. they just create another, different, pointless boondoggle.

      The origins of the problem – insincerity to address “real world” problem at hand. Started with Apollo “flags and footprints” mindset. Go go go, spend spend spend, and … stop.

      Same with ISS. Same would have happened with CxP, only 100 -1,000x worse budget hole than ISS(!).

      Way out of this dilemma – get away from “faith based” HSF of any kind, and into “evidence based” HSF (and exploration and economic development).

      This case in point – upping ISS crew (unlike rationale for downgrading crew as in past). “These successful experiments have used up N man hours, getting M more will yield this increase”. Or – “Semi- or biotech- industry experiments need N man hours, but we only have less than N hours – if we had the capability and address the needs for these experimenters, we can make a case for scaling up industry utilization of the ISS”.

      A lot can go wrong with this kind of approach.  Or any approach.

      But with ISS, lunar, Mars, … anything – you upgrade off of a valid justification, to get more. In all of these – we need to get more.

      • DTARS says:
        0
        0

        Clear 🙂

        Key to building railroad block by block is more like building a stone wall, You need to select just the right stone to fit your need before building on top of it.

        So a space economy and the hardware is best all done with an incremental approach?? Right?? That would assure progress and minimize mistakes.

  4. Steve Whitfield says:
    0
    0

    I wonder if there would be an overall gain, everything considered, by adding another crew member.  I can’t help but notice that both op ed comments and reader comments make a point of mentioning the US side and the Russian side of the ISS.  Shouldn’t crew considerations be evaluated primarily in terms of work to be done and available resources, instead of making it into yet another political issue?  This, I think, is one of the reasons why the ISS has been much less effective than it should have been.  Nobody seems to take the I in ISS seriously.  The worst part of an “us and them” situation is the fact that we create and perpetuate them ourselves.

    Steve

    • Ralphy999 says:
      0
      0

      We want value for our money. We spent a vast amount of our treasury on this thing only to be second place on the roster? Being international doesn’t mean being a wlecome mat all the time. Let the Russians switch down to two instead of three from time to time. If they have some kind of scientific experiment going on we can make allowances for that but eventually to be “fair” not just “international” the American taxpayer needs to be adequately represented off and on. Eh?

      • DTARS says:
        0
        0

        I would think that the added rubber room that NASA could add could be a complete stand alone system that could even fly Seperate as Marcel and tinker talked about. My point is that spending a little money, plus R and D, to get bigelows factory started soon seems like a wise use of money to me.

      • Steve Whitfield says:
        0
        0

        Ralphy,

        You make my point — Us and Them — one of the most counterproductive forces in the universe. You say “value for our money”; define value. Would it matter who was doing the actual experimental work if everyone was sharing in the results of all of the experiments? Does it makes any sense for different countries to be up there doing exactly the same research, each for their own exclusive use? Doesn’t it make a lot more sense — and get you more for your money — if we split up the workload among those on station, wherever they’re from, and then share the results? Or are you advocating living in the Cold War world for ever? And to be perfectly honest, if America isn’t getting the “value” for money spent that you think it should, it’s not the fault of Russia or any other country; it’s the result of a whole lot of damn poor decisions made by certain powerful Americans, combined with the bloated costs that come from union mentality workers and pork-dealing politicians.

        Being proud of your nation and your heritage is one thing, a good thing, but adversarial nationalism is a destructive disease that smart people are trying hard to cure. Promoting adversarial nationalism does nothing useful; it only continues to drag us back into the past and endanger innocent lives. This is such an obvious idea that I’m breaking my own rule and not even qualifying it as an opinion. The free world is becoming more united every day, and the number of the world’s countries that can be considered free, and technical, grows every day. People with the attitude which your comment suggests that you have are going to be left behind, and better so.

        If you want “value” for your money, then stop thinking like a TV red neck and join the human world of the future that’s coming, and has already begun. It truly baffles me how someone can have a forward-looking interest in space and a backward-looking attitude about national relations at the same time.

        Steve

        • Ralphy999 says:
          0
          0

          Consistently having three Russian cosmonauts vs. two US astronauts will eventually work against US public support for for future space cooperation. Why not trade off from time to time? At least make a gesture toward an appearance of equal participation. In light of that then I am OK with sending another US astronaut to the ISS if living accomodations can be made. The way it is now, in general no one in the US is seeing any benefit to participating in the ISS, It’s just a manned space flight program to send astronauts and something for JSC to do. We have to do all we can to correct this situation. We have the AMS experiment on board the ISS which may ultimately prove to be a major discovery for us. We need more such experiments in my view especially private industry development experiments. While technically it doesn’t make any difference whether a Russian or American conducts such experiments  why teach foreign miltiary nationals some of your techniques? In especially in light of their current industrial espionage activities.

          The fact that you have slammed me with “TV red neck thinking” when I am in agreement with James Oberg, a renowed authority on Soviet era and current Russian space development, concerning the unfairness of a 3:2 ratio of Russian/American participation, tells me that you have no idea of how international cooperation should be achieved or what fairness means for that matter.

          • pathfinder_01 says:
            0
            0

            Ah some pointers.

            It is 3 NASA crew and 2 Russian on the ISS and NASA pays the
            Russians for crew transport and lifeboat duty at the moment via Soyuz.  Of the 3 NASA crew one of which maybe from CSA
            (Canada), ESA (Europe) or JAXA (Japan) since NASA must provide transport for
            them. The commander of the station rotates between NASA and Russia. So on
            expedition 31-32, the commander was Russian on expedition 33-34 the commander
            will be from a NASA crew.  So far one ESA
            astronaut has been station commander.

            Anyway in the future Russia plans to launch a module that
            will bring a third crew station aboard such at it will be 3 Russian (once NASA
            stops paying for Soyuz). One commercial crew is up in the US, we will be able
            to carry 4 crew  (since the ccdev craft
            have room for 7).  

  5. John Gardi says:
    0
    0

    Folks:

    Some day we’re going to have to get beyond the idea of ‘a seat home for everybody’. Marcel’s point about having multiple stations on the same orbital plane would definitely help ween us off that. Transfer between stations could be done in spacesuits on open cage ‘scooters’ using cold gas thrusters. Folks would have to coordinate station reboosts to stay close to one another but no big deal there. A good case for ion/electric station keeping thrusters.

    Trans lunar flights are best done with purpose built vessels too. Ones designed for aerobraking instead of reentry, for instance.

    I suppose it’s fair to say the we have a healthy respect for the environment of space and an outright visceral fear of our home planet’s gravity well… but we’ll get over it :).

    tinker

    • pathfinder_01 says:
      0
      0

      “Some day we’re going to have to get beyond
      the idea of ‘a seat home for everybody’. Marcel’s point about having multiple
      stations on the same orbital plane would definitely help ween us off that.”

      I don’t think
      people or NASA has that problem. What I mean is that the number one reason to
      leave a space stations early according to the Russians has been medical not technical.
      The ISS can handle some medical emergencies, but for others you need to get to
      a doctor (Kidney stones for instance…which being in zero g seems to help
      form). There also has been a mission where a crew member had a psychological problem
      (grew depressed).

      If you are in
      earth orbit having the ability to return is easy (just use the craft you came
      in, you can even use it to go between stations as the last crew of Salyut 7 did
      as they went to MIR) and necessary (it will be a long time before you have
      medical capacities in space that match the ground).  Sure we would like sci fi ideas of spaceships
      coming to the rescue of others but we are just not there yet.
       

  6. bobhudson54 says:
    0
    0

    Expanding the crew size of the ISS would mean increasing the logistics of the station, as in additional crew space,support,operations. This could be done with support from private industries.NASA shouldn’t expect itself to be the sole supporter of the ISS not should it be. I’d love to see it double its expansion in crew and size but in doing this NASA should outreach to the private sector.

    • DTARS says:
      0
      0

      NASA should have called Bigelow to add a rubber room to ISS to get them up and running! Right???

      But I heard the money for that is going to SLS

      • Ralphy999 says:
        0
        0

        It’s not just adding another container to the ISS. There are electrical power considerations, life support operations and whole host of other issues of which I admittedly know nothing about that has to be taken into consideration. Sure, for all I know it could be realtively easy to expand the ISS with an inflatable compartment but I’m willing to bet there is more than just a docking procedure involved.

        • DTARS says:
          0
          0

          I would think that the added rubber room that NASA could add could be a complete stand alone system that could even fly Seperate as Marcel and tinker talked about. My point is that spending a little money to get bigelows factory started soon seems like a wise use of money to me.

  7. Arnie T says:
    0
    0

    I’ve always wondered why a crew is sent back to Earth BEFORE a new one arrives. More could get done with face2face handover & temporary 9 crew. Ask a nurse about change-of-shift reports, etc.

  8. DTARS says:
    0
    0

    Manned Leo space mission

    Can a dragon dock to ISS with it’s second stage attached?

    Does that require the manned docking ring??

    Before dragon has it’s LAS shouldn’t they put in seats, air system, and control system. And fly some orbital missions.

    Couldn’t such a dragon rider dock to ISS with it’s second stage attached. Then undock and use that fuel to lap ISS. This could be done robotically too.

    How much fuel do you need in a dragon second stage to boost a dragon from ISS around the moon???

    Shouldn’t dragons be used like Gemini to teach us to fly in space again!!!!!!

    Wasn’t Gemini an incremental program????

    With falcon or recoverable falcon plus a small Bigelow hab about sun dancer size which dragon pickups at ISS couldn’t you send 6 tourist and a pilot around the moon pretty cheap????

    With the new falcon v 1.1 first stage booster couldn’t it put the old smaller second stage in orbit with lots of left over fuel for on orbit manurers ???? Or a mission around the moon???

    • John Gardi says:
      0
      0

      DTARS:

      Just like the external tank of the Shuttle, the Falcon second stage makes orbit. So far, all of the Falcon second stages (except one) stayed on orbit, intact, for extended periods of time. Because the liquid oxygen in the stage has a limited life, it’s usefulness would be measured in days at the most. The Falcon second stage does have a few Draco thruster for maneuvering though.

      The Falcon v1.1 second stage will be longer than the original and, if my guess is correct, will use Dracos for powered landings too, essentially a Dragon service module wrapped around it’s Merlin 1d. So, on orbit, a connected Dragon and second stage would have maneuvering thrusters front and rear, like the Shuttle, so that, together, the whole stack could be controlled. If, as Spacex claims, the second stage can be recovered, we have the makings of something useful… besides being a recoverable second stage, that is :).

      Remember, even with the Merlin 1d (1000 pounds), the second stage doesn’t weigh much more than a Dragon capsule. Once Spacex proves recoverability and powered landing, you have the makings of a slightly larger spacecraft than Dragon. Dragon v1.1?

      Using the ‘dry lab’ method, a recoverable second stage could be outfitted on the ground for crew or cargo (or both) and then stacked on top of a Falcon v1.1 (9 or Heavy) for launch. No Merlin 1d necessary for this config. You now have a recoverable spacecraft with twice the interior volume of Dragon.

      Using the ‘wet lab’ method, the stage would be left attached to Dragon after launch and guided it’s destination for outfitting.

      Either way, what could one fit into a space 12 feet in diameter and 20 feet tall? That would be more room then Shuttle to play with.

      So, yeah, it could be done… should be done!

      tinker

      • DTARS says:
        0
        0

        Tinker 

        Thanks for making the point clear about the very limited life of liquid oxygen in a tank in space. Which makes the point that I have no idea what type of fuel is used in deep space vehicles. Nor how you would  process fuels from planets for depots and how you would store that fuel for long periods time till it’s needed.
        Obviously a little study is in order for this Joe Q 
        Any general outline help would be appreciated.

        Curious George

        • John Gardi says:
          0
          0

          DTARS:

          Deep space probes and just about any large satellites in Earth orbit use hydrazine as fuel too. Some use cold gas jets and many modern communication satellites have electric ion engines for station keeping  and slot changing (moving along the Clarke orbit to another spot.

          My money is on hydrazine fueled thrusters and ion engines as the tools of choice in cis-lunar space for the near term. They work, are well understood and we can use them now.

          Tinker’s tenents;

          – Don’t over-think stuff.
          – Live off the land (make use of the resources around you).
          – If it ain’t broke… make it better!

          tinker

          • DTARS says:
            0
            0

            Thanks answered so you would know I read it. Please give me input on my wing jet rocket horizontal flyback booster question if you get time.

      • DTARS says:
        0
        0

        http://www.universetoday.co

        Why not just aero brake into an eliptical orbit and add a few days to your trip. Or would several aero brake passes take months????

        Curious George lol

        I had the nick name curious as a kid lol

        Curious