Author Topic: Seven crew members  (Read 18533 times)

Online Pipcard

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Seven crew members
« on: 01/15/2015 02:41 AM »
Since the ISS only supports a crew of six, are they really anticipating the availability of destinations such as small commercial space hotels?
« Last Edit: 01/15/2015 02:42 AM by Pipcard »

Online guckyfan

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Re: Seven crew members
« Reply #1 on: 01/15/2015 04:23 AM »
Since the ISS only supports a crew of six, are they really anticipating the availability of destinations such as small commercial space hotels?

I think the seven crew is just to say they can do the same number of passengers as the Space Shuttle did. Bragging rights. ;D

Offline Burninate

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Re: Seven crew members
« Reply #2 on: 01/15/2015 05:55 AM »
Since the ISS only supports a crew of six, are they really anticipating the availability of destinations such as small commercial space hotels?
The ISS program is intended to support a crew of seven.

Six has been the interim guideline while the station's lifeboat count minimum is two Soyuz capsules (with three crew each).  With a 4-person commercial crew capsule attached, and one Soyuz attached, the station can support seven safely.  NASA suggested a bonus capability in decisionmaking would be a 7-person capsule to evacuate the whole station, in order to provide contingency lifeboat access if zero Soyuz capsules are operational for some reason connected to the evacuation.  In routine operation, that extra space will be filled with non-human downmass, and I doubt Russia would voluntarily go without a single Soyuz capsule attached for any length of time.
« Last Edit: 01/15/2015 05:57 AM by Burninate »

Offline mheney

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Re: Seven crew members
« Reply #3 on: 01/15/2015 05:18 PM »
Since the ISS only supports a crew of six, are they really anticipating the availability of destinations such as small commercial space hotels?

I think the seven crew is just to say they can do the same number of passengers as the Space Shuttle did. Bragging rights. ;D

Actually, the shuttle flew 8 on STS-61A (Challenger, 1985); and STS-71 (a Mir mission) was 7up/8 down.
So a crew size of 7 falls short of demonstrated shutle capabilites...

Online pathfinder_01

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Re: Seven crew members
« Reply #4 on: 01/15/2015 09:02 PM »
Since the ISS only supports a crew of six, are they really anticipating the availability of destinations such as small commercial space hotels?

The commercial crew program for the ISS only needs to be able to produce an craft able to support 4( the number of U.S.  crew). Anything beyond that is just gravy and the companies have set the max. goal for each. Right now in regards to space tourism the only destination is the ISS and so an small commercial hotel is going to have to make do  with 6-7 person crafts.

In time perhaps crew capacity will grow as it did with passenger travel by air and just about every means of transit invented but it is an start.  The ISS can support an crew of 7 with surge capacity(i.e. short time and need extra cargo) of 14 and the US needs only 4. That leaves 2-3 seats that could be used for tourist or cargo at the ISS. If an totally commercial destination occurs that would leave an crew of 5-6 for an small hotel.

Offline Herb Schaltegger

Re: Seven crew members
« Reply #5 on: 01/16/2015 02:01 AM »
While we're picking nits, the ECLSS in the USOS is, almost to a "T," the very same ECLSS designed for Space Station Freedom, which was baselined for a crew of 8 - two independent ARS racks and two independent WRM system racks, each planned to support a nominal 4-person metabolic load, with capacity to handle 8 if necessary (during repairs, contingencies, etc). While the module locations for some of the racks and support equipment have changed, the basic guts of the systems haven't.

That said, the crew sizes for commercial vehicles are based on the general consensus of what's the best overall compromise between mass, cost and capability.
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Offline baldusi

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Re: Seven crew members
« Reply #6 on: 01/16/2015 06:50 AM »
While we're picking nits, the ECLSS in the USOS is, almost to a "T," the very same ECLSS designed for Space Station Freedom, which was baselined for a crew of 8 - two independent ARS racks and two independent WRM system racks, each planned to support a nominal 4-person metabolic load, with capacity to handle 8 if necessary (during repairs, contingencies, etc). While the module locations for some of the racks and support equipment have changed, the basic guts of the systems haven't.

That said, the crew sizes for commercial vehicles are based on the general consensus of what's the best overall compromise between mass, cost and capability.
Volume and evacuation concerns may play a part in it, too. But I guess the real issue is market. There's barely market for 8pax/yr from NASA, what's the point of carrying 10 non-existing passengers to a non existing commercial space station, if you're not going to get your money back. If there was a sudden demand, I wouldn't be surprised to see a 5m Dragon, or even an HL42 DreamChaser (at 16 passengers on a reusable Falcon Heavy, it would significantly lower the transport cost per passenger).

Offline sdsds

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Re: Seven crew members
« Reply #7 on: 01/16/2015 07:06 AM »
two independent ARS racks and two independent WRM system racks

On that topic, I wonder whether you could comment any on the wikipedia coverage:
http://en.wikipedia.org/wiki/ISS_ECLSS#Air_revitalisation_system

It seems to imply (by using the singular) the ISS has only one ARS rack. Is it ... simply wrong?

Thanks in advance for any insight you can provide.... Is there a good place to read about what's really up there?
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Offline Herb Schaltegger

Re: Seven crew members
« Reply #8 on: 01/16/2015 01:24 PM »
two independent ARS racks and two independent WRM system racks

On that topic, I wonder whether you could comment any on the wikipedia coverage:
http://en.wikipedia.org/wiki/ISS_ECLSS#Air_revitalisation_system

It seems to imply (by using the singular) the ISS has only one ARS rack. Is it ... simply wrong?

Thanks in advance for any insight you can provide.... Is there a good place to read about what's really up there?

Yeah, that article seems pretty out of date. I believe there are two ARS racks now, one in Node 3 ("Tranquility" I guess they're calling it now in Touchy-Feely SpaceSpeech ... ;) ) and one in the U.S. Lab. I don't know what, exactly, they have packaged into each one but the racks were each originally intended to hold one CDRA, one TCCS, one MCA, one TCM (Trace Contaminant Monitor - basically a GC mass spectrometer), and scarred to hold a Carbon Dioxide Reduction Assembly - either a Bosch or Sabatier reactor. A Sabatier is indeed installed and operating in one of the ARS racks now, but I don't recall its location.

There's almost certainly L2 documentation on the current state - what's installed and where, but I'm too lazy to go look for it right now. It's like looking for a needle in a haystack sometimes, given the almost 20 years' worth of planning, contingency and operational documents available to dig through.
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Offline Ben the Space Brit

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Re: Seven crew members
« Reply #9 on: 01/16/2015 01:26 PM »
I've always thought it was a case of one pilot + a full ISS crew in the event of a total swap-out or an emergency evacuation. It's the theoretical maximum of the design, not an anticipated baseline capability.
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Offline sdsds

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Re: Seven crew members
« Reply #10 on: 01/18/2015 03:58 AM »
A Sabatier is indeed installed and operating in one of the ARS racks now

Very cool! Apparently it is in Node 3, unless I'm misreading this article (with pretty photos) from 2013:

http://www.nasaspaceflight.com/2013/10/iss-hardware-providing-lessons-learned-deep-space-missions/
« Last Edit: 01/18/2015 03:59 AM by sdsds »
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Offline erioladastra

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Re: Seven crew members
« Reply #11 on: 01/18/2015 10:26 AM »
I've always thought it was a case of one pilot + a full ISS crew in the event of a total swap-out or an emergency evacuation. It's the theoretical maximum of the design, not an anticipated baseline capability.

Nope - 4 is the baseline for commercial crew to bring the total up to 7.  That is a full USOS crew.  Pilot will be part of  the crew.

Offline Nomadd

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Re: Seven crew members
« Reply #12 on: 01/20/2015 01:32 PM »
 I'm sure there are contingency plans to support Russian crew if Soyuz has to stand down for some reason.

Offline Moe Grills

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Re: Seven crew members
« Reply #13 on: 01/21/2015 05:24 PM »
  The title here is? Seven Crew Members.
I assumed it referred to the capacity of the SpaceX Dragon v2.
But you mention Soyuz??? Why??
Maybe the moderator could clear things up here.

But since Seven Crew Members is the title, and Soyuz only carries one space tourist at a time, why couldn't a Dragon v2 carry two crew and five space tourists aloft?
Advantages?
1) You don't need to learn Russian.
2) You don't need to spend 6-12 months training in Russia.
3) 20-40 million dollars divided by five. And in fact, since Elon Musk pushes the economic virtues of his boosters and space business, that 4-8 million per space tourist can be reduced to perhaps only 2 million dollars per space tourist to orbit the Earth and a short visit to an inflatable Bigelow orbital facility/hotel.

Offline arachnitect

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Re: Seven crew members
« Reply #14 on: 01/21/2015 05:51 PM »
  The title here is? Seven Crew Members.
I assumed it referred to the capacity of the SpaceX Dragon v2.
But you mention Soyuz??? Why??
Maybe the moderator could clear things up here.

But since Seven Crew Members is the title, and Soyuz only carries one space tourist at a time, why couldn't a Dragon v2 carry two crew and five space tourists aloft?
Advantages?
1) You don't need to learn Russian.
2) You don't need to spend 6-12 months training in Russia.
3) 20-40 million dollars divided by five. And in fact, since Elon Musk pushes the economic virtues of his boosters and space business, that 4-8 million per space tourist can be reduced to perhaps only 2 million dollars per space tourist to orbit the Earth and a short visit to an inflatable Bigelow orbital facility/hotel.

I think the question OP is asking, is something to the effect of "If our $150 Billion space station can only support 7 crew, how will commercial space stations make any money?"

If I understand the intent correctly, maybe the thread should be in commercial spaceflight general? I think placement in this topic is throwing people off.

Offline The Amazing Catstronaut

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Re: Seven crew members
« Reply #15 on: 01/21/2015 07:15 PM »

I think the question OP is asking, is something to the effect of "If our $150 Billion space station can only support 7 crew, how will commercial space stations make any money?"


Bigelow modules. Cost less, higher crew.

And agreed, if this is the true topic, it needs to move.
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Online Pipcard

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Re: Seven crew members
« Reply #16 on: 01/25/2015 05:37 PM »
No, my question is about commercial crew vehicles, asking why all of the CCtCap candidates have a 7 crew member capacity when the ISS already has 6 crew members and is already being serviced by at least one Soyuz.
« Last Edit: 01/25/2015 05:39 PM by Pipcard »

Offline erioladastra

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Re: Seven crew members
« Reply #17 on: 01/25/2015 10:18 PM »
No, my question is about commercial crew vehicles, asking why all of the CCtCap candidates have a 7 crew member capacity when the ISS already has 6 crew members and is already being serviced by at least one Soyuz.
No, my question is about commercial crew vehicles, asking why all of the CCtCap candidates have a 7 crew member capacity when the ISS already has 6 crew members and is already being serviced by at least one Soyuz.

Because they are all trying to market tourists for the ISS and possible vehicles for trips like bigelow.

Offline RonM

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Re: Seven crew members
« Reply #18 on: 01/25/2015 10:42 PM »
No, my question is about commercial crew vehicles, asking why all of the CCtCap candidates have a 7 crew member capacity when the ISS already has 6 crew members and is already being serviced by at least one Soyuz.
No, my question is about commercial crew vehicles, asking why all of the CCtCap candidates have a 7 crew member capacity when the ISS already has 6 crew members and is already being serviced by at least one Soyuz.

Because they are all trying to market tourists for the ISS and possible vehicles for trips like bigelow.

Before Commercial Crew, when the ISS was a destination for Orion, the max crew for an Orion was seven. That capacity is probably a holdover from Orion because NASA wanted the same capacity. The actual number of crew will be four and the rest of the capacity will be cargo.

Just because you can put seven seats in a capsule doesn't mean you have to. Look at Apollo. It had a crew of three, but could carry five.

http://en.wikipedia.org/wiki/Skylab_Rescue

Offline arachnitect

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Re: Seven crew members
« Reply #19 on: 01/25/2015 11:00 PM »
No, my question is about commercial crew vehicles, asking why all of the CCtCap candidates have a 7 crew member capacity when the ISS already has 6 crew members and is already being serviced by at least one Soyuz.
No, my question is about commercial crew vehicles, asking why all of the CCtCap candidates have a 7 crew member capacity when the ISS already has 6 crew members and is already being serviced by at least one Soyuz.

Because they are all trying to market tourists for the ISS and possible vehicles for trips like bigelow.

Not a holdover from lifeboat/acrv days?

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