Extra modes for Commercial crew utilization

[Ronsmytheiii]

One of the biggest looming issue for commercial crew is the limited number of flights necessary for crew change-out on the USOS, which amounts to about two flights per year.  Now this is hardly enough to support two commercial crew vehicles, so logically it would be prudent to increase the flights to three or four flights per year.  That amount would leave a large unfilled capacity, so the question now becomes what to do with that capacity,and how the crew changeout would occur. SO here are some ways to utilize:

1.  All crew on one flight, cargo would be on another.  Basically another CRS flight, albeit probably more expensive.

2. Split the crew to two USOS members per flight. Gives the ground time to react more quickly in crew training for ongoing issues on the station. additionally excess capacity for each flight can be used to:

a.  bring up cargo on each flight.
b. Commercial spaceflight participants (ie Space Adventures)
c. short term crew for specialized activities (ie EVA crew like used on shuttle)

anyone else have any ideas?

[Joris]

Would the ISS crew increase when commercial crew happens, since it is currently limited due to Soyuz' capacity?

The potential bigelow stations could influence this issue heavily.

[rklaehn]

One of the biggest looming issue for commercial crew is the limited number of flights necessary for crew change-out on the USOS, which amounts to about two flights per year.  Now this is hardly enough to support two commercial crew vehicles, so logically it would be prudent to increase the flights to three or four flights per year.  That amount would leave a large unfilled capacity, so the question now becomes what to do with that capacity,and how the crew changeout would occur. SO here are some ways to utilize:

1.  All crew on one flight, cargo would be on another.  Basically another CRS flight, albeit probably more expensive.

2. Split the crew to two USOS members per flight. Gives the ground time to react more quickly in crew training for ongoing issues on the station. additionally excess capacity for each flight can be used to:

a.  bring up cargo on each flight.
b. Commercial spaceflight participants (ie Space Adventures)
c. short term crew for specialized activities (ie EVA crew like used on shuttle)

anyone else have any ideas?

The ISS is a research station. So why not send the scientists that do a particular experiment up to perform the experiment, and then return them after the experiment is concluded? There would still be a permanent crew to do housekeeping tasks and to operate long duration experiments.

I think that many scientists have complained that the lead times for performing experiments on the ISS are so long that it is easier to perform them in a different way. Frequent crew and equipment exchange would be a way to alleviate this complaint.

[Ronsmytheiii]

Would the ISS crew increase when commercial crew happens, since it is currently limited due to Soyuz' capacity?

The potential bigelow stations could influence this issue heavily.

I think there has been talk about increasing from 6 to 7 expedition crew, but Station can only support so many people long term.

[Jason1701]

To elaborate on the Bigelow point, here are some statistics from their ISDC presentation:

-EACH BA 330
REQUIRES MINIMUM
OF 4 FLIGHTS PER
YEAR FOR CREW
ROTATION [starting in 2015-16]
-SPACE STATION
COMPLEXES WITH
MULTIPLE BA 330s
WOULD REQUIRE 4
CREW FLIGHTS PER
YEAR PER MODULE
-BA 2100 has a crew size of 16
[starting later than 2016]

http://images.spaceref.com/news/2011/bigelow.chrtz.isdc.pdf

[butters]

Periodically (maybe 4 times per year) send a surge crew to do housekeeping and maintenance for two weeks, freeing the full-time crew for utilization.

Also most of the the commercial crew vehicles can double as unmanned cargo vehicles, so the flight rates may not be too much of a problem.

[bobthemonkey]

Increasing docking events is fundamentally a bad idea in so much that it ruins the microgravity environment by shortening the quiescent period duration.

It could also be argued that it reduces the fidelity of ISS as a BEO analogue.

[Jason1701]

Increasing docking events is fundamentally a bad idea in so much that it ruins the microgravity environment by shortening the quiescent period duration.

It could also be argued that it reduces the fidelity of ISS as a BEO analogue.

How much of a problem is the tiny acceleration imposed by docking? What about berthing, if the arm moved slowly enough?

[erioladastra]

Would the ISS crew increase when commercial crew happens, since it is currently limited due to Soyuz' capacity?

The potential bigelow stations could influence this issue heavily.

I think there has been talk about increasing from 6 to 7 expedition crew, but Station can only support so many people long term.

The plan is to expand to 7 when the commercial crew vehicle(s) are ready.  They requirement for them is to be abel to transport 1-4.

[erioladastra]

Periodically (maybe 4 times per year) send a surge crew to do housekeeping and maintenance for two weeks, freeing the full-time crew for utilization.

Also most of the the commercial crew vehicles can double as unmanned cargo vehicles, so the flight rates may not be too much of a problem.

Biggest problem:  $$$$$$

[Robotbeat]

Would the ISS crew increase when commercial crew happens, since it is currently limited due to Soyuz' capacity?

The potential bigelow stations could influence this issue heavily.

I think there has been talk about increasing from 6 to 7 expedition crew, but Station can only support so many people long term.

The plan is to expand to 7 when the commercial crew vehicle(s) are ready.  They requirement for them is to be abel to transport 1-4.

Good to know this from a trusted source!

[manboy]

Would the ISS crew increase when commercial crew happens, since it is currently limited due to Soyuz' capacity?

It seems to be inferred.

No. In fact, we’re 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 don’t 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 don’t 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

[deltaV]

Periodically (maybe 4 times per year) send a surge crew to do housekeeping and maintenance for two weeks, freeing the full-time crew for utilization.

It seems kind of silly to spend hundreds of millions of dollars to transport crewmembers to the ISS and then only leave them there for a few weeks. Why not send the surge crewmembers only twice a year but have them stay for 4 months? This would free half of those four flights per year for cargo flights to keep those extra crewmembers fed.

The tradition of surge crews made sense with the shuttle due to its limited lifetime in orbit and built-in crew, but not much sense going forward as far as I can tell.

[Jason1701]

Periodically (maybe 4 times per year) send a surge crew to do housekeeping and maintenance for two weeks, freeing the full-time crew for utilization.

It seems kind of silly to spend hundreds of millions of dollars to transport crewmembers to the ISS and then only leave them there for a few weeks. Why not send the surge crewmembers only twice a year but have them stay for 4 months? This would free half of those four flights per year for cargo flights to keep those extra crewmembers fed.

The tradition of surge crews made sense with the shuttle due to its limited lifetime in orbit and built-in crew, but not much sense going forward as far as I can tell.

Because ISS can't support 13 crew for four months.

[oldAtlas_Eguy]

It costs the same to send 4 up on commercial crew as it would to send 7. So the extra people staying for a couple of weeks go for free.

[grr]

To elaborate on the Bigelow point, here are some statistics from their ISDC presentation:

-EACH BA 330
REQUIRES MINIMUM
OF 4 FLIGHTS PER
YEAR FOR CREW
ROTATION [starting in 2015-16]
-SPACE STATION
COMPLEXES WITH
MULTIPLE BA 330s
WOULD REQUIRE 4
CREW FLIGHTS PER
YEAR PER MODULE
-BA 2100 has a crew size of 16
[starting later than 2016]

http://images.spaceref.com/news/2011/bigelow.chrtz.isdc.pdf

2100 will not occur anytime in this decade. It weighs 65,000 KG. The only thing that will be capable of launching that would be SLS and I have serious doubts that it will happen at all.
OTH, a BA-1600 give or take would be possible on the FH.

[go4mars]

2100 will not occur anytime in this decade. It weighs 65,000 KG. The only thing that will be capable of launching that would be SLS and I have serious doubts that it will happen at all.
OTH, a BA-1600 give or take would be possible on the FH.

FH with raptor stage might do it within this decade. 

[Robotbeat]

2100 will not occur anytime in this decade. It weighs 65,000 KG. The only thing that will be capable of launching that would be SLS and I have serious doubts that it will happen at all.
OTH, a BA-1600 give or take would be possible on the FH.

FH with raptor stage might do it within this decade. 

...unlikely. Falcon Heavy may launch a few times this decade, but SpaceX has no experience with hydrolox engines, let alone relatively-high-performing ones like Raptor is supposed to be. Also, Bigelow would need to build a new factory at a new location, since the existing factory would be unable to ship such a large payload out of it (no barge access).

Seriously, I'd be absolutely ecstatic with just several BA-330s being built, launched, and manned this decade.

[ugordan]

but SpaceX has no experience with hydrolox engines

Says who? Tom Mueller worked on some pretty high thrust LH2 stuff back with TRW. I imagine the rest of their propulsion department aren't a bunch of hobbyists, either.

[docmordrid]

Could FH fly a single J2X second stage? Fact sheet says it's 120" wide and FH is ~144".

[kch]

Could FH fly a single J2X second stage? Fact sheet says it's 120" wide and FH is ~144".

That should physically fit (with about a foot of clearance all around).

[Ben the Space Brit]

I've always thought that commercial crew could easily have far more than 2 flights a year.  Just off the top of my head, the three mission types are:

* NASA/ESA crew swap at mid-expedition duration;
* Expedition launch and lifeboat duty (whole crew rotation);
* Short duration Extended Operation Capability (EOC) with the extra personnel staging off the crew taxi rather than the station itself.

If you had a two-phase swap out, one by commercial and one by Soyuz at mid-expedition (changing all the science personnel but leaving the flight engineers), then that would total four Soyuz and three commercial crew flights to the ISS per year.  The EOC missions would be additional to that figure and would depend on a particular mission (maybe maintenance spacewalks that require training that the expedition crew does not have).

Could FH fly a single J2X second stage? Fact sheet says it's 120" wide and FH is ~144".

Propellent would be an issue.  J-2X is both hydrolox and fuel-hungry, so it's even money whether the FH core could lift an upper stage with great enough volume without over-balancing or something.

An EELV-scaled engine like RL-60 would probably be a better choice.


[edit]
Added thoughts on mission types and flight rate

[docmordrid]

Thought the SpaceX cores were built with a 40% margin vs ULA's 20% and 25%. If so why couldn't they use up 10 points or so of margin to spec a heavier stage? Maybe for cargo only?

Edit re balancing: perhaps, but I'd love to see it modeled.

[oldAtlas_Eguy]

The one thing I always wondered at was is the 40% loads margin for its original design loads of the F9H (32MT) configuration or just the F9 (10.5MT) design loads.