ISS Commercial Resupply Services 2 (CRS2) 2017-2030

[MikeAtkinson]

SpaceX may try and go for it all. A pressurized version of the extended trunk could carry about 30 m^3 of cargo, so 4 flights per year (2 with a pressurized trunk) would give 100 m^3 of pressurized up-volume and 28 m^3 of unpressurized up-volume. By using the unpressurized trunk flights to carry denser cargo I reckon about 16 tonnes of pressurized cargo and up to 4 tonnes of unpressurized cargo can be carried.

Alternatively they could do it with 8 flights/year of F9R + reused Dragons at about $70M/flight. NASA would have to change the requirements before the RFP for this to be possible .

Alternatively a large Dragon (5-5.5m diameter) could probably meet the requirements - but this is probably only worth doing for SpaceX if they had another customer.

The cost to SpaceX is roughly the same for each of these options, possibly  in the order of $400M.

[rpapo]

Alternatively a large Dragon (5-5.5m diameter) could probably meet the requirements - but this is probably only worth doing for SpaceX if they had another customer.

The problem with this is the same problem that gives us a tall skinny Falcon: road clearances on American highways.  I don't think they will fabricate a wider pressure shell in two or more pieces to be assembled at the launch site.

[Robotbeat]

This is the only reason I brought up MCT as a possible part of their bid. More likely than a large Dragon, about on par with a pressurized "trunk". Dragons are a little too small for cargo if you're limited to just 4 or 5 per year for 15t. It can be done, if a lot of the mass is stuff like water, but it's tight.

[Lars_J]

SpaceX may try and go for it all. A pressurized version of the extended trunk could carry about 30 m^3 of cargo

Please explain how *that* would work. A bit far-fetched IMO.

[Coastal Ron]

The cost to SpaceX is roughly the same for each of these options, possibly  in the order of $400M.

NASA isn't providing any development funds for cargo - they already did that with the COTS program.

Unless there is some deficit that NASA currently sees that needs to be addressed with the current cargo providers, I'm sure they would quite happy if they continued to use the current Orbital Sciences and SpaceX cargo transportation systems.  Between the two of them they provide everything that the station needs, and if they need something else they can create a separate contract to handle that.

And I'll state again that from my perspective if we're not LOWERING the overall cost to support the ISS, then we don't yet know enough to expand humanity out into space.  And isn't that really the goal we all want?

[MikeAtkinson]

SpaceX may try and go for it all. A pressurized version of the extended trunk could carry about 30 m^3 of cargo

Please explain how *that* would work. A bit far-fetched IMO.

Have the trunk as a pressure vessel. Berthing port at the lower end (opposite end to Dragon). Fly to ISS, berthed to ISS by the berthing port on trunk. After offload and load of cargo fly away. Use Dragon only as a tug.

Extra marks if the Dragon can be used to carry cargo as well, but this needs a second berthing which seems to be outside the spirit of the RFI.

[guckyfan]

SpaceX may try and go for it all. A pressurized version of the extended trunk could carry about 30 m^3 of cargo

Please explain how *that* would work. A bit far-fetched IMO.

Look at Chris Bergins article.

http://www.nasaspaceflight.com/2014/02/nasa-iss-resupply-options-through-2024/

They could do it similar to the ATK proposal. Should not be hard to implement. That vessel can be almost totally passive.

[InfraNut2]

SpaceX may try and go for it all. A pressurized version of the extended trunk could carry about 30 m^3 of cargo

Please explain how *that* would work. A bit far-fetched IMO.

Have the trunk as a pressure vessel. Berthing port at the lower end (opposite end to Dragon). Fly to ISS, berthed to ISS by the berthing port on trunk. After offload and load of cargo fly away. Use Dragon only as a tug.

Extra marks if the Dragon can be used to carry cargo as well, but this needs a second berthing which seems to be outside the spirit of the RFI.

This generates too many operational and other problems IMHO.

It would be better to have a separate pod in the extended trunk. You could fit a pod the size of the cygnus standard PCM, only slightly shorter and wider. I.e. up to around 20m² (edit: but even 10m² would be really useful). This would operate the same way as for the Bigelow BEAM payload on SpX-8, except it is returned to the trunk afterwards (edit: and not inflated of course). Or in some respects more like the MPLM or the proposed ATK liberty cargo pod.

Both Dragon itself and the pod will be available for unloading+loading simultaneously. edit: this would be especielly neat for a docking crew/cargo dragon.

It would also fit on any flight without other external payloads. It would be no more tricky that any other external payload except for being bulkier and possibly heavier.

[Lurker Steve]

CST-100 would have down-mass capabilities. They may bid on CRS-2. But Dragon obviously is far ahead in this regard, since, um, they've already flown to ISS 4 times doing cargo up and down.

Obviously, both of the existing CRS providers have an advantage since they already have cargo vehicles developed and already have some sort of operational flow going with regards to unmanned cargo flights. Everyone else would need to fund the development of a cargo version of their vehicle in-house.

It would be interesting if Orbital decided to add some optional downmass or unpressurized cargo capability to the existing Cygnus in the future. With the current production flow for Antares / Cygnus, I think they could handle the LON capability today. SpaceX would need to somehow throttle back their manifest, so that they could keep an extra Dragon and F9 in storage someplace near, but not necessarily at the launch pad.

[Robotbeat]

Cygnus has a ballute recovery concept that would allow down mass using the Cygnus spacecraft. Don't know how far the idea is.

[dror]

I'd love to see Biglow offering their space tug concept for affordable space access.

Off topic.

The Bigelow space tug is an inspace only vehicle.  It has neither the high thrust engines nor the thermal protection system (heat shield) needed to operate in an atmosphere.  It may however end up being a second customer for the CRS2 launch vehicles.

Sorry A_M, I dont get your point.
Of course a space tug has to be complementry to a LV. The launch vehicle takes the cargo module out of the atmosphere and the tug takes it from there. Then the tug returns the used cargo module to a decay orbit, and comes back to park at iss or waits on orbit. Once being launched, the tug does not need to enter the atmosphere, and you dont get to burn a $50mil bus on every flight.

Earlier on the thread I got a good reason why it wont be possible at crs2:
http://forum.nasaspaceflight.com/index.php?topic=34093.msg1163268#msg1163268
I think that not developing a space tug earlier shows lack of insight by nasa, as it could have saved money while advancing science. Therefore I said Id love to see it happen now

[manboy]

Cygnus has a ballute recovery concept that would allow down mass using the Cygnus spacecraft. Don't know how far the idea is.

Or something like the VBK-Raduga.

[Comga]

SpaceX may try and go for it all. A pressurized version of the extended trunk could carry about 30 m^3 of cargo, so 4 flights per year (2 with a pressurized trunk) would give 100 m^3 of pressurized up-volume and 28 m^3 of unpressurized up-volume. By using the unpressurized trunk flights to carry denser cargo I reckon about 16 tonnes of pressurized cargo and up to 4 tonnes of unpressurized cargo can be carried.

Alternatively they could do it with 8 flights/year of F9R + reused Dragons at about $70M/flight. NASA would have to change the requirements before the RFP for this to be possible .

Alternatively a large Dragon (5-5.5m diameter) could probably meet the requirements - but this is probably only worth doing for SpaceX if they had another customer.

The cost to SpaceX is roughly the same for each of these options, possibly  in the order of $400M.

We have seen a drawing from SpaceX of an extended, but still unpressurized trunk.
Do you have any reference to a SpaceX discussion of a pressurized trunk?  I don't think it exists.
It is even less likely that you have seen a SpaceX discussion of a larger Dragon.
I believe that others here might say that your pricing of F9R/Dragon flights is "Unsubstantiated".

[Jim]

I think that not developing a space tug earlier shows lack of insight by nasa, as it could have saved money while advancing science. Therefore I said Id love to see it happen now

Nonsense.  NASA as no need for such a device based on launch frequency.   Science missions don't need it and ISS is complete.

[Coastal Ron]

I think that not developing a space tug earlier shows lack of insight by nasa, as it could have saved money while advancing science. Therefore I said Id love to see it happen now

Nonsense.  NASA as no need for such a device based on launch frequency.   Science missions don't need it and ISS is compete.

I agree that NASA has not needed space tugs yet, and the good news is that the basic technology for them has already been demonstrated by the ATV, HTV and Cygnus supply vehicles.  Cygnus especially has a Service Module that is already separate from it's Pressurized Cargo Module, and could act as a tug for other cargo quite easily.

We don't lack the ability to move dumb mass to specific points in LEO, and no doubt the same technology can be used if we need to move dumb mass to points beyond LEO.  All without the need of a new launcher.

[Jim]

I agree that NASA has not needed space tugs yet, and the good news is that the basic technology for them has already been demonstrated by the ATV, HTV and Cygnus supply vehicles.  Cygnus especially has a Service Module that is already separate from it's Pressurized Cargo Module, and could act as a tug for other cargo quite easily.

And Orbital Express. 

[BrightLight]

All in all the CRS-2 contract is pretty good deal for the US taxpayer.  CRS 1 was about 88M per ton in 2008.  Taking inflation into account using standard CPI calculators, that $88M is equivalent to $95.61M in 2014 dollars.  CRS-2 has at the upper end about $100M per ton delivered and and about $66M at the lower end.
Also included is the returned down mass
"The following items are part of the total return capability required but require additional support from the service provider.
   Return of 24-30 powered lockers per year.  The same power and data services as described above are required for the return flight. 
   Return of 24-30 conditioned stowage bags per year. 
   Return of 20-25 CTBEs of passive cargo per year.  "
to me, this is clear progress towards a non-government operated LEO capability.

[yg1968]

Note that the number of cargo flights (4 or 5) to the ISS isn't set in stone. The RFI says the following on this topic (see the last sentence in bold):

Funds Available to Procure the Service

NASA’s budget to procure this service is anticipated to be between $1.0B and $1.4B per year. If the described services cannot be provided as defined within this budget range, NASA requests feedback on options to procure the required upmass and downmass for the defined budget. Identify which services would need to be modified or removed to stay within the available budget. For example, propose a different number of flights per year that still meets the required upmass and downmass required.

This implies that a provider could offer in its proposal more or less than 4 or 5 flights per year provided that they stay within the budget.

[dror]

I think that not developing a space tug earlier shows lack of insight by nasa, as it could have saved money while advancing science. Therefore I said Id love to see it happen now

Nonsense.  NASA (h)as no need for such a device based on launch frequency.   Science missions don't need it and ISS is complete.

Evidently, your right. If we give nasa the credit for them probably have done all the checkups and came to your conclusion that it is not cost effective based on launch frequency.
But I cant find the way to get to this conclusion by myself.

[Llian Rhydderch]

CST-100 would have down-mass capabilities. They may bid on CRS-2. But Dragon obviously is far ahead in this regard, since, um, they've already flown to ISS 4 times doing cargo up and down.

We'll see what the selection criteria are but I suspect that they will be similar to CCtCap. If that is the case, price will be very important (as it should be). I suspect that SpaceX will come out on top because of prices again. But after SpaceX, the competition is wide open. Isn't competition, great?

Competition, and more specifically, the ability of new entrants to freely enter the market ^{(and of existing firms to exit the market when their offerings are no longer competitive, and when they do not choose to expend the development and operational resources to innovate and develop new technologies to remain competitive)}, is absolutely essential to bringing into being the sort of dynamic and innovative space future needed to get humanity into a new and vibrant space age version 2.