ISS Commercial Resupply Services 2 (CRS2) 2017-2030

[Lars_J]

Or Boeing could team with ATK for a variant of the Liberty Logistics Module.

I think that concept has been staked through the heart several times now. It could come back, but that is very unlikely.

But the option of delivering cargo through docking hatch does open up the possibility of overlap with a crew variant - or at least a cargo version of DC or CST-100.

[manboy]

A big, fat giant-Cygnus (ie MPLM-sized) on an Atlas V may be pretty competitive.

Maybe also include an unpressurized cargo container (think HTV). This new spacecraft bus could also be used to deliver new modules (not that there's money for them). But I don't think Orbital would want to launch Cygnus on the Atlas V because it's Antares' only payload.

No, Cygnus can be flown in an unpressurized variant.

I'm not sure if the current design can (thrusters are mounted on the PCM).

[yg1968]

But the option of delivering cargo through docking hatch does open up the possibility of overlap with a crew variant - or at least a cargo version of DC or CST-100.

I don't know what the timing of the award of CRS-2 will be. But the best scenario would be for it to be awarded after CCtCap so that whomever gets downselected under CCtCap is unlikely to be much of a contender for CRS-2.

[Space Pete]

Looking at the needs of the ISS out to 2024, here's how I think any CRS-2 bidders could gain a competitive edge:

. Ability to launch and return racks

. Ability to launch and return large external ORUs

. Possible combination of crew and cargo delivery:

-For "rent-a-car" model, MPLM-sized module launches with crew, containing all items (scientific and crew support) needed for that particular increment. Remains at ISS for duration of increment and returns to Earth/is jettisoned with crew at end of increment.

-For "taxi" model, small logistics module launches with inbound crew, spacecraft commander & pilot (likely ISS-trained NASA astronauts) spend their short time at ISS unloading logistics module and filling it with trash/return items, then module returns to Earth/is jettisoned after two weeks along with outgoing crew.

[Jim]

Looking at the needs of the ISS out to 2024, here's how I think any CRS-2 bidders could gain a competitive edge:

. Ability to launch and return racks

. Ability to launch and return large external ORUs

. Possible combination of crew and cargo delivery:

-For "rent-a-car" model, MPLM-sized module launches with crew, containing all items (scientific and crew support) needed for that particular increment. Remains at ISS for duration of increment and returns to Earth/is jettisoned with crew at end of increment.

-For "taxi" model, small logistics module launches with inbound crew, spacecraft commander & pilot (likely ISS-trained NASA astronauts) spend their short time at ISS unloading logistics module and filling it with trash/return items, then module returns to Earth/is jettisoned after two weeks along with outgoing crew.

Not really.  It doesn't do them any good if it is outside of the scope of the contract.  NASA will only contract for tasks it has money set aside for.  If NASA isn't going to contract for rack swap outs, then there is no return for somebody to design for that capability.

[Robotbeat]

But the option of delivering cargo through docking hatch does open up the possibility of overlap with a crew variant - or at least a cargo version of DC or CST-100.

I don't know what the timing of the award of CRS-2 will be. But the best scenario would be for it to be awarded after CCtCap so that whomever gets downselected under CCtCap is unlikely to be much of a contender for CRS-2.

Why? This may allow the next-best-thing to having 2 crew providers.

[Robotbeat]

If like to see a diagram comparing Cygnus's mini-CBM to a NDS (or whatever it's called now) docking port with the petals removed.

[Space Pete]

Not really.  It doesn't do them any good if it is outside of the scope of the contract.  NASA will only contract for tasks it has money set aside for.  If NASA isn't going to contract for rack swap outs, then there is no return for somebody to design for that capability.

True, however I hope the contract leaves room for NASA to consider "any additional capabilities" that bidders may propose - looking past 2020, having the capability to return failed racks for repair, or disposing of old racks to make room for new racks could be useful.

[yg1968]

But the option of delivering cargo through docking hatch does open up the possibility of overlap with a crew variant - or at least a cargo version of DC or CST-100.

I don't know what the timing of the award of CRS-2 will be. But the best scenario would be for it to be awarded after CCtCap so that whomever gets downselected under CCtCap is unlikely to be much of a contender for CRS-2.

Why? This may allow the next-best-thing to having 2 crew providers.

Let's say that one company (say Boeing) gets downselected under CCtCap. I think that their chance of winning a CRS-2 award would be small. Under such a scenario, SpaceX and SNC could each win both a CCtCap and a CRS-2 award.  The advantage of this scenario is that it allows NASA to maintain two commercial crew companies even after post-certifications missions are completed. The current plan is to eventually downselect to one commercial crew provider for the crew transportation system (CTS) contract. However, this scenario would allow NASA to maintain a backup crew provider for CTS through its CRS-2 cargo contract.

[dror]

Is there a possibility to offer a  reusable space tug to this contract.
of course RnD will be much more expensive but operation will be a lot cheaper.

http://en.m.wikipedia.org/wiki/Parom

[dror]

A big, fat giant-Cygnus (ie MPLM-sized) on an Atlas V may be pretty competitive. That's a lot of cargo...

a falcon 9 will be a much more economical choice.
there is no reason why spacex wont want to participate with orbital, and orbital are used to outsourcing.
this will allow more flights of falcon9 every year, making it even more economical, and allowing it to better integrate reuseability.

[Coastal Ron]

I'm not sure if the current design can (thrusters are mounted on the PCM).

According to Orbital the Cygnus Service Module is based on Orbital's GEOStar Satellite bus and handles all the transportation tasks.  It appears to be completely independent of the cargo it carries.

I'm not sure how scaleable the current SM is, but if we ever need to add more modules onto the ISS or build a new station in LEO, the Cygnus SM could probably be the tug to deliver station elements to a robotic construction arm.  Might need to launch it on something other than Taurus though.  No doubt tug versions of the ATV and HTV could do the same, so we have already been testing and validating that we don't need something like the Shuttle to build or expand space stations.

Regarding the CRS2 contract, while Dragon, CST-100 and Dream Chaser would provide flexibility, Cygnus provides less expensive one-way transportation for bulky cargo.  The question is whether there is a big need for that during the CRS2 contract period, or if NASA can live with the volume constraints of a Dragon or other spacecraft?

[Hauerg]

Is there a possibility to offer a  reusable space tug to this contract.
of course RnD will be much more expensive but operation will be a lot cheaper.

http://en.m.wikipedia.org/wiki/Parom

The services have to be available from 2017 onwards. That is 3 years from now. No time for fancy new developments.
Except maybe for a company that is VERY quick in producing fresh hardware. (A certain one is coming to moind.)

[jongoff]

No, Cygnus can be flown in an unpressurized variant.

Not at present.

Very true. But when you look at the complexity of making a pressurized cargo vehicle that can safely berth with the ISS, and a brand new launch vehicle to launch it, I think making an unpressurized version of Cygnus is relatively easy compared to what OSC has already proven it can do for a relatively small budget.

~Jon

[arachnitect]

If like to see a diagram comparing Cygnus's mini-CBM to a NDS (or whatever it's called now) docking port with the petals removed.

Cygnus  is 94 cm square.
NDS (w/ petals installed) is 80 cm circular.

Not sure if petals are still removable. References to removing the guide petals have disappeared from the latest document I've found. If you pull the whole Soft capture system out you get 125 cm circular at best. The minimum clearance could also be in the APAS/NDS adapter on the PMA.

[simonbp]

IMHO, the ability to deliver cargo through the hatch is going to mean the end of Cargo Dragon, allowing SpaceX to focus on just one variant for the next version of Dragon. I could easily see them proposing to do crew flights with new-build Dragon capsules and then cargo flights with reused Dragons, as a low-risk way of building up reusable flight hours.

[manboy]

If like to see a diagram comparing Cygnus's mini-CBM to a NDS (or whatever it's called now) docking port with the petals removed.

The petals can no longer be removed on orbit. I don't have time to toss together a diagram (maybe later) but here are the dimensions.

CBM with standard hatch, passage size: 50 in (1270 mm) by 50 in (1270 mm)
CBM with mini hatch, passage size: 37 in (940 mm) by 37 in (940 mm)
NDS/IDSS (post-SIMAC redesign) passage size: 31 inches (800 mm) in diameter

[Robotbeat]

Isn't it possible the cargo contenders would propose a compatible system that DOES allow the petals to be removed? I don't see why they'd be forced to use the SIMAC design.

[Space Pete]

I don't see why they'd be forced to use the SIMAC design.

Because the corresponding docking adapters (IDAs) on ISS will use SIMAC.

[Robotbeat]

I don't see why they'd be forced to use the SIMAC design.

Because the corresponding docking adapters (IDAs) on ISS will use SIMAC.

Ah, you're right... there are petals on both sides...

It seems pretty short-sighted to me that the petals are non-removable.