Interim Cryogenic Propulsion Stage (ICPS) for SLS

[Ronsmytheiii]

Any chance to see proposals from other companies than Boeing? For example the new engine from SpaceX should be announced soon (if its one for an upper stage)

We will see, SpaceX has a lot on their plate with cargo/Crew Dragon and Falcon Heavy, not to mention the re-usability plans.

I am certain that ACES and other u/s could be proposed, but considering the timescale and the small procurement numbers would imagine that Delta Heavy u/s is almost the predetermined winner, hard to argue against a flight proven u/s for such limited numbers needed.

[apace]

would imagine that Delta Heavy u/s is almost the predetermined winner, hard to argue against a flight proven u/s for such limited numbers needed.

But it's not already human-rated? For 2017 flight it needs to be human retable and for 2020 human-rated. The engines should be not a problem, as the RL10 was always human-rated as I know.

[MP99]

7. Constraints a. Axial acceleration, during stage burns, not to exceed 2g

MPCV will undergo higher accelerations during ascent, so why this restriction?

Would solar panels be deployed during the injection burn, perhaps?

cheers, Martin

[strangequark]

The engines should be not a problem, as the RL10 was always human-rated as I know.

Who says RL-10 is human rated?

[robertross]

would imagine that Delta Heavy u/s is almost the predetermined winner, hard to argue against a flight proven u/s for such limited numbers needed.

But it's not already human-rated? For 2017 flight it needs to be human retable and for 2020 human-rated. The engines should be not a problem, as the RL10 was always human-rated as I know.

Eight years to 'human rate' an existing design does not seem outside of the envelope. The important thing to remember is the statement of the U/S to be 'human-ratable', but that does not mean the first deliverable 'has' to be, it just needs to have sufficient work underway, or have enough documentation to support an easily attainable target.

Engines, plumbing, structure, wiring, electronics, valves...

It would be in good hands considering the supplier in question.

[Robotbeat]

7. Constraints a. Axial acceleration, during stage burns, not to exceed 2g

MPCV will undergo higher accelerations during ascent, so why this restriction?

Would solar panels be deployed during the injection burn, perhaps?

cheers, Martin

Perhaps the load paths from the ICPS to the MPCV will be different than from the rest of the SLS to MPCV, i.e. a big fairing or interstage is intended to cover the ICPS (and transmit the load from SLS to MPCV) until ICPS/MPCV separates from the rest of SLS.

Or, they wanted to further restrict the available options to only at most ~2 RL-10 engines so that their desired solution is picked. This is what happens when you design something for a certain upper stage and only then go out to bid for it.

[notsorandom]

How easy would it be to stretch or increase the diameter of the Centaur to increase the propellant load? Before the ACES stage wasn't a wide body 5.4m Centaur being talked about as an upgrade? I guess I may be a bit partial to seeing a Centaur based ICPS because it may influence NASA towards an upper stage using Centaur heritage like the Jupiter upper stage.

[alexw]

Also, ACES could be readied for this?

I dunno, Jim.  It seems a bit of an outside chance.  ACES is practically a spacecraft in its own right, IIRC.  Common Centaur (1, 2 or 4 x RL-10B-2) may be doable in 4-5 years but all the extra bells and whistles on ACES may make it difficult.

     FWIW, [ZKB2009] "A Commercially Based Lunar Architecture", pg.24, has a sandplot with one of the few references to development time for ACES: starting in 2010, finishing just shy of 2016.
     [BK2010] "Phase 2 EELV – An Old Configuration Option with New Relevance to Future Heavy Lift Cargo" says, pg.2, "The Phase 2 EELV could be ready to fly as early as 2016 ...."

    That suggests that delivery by 2016Q4 (fiscal), given that it's 2012 right now, is too tight.
 
    It's an interesting question exactly what would be the pacing items. Could the basic 5m Common Centaur (actually, a shortened version of ~30mT, although perhaps NASA would be willing to revise that cap!) be ready by then, leaving aside the more sophisticated thermal structures and IVF of ACES?

    Since NASA hasn't been willing to just spring for ACES, we'd seem to be pretty happy with an interim stage that provides the framework to evolve and flight test the features needed long-term.
    -Alex

[sdsds]

If Delta IV is the only stage, will Boeing provide it or will they let ULA?

Really good question.  By soliciting bids, NASA is allowing the entities involved to hash out which one will respond with an offer.  Conceivably Boeing and LM could create a new entity specifically for the purpose of providing this hardware, just as they created ULA to provide launch services.

[simonbp]

Would solar panels be deployed during the injection burn, perhaps?

Well, the second mission listed was "high lunar orbit", which would imply a capture burn by the iCPS, which means the solar arrays would be deployed. So yes, that's the most likely reason.

[MP99]

Would solar panels be deployed during the injection burn, perhaps?

Well, the second mission listed was "high lunar orbit", which would imply a capture burn by the iCPS, which means the solar arrays would be deployed. So yes, that's the most likely reason.

Firstly, the dV requirement doesn't include Lunar capture.

Secondly, CxP's "Lunar" Orion includes substantial dV to rendezvous with Altair in support of "anytime return", plus the dV to escape from LLO.

Taken together, it's my understanding that MPCV has sufficient dV to insert itself to a highly eliptical HLO plus then perform TEI.

cheers, Martin

[Ben the Space Brit]

Secondly, CxP's "Lunar" Orion includes substantial dV to rendezvous with Altair in support of "anytime return", plus the dV to escape from LLO.

Taken together, it's my understanding that MPCV has sufficient dV to insert itself to a highly eliptical HLO plus then perform TEI.

It's OT but I really wonder why this mission is being contemplated, other than to say they've been.  Just as an alternative, would lunar MPCV + iCPS as specified be able to insert to EML-1 with enough reserves for the return burn?

[A_M_Swallow]

It's OT but I really wonder why this mission is being contemplated, other than to say they've been.  {snip}

For the sound of it the highly elliptical orbit for the Orion followed by Trans-Earth Injection is to test the heat shield.  The heat shield and side walls will not get as hot as during a re-entry from the Moon but close.

Edit : correct quote boxes

[Jim]

It's OT but I really wonder why this mission is being contemplated, other than to say they've been.  {snip}

For the sound of it the highly elliptical orbit for the Orion followed by Trans-Earth Injection is to test the heat shield.  The heat shield and side walls will not get as hot as during a re-entry from the Moon but close.

EFT-1 accomplishes this.

[Zed_Noir]

Is there other plausible candidates for the iCPX contract other than the DCSS?