Author Topic: NASA requests alternative options to RS-25s on SLS core stage  (Read 5410 times)

Online Chris Bergin

https://www.nasaspaceflight.com/2018/04/nasa-request-alternative-rs-25s-sls-core-stage-uncontested/

With cool renders from Nathan Koga of course.

--

RFI:

Space Launch System (SLS) Core Stage Engine (CSE)
Solicitation Number: NNM18ZXP006L

https://www.fbo.gov/notices/f3a95ea8ec325e3eede60b0191395aa4

This is for eighteen core stage engines, first four for delivery by July 2025.

Requirements document:

https://www.fbo.gov/utils/view?id=42ce7df221f61a348d2c44899ded6465
« Last Edit: 04/11/2018 07:19 PM by Chris Bergin »

Online Coastal Ron

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Great article about a routine process for a controversial program.

I think the bottom line for this RFI is boiled down by this line from the article:

Quote
The latest RFI provides another example that one person involved with SLS told NSF was “like the Russian Presidential election. You have to have one, but there’s only going to be one winner.”

Which should not be surprising, since rockets are usually built around engines, and it's expensive to make major changes.

My prediction is that few responses will be received, and that Aerojet Rocketdyne will win the future RFQ...
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline TrevorMonty

Only only domestic option is Be3 and that would require 20 of them and major redesign. Plus ISP is likely to be lower. Engine set price would be lot cheaper probably $50-100m, but redesign costs would probably pay for few sets of RS25s.

At one flight a year its not worth messing with design.

Offline Rocket Science

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Thank you for the article and renders gentlemen. The office at Marshall sure is great for generating paperwork...
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Offline envy887

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Only only domestic option is Be3 and that would require 20 of them and major redesign. Plus ISP is likely to be lower. Engine set price would be lot cheaper probably $50-100m, but redesign costs would probably pay for few sets of RS25s.

At one flight a year its not worth messing with design.

I doubt any existing engine meets the specific impulse, thrust, mixture ratio, weight and throttling requirements, which are quite specific to RS-25.

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OMS RFI all over again....

Are they mandated to release a RFI for things even though all decisions have already been made?  I just don't see the point otherwise.

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They need a higher thrust option to make up for the relative lack of thrust; because SLS was originally envisaged to need 5x corestage engines!

EDIT: Although it's the monstrously heavy Solid Rocket boosters that are the long pole in the tent to get the SLS payload capability towards the desired goal of more than 120 metric tons to Low Earth Orbit. The Super 'Dark Knights' boosters would push that goal nearly within reach and an upper stage upgrade is also needed to close the deal. It remains to be seen if funding and support for these upgrades and a decent flight rate will be within reach... :(
« Last Edit: 04/12/2018 12:46 AM by MATTBLAK »
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Offline chipguy

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I think this statement from the article is crucial:

The total engine stock, based on Shuttle’s “hand-me-down” engines, an additional stock created from spare parts, and the six engines ordered via Aerojet Rocketdyne would support SLS’ first five missions, taking into account the need for flight spares, etc.

What is the likelihood that SLS will ever exceed 5 flights?

Given the ever receding horizon for SLS first flight, lack of credible missions, and near future changes
in the industry and Congress I am doubtful that even the RS-25E already ordered will be needed.

Offline space_dreamer

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So NASA has paid 1.5 Billion for 6 engines? enough for less than two flights. Er... That sounds like a bad deal to me but does anybody know what a order for 60 engines cost?

Would economies of scale get the price down to something reasonable?

I wish nasa went with The Ares Mars Direct design, same lift as SLS but the engines get reused...

Online spacenut

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With a cluster of BE-3U's, they could make it be able to land the core with a little core stretch, and make it reusable.  Then a BE-3U upper stage. 

Offline envy887

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They need a higher thrust option to make up for the relative lack of thrust; because SLS was originally envisaged to need 5x corestage engines!

EDIT: Although it's the monstrously heavy Solid Rocket boosters that are the long pole in the tent to get the SLS payload capability towards the desired goal of more than 120 metric tons to Low Earth Orbit. The Super 'Dark Knights' boosters would push that goal nearly within reach and an upper stage upgrade is also needed to close the deal. It remains to be seen if funding and support for these upgrades and a decent flight rate will be within reach... :(

The RFI specs 520 klbf thrust, same as the RS-25D at 111% RPL. So no thrust upgrades requested here.

Offline envy887

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With a cluster of BE-3U's, they could make it be able to land the core with a little core stretch, and make it reusable.  Then a BE-3U upper stage.

BE-3 does not meet most of the specs from the RFI. The core stage is already the longest and largest in the world, a "little stretch" is a big deal. Keeping the core stage reentry velocity somewhere between "theoretically possible" and "and totally insane" would require a huge upper stage, which with a core stretch would be totally impractical and also run into VAB height constraints.

To actually pursue core stage reuse, the core should be smaller, and MECO should happen less than a minute after SRB sep. But that is all far outside the scope of this RFI.

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They need a higher thrust option to make up for the relative lack of thrust; because SLS was originally envisaged to need 5x corestage engines!

EDIT: Although it's the monstrously heavy Solid Rocket boosters that are the long pole in the tent to get the SLS payload capability towards the desired goal of more than 120 metric tons to Low Earth Orbit. The Super 'Dark Knights' boosters would push that goal nearly within reach and an upper stage upgrade is also needed to close the deal. It remains to be seen if funding and support for these upgrades and a decent flight rate will be within reach... :(

The RFI specs 520 klbf thrust, same as the RS-25D at 111% RPL. So no thrust upgrades requested here.
Yeah, I get that. Though reading through old articles once told me that more than one RS-25 was tested to destruction at 120%. I think it would be reasonable to assume 114-115% could be reliably achieved; especially in the years since there has been the Block II upgrades and beyond.
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Offline Khadgars

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So NASA has paid 1.5 Billion for 6 engines? enough for less than two flights. Er... That sounds like a bad deal to me but does anybody know what a order for 60 engines cost?

Would economies of scale get the price down to something reasonable?

I wish nasa went with The Ares Mars Direct design, same lift as SLS but the engines get reused...

Thats a strange way of looking at it.  NASA paid $1.5B to restart production of the RS-25, plus additional upgrades to it, in addition to the 6 engines.  That $1.5B is over 10 years if I remember correct.

Offline whitelancer64

I think this statement from the article is crucial:

The total engine stock, based on Shuttle’s “hand-me-down” engines, an additional stock created from spare parts, and the six engines ordered via Aerojet Rocketdyne would support SLS’ first five missions, taking into account the need for flight spares, etc.

What is the likelihood that SLS will ever exceed 5 flights?

Given the ever receding horizon for SLS first flight, lack of credible missions, and near future changes
in the industry and Congress I am doubtful that even the RS-25E already ordered will be needed.

But if NASA behaved like that was the case, then the program would be cancelled and the funding removed.
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Offline envy887

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So NASA has paid 1.5 Billion for 6 engines? enough for less than two flights. Er... That sounds like a bad deal to me but does anybody know what a order for 60 engines cost?

Would economies of scale get the price down to something reasonable?

I wish nasa went with The Ares Mars Direct design, same lift as SLS but the engines get reused...

Thats a strange way of looking at it.  NASA paid $1.5B to restart production of the RS-25, plus additional upgrades to it, in addition to the 6 engines.  That $1.5B is over 10 years if I remember correct.

No, it's not strange at all. If someone else responds to this RFI with another engine that meets the specs and eventually is contracted to put it into production starting in 2025, NASA will still have paid the $1.5 billion to restart RS-25 production, plus the $57 million per engine for the currently contracted 6 engines out to 2025. That's a total of $1.6 billion paid to AJRD for only 6 engines delivered to NASA.

Of course, the chance of such an alternative engine appearing is vanishingly small, to the point where this RFI results only in an already forgone conclusion: it will be RS-25, and the $1.5 billion will be spread over more engines after 2025, so long as the entire SLS isn't cancelled.

Online Coastal Ron

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So NASA has paid 1.5 Billion for 6 engines? enough for less than two flights. Er... That sounds like a bad deal to me but does anybody know what a order for 60 engines cost?

The contract I see is for $1.16B, which is for redesigning the RS-25 to be modernized and manufacturable, and "...allows for a potential future modification that would enable NASA to order six flight engines."

That money goes towards some redesign effort, which is always costly for a human-rated rocket engine, and for getting the production line ready to build new engines. With a rocket the scale of the SLS, nothing is inexpensive, especially when using old designs.

Quote
Would economies of scale get the price down to something reasonable?

For the most part, no.

The production rate of this engine is too low, and the design is likely too complicated to benefit from normal cost-reduction strategies.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline SWGlassPit

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OMS RFI all over again....

Are they mandated to release a RFI for things even though all decisions have already been made?  I just don't see the point otherwise.

The FARs are pretty specific with regard to what must be done for government procurement.  In general, any procurement that is not competed -- any "sole source" procurement -- must have a JOFOC (Justification for Other than Full and Open Competition) stating why the procurement meets one of seven statutory exemptions:

1) Only one responsible source and no other supplies or services will satisfy agency requirements
2) Unusual and compelling urgency
3) Industrial mobilization; engineering, developmental, or research capability; or expert services
4) International agreement
5) Authorized or required by statute
6) National security
7) Public interest

Of these, only the first exemption is really applicable in this case, and there need to be defensible justifications and announcements associated with it.

The relevant regulations are 48 CFR 6.300 through 48 CFR 6.305, available at https://www.acquisition.gov/far/html/Subpart%206_3.html

Offline JonathanD

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Of these, only the first exemption is really applicable in this case, and there need to be defensible justifications and announcements associated with it.

I just don't see anyone sticking their neck out and proposing to build a hydrolox engine that could compete with the RS-25 when all signs point to NASA sticking with AJR.  BO and SpX are headed down the methalox road already and I don't think either are interested in taking a detour. 

Sadly I think we just have to hope they won't ever really be needed.  I love the capability of SLS, but the window on outrageously expensive fully expendable rockets needs to close.

Offline Steve G

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Rather than asking for alternative options for the RS-25s, they should have asked for alternative options for the entire core stage. No restrictions on engine size, quantity, or propellants. Just performance.

Offline envy887

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Rather than asking for alternative options for the RS-25s, they should have asked for alternative options for the entire core stage. No restrictions on engine size, quantity, or propellants. Just performance.

SLS doesn't work well unless the upper stage, boosters, and pad support all match the core stage. Which either puts a pretty strict set of bounds on what the core stage looks like, or results in a near-complete redesign of most of the program.

Offline Steve G

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That would obviously be part of the stipulation. It would have been interesting if SpaceX or Blue Origin would have accepted the challenge.

Offline Jim

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Rather than asking for alternative options for the RS-25s, they should have asked for alternative options for the entire core stage. No restrictions on engine size, quantity, or propellants. Just performance.


not a viable option

Offline AncientU

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Rather than asking for alternative options for the RS-25s, they should have asked for alternative options for the entire core stage. No restrictions on engine size, quantity, or propellants. Just performance.

SLS doesn't work well unless the upper stage, boosters, and pad support all match the core stage. Which either puts a pretty strict set of bounds on what the core stage looks like, or results in a near-complete redesign of most of the program.

The procurement should be for the entire launch capability (100-200t to orbit annually? or 50-100t to the Lunar vicinity annually?), but then there would be more than one bidder, which NASA and its cohort cannot tolerate.
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Offline SWGlassPit

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Rather than asking for alternative options for the RS-25s, they should have asked for alternative options for the entire core stage. No restrictions on engine size, quantity, or propellants. Just performance.

SLS doesn't work well unless the upper stage, boosters, and pad support all match the core stage. Which either puts a pretty strict set of bounds on what the core stage looks like, or results in a near-complete redesign of most of the program.

The procurement should be for the entire launch capability (100-200t to orbit annually? or 50-100t to the Lunar vicinity annually?), but then there would be more than one bidder, which NASA and its cohort cannot tolerate.

Umm... they did that more or less, within the confines of their procurement policies.  You clearly have no idea what you're talking about.  You do know that there are multiple contractors building this, right?  Where do you think the contracts came from?

Offline AncientU

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Rather than asking for alternative options for the RS-25s, they should have asked for alternative options for the entire core stage. No restrictions on engine size, quantity, or propellants. Just performance.

SLS doesn't work well unless the upper stage, boosters, and pad support all match the core stage. Which either puts a pretty strict set of bounds on what the core stage looks like, or results in a near-complete redesign of most of the program.

The procurement should be for the entire launch capability (100-200t to orbit annually? or 50-100t to the Lunar vicinity annually?), but then there would be more than one bidder, which NASA and its cohort cannot tolerate.

Umm... they did that more or less, within the confines of their procurement policies.  You clearly have no idea what you're talking about.  You do know that there are multiple contractors building this, right?  Where do you think the contracts came from?

More less than more...
The SLS vendors were dictated by Congress, as a carry-over from a cancelled program called Constellation, completely ignoring their own body of procurement policies.  Since they also skipped the program budget definition step, the contractors got a blank check to spend whatever was given to them and extend the period of performance indefinitely -- at which they are succeeding famously.

Nothing in Federal law prohibits NASA from procuring launch services competitively... in fact, they are by law required to procure services commercially whenever possible.

Quote
To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0
Thanks for the frequent reminder, Robotbeat

In this case, 50-100t annually to the Lunar vicinity starting in 2025, they probably would get bids from 4 companies, bidding six rockets/services approaches(in no particular order):
1. Vulcan/CentaurV with distributed launch
2. Falcon Heavy
3. New Glenn, possibly with distributed launch
4. Next Generation Launcher/Heavy
5. BFR/BFS
6. New Armstrong

The USAF is soliciting launch services with flights starting in 2022 from this same gaggle of commercial providers, so don't tell me they don't exist or the USG cannot just buy launch services.

NOTE: If SLS Block 1B tried to enter the bidding for USAF services, it wouldn't be ready in time.  The SLS maiden launch might not even occur before a majority of these launchers are flying.
« Last Edit: 04/12/2018 08:39 PM by AncientU »
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Online Lars-J

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Why is this needed? Haven't AJR been contracted to restart production with a $1.5 billion contract? At this point, all they should have to do is issue a purchase contract for new RS-25 engines.

But AJR is the master of huge contracts with little or nothing to show for it. Remember the domestic RD-180 contract? Yeah, we can do this. Oh wait you actually wanted us to do it?   :-X

Offline Steve G

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Rather than asking for alternative options for the RS-25s, they should have asked for alternative options for the entire core stage. No restrictions on engine size, quantity, or propellants. Just performance.


not a viable option

Why not a viable option? (It's not going to happen, but absolutely viable). What would prevent SpaceX or Blue Origin from building a core alternative?

Offline woods170

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Rather than asking for alternative options for the RS-25s, they should have asked for alternative options for the entire core stage. No restrictions on engine size, quantity, or propellants. Just performance.


not a viable option

Why not a viable option? (It's not going to happen, but absolutely viable). What would prevent SpaceX or Blue Origin from building a core alternative?

They won't be interested given that they have other things on their mind: actually flying stuff in stead of being a jobs program.
« Last Edit: 04/13/2018 07:18 AM by woods170 »

Offline rst

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Why not a viable option? (It's not going to happen, but absolutely viable). What would prevent SpaceX or Blue Origin from building a core alternative?

Doubtful that either SpaceX or Blue has any interest in building anything that has the same interfaces to other launcher components (solid-fuel boosters, upper stages, etc) as the current core stage. They'd both probably be thrilled to bid their next-generation superheavy projects as clean-sheet replacements for SLS as a whole, if that were ever put out to bid. (And there was recently a bit of discussion in the ULA section about them bidding ACES and distributed lift, in the same unlikely hypothetical situation.) But that would require scrapping a lot of the Congressional mandates for the SLS project as it currently exists.
« Last Edit: 04/13/2018 06:52 PM by rst »

Offline oldAtlas_Eguy

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In rocket design the engines define the rocket design. If the rocket design is not to be changed at all. The the engines have to be the same as current.

The RFI will go nowhere and may not even get a response from AJR.

Offline A_M_Swallow

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In rocket design the engines define the rocket design. If the rocket design is not to be changed at all. The the engines have to be the same as current.

The RFI will go nowhere and may not even get a response from AJR.

When someone is going to give you a large sum of money it is polite to allow him to tick off a box on his task sheet by sending a sales proposal.

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