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Rocket Design Agency - A Playtesting Quest

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Cast and Characters
  • Informational
    • NASA
    Brad L. Whipple - Director, New Alleghany Space Administration

    Payload Design - +1
    Rocket Design - +2
    Engine Design - +3
    Mission Planning - +1
    Flight Control - +2
    Damage Control - +0
    Spacecraft Activity - +0
    Extravehicular Activity - +0
    Experimental Activity - +2

    Flight Objectives
    - Continue scientific launches, progressing to probes into the space beyond orbit by year end 1959.
    - Begin experiments which will allow a progression to human spaceflight before year end 1960.
    - Cooperate with the Armed Forces in developing their abilities through the application of spaceflight.

    Mission Schedule - Current Date: January 1960
    - Low Orbit 1 (Summer 1958) - Hope-2 (Partial failure)
    - Re-entry test 1 - Sub-orbital - Full Success, August 1958
    - Low Orbit 2 - Partial Failure, Hope-3 , October 1958
    - Re-entry test 2 - Failure, November 1958
    - Military Communications - Success, ARTS, December 1958
    - High Orbit 1 - Success, Hope-4, January 1959
    - Re-entry test 3 - Success, March 1959
    - Bio-sciences - Launch Failure, July 1959
    - Discovery 1, Success, September 1959
    - High Orbit 2 - Success, Hope-5, October 1959
    - Lunar Probe - Launch Failure, Artemis-Lunar, November 1959
    - Bio-sciences - Success, Astrocaphe-Chuck, December 1959
    - Discovery 2 - Failure, January 1960
    - Astrocathe test - Success, animal in space, February 1960
    - March lost due to Artemis redesign
    - NAN payload - April 1960 - First Hermes Flight
    - Crown 3 - Spring/Summer 1960
    - Commercial payload - Summer 1960
    - IRVOS 1 - Summer 1960
    - NAA Communications - Summer/Fall 1960
    - Space Camp test - Summer/Fall 1960
    - NAN payload - Fall/Winter 1960
    - Commercial payload -Winter 1960
    - Astrocathe test - Winter 1960
    - NAA Communications - Spring 1961

    - Astrocaphe phase 1 (3 crewed flights)
    - Astrocaphe phase 2 (3 crewed flights)

    Hardware
    - Prometheus (1M to LEO)
    - Hermes-L (6M to LEO)
    - Hermes-B (8M to LEO)

    Andre Larkin - Team Lead at EPL
    Rocket Design 0
    Engine Design +2


    EPL Design Team
    Antony Miratha, Aerodynamics
    Susan Stone, Astrophysics
    Michael Cole, Rocket Engineering
    Amy Mathews, Trajectory Planning
    Simon T. Harrison, Chemical Engineering

    +2 Rocket Design, +2 Payload Design +1 Engine Design, +1 Fuel Selection, +1 Flight Planning

    Side Characters
    Dr. Evan Hart - Research Director at EPL
    Arthur Ley, proponent of Lunar flight.
    Franz Haber, Doctor and researcher.
    Dieter von Markand, Pacifist and astrophysicist.

    EPL Facilities
    Design workshop
    Chemical research laboratory
    Launch analysis equipment
    (Please note that EPL has neither rocket nor engine manufacturing facilities)
     
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  • Informational
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    C3P5
  • Threadmarks
    • It would be significantly easier to achieve the range requirements for the Ajax program if you could dump mass halfway through the rocket's flight - so that's exactly what you're going to do. Creating a two stage design will give the EPL Ajax a significant boost in range without having to make it so massive or so expensive that it will never be useful to the military.

    The payload takes no real thought. Nothing in the contract package gave you any idea of what the mission of the rocket will be but there's only so much the army is going to use a four ton payload to do, especially with the desired thousands upon thousands of kilometres of range.

    So starting from the top, since the lowest stage is going to have to lift everything - the payload defines itself, and putting aside a few hundred kilos for guidance is all inclusive. Thus the upper stage is where you first actually get to stretch your engineering legs and put pencil to paper on a draft;

    Upper stage: 2M tank, 40 M fuel; 1x UA LF-1+ (2.12M, 4.64C); Carbon Verniers (0.21M, 0.42C)
    Stage Mass: 44.33/4.33
    Stage Cost: 13.28
    Stage dV: ~2650ms-1 (payload inclusive)

    You look at the finished draft when the team comes back together. It is not as capable as it could be, and you'll need a massive first stage to lift the fourteen and a half tons high and fast enough that it will deliver the payload as the military asked for. Initial calculations suggest a booster of ninety tons at least which would require a cluster of eight to ten LF-1+ engines.

    Well. That's not encouraging.

    Seek resolution:
    [ ] Design the massive second stage. The army get what it asks for.
    [ ] Find an alternate solution - more stages, perhaps, or solid boosters.
    [ ] Inform the army that their request is currently extremely ambitious.
    [ ] Write in.
     
  • Threadmarks
    • ...This thing is going to have a nuclear warhead on it, won't it?

    The army guy originally said "We don't like the look of what the other guys are coming up with", so giving them a ginormous first stage might not be in their best interests, and telling them that the requirements are too hard looks bad too.

    I wonder if we can ask them, hey, we could do this and it'd probably work but $$$$$, or we can look into something else, it takes longer, but we'd probably get something for $$$?
     
    [X]Request UA design a vacuum-optimized engine based on the UA-1+ for use on the upper stage - perhaps just enlarge the nozzle?
    It's not a whole new engine, but the improved efficiency could be highly valuable.
     
    [x] Send an update to the Army with the fully designed upper stage, to show we're making progress, and ask if they would prefer we develop a more expensive design quickly (including a very rough estimate of just how pricey it would be), or if we should look into a more efficient design that may lead to delays.
     
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    [x] Send an update to the Army with the fully designed upper stage, to show we're making progress, and ask if they would prefer we develop a more expensive design quickly (including a very rough estimate of just how pricey it would be), or if we should look into a more efficient design that may lead to delays.
     
    [x] Send an update to the Army with the fully designed upper stage, to show we're making progress, and ask if they would prefer we develop a more expensive design quickly (including a very rough estimate of just how pricey it would be), or if we should look into a more efficient design that may lead to delays.
     
    Just gonna state (for the 2nd time I think?) that at this point @Estro is basically my co-author on this and this wouldn't be possible without all her help on rocket design, maths, physics and so on.
     
    4WheelSword said:
    [ ] Design the massive second stage. The army get what it asks for.
    Click to expand...
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    You have a typo here.

    [X] Design the massive first stage. The army get what it asks for.

    So there's a few things to keep in mind:

    1) Simple is better for weapons. Lots of boosters will make it more likely we lose the competition on economic grounds.
    2) Having a big first stage will mean when we do put boosters on it, the results will be even more impressive.

    We do this right, when it comes time to design an orbital LV, we can just take this design and focus on improving safety and ISP and such.

    fasquardon
     
    fasquardon said:
    You have a typo here.

    [X] Design the massive first stage. The army get what it asks for.

    So there's a few things to keep in mind:

    1) Simple is better for weapons. Lots of boosters will make it more likely we lose the competition on economic grounds.
    2) Having a big first stage will mean when we do put boosters on it, the results will be even more impressive.

    We do this right, when it comes time to design an orbital LV, we can just take this design and focus on improving safety and ISP and such.

    fasquardon
    Click to expand...
    Click to shrink...
    Problem is, the number of engines supposed to be on the first stage for this thing makes everything other than the N1 look sensible - 9-10 LF-1 engines on the first stage, which would be almost as many chambers as we were lighting with the MISIT, every time they want to fire Ajax. This induces complexity, which is fine-ish in the early 2000s, but is sub-optimal for early, less reliable engines on heavy stages.

    [x] Send an update to the Army with the fully designed upper stage, to show we're making progress, and ask if they would prefer we develop a more expensive design quickly (including a very rough estimate of just how pricey it would be), or if we should look into a more efficient design that may lead to delays.

    I like this, because it says "hey, we're making good progress on this, do you want it expensive but fast, or probably cheaper per unit at the cost of potentially longer development time?"
     
    Ash19256 said:
    Problem is, the number of engines supposed to be on the first stage for this thing makes everything other than the N1 look sensible - 9-10 LF-1 engines on the first stage, which would be almost as many chambers as we were lighting with the MISIT, every time they want to fire Ajax. This induces complexity, which is fine-ish in the early 2000s, but is sub-optimal for early, less reliable engines on heavy stages.
    Click to expand...
    Click to shrink...

    I am not convinced that 7-9 engines is enough of a problem to make this approach worse than your proposal.

    The Saturn 1 and the R-7 both are very much multi engine designs. The R-7 is even a multi-engine design with multiple separation events.

    I think the N-1 case, which was done on a shoestring budget, with extreme time pressure and with a severe lack of testing facilities, is not at all applicable to what we're doing here.

    Oh, and the N-1 had over 30 engines on the first stage.

    fasquardon
     
    fasquardon said:
    I am not convinced that 7-9 engines is enough of a problem to make this approach worse than your proposal.

    The Saturn 1 and the R-7 both are very much multi engine designs. The R-7 is even a multi-engine design with multiple separation events.

    I think the N-1 case, which was done on a shoestring budget, with extreme time pressure and with a severe lack of testing facilities, is not at all applicable to what we're doing here.

    Oh, and the N-1 had over 30 engines on the first stage.

    fasquardon
    Click to expand...
    Click to shrink...
    Keep in mind that the R-7 was basically only used because they had nothing better - we don't have the luxury of being New Alleghany's only missile program. And the Saturn 1 was not only built with an extra decade of technological development, but was also built by a space program with a significantly larger budget per rocket than we have, especially for a military project.

    Frankly, N-1 could maybe have worked if it had been using tech from the 80s-90s. I don't want us trying something that worked 8-10 years into the future IRL, and being disappointed when we don't have the tech to make it work.

    If we were using N2H4/RFNA or N2H4/IRFNA, I might be inclined to agree with you, but we aren't, and we have to take the difficulties in starting engines into account in this era. Keep in mind that we nearly had a failure to launch with MISIT because one of the engines gave us trouble when it came time to ignite it. If the Army has to roll the dice on Ajax working with the level of difficulty we had making sure that MISIT launched reliably, I could see them going with a less capable design.
     
    [x] Send an update to the Army with the fully designed upper stage, to show we're making progress, and ask if they would prefer we develop a more expensive design quickly (including a very rough estimate of just how pricey it would be), or if we should look into a more efficient design that may lead to delays.
     
    [x] Send an update to the Army with the fully designed upper stage, to show we're making progress, and ask if they would prefer we develop a more expensive design quickly (including a very rough estimate of just how pricey it would be), or if we should look into a more efficient design that may lead to delays.
     
    C3P6
  • Threadmarks
    • You come up with a few drafts for a first stage for the Ajax, but no matter what you do it's always a massive, complex almost hundred ton debacle of a design. You look over them and chew your lips. There is no way that the army is going to accept something with ten first stage engines or which would need what amounts to a construction crew to transport and launch it.

    No, better to admit your issues and see if you can't come to some sort of arrangement. With the deadline hanging over your heads you are either going to produce a slapdash piece of garbage or they're going to have to accept a delayed, over-budget rocket that can do what they ask of it. But right now, that's not what you've got to offer.

    Instead you go for a third option. You have the team assemble a dossier on the upper stage design in full with a conceptual look at what could be possible with the main stage in place as well. You also make it clear that current capabilities are making this rocket an exceptionally difficult prospect and that it will take more time than you've currently been allotted in order to complete. With a month to go before the deadline hits, you send it off to Major Gibson and hope.

    When the reply comes, it is a single telegram that reads "Understood. Await reply."

    The reply does not come quickly. You work haphazardly in the last month, trying to find something that will work for this design, but nothing really proves useful. Finally a thin envelope appears on your desk marked 'Secret - Confidential'. In it are an entirely new set of objective that might as well be for a new rocket.

    Project Ajax Redefined Objective:

    • Payload: 12 mass (3 tons) not including guidance
    • Cross- Range: Minimum 1000 kilometres (3200ms), Ideal 1500 (4000ms) kilometres
    • Deadline extended by 4 weeks for provisional entries.

    Upper stage: 2M tank, 40 M fuel; 1x UA LF-1+ (2.12M, 4.64C); Carbon Vanes (0.21M, 0.42C)
    Stage Mass: 44.33/4.33
    Stage Cost: 13.28
    Stage dV: ~2660ms-1 (Atmo)/ ~3000ms-1 (Vac)

    You're a little stunned that they would change the requirements so dramatically, but at least you have a chance of competing. And maybe you can find a way to keep some of your work included.

    How do you complete Ajax?
    [ ] Expand the upper, to make a one stage design for ease of use.
    [ ] Shrink the upper, the first stage will do most of the lifting.
    [ ] Keep the upper, the first stage will just be a booster.
    [ ] Write in.
     
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  • Threadmarks
    • I almost wonder about the viability of declaring what we have to now be the first stage and putting a little second stage on top. Seems like it might be more efficient than putting a booster on it and require less work than anything more drastic.
     
    Hmm. I'm sort of thinking it might be easier to go with expanding the upper stage and basically make it a first stage honestly? The math works out I think, and I think should be able to form a basis for a future rocket to carry stuff up (with a new upper stage on top of it and a much reduced payload).

    [X] Expand the upper, to make a one stage design for ease of use.
     
    Huh. Okay, thinking about that, I can definitely see why they might have redefined the goals of the program.

    Because we gave them a rocket that could achieve part of the range they were looking at, then also gave them a partial design of what was possible right now for making the rocket reach the full range in theory that they were wanting. Then asked them if they wanted something like that now, or if they'd want something later that was a better fit to their needs.

    Then they looked at the design, said 'That does not fit our needs, and we want something now' so instead changed the aim to something closer to what was achievable right now that fit their needs... Just with a shorter range than they would have preferred if they could get everything they wanted.
     
    [X] Keep the upper, the first stage will just be a booster.

    Let's keep this simple. The upper stage looks good, so let's put the extra time into making the lower stage the best we can.

    Pyro Hawk said:
    Huh. Okay, thinking about that, I can definitely see why they might have redefined the goals of the program.

    Because we gave them a rocket that could achieve part of the range they were looking at, then also gave them a partial design of what was possible right now for making the rocket reach the full range in theory that they were wanting. Then asked them if they wanted something like that now, or if they'd want something later that was a better fit to their needs.

    Then they looked at the design, said 'That does not fit our needs, and we want something now' so instead changed the aim to something closer to what was achievable right now that fit their needs... Just with a shorter range than they would have preferred if they could get everything they wanted.
    Click to expand...
    Click to shrink...

    If this is anything like the US and the Soviet Union in this period, the military planners aren't sure what they need (except for something to compete with the massive US bomber fleet, which in some ways was a bigger problem for the US Army than it was for the Red Army) and the bombs are changing fast too.

    @4WheelSword: would it be possible to switch to fuming nitric acid instead of LOX in the time we have?

    fasquardon
     
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