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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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    C12P6 - It's getting tight.
  • Threadmarks
    • Caspia was first to blink. She declared that she was standing down her atomic forces in a view to encouraging world peace, and soon embassies reappeared world-wide. These diplomats sent desperate messages to both Dyskelande and New Alleghanian premiers seeking a resolution that didn't mean the fiery end of Europa of Vespasia.
    New Alleghany and Dyskelande stared at each other across an Ocean. Advisors disappeared in Cathay as Europan forces retreated into defensive positions. Alleghanian carrier groups were deployed to the Cathayan seas. Everyone waited with bated breath.

    Roll 2 x 2d10+1 for Dyskelande and New Alleghany.

    Mccall Corrosive
    Payload - 40 mass (10 tons)
    Stage 2 -
    Structural steel (20M) - N2H4/RFNA (400M)
    Other systems - (15M estimated)
    Total - 435M wet, 35M dry, estimated dV 6000m/s
    Stage 1 -
    Structural steel (50M) - N2H4/RFNA (1000M)
    Other systems - (40M estimated)
    Total - 1090M wet, 90M dry, estimated dV 3200m/s
    Estimated cost - 400C

    Alti-high 14 ton
    Payload - 56 mass (14 tons)
    Stage 3 -
    Balloon tanks (10M) - RP-1/LOX (250M)
    Other systems (10M estimated)
    Total - 270M wet, 20M dry, estimated dV 4200m/s
    Stage 2 -
    Balloon tanks (25M) - RP-1/LOX (625M)
    Other systems (20M estimated)
    Total - 670M wet, 45M dry, estimated dV 3000m/s
    Stage 3 -
    Structural steel (50M) - RP-1/LOX (1000M)
    Other systems - (40M estimated)
    Total - 1090M wet, 90M dry, estimated dV 2000m/s
    Estimated cost - 600C

    At the cape, design reports started arriving. Alti-high, the new company, had the biggest payload wise. Mccall had a cheap one. But BRMJ had done something brand new - they were suggesting a design which could be used and reused and used again.

    Choose two designs to take forwards for development
    [ ] Alti-high's 14 ton balloon.
    [ ] BRMJ's reusable design.
    [ ] Mccall's corrosive driven low cost design.
     
  • Threadmarks
    • Ash19256 said:
    What did the reusable design use as fuel again?
    Click to expand...
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    The first stage is aerozine/N204 (toxic, but not considered corrosive. Chosen because it offers the best performance in the atmosphere and because, in universe, hypergolics make a lot of sense for a dead simple preasure fed engine that is meant to survive sea water exposure)

    The second and third stages are RP-1/lox.

    Edit: Going to speak a little more about my design here.

    Yes, the reusability adds a fair bit of cost and mass, but after you buy a first stage, there is only about 61 cost of new hardware for each additional launch, plus however much the refurbishment ends up being. I don't expect it to be excessive, since it's an overbuilt, dead simple stage that doesn't have to deal with things like orbital reentry, but the fact that it is using toxic fuel would tend to increase the costs of working with it. However, that's actually not where a lot of the extra mass (and thus cost) comes from. The other thing that sets my design apart is high safety. I am using the more expensive guidance and have a good stability bonus and verniers on all stages for control, but most significantly, using pressure fed rockets and a heavy duty tank for the first stage gives a +2 safety bonus. The added cost and weight is significant (though most comes from the oversized engines rather than the tank, surprisingly), but with my design you only have to pay for it once, so I figured it was justified. Compare this to the other two, which are taking penalties from corrosive fuel in one case and balloon tanks in the other. This is the rocket to buy if you are tired of losing payloads.

    The reuse rate on these will not be terribly high, but it doesn't need to be. Early refurbishment means a first stage is ready for reuse in 4 to 13 months. We'll need to keep a pretty decent number of them around depending on how many launches in this size range we want to do, but they should still pay for themselves pretty quickly. In terms of just the hardware costs, they pay for themselves relative to the Alti-high design in two launches, the Mccall in three. Refurbishment costs of 10% of the cost of the stage means it takes four to beat the Mccall. Even at a rather extreme 25%, it does it in 6 and beats the Alti-high in 3. So, under fairly conservative assumptions these do pretty well for us within a couple years. Under the most optimistic set of assumptions, these things could see a lifetime cost per launch of around 100, though I really doubt it will be quite that good.

    The really big thing here, though: this sets a precedent. If it works, and more or less lives up to the promises, then it paves the way for actual, working, cost effective reusabilty to become a standard thing that launch vehicles try for. That has huge long term effects on the trajectory of this timeline. It makes cheap access to space start to look possible. And yes, we'd eventually want improved reuse/refurbishment technology, and flyback or vertical landing designs, but that's an easier step to hand over the cash for once this exists.

    [X] BRMJ's reusable design.
    [X] Alti-high's 14 ton balloon.
     
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    [X] BRMJ's reusable design.
    [X] Alti-high's 14 ton balloon.

    Honestly, the shiny that is re-usability, especially considering that it's a really dirt simple form of reusability, is just a bit too attractive to pass up - especially because Aerozine/N2O4 is not much worse than the current Hydrazine/LOX mixtures in use with a number of rocket designs.

    As for design 2, I don't want anything to do with a pure corrosive fuel lifter, so instead we'll be looking more closely at Alti-high's Atlas-esque proposal. It's more expensive than Mccall's corrosively fueled proposal, but has theoretically more performance, and, like BRMJ's design, does not use corrosive propellants. I don't have terribly high hopes for the balloon tanks, but it's better than trying to do awesome things with obsolete tech.
     
    I just figured out something neat. If you stick a reusable second stage on top of my design built with the same approach as the first and a vacuum version of the first stage engine, then put the normal third stage on top of that, you can launch 16 mass on under 8 cost of expended hardware. That strikes me as a really excellent configuration for launching payloads that we'd normally put on the Hermes, as well as things like the astroscaphe v2. If and when there is a contract put out for a launcher for the next phase of the manned program, expect to see something like that. That's even cheap enough that things like orbital propellant depots start to look really good.

    Edit: Rolling for avoiding the end of the world. Someone should take the other one.
    brmj threw 2 10-faced dice. Total: 10
    2 2 8 8
     
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    Okay, this is big enough to deserve its own post. I had been using the 10000 km/s delta-v number from the requirements for one of the previous rounds of rockets, on the assumption that we were wanting that kind of margin for safety or higher energy orbits or whatever. Well, actually 10750 because of drag losses. If I instead load in the 9200 number the other rockest were using, again adjusted up for drag, it looks like my rocket can put 57 mass in orbit. I'm not going to go back and shrink it to compensate or anything because that would be pretty bullshit at this stage and because that sounds like work, so the end result is that mine is also the highest capacity by a hair if you throw out the rather generous margin. This would also mean that they hypothetical reusable second stage derivative could put 26 mass into orbit.
     
    Wow, the low-cost solution is corrosive and the expensive one is 40% more payload for 50% more cost. 3 stages though is pretty harsh in terms of reliability.

    If I understand correctly though, it's only a single 2d10 per stage, and it gets +2 due to the lack of corrosion. Looking at the chance of catastrophic failure:

    2d10 < 6 is 90%
    2d10+2 < 6 is 97%, squared for two stages is 94%, which is better than a single stage.

    Even at 11, the limit for partial success, the corrosive design is only a bit better (45% vs 41%). Thus I'm gonna go with

    [X] BRMJ's reusable design.
    [X] Alti-high's 14 ton balloon.

    Anydice link to the math.

    Though BRMJ's is looking pretty amazing based on what he's said so far.
     
    9200 was a lazy delta v choice. The number will have to increase during the design process but I think it will via mass efficiencies and that.
     
    Figured I'd write this up too, since it's a thing people might be interested in and NASA would probably be passed at least an outline of these plans as additional encouragement to go reusable.

    Fuel type: Aerozine/RFNA (toxic)
    Cycle: Pressure fed (21M, 3.15M mass flow, +1 safety)
    Injector: Centripetal
    Nozzle: Vacuum (12.6M)
    Upgrades: Multi Axis Vernier (+1 control)
    ISP: 353.97
    Thrust: 3015.866876kN
    Mass: 34.608
    Cost: 47.888
    This is literally just the first stage engine, but with a vacuum bell and a full set of verniers. Should be a relatively simple project as such things go.

    Payload - 21 Mass (5.25 tons)
    Stage 3 Mass - 112.6432 Mass (28.16 tons)
    Stage 2 Mass - 1023.517249 Mass (255.879 tons)
    Stage 1 Mass - 1763.440219 Mass (440.860 tons)
    Total Mass - 2930.246717 Mass (732.56 tons)
    Stage 3 Cost- 7.7688 Cost
    Stage 2 Cost - 96.6689 Cost
    Stage 1 Cost - 814.5596 Cost
    Total Cost- 956.5226089 initial, 7.768825 + refurb for each additional launch
    Stage 3 Thrust - 419kN
    Stage 2 Thrust - 3015.866876kN
    Stage 1 Thrust - 14723kN
    Stage 1 Delta-V - 1523.3m/s
    Stage 2 Delta-V - 4281.2m/s
    Stage 3 Delta-V - 4966.8m/s
    Total Delta-V - At least 10750m/s (Over 1000 after DMR penalty)

    Stage 1 Design
    Engine - 6 x LE-21A, ISP: 288 (205.38M/287.289C, +1 safety, +1 control)
    Stage - 127M (2.54C) Heavy Duty, 1270M fuel (+1 safety)
    Avionics: Basic gyroscopic guidance (+2 control)
    Control: Small fins (+1 stability)
    Suborbital heat-shield
    Parachute
    Separator: Explosive Bolt
    Launch TMR >2 (+1 stability)
    DMR 1.5/1 (+1 stability)
    Totals: +2 safety, +3 control, +3 stability

    Stage 2 Design
    Engine - 1 x LE-21V, ISP: 353.97 (34.608M/47.888C, +1 safety, +1 control)
    Stage - 82M (1.64C) Heavy Duty, 820M fuel (+1 safety)
    Avionics: Basic gyroscopic guidance (+2 control)
    Suborbital heat-shield
    Parachute
    Separator: Explosive Bolt

    Stage 3 Design
    Engine - 1 x LE-18V, ISP: 364.6075 (3.9202M/6.2555C, +1 control)
    Stage - 5M (.5C) Structural Steel, 100M fuel
    Avionics: Basic gyroscopic guidance (+2 control)
    Separator: Explosive Bolt

    This is literally just my design with the second stage replaced by a new one built like stage 1, but shorter and with a single engine with a vacuum nozzle. It puts 21 mass in orbit with the same generous 10000 m/s delta-v as before, and only requires replacement of the 7.76 cost third stage for each launch. I would imagine that something like this was a plan from day one, and would probably be the next thing on the agenda as soon as the first stage has been validated by practical usage in the original design. The second stage would, after all, experience more heating and larger aerodynamic forces, and would likely spend more time at sea.

    Both this second stage and the expendable one are probably the same width as the first stage, since they have to hold about two thirds as much fuel. This simplifies design and construction of the reusable stage two as well; it's in effect a shortened, single engine stage 1.

    In universe, the reason for going with the expendable second stage for the 40 mass launcher is probably a mixture of avoiding excess technical risk and preventing the sticker shock that a 40 mass launcher with two reusable stages might inspire, combined with a belief that there will be relatively little demand for ten ton launches compared to smaller ones. Put together like that, it's a pretty neat system if you don't know how big future payloads are going to sometimes get. Out of universe, I will note that by the time we want really, really big payloads, we should perhaps be thinking about other reusability schemes, or at least upgrading from basic to intermediate, and maybe to reuse rather than refurbishment.

    Edit: Also, the higher initial costs and the relatively small savings compared to first stage reuse means that to extent to which this does or does not make sense is very much tied to what the refurbishment costs and stage lifetimes end up being. If refurbishment is cheap and the stages fly 20 flights, this is a good idea. If it is expensive and they fly 5 times each, maybe the effort is better spent elsewhere. In any case, in all but the most optimistic cases, this version is more about helping this launcher scale down to cost effectively launch smaller payloads, rather than drastically lowering their cost. It can work out surprisingly evenly. I like it a lot as a way to leverage this technology for manned use and a wider range of other payloads, but it isn't a game changer on its own. We'll need rapid, low cost reuse or something similarly good to improve costs this dramatically again.
     
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    [X] BRMJ's reusable design.
    [X] Alti-high's 14 ton balloon.

    Not really a fan of corrosive propellants, and the reusable design is clever and I approve.
     
    We need to get some other people playing with the vehicle design rules more. It's surprisingly fun and easy with even just my rudimentary spreadsheet, and I could use some more competition.
     
    Brmj Demonstration Design & Rules
  • Informational
    • FrangibleCover said:
    Okay, I'm here now. Point me to the design rules.
    Click to expand...
    Click to shrink...
    Rocket construction rules 0.8

    Here's the game rules, since it will matter for lookign up things like what stats are used for which rolls, and volume thresholds for crew stress and such:
    Space Race Co-op/Comp

    And here's my shitty spreadsheet cluttered with stuff from this latest project. The engine design is pretty foolproof, but the rocket and spacecraft stuff is all hacked together on the fly. Still, it should be pretty obvious how it works if you poke around a little.
    Google Sheets - create and edit spreadsheets online, for free.
     
  • Informational
    • Certainly not meaning to pester, but is this likely to be coming back? I at least was having a whole lot of fun.
     
    So, we are somewhere in this flight routine:
    - 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

    Though I'm not 100% where. I think I was keeping a lot of things in my head which have slipped because my head isn't a hugely fun place to be right now. We have two rockets going forward to be the space camp launchers, we have a solid idea of what the camp will look like and we have an idea of when the first crewed launch will be.
    So I'm going to put a vote down and it will guide the rest of this game:

    What would you like the rest of this game to look like:
    [ ] A continued deep dive into alternate history, geopolitics and characters with many, many launches (Slow)
    [ ] A skim across the history, with designs for some of the 'big milestones' and so on, with space for Omake's (Fast)
    [ ] A balanced version, with less focus given to every launch or the geopolitics (medium)
     
    [X] A continued deep dive into alternate history, geopolitics and characters with many, many launches (Slow)

    This is my personal preference.
     
    I feel that launches and politics need to be separate questions. I'd prefer more designing and politics and less launching and rolling loads of dice.

    Edit: Also, it would be neat to have a system where we have to find and remediate whatever system fails on a launch. If we find it, we get a bonus on the roll for that part (we work out the bugs like in real life) or we take a penalty on the roll for leaving it unfixed. Just like in real life it would lead to launchers getting more reliable over time. Also, it would force us to make additional tradeoffs for that reliability.
     
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    [X] A continued deep dive into alternate history, geopolitics and characters with many, many launches (Slow)

    It's close between this and the balanced approach for me. I think it's fine to skim over some things to avoid having to roll fifty billion dice for all the utterly routine launches every year, but I like having a greater degree of control over operations, not to mention mission, rocket and payload design in the instances when it is interesting but not necessarily a flagship program.
     
    brmj said:
    It's close between this and the balanced approach for me. I think it's fine to skim over some things to avoid having to roll fifty billion dice for all the utterly routine launches every year, but I like having a greater degree of control over operations, not to mention mission, rocket and payload design in the instances when it is interesting but not necessarily a flagship program.
    Click to expand...
    Click to shrink...
    What this person said - I'm not voting, because I'm not entirely sure if I'm parsing the options correctly. Which option would get something like this?
     
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