Canon EOS 5D Mark II
ƒ/3.2
100 mm
1/100
800

This Valve Package Assembly (VPA) is a Q4 1965 prototype of the control valves for the ascent engine of the Apollo Lunar Module (RS-18).

I can see now why Neil Armstrong had nightmares about this specific system.

It’s a wildly complex design compared to all of the other hypergolic bipropellant motors I have from Apollo (R-4D, SE-8, LMDE) and Gemini (SE-6). The VPA was a mission critical assembly; had the solenoid valves failed to open and supply propellant to the Ascent Engine, there was no getting home.

Neil’s nightmare was that at the completion of the mission, he pushes the button, and nothing happens. It’s a setup for a sequence of tough decisions. Do you go for a long walk?

Some historical notes from spaceaholic: Notice the fuel ducting on the left appears larger and more bulbous then its companion oxidizer line. During testing of the Ascent engine, pre-ignition pressure spikes were observed; this was resolved by lengthening the path the fuel had to take so that timing of its arrival at the injector was delayed to occur until slightly after the oxidizer (the ducting wraps back on itself to extend the path length).

19 responses to “Lunar Module Ascent Engine Valve Package Assembly”

  1. jurvetson Avatar
    jurvetson

    From the side; note the branching:

    IMG_6741

    Backside:

    IMG_6742

    And, in this photo from the USSRC (on loan from the Smithsonian), the VPA harness is identical with the exception of an external gray mylar sheath which was added during engine final assembly. Differences reflect evolution of the design between 1965 when Bell was struggling with combustion instability and the mature VPA in late 1967 that helped address some of these issues (the finishing touches on the RS-18 were not even finalized when Apollo 8 flew in 1968 – mostly refinements to the injector at that point).

    ussrc_rs18

    Reply
  2. A Tout Le Monde Avatar
    A Tout Le Monde

    And of course it was built by the low bidder. Looks like flare fittings that you might see on a car fuel line. I would have been very worried!

    Reply
  3. ▓▒░JASE░▒▓ Avatar
    ▓▒░JASE░▒▓

    looks very steampunk.

    Reply
  4. jurvetson Avatar
    jurvetson

    heh… I used that term today while brainstorming how we should bling up a quantum computer (like the blinky lights of the Connection Machine)… but with the cryogenic outgassing as a muse, I thought brass rivets and big metal controls could make the ensemble hum…

    And here you can see the testing history. My assembly is -21 midway down the 2nd page:
    Bell VPA p1

    Bell VPA doc

    P.S. I love that they call it a "V-2" in the table header… =)

    Also, as I learned from a separate Apollo auction for a surface checklist page, Neil’s fears came into play, as described by Buzz Aldrin:

    "A few hours earlier, after we returned to the LM interior once completing the first lunar moon walk, I noticed that the ascent engine arming breaker push/pull switch was broken. Apparently during movement wearing our large space suit ‘backpacks,’ either Neil or I bumped into this panel and broke off that particular switch. This switch was the direct means of arming our Ascent Stage engine which would allow us to leave the lunar surface. Mission Control verified that the switch was open, meaning that the engine was currently unarmed. If we could not get the engine armed, we would be stranded on the Moon. They advised us to leave the switch in the open position until the timeline called for it to be engaged. I started to think of ways to activate the switch if pushing it by hand failed. As it turned out, the very pen I used to record these notes was the perfect tool to engage this circuit breaker."

    Reply
  5. Minnesota's Ryan Avatar
    Minnesota’s Ryan

    I couldn’t have imagined, "uh, Buzz, where do you want to sleep? In here, or out there?" All because a stuck valve in -250′ F, Thank you very much for sharing this cool piece, I’ve seen the ascent engine in S.A&S, Washington D.C. and remember him talking about that moment while looking at it. I love looking at the assembly close-up, great capture, historic.

    Reply
  6. jimheid Avatar
    jimheid

    This is wonderful, and it reminded me of this recent radio piece — a dramatization of what might have happened had Apollo 11 crash landed. It’s based on the "In the event of moon disaster" speech that William Safire wrote for Nixon…just in case.

    Thought you might like:
    http://www.prx.org/pieces/51002-moon-graffiti

    Reply
  7. Astrocatou Avatar
    Astrocatou

    great stuff..
    sort of a Scott- Oates scenario at the South Pole…
    (injures Oates,to companions; "I am just going outside and may be some time…")

    luckily not.
    thanks for posting it.

    Reply
  8. faint yarn Avatar
    faint yarn

    ^^aha… the only difference is that moon_a_holics have never slept over with a 12-years old like a ‘very gallant gentleman’ did;))

    Reply
  9. Dr DAD (Daniel A D'Auria MD) Avatar
    Dr DAD (Daniel A D’Auria MD)

    I think that those of us who lived through the moon landings and probably most of us with little technical insight into the world of “rocket science” are astounded to hear that the concerns that resounded in some of our minds actually were conscious thoughts of some of the astronauts involved. I am always amazed that so much of what was done, was done without a backup plan. They were virtually flying “by the seat of their pants”. I venture to say that there are probably more safety devices and fail -safes in today’s automobiles than in the Apollo rockets.

    Reply
  10. Astrocatou Avatar
    Astrocatou

    [http://www.flickr.com/photos/drdad/]
    Agree…hearing more about their thoughts…and the human aspects in general, would be a good read.

    [http://www.flickr.com/photos/28820652@N07/]
    PM me with a link to that please

    Reply
  11. jurvetson Avatar
    jurvetson

    Dr. D: even Soyuz has more safety layers… sometimes macabre in their preparations for failure…

    jimheld: and an alternative history, straight outta Paris:

    Alternate Realities

    Reply
  12. Dr DAD (Daniel A D'Auria MD) Avatar
    Dr DAD (Daniel A D’Auria MD)

    Looks like the Russians cornered the market on "canned astronaut". Just pop the top, peel open, and serve! Wouldn’t have helped much on the moon though.

    Reply
  13. jafrado Avatar
    jafrado

    Nice!

    Reply
  14. momentous growth Avatar
    momentous growth

    This is great!
    Thanks for sharing… 🙂

    Please check my photos here

    Reply
  15. jurvetson Avatar
    jurvetson

    thanks y’all. Here are a couple cool diagrams from spaceaholic (the guy I bought this from):

    vpa_schematic

    I can see why Neil thought it was overly complex…

    vpa_ascentenginediagramx

    Reply
  16. jurvetson Avatar
    jurvetson

    and a tribute of Armstrong memories for his birthday…

    Happy Birthday Neil Armstrong

    Reply
  17. jurvetson Avatar
    jurvetson

    Just saw the Smithsonian VPA on loan to Tellus Science Museum in Georgia:

    Reply
  18. jurvetson Avatar
    jurvetson

    A cool cutaway version in the Niagara Aerospace museum, and a nice video of its operation

    Reply
  19. jurvetson Avatar
    jurvetson

    and a nice use in a new essay on space valve reliability: twitter.com/TheOldManPar/status/1747358587049959434

    Reply

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