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Today is the 50th anniversary of the first American in orbit, John Glenn flying a Mercury Atlas. Basically, he strapped himself atop a modified ICBM and circled the Earth three times.

So I thought it would be timely to share some of the technology that came out of that program.

Assembled in 1960, this vernier motor provides attitude adjustment during the rocket’s launch. It has many of elements of the liquid fuel engines that later powered the Apollo and SpaceX rockets– with regenerative cooling of the nozzle, electric igniter, RP1 and LOX valves, and dual pistons for directional pointing.

Detailed photos and an example in flight below…

19 responses to “Mercury Atlas Vernier Motor — Truax Variant”

  1. Here is a Mercury Atlas Launch with gimbaled vernier providing vehicle attitude control
    atlas_vernier

    Here is the bottom of the fuel valves
    IMG_0586

    And the injector plate at the top of the combustion chamber
    IMG_0593

    And a side view, with readings of 800 PSI for fuel and oxidizer, Part Number 133ED7, Serial Number 295, Assembled 9/60, NAA Serial Number N0148C Spec -1
    IMG_0588

    And some spaceaholic details from the predecessor version:
    “An LR101-NA Vernier rocket engine assemblage manufactured by ROCKETDYNE Corporation for installation onboard an Atlas SM-65 ICBM (Atlas “A”/XLR 89 NA-1). These engines were employed in various configurations to provide attitude (roll, pitch and yaw) control onboard the Mercury-Atlas, Atlas, Thor ICBM, Delta propulsion systems. A fixed-thrust, single-start, liquid bipropellant engine producing of maximum of 1000 pounds of thrust (nominal seal level), the engine design allows postoperative purging, regenerative cooling, thrust chamber gimbaling, and full-thrust runs of 325 seconds duration. It has a dry weight of 54 pounds and measures approx 28 x 27 ¼ x 20 inches (normal gimbaling arcs included). Designed propellant mixture is combination RP1 (highly refined liquid Kerosene) and LOX (liquid oxygen).

    The engine consists of a thrust chamber assembly (a steel double-walled structure with a copper spiral regenerative cooling coils between the inner and outer walls), a pneumatically operated propellant valve with a valve position-indicating switch, an electrically fired igniter assembly, a pneumatically controlled oxidizer bleed valve, a fuel manifold pressure switch, a manifold gimbal assembly, propellant orifices, and pneumatic purge check valves. These components along with interconnecting electrical cabling and tubing assemblies are fixed in position on a welded tubular engine mount.

    Gimbaling is facilitated via a pitch gimbal shaft, which provides for movement of the thrust chamber through a pitch-roll correct arc of 70 degrees on either side of the neutral position; and a yaw gimbal shaft which permits movement of the vernier thrust chamber through a yaw correction arc of 30 degrees (outboard) and 20 degrees (inboard) of the neutral position. In addition to performing the thrust direction gimbal function, the yaw shaft serves as a manifold for passage of fuel and oxidizer to the thrust chamber.”

  2. when i read about glenn today i immediately thought of you!

  3. Another off topic: This from the London Review of Books by Slavoj Zizek
    http://www.lrb.co.uk/v34/n02/slavoj-zizek/the-revolt-of-the-sala...
    I would say to anyone interested that if they can take this text apart and reassemble it without too many pieces left over, they could begin to consider themselves intellectuals… or at least hold their own at any cocktail party in the world.

  4. From your collection ?

  5. yes…. along with these flown Mercury artifacts: Liberty Bell 7 Component

    Mercury Space Flight Artifacts Mercury Redstone MR-1 Connector

  6. I had no idea the verniers were on gimbals. Is that standard? So are there just two of these, one on each side?

  7. I am also curious about these…
    I would assume there were 3…or 4
    But were they an add on for this capsule launch program..?
    This booster was originally designed for an ICBM…and I think they were supposed to be fueled and launched in less than 20 minutes..(?)
    That would be an interesting bit of history…keeping giant tanks of fuel sitting ready 24/7…
    w3.uwyo.edu/~jimkirk/atlas.html
    edit:;There were two of them
    strategic-air-command.com/missiles/Atlas/images/Atlas_bus…

  8. There were just two per launch vehicle for attitude control – the Atlas boosters and sustainer were also gimbled for thrust vectoring. The same arrangement was also applied to the early Delta and Thor launch vehicles. RP1 (highly refined liquid kerosene), is storable/stable propellant.

  9. I wondering more about how they managed to keep the LOX available …

    And what it felt like "filling the missile" with gas,and going through all the launch steps.. while waiting for an incoming nuclear strike..
    That’s got to be a huge human interest story for the guys that did that job.
    Anyone know of a good book from that ?

  10. still topical today. I just read: ""Unfortunately, the first flight of our new Antares medium-capacity launch vehicle, the rocket we formerly referred to as Taurus 2, was delayed again in the quarter. This was caused by problems of completing construction work on the launch pad’s propellant handling and pressurization systems." (from SpaceflightNow)

  11. [http://www.flickr.com/photos/daveh56] The silo’s included refrigerated storage tanks for LOX…the oxidizer could be uploaded (in the case of Atlas F) fast enough to allow for a 10 minute launch from receipt of an authenticated order.

  12. Yes…but they would have required constant replenishing……and I think the missiles were stored horizontally…
    ? Twice weekly delivery truck or on site plant…
    Pretty amazing…the whole thing.

    Yet the whole system was essentially replaced within a few years..
    Now you can have a nice home with a large lot and your own missile silo;
    http://www.missilebases.com/

  13. Only the early versions of Atlas were stored horizontally (those were in service for a very short time); the Atlas F was stored vertical in its Silo

  14. and this just in… I have loaned this artifact to a stealth space startup, and it now adorns their lobby:
    Atlas Truax on Display

    From the information display in the background, I notice that my photo up above is now used on wikipedia

  15. P.S. I really like this Truax fellow. He clustered four of these vernier motors into a manned space rocket @ home:

    truax moteurs

    The Truax Moteurs Volksrocket… a garage hobbyist in Silicon Valley (Saratoga)…

    From wikipedia:

    "The X-3 Volksrocket (other names: Arriba One, Skycycle X-3) was a reusable space tourism rocket planned by Robert Truax after Evel Knievel provided a $1,000 research grant for a pilot study. Truax was looking for volunteers with enough money to help fund the effort and who were crazy enough to want to fly aboard his rocket. He got thousands of volunteers, many of which were crazy enough but few of which had the financial resources."

    And the NYT obit in 2010:

    "When Evel Knievel failed to leap the Snake River Canyon in 1974, he rode a vehicle powered by Robert C. Truax’s rockets.

    His early research for the Navy laid the foundation for the liquid-propelled rockets that are the centerpiece of American space efforts, and he was a leader in developing the Thor, Viking and Polaris missile programs.

    When Wernher von Braun and other German rocket experts came to the United States, Mr. Truax led the team that debriefed them.

    The Encyclopedia Astronautica called him “one of the great originals of American rocketry.” In an interview, Rick W. Sturdevant, an Air Force historian, called him “an artist when it came to rocketry.”

    Mr. Truax was more modest: “I just like to go out and play with rockets.”

    And from a NYT Rocket Review in 1981:

    ”The astronaut doesn’t have to be anyone special,” Truax said. ”A woman in a bikini would be nice. It would cut down on weight and besides it’s going to be pretty warm in there.”

  16. The ones on the Atlas Rocket could gimbal all the way around, in fact they were used for orbital positioning and separation. Here is what they looked like:
    http://www.rocketrelics.com/atlasgimbalview2.jpg

  17. Thanks… and thanks for the visual inspiration for what one looks like in a test firing:

    Static Test Elcentro LR101

    and the estimate that "with 600 lbs of fuel in a 200 lb vehicle, it would be an S impulse class (5.5M N*S) and get up to 100km."

  18. I remember this engine/gimbal assembly when it sold on eBay. Do you know who made it? (Truax?)

    Are you interested in trading artifacts? I have some early American engines you might be interested in. I think I’m near you (sfbay).

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