Skip to main content
Go to accessibility notice


    Apollo Command Module Environmental Control System Hardware: Two Steam Duct Pressure Switches, AiResearch Part 836114 (Contract NAS-9-150). Each metal box, 4.125" (overall) x 1.5" x 2.75", has multi-pin electrical and screw-on pressure connectors on one end with a red "Warning/ Dielectric/ Testing/ Completed" sticker. A metal ID plate along one side presents the following data: "Consolidated Controls Corp./ Bethel Connecticut/ Switch, Pressure/ CCC Part No. 21PA6-2/ Date of Mfg. 7/66/ Mfg'd for Airesearch Per 836114-1-1/ [Serial No] 0009809/0009810". Included are several pages copied from a 1973 abstract prepared by AiResearch for the NASA MSC titled "Environmental Control System Transducer Development Study". It reads, in part: "The back pressure transducer was implemented in the initial stages of Apollo ECS as an obsolute pressure switch that sensed the pressure in the glycol evaporator steam discharge duct. The transducer functioned as a safety device to prevent the steam discharge pressure from falling below 5 mm Hg. The requirement of this transducer in the Apollo Block II ECS was eliminated, and the production of this transducer was discontinued." Both very fine.

    Fees, Shipping, and Handling Description: Miscellaneous Collectibles, Small (view shipping information)

    Sales Tax information  |  Terms and Conditions

    Bidding Guidelines and Bid Increments

    Glossary of Terms

    Auction Info

    Auction Dates
    November, 2014
    12th Wednesday
    Bids + Registered Phone Bidders: 0
    Lot Tracking Activity: N/A
    Page Views: 510

    Buyer's Premium per Lot:
    25% on the first $100,000 (minimum $14), plus 20% of any amount between $100,000 and $1,000,000, plus 12% of any amount over $1,000,000 per lot.

    Sold for: Sign-in or Join (free & quick)

    Heritage membership

    Join Now - It's Free

    1. Past Auction Values (prices, photos, full descriptions, etc.)
    2. Bid online
    3. Free Collector newsletter
    4. Want List with instant e-mail notifications
    5. Reduced auction commissions when you resell your
    Consign now
    • Cash Advances
    • More Bidders
    • Trusted Experts
    • Over 200,000 Satisfied Consignors Since 1976
    Consign to the 2020 October 27 Domain Names Signature Auction - Dallas.

    Learn about consigning with us

    The resulting auction of my property overwhelmed me. I want to thank Tom Slater and the Heritage team for a very satisfactory experience and profitable result with my historical consignment.
    Henry L.,
    Lexington, KY
    View More Testimonials receives more traffic than any other auction house website. (Source:

    Video tutorial

    Getting the most out of search

    Recent auctions

    2018 March 17 Western Americana & Texana Grand Format Auction - Dallas
    2018 March 17 Western Americana & Texana Grand Format Auction - Dallas
    REALIZED SO FAR $327,896