Jul 292008

In 1964, NASA and numerous contractors studied “Post Saturn” launch vehicles. A common design element was a payload of one million pounds to low Earth orbit. Designs such as the Douglas ROMBUS, the Aerojet Sea Dragon, the Boeing MLLV and the Convair Nexus were all a part of this.

I have done some digging into the Post Saturn projects, and in some cases (Sea Dragon, MLLV) turned up nicely detailed reports; in the case of ROMBUS, I got about halfway to the good stuff, and in the case of Nexus I was only able to get some surface details. I tried several times to get the actual final reports from NASA through FOIA, but was shot down every time; it took a while, but I was finally able to get an answer as to why the reports were unreleasable: “They have drawings of rockets in them.” Grrrrr.

While the final Nexus reports have continued to elude me, I’ve picked up bits and pieces over the years. Below is a derivative of the Nexus, equipped with gasc core nuclear rocket engines. The nukes were to have an Isp of 2220 seconds, giving the vehicle a payload delivery to the Moon (likely lunar orbit, not surface) of one million pounds. I’ve found no further data on this design so far. Gas core nukes showed high promise in the early sixties, but unfortunately the practical problems of building such an engine were not overcome. Not that the anti-nuke movement would have allowed them to be built anyway…


 Posted by at 10:06 am
  • Michel Van

    Holy S#!T
    that Monster launch direct 453,59 metric tons to Moon or Mars orbit
    NOVA rockets were planned to bring this weight only in low orbit

    Nexus is bigges Rocket of all time, even Boeing SPS SSTO is smaller.

    but the gas core nuclear rocket engines muss be ignited in high altitude.
    can not imagine that Convair launch a NTR from ground !

    by the way you got ROMBUS stuff for this Blog ? thanks !

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  • John F

    Very nice article, great concept. Darn shame that the government space programs had no use for such a thing.
    The title is incorrect, though.
    Some Project Orion ground-launched nuclear pulse variants were up to 16,000 tons lift-off mass.
    One of the bigger ones would take off from Jackass Flats testing site to Saturn’s moons. Back to Mars orbit to drop off a base and crew, and 1400+ tons payload back to LEO. In a single stage.
    A 550 ton 10 meter variant was designed for loft to orbital altitude by Saturn-V booster, Others broke the ship into sections lifted & assembled in space for detonation only above HEO.
    Designs for post-Saturn boosters were bigger. Nexus would be ideal 🙂
    Crew carriers ignore Hohman trajectories and go from Earth-Mars in 21 days. To Jupiter in a few months. Hundreds of km/sec Δv (No new inventions needed). Cargo-only ships take minimum-energy courses with 85% of the mass in EO being cargo.