We’re building nuclear spaceships again—this time for real
arstechnica.com
The military and NASA seem serious about building demonstration hardware.

Phoebus 2A, the most powerful space nuclear reactor ever made, was fired up at Nevada Test Site on June 26, 1968. The test lasted 750 seconds and confirmed it could carry first humans to Mars. But Phoebus 2A did not take anyone to Mars. It was too large, it cost too much, and it didn’t mesh with Nixon’s idea that we had no business going anywhere further than low-Earth orbit.

But it wasn’t NASA that first called for rockets with nuclear engines. It was the military that wanted to use them for intercontinental ballistic missiles. And now, the military wants them again.

  • DickFiascoEnglish
    6·
    4 months ago

    We need to get Solomon Epstein working on this.

    • spinnetrouble@sh.itjust.worksEnglish
      2·
      4 months ago

      Step 1: Colonize Mars

      Step 2: Treat Mars like an Earth colony instead of an independent nation and make them really resentful of it lol

  • AutoTL;DR@lemmings.worldBEnglish
    3·
    4 months ago

    This is the best summary I could come up with:

    In chemical rockets, hydrogen had to be mixed with an oxidizer, which increased the total molecular weight of the propellant but was necessary for combustion to happen.

    Fuel rods made with uranium 235 oxide distributed in a metal or ceramic matrix comprise the core of a standard fission reactor.

    This reaction is kept at moderate levels using control rods made of neutron-absorbing materials, usually boron or cadmium, that limit the number of neutrons that can trigger fission.

    The hotter you make the exhaust gas, the more you increase specific impulse, so NTRs needed the core to operate at temperatures reaching 3,000 K—nearly 1,800 K higher than ground-based reactors.

    Then there was the hydrogen itself, which is extremely corrosive at these temperatures, especially when interacting with those few materials that are stable at 3,000 K. Finally, standard control rods had to go, too, because on the ground, they were gravitationally dropped into the core, and that wouldn’t work in flight.

    Los Alamos Scientific Laboratory proposed a few promising NTR designs that addressed all these issues in 1955 and 1956, but the program really picked up pace after it was transferred to NASA and Atomic Energy Commission (AEC) in 1958, There, the idea was rebranded as NERVA, Nuclear Engine for Rocket Vehicle Applications.

    The original article contains 642 words, the summary contains 211 words. Saved 67%. I’m a bot and I’m open source!