27 -- Troy Howe - Pulsed Plasma Rocket- Developing a Dynamic Fission Process

Background: To realistically establish a human presence on Mars or to enable faster transit on any deep-space mission, high specific impulse and high thrust are key. Having each of these would allow for efficient propulsion and fast transit, eliminating restrictive launch windows and risks of long-term radiation exposure to crewed missions. The Pulsed Plasma Rocket (PPR) aims to meet these needs via a fissioning propulsion system that produces rapid plasma bursts. Previous efforts have examined pulsed propulsion methods, including the use of plasma as propellant, but the PPR achieves these plasma bursts via a fission-based system, wherein a highly moderated fuel projectile is propelled through a uranium barrel to reach supercriticality. The barrel and projectile material architecture results in much higher energy deposition in the projectile than in the barrel. After experiencing significant fission events, the projectile changes from a solid to a plasma over a period of a few microseconds, and is expelled through a magnetic nozzle.
Methods: Performed for a Phase I NASA NIAC study to determine feasibility and performance. Computational modeling has been performed using MCNP, MOOSE, and SERPENT neutronics programs. Thermal systems analyzed using COMSOL Multiphysics. Plasma interactions modeled with SPFMax.
Results: Neutronics modeling has determined the projectile constituents to include a high-assay low enriched uranium water-ice mix encased in a thin iron shell. Control drums generate a pulse of extreme supercriticality by rotating at different rates to create a Fourier series delta function which flashes the projectile into an ionized plasma at the end of the barrel. With the combined use of a coilgun as the initial propellant injector and a magnetic coil and nozzle for exhaust, the projectile is able to produce a thrust of roughly 100 kN with an Isp of 5,000s.
Conclusions: The necessary criticality to reach plasma-generating temperatures can be achieved in the projectile, while maintaining overall system integrity. The ship is capable of a 2-month transit to Mars, consumes no highly enriched uranium material, and can power itself by recuperating energy from the propulsion system.

[@SincereSentinel]

Excited to see this transport humans+cargo to Mars and elsewhere.

[@Blackburn_Motives]

Man uploaded the real thing...😮😮😮

[@PlanXV]

16:45 mass impacter 😅

[@buddy.boyo88]

what if in stead of the uranium barrel you shoot two uranium bullets at each other from the sides and they meet in the middle of a big bell nozzle. there is nothing to control or cool except cooling the nozzle. the deflagration happens at some distance and you get high yield. or you could shoot first a slow uranium cylinder from a wide bore gun then a very fast bullet from a coaxial narrow barrel situated forward of the wider barrel. this second gun would shoot the smaller bullet through the bigger gun cavity and the bullet will catch up with the uranium cylinder in the middle of the nozzle. then (Allah willing) the smaller bullet will wedge itself exactly in the cavity of the cylindrical bigger bullet and BAM. basically shooting a bullet with a bullet. also make the nozzle really big more like a sail. and have the two bullets collide far away so you avoid much of the radiation and neutron problem by having them disperse over a wide surface area of the engine so the heat load is more bearable.

[@howeindustries8883]

Yeah that's a good idea, good thinking outside the box. The two bullet idea is pretty close to the Manhattan project design for little boy and the bullet that catches up to a bullet seems clever. Seems like the thing to check out would be timing and if you could get a fast enough increase in criticality to ionize before the plasma hit the wall. As usual it all comes down to running the numbers, its tough to tell if it would spike sharp enough. Good ideas for replacing (or augmenting) the spinning drums tho.

[@robinpettit7827]

Great concept but it still carries some political risk by needing to boosting some amount of Uranium to orbit. I wish you the best though.