So a while ago, NASA started to look for alternative means of propulsion for spacecraft meant to visit not only Mars, but also the outer planets. The focus quickly fell on something called Nuclear Thermal Propulsion (NTP).
In itself, the idea is not new, but was never put to use on a spacecraft. It basically means a uranium nuclear core where fission occurs, with atoms splitting to release heat. The same core is flooded with fuel, like say liquid hydrogen. The heat produced by the reactor converts the fuel to gas, which is pushed out through the back of the spacecraft to produce thrust.
There are a number of advantages to such a solution, including the fact they are twice as efficient as chemical rockets, as per the Office of Nuclear Energy. They are also faster and could reduce travel time to neighboring Mars, which usually takes about nine months, by about a quarter. That’s by more than two months, and in the economy of a crewed mission there, it’s like getting the planet closer to our home to make it easier to reach.
NASA has been looking for such solutions for a while now, but we know of no NTP being close to becoming a reality. Yet, this isn’t stopping people from coming up with their own ideas on the matter.
Among them is Ryan Gosse from the University of Florida, Gainesville. His idea is complicatedly called Bimodal NTP/NEP with a Wave Rotor Topping Cycle and received a NASA Innovative Advanced Concepts (NIAC) Phase 1 grant earlier in January.
There’s a visual breakdown of the concept’s components featured as the main photo of this piece. We see the usual controllers, reaction and thrust chambers, and the nozzle, but also something called a wave rotor.
It’s this piece of technology that’s key to this design. You see, a regular NTP design provides a specific impulse (the thrust resulting from a specific amount of fuel) of 900 seconds. That’s not bad, considering a chemical rocket’s specific impulse is half that, but horrible when compared with the maximum potential of the NTP, which could go as high as 4,000 seconds.
So, the wave rotor topping cycle this scientist is proposing should increase the specific impulse to up to 4,000 seconds under the right conditions.
What does that mean for a spaceship traveling to Mars? Well, instead of the nine months on chemical rockets, or seven using a standard NTP, a ship rocking this tech could potentially reach the Red Planet in about 45 days.
It's like the other planet was somehow moved right next door, and this could forever change the face of our expansion into the solar system. Sadly, the entire idea is at the NIAC Phase I stage, and that means people have not nearly begun making it a reality.