A round trip to the Red Planet is expected to take up to two years to complete, a long time for any astronaut even aside from concerns that exposure to chronic, low-dose radiation in space could cause neural and behavioural impairments over time.
But Nasa is hoping to shorten this timeframe by exploring the potential of nuclear electric propulsion, which employs a nuclear reactor to generate electricity that ionises, or positively charges, and electrically accelerates gaseous propellants to provide thrust to a spacecraft.
Researchers at Nasa’s Langley Research Center are working on a project dubbed Modular Assembled Radiators for Nuclear Electric Propulsion Vehicles, or MARVL. The project aims to take a critical element of nuclear electric propulsion, its heat dissipation system, and divide it into smaller components that can be assembled robotically and autonomously in space.
“By doing that, we eliminate trying to fit the whole system into one rocket fairing,” said Amanda Stark, principal investigator for MARVL. “In turn, that allows us to loosen up the design a little bit and really optimise it.”
Engineers had previously suggested fitting the entire nuclear electric radiator system under a rocket nose cone, an incredibly difficult task considering that, fully deployed, the heat dissipating radiator array would be roughly the size of a football field.
Rather than cram the whole system into an existing rocket, the MARVL system would allow researchers the flexibility to send pieces of the system to space in whatever way would make the most sense, then have it all assembled off the planet.
Once in space, robots would connect the nuclear electric propulsion system’s radiator panels, through which a liquid metal coolant, such as a sodium-potassium alloy, would flow.
Julia Cline, a mentor for the project, said: “Existing vehicles have not previously considered in-space assembly during the design process, so we have the opportunity here to say, ‘We’re going to build this vehicle in space. How do we do it? And what does the vehicle look like if we do that?’ I think it’s going to expand what we think of when it comes to nuclear propulsion.”
Additional support for MARVL comes from the agency’s Space Nuclear Propulsion project. The project’s ongoing effort is maturing technologies for operations around the Moon and near-Earth exploration, deep space science missions, and human exploration using nuclear electric propulsion and nuclear thermal propulsion.
Source: E&T
