Artist depiction of Modular Assembled Radiators for Nuclear Electric Propulsion Vehicles (MARVL).
One of the biggest goals in space exploration is getting humans to the distant planet, Mars. However, reaching Mars involves not just one but myriad engineering challenges, including the long distance.
Mars missions are currently estimated to take around 2-3 years for a round trip — given the huge distance of 140 million miles from Earth.
Nuclear electric propulsion could speed things up and possibly shorten this journey time.
Researchers at NASA Langley are developing a next-gen system called MARVL (Modular Assembled Radiators for Nuclear Electric Propulsion Vehicles) that aims to advance the feasibility of nuclear electric propulsion for space travel.
The MARVL project focuses on developing a modular heat dissipation system for nuclear electric propulsion. Interestingly, this system will be comprised of smaller components that can be assembled by robots in space, making it more practical for large-scale space missions.
“By doing that, we eliminate trying to fit the whole system into one rocket fairing. In turn, that allows us to loosen up the design a little bit and really optimize it,” said Amanda Stark, a heat transfer engineer at NASA Langley and the principal investigator for MARVL.
An artist’s rendering that shows the different components of a fully assembled nuclear electric propulsion system. NASA
Robotic assembly
Nuclear electric propulsion uses a nuclear reactor to produce electricity. This electricity is then used to ionize and accelerate gases, creating a powerful thrust for spacecraft propulsion.
However, a nuclear reactor needs the generation of immense heat generated for long-distance space travel.
Traditional designs envisioned gigantic radiators, which could be impossible to fit inside the tip of a rocket.
When fully extended, the heat-dissipating radiator array would stretch out to cover an area roughly equivalent to a football field. Hence, folding it up within a rocket has been cited as a major design challenge.
That’s where the MARVL project comes in. Modular Assembled Radiators aims to solve this problem by enabling the assembly of the radiator system in space. Instead of launching the entire system at once, individual components can be transported. This approach offers greater flexibility in design and transportation logistics.
NASA plans to use robots to put together the radiator panels of the nuclear electric propulsion system. As per NASA release, these panels will facilitate the flow of a liquid metal coolant, such as a sodium-potassium alloy, to effectively dissipate heat.
“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,” said Julia Cline, a mentor for the project in NASA Langley’s Research Directorate.
Small-scale prototype will be ready in two years
The MARVL project received funding from NASA’s Space Technology Mission Directorate through the Early Career Initiative.
The team, including collaborators from Boyd Lancaster, Inc., NASA Glenn, and NASA Kennedy, has two years to develop the concept. They aim to conduct a small-scale ground demonstration of the MARVL design after this period.
Several space agencies and commercial entities are exploring the use of nuclear propulsion for faster Mars missions.
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In December 2024, US companies, Ad Astra Rocket Company and The Space Nuclear Power Corporation (SpaceNukes), formed a partnership to advance high-power nuclear electric propulsion (NEP) technology.
This collaboration aims to accelerate the development of faster and more reliable space travel for both human and robotic missions to Mars.
