The DoD Wants Companies to Build Nuclear Propulsion Systems for Deep Space Missions

Solar power doesn't cut it in deep space.
Ameya Paleja
Illustration of a conceptual spacecraft enabled by nuclear thermal propulsion.NASA

In what looks like a continuation of past President Donald Trump's order, the Department of Defense (DoD) is now seeking proposals for advanced nuclear propulsion and power systems for small and medium spacecraft. A call for proposals floated by the Defense Innovation Unit (DIU) explains that the light and portable power systems must support propulsion and also power sensing and communication on the small- and medium-sized spacecraft. 

The executive order signed towards the end of Donald Trump's term was mainly aimed at developing portable nuclear reactors that could power American bases abroad, however, it also stated that they could be further developed to power human habitats on other planets. Earlier this year, a nuclear fusion company also proposed the idea of using nuclear power to send missions to Mars.

The call from DIU explains that electric and solar-powered propulsion are unsuitable for missions beyond Earth's orbit. As we move towards a new generation of spacecraft, the space constraints will increase along with the demand for power as the new age spacecraft perform new capabilities in orbit. Although these technologies are in the making, the DIU wants to "adopt mature technologies in the near term", the press release read.

Listing desired capabilities, DIU said that the proposed solution must have a high-delta V (>10 km/s), heat spacecraft systems in shadowed environments, and have a lifetime above three years. Given that nuclear power comes with its own risks, the proposal specifically asked for technologies that minimized risk for ground staff during integration and the fuel to have feasible manufacturing capabilities along with minimizing ionizing radiation impacts on electronic components, integrated circuits, avionics.