WASHINGTON — The Defense Innovation Unit last week issued a call for bids for small nuclear-powered engines for space missions beyond Earth orbit.

DoD wants “lightweight, portable and long-duration power sources that can support propulsion and on-station power for sensing and communication on small- and medium-sized spacecraft,” says the solicitation.

DIU says electric and solar-based propulsion systems are not suitable for missions beyond Earth orbit and are too bulky for use on modern commercial spacecraft. “Advanced propulsion technology that enables high delta-V and electrical power to payloads, while maintaining fuel efficiency, is required to enable new DoD mission sets in space.”

Submissions are due Sept. 23. DIU could award contracts within 60 to 90 days. These will be “Other Transaction” contracts for laboratory-based prototype testing. Under OT awards, companies and the government agree to invest in the project.

Bidders have to show “credible manufacturing, regulatory, and licensing paths toward prototype development within three to five years and a follow-on path to flight based testing.”

NASA and the Defense Advanced Research Projects Agency currently are funding the development of fission-based propulsion and power such as nuclear thermal propulsion technology.

DIU says it is not duplicating existing programs but is seeking to support current government projects with “mature commercial technologies that can provide power and propulsion in the near term.”

Making sure that these systems are safe is another concern. DIU wants systems that “minimize radiation exposure to ground personnel during spacecraft integration and radiation exposure on surrounding electronic components.”

Sandra Erwin writes about military space programs, policy, technology and the industry that supports this sector. She has covered the military, the Pentagon, Congress and the defense industry for nearly two decades as editor of NDIA’s National Defense...