nuclear-news

Military interest in nuclear-powered space travel, but solar-powered is just as good, -and safer.

2 Government, Industry Explore Nuclear, Solar Space Engines

COLORADO SPRINGS, Colorado — More commercial and military activity is taking place in space, and the Defense Department and industry are investing in emerging propulsion technologies to move systems in orbit faster, farther and more efficiently.

……………………………………..In 2021, the Defense Advanced Research Projects Agency selected Lockheed Martin as one of three prime contractors — along with General Atomics and Blue Origin — for Phase 1 of its Demonstration Rocket for Agile Cislunar Operations, or DRACO, program to showcase the potential of a nuclear thermal propulsion system in space, a DARPA release said.

This January, NASA announced it had partnered with DARPA on the DRACO program, describing a nuclear thermal rocket engine as “an enabling capability for NASA crewed missions to Mars.” The goal is to demonstrate the system in orbit in fiscal year 2027, with the Space Force providing the launch vehicle for the DRACO mission, a DARPA statement said.

The program is about to enter Phase 2, which “will primarily involve building and testing on the non-nuclear components of the engine” such as valves, pumps, the nozzle and “a representative core without the nuclear materials in it,” DARPA’s program manager for DRACO Tabitha Dodson said during a panel discussion at the Space Foundation’s Space Symposium in April. Dodson said then a Phase 2 decision is “quite close.” However, at press time in mid-July, no contracts have been awarded.

…………………………………“There are no facilities on Earth that we could use for our DRACO reactor’s power test … so we’ve always baselined doing our power test for the reactor in space,” Dodson said. Once in space, DARPA will “very gradually” ramp up the system to “full power thrust,” she said…………………………………………………………………………………………………………………………………………
Despite DARPA’s commitment to safety, nuclear propulsion systems face an uphill battle getting deployed on spacecraft at scale, said Joel Sercel, founder and CEO of TransAstra, a space technology company.

………………………………………………………………………………..In May, the Space Force awarded TransAstra a Phase One Small Business Innovation Research contract to explore new applications for the company’s propellant-agnostic Omnivore thruster.

The Omnivore thruster uses solar reflectors to focus sunlight onto a solar absorber, which then superheats the system’s propellant to generate thrust “typically six times faster and eight times cheaper than electric systems,” a company release said.

Additionally, TransAstra calculated an Omnivore thruster “using liquid hydrogen propellant … will perform similarly to nuclear rockets, but without nuclear materials, costs or risk.”

Sercel said Omnivore has “80 percent of the performance of nuclear at 1 percent of the cost.” The system is essentially nuclear powered, “but the nuclear reactor in question is the fusion reactor at the center of the solar system called the Sun,” he added.

“The nice thing about nuclear reactors is that you have a small, compact reactor versus large deployable solar reflectors, but the basic performance of solar thermal rockets and nuclear rockets is about the same,” he said. And with Omnivore “you don’t have all these safety concerns and radioactive material and reactor control issues and so on. So, we think it’s a much more practical approach.”

Omnivore could have multiple mission applications for the Defense Department, Sercel said. Using liquid hydrogen propellant, the thruster “can deliver hundreds of kilograms” of spacecraft to geosynchronous orbit “on small launch vehicles, and the Space Force seems to be very excited about this,” he said. The system could also deliver spacecraft weighing more than 100 kilograms to cislunar space, he said.

Additionally, TransAstra has an Omnivore variant that uses water as the propellant, the solar absorber superheating the water vapor and releasing the gas through a nozzle to generate thrust.

The water-based variant can be placed on the company’s Worker Bee small orbital transfer vehicles, about 25 of which can fit on a single Falcon 9 rocket, Sercel said.

“Each [Worker Bee] could deliver up to six small [satellites] to their orbital destinations. So, we can deliver a full constellation of 100 small or micro [satellites] to all different inclinations, and you would get global coverage in one launch.”…………………………………………………………more https://www.nationaldefensemagazine.org/articles/2023/7/31/government-industry-explore-nuclear-solar-space-engines

August 1, 2023 - Posted by Christina Macpherson | renewable, space travel, USA