Is the use of nuclear power considered for more durable space probes?
Bertrand Roy
Yes. There should be flights in Earth orbit in the next few years and operational applications in the next decade.
“Nuclear propulsion is the only one that will allow the flexibility necessary for future Earth and lunar orbital missions,” explains Scott Rauen, the nuclear engineer who leads the DRACO program at Lockheed Martin, an aerospace company. “For a Mars mission, we could reduce the transit from six to nine months to three or four months. And a Mars mission could turn around midway in an emergency. »
DRACO (demonstration rocket for agile cislunar operations) is a partnership between Darpa, the United States military technology development agency, and NASA. The flight is planned for early 2027.
Mr. Rauen worked until 2014 for the US Navy, on aircraft carriers and nuclear-powered submarines. The company that manufactures reactors for the navy, BWXT, is the one that will build the reactor DRACO and other Lockheed nuclear space projects.
Probes that explore the far reaches of the solar system, such as Cassini (launched in 1997 towards Saturn) and New Horizons (launched in 2006 towards Pluto), are equipped with nuclear batteries which produce electricity thanks to their heat, but which do not provide propulsion.
For current probes, we are talking about a power of a few dozen watts, for a maximum of 200 watts. With nuclear propulsion, we arrive at several kilowatts, perhaps 1 megawatt.
Scott Rauen, nuclear engineer
The two obstacles to space nuclear propulsion are continued funding and public fears.
Cosmos 954
In 1978, the Soviet military satellite Cosmos 954 crashed in northern Canada. It was powered by a nuclear reactor and thousands of square kilometers were irradiated.
PHOTO FROM WIKIMEDIA COMMONS
In 1978, a Soviet nuclear satellite crashed in northern Canada, necessitating a search for radioactive debris.
“It’s been a nightmare for nuclear space propulsion,” says Mr. Rauen. We did a lot of research on the subject in the 1960s and 1970s. Things were progressing well. »
The opprobrium that followed confined nuclear power to batteries like those of Cassini and of New Horizons. “These are nuclear materials that are completely inert before they are activated in orbit,” says Mr. Rauen. Even if the probe crashes to Earth shortly after launch, as for Cosmos 954, there is no risk of contamination. »
The reactor of Cosmos 954 was powered by military-grade enriched uranium, which was much more dangerous, according to Mr. Rauen.
Concern over nuclear space propulsion is compounded by plans for nuclear weapons in orbit, as has recently been raised for Russia.
Another project is a nuclear reactor for a lunar base. “Other countries have announced that their lunar base will be powered this way,” says Mr. Rauen. I think we’ll get there in the 2030s.”
For a probe going to the confines of the solar system, nuclear propulsion would make it possible to go there more directly, without the accelerations by gravity with different planets (gravity assist maneuver), and more energy-consuming instruments. “Imagine going to one of the icy moons like Europa with surface penetrating radar,” says Rauen.
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- 499 million US
- Budget of DRACO
Source: NASA