Space

NASA looks at reviving atomic rocket program

A new engine being developed for NASA will use low-enriched uranium Cermet fuel rods
A new engine being developed for NASA will use low-enriched uranium Cermet fuel rods
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A new engine being developed for NASA will use low-enriched uranium Cermet fuel rods
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A new engine being developed for NASA will use low-enriched uranium Cermet fuel rods
Advances in materials technology could lead to the production of LEU NTP fuel elements
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Advances in materials technology could lead to the production of LEU NTP fuel elements
Some testing can take place in non-nuclear facilities
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Some testing can take place in non-nuclear facilities
A test facility for the LEU engine
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A test facility for the LEU engine

When the first manned mission to Mars sets out, it may be on the tail of an atomic rocket engine. The Space Race vintage technology could have a renaissance at NASA after the space agency's Marshall Space Flight Center in Huntsville, Alabama signed a contract with BWXT Nuclear Energy to develop updated Nuclear Thermal Propulsion (NTP) concepts and new fuel elements to power them.

The Apollo missions to the Moon demonstrated many things. They showcased human ingenuity, determination, and courage. They proved what American engineering and industry could accomplish in short order when let loose on a goal and demonstrated that humankind need no longer be confined to a single planet.

Unfortunately, it also showed the fact that chemical rockets, even at the dawn of the conquest of space, had reached their technical limits. True, they could send astronauts to the Moon, but only by using a disposable rocket the size of a skyscraper of which only a capsule with the roominess of an SUV returned. And even this was in no shape for anything except a museum.

Advances in materials technology could lead to the production of LEU NTP fuel elements
Advances in materials technology could lead to the production of LEU NTP fuel elements

What was apparent even in 1969 was that, at the very most, chemical rockets could send an expedition to the planet Mars. However, even this could only be accomplished under the most favorable of conditions and in a configuration that made the voyage little more than a stunt or a protracted suicide mission.

If humanity was ever going to explore and exploit the Solar System in person, a much more powerful propulsion system was needed: an atomic engine.

Atomic or nuclear engines for spacecraft were conceived of almost before the ink was dry on Albert Einstein's famous E=mc² equation. The exploding of the first fission bomb in 1945 and the development of the first power reactors shortly thereafter made the idea seem feasible, and from 1955 to 1972 the US government pursued a test program to create a practical engine.

Some testing can take place in non-nuclear facilities
Some testing can take place in non-nuclear facilities

The reasons for this were obvious. With its higher exhaust velocities and greater specific impulse, a nuclear rocket could carry larger payloads or smaller payloads at greater speeds. Today, as the hazards of spaceflight are better known, such engines are particularly attractive because they could cut months off a trip to Mars, resulting in less exposure time of astronauts to weightlessness and cosmic rays. In addition, once on Mars, the engine's reactor could provide a round-the-clock, high-density power supply for an outpost.

Under the NERVA project, a workable engine was developed, but it was never used on any space mission. Part of the reason was that, though the rocket was twice as efficient as chemical rockets, its need for highly-enriched uranium as fuel, plus its need to operate at temperatures of 3,000 K (2,727° C, 4,940° F), made it the very definition of "risky". Small wonder then that when the Apollo program wound down and the NASA Mars mission was scratched, so was NERVA.

Today, with NASA once again considering the challenges of sending astronauts to Mars, the nuclear option is back on the table as part of the agency's Game Changing Development program. Under this, NASA has awarded BMXT, which supplies nuclear fuel to the US Navy, a US$18.8-million contract running through September 30, 2019 to look into the possibility of developing a new engine using a new type of fuel.

A test facility for the LEU engine
A test facility for the LEU engine

Unlike previous designs using highly enriched uranium, BMXT will study the use of Low-Enriched Uranium (LEU), which has less than 20 percent of fissile uranium 235. This will provide a number of advantages. Not only is it safer than the highly enriched fuel, but the security arrangements are less burdensome, and the handling regulations are the same as those of a university research reactor.

In addition, LEU allows much of the testing of the technology to be done without any fuel at all because the destructive radiation effects are much lower. Also, the initial live engine tests can take place in a single, closed-loop facility that has no outlet to the natural environment.

Key to the concept is the development of an isotopically pure form of tungsten that, mixed with uranium, could be used to create a ceramic-metallic (Cermet) fuel, which would be more stable under the tremendous heat created by the engine.

Under the contract, BMXT and NASA will manufacture and test prototype Cermet fuel elements with 90-percent pure tungsten, as well as look to solve problems in making the fuel, seeing if an LEU engine will have the required thrust, and work on resolving nuclear licensing and regulatory requirements. In addition, BMXT will study the costs of building and operating such an engine.

If NASA determines next month that the LEU engine is feasible, the project will conduct testing and refine the manufacturing process of the Cermet fuel elements over the course of a year, with testing of the full-length Cermet fuel rods to be conducted at Marshall.

The video below outlines the new LEU engine concept.

Source: NASA

Nuclear Thermal Propulsion (NTP)

13 comments
IanHoldsworth
Looks more promising than Project Orion https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)
windykites
What realistically is the point of sending men to Mars? Is there anything valuable there? Robots seem to doing a good job of exploring.
juanhollisDS4E
There is noway a space craft/ship can be propelled in space it has to be impelled i.e impulsion where the NTI Engine produces an energy pulse behind it that pushes the craft/ship forward, better yet is to develop EMGD (ELECTRO-MAGNETIC GENERATED DRIVE) so instead of moving thru space you make space move so a voyage to mars would take a mere sixy seconds!
EZ
I am convinced that the military, including NASA, already have anti-gravity technology and can extract electrons from the "Ether." They just don't want anybody to know it, so they keep the facade up that they still need to spend more money. I base this on what I've seen and what others have experienced. No BS. This is interesting.
Douglas Bennett Rogers
It is almost as if Mars were put there for human occupation. The .3 g gravity is much more suitable for the human form. The 50% insolation is more tolerable by humans. Space is much more accessible by rail gun or elevator. There is a huge supply of nitrogen in the outer solar system for terraforming. The absence of magnetic field is not as important as people think. Water appears to be fairly common. The land area is about the same as Earth.
Robert Bernal
About time someone takes nuclear propulsion seriously. It doesn't have to be just for manned missions, either, assuming that astronauts don't have to deal with nuclear engines, anyways. Low enriched is the key, as that should be good enough to ward off anti nuclear hysteria. Perhaps this new cermet tungsten fuel could work at home, should the molten salt reactor prove more cumbersome than the paper versions. The object here is not to go back to the Moon or, to Mars, just to set for and then leave. No, the object is to build a Dyson swarm complete with a few billion spinning space cities at least a few kilometers in diameter, and up to 5 thousand miles in diameter when graphene gets common. Unlimited clean energy and unlimited space around Earth and sun. That's the future (then we could afford to tinker with Mars)!
HoppyHopkins
Even with this low enriched Uranium fuel, the Nerva design was inefficient, which is why it was abandoned, not the risk problem of highly enriched Uranium. The more promising design was the Dumbo reactor with its more efficient thermal transfer design. But for deeper space exploration, variants of the Orion/Medusa Nuclear explosion impulse bomb system give enough velocity for interstellar voyages. However, the EM drive being tested and the reports of the Bose-Einstein gravitation negation experiments show promise of actual Faster Than Light drives on the horizon.
DomainRider
@HoppyHopkins - no, the Bose-Einstein condensate 'negative mass' experiment was referring to 'effective' mass, not fundamental mass. It's not some kind of anti-gravity or inertia-less breakthrough, it's just the way excitations in the condensate behave. The atoms in the condensate (and the BEC as a whole) still couple to the gravitational field like ordinary mass and have inertia.
Nygaard
Earth is becoming unlivable quick everyone to Mars its lovely there. Well just have to figure out how to "TeraForm" that isn't far off. But we could always just stay here and TeraForm Earth every few thousand years. We could hold a world wide vote on the theme for every reform! If the sky isn't falling we will lose funding (Theft of our tax dollars.)
PrometheusGoneWild.com
With the successful launch of a US aircraft carrier with electromagnetic launch capabilities, I am hoping NASA would figure out that with a rail system run up the side of a mountain, chemical rockets could be built much safer. The rail would expensive. But only one would be needed. An atomic engine would make more sense in space, where there would be little chance of nuclear contamination from an accident....