NASA is exploring nuclear propulsion a project started by the agency 60 years ago – Houston Chronicle

With Americas eyes trained on the impending moon mission in the 1960s, NASA officials began quietly working on a project that could transform space travel.

They were trying to build a nuclear rocket engine, capable of getting astronauts to Mars in four months about half the time of a conventional chemical rocket.

Though the program showed early promise, it died due to inadequate funding.

Almost 60 years later, NASA is picking up where it left off, working again to develop a nuclear propulsion system that could carry humans farther than ever. President Donald Trump recently issued an executive order calling on NASA to develop and launch nuclear space systems, and Congress has provided $100 million to study the cost and feasibility of building such a rocket over the next year.

The main rationale for pursuing this again is human Mars missions, said Jeff Sheehy, chief engineer in the Space Technology Mission Directorate at NASA headquarters in Washington, D.C. Theres been a re-emphasis on going to the moon and doing those things on the moon that are necessary to develop the systems and demonstrate the capability to go to Mars.

But there still is a long way to go before NASA personnel can even begin to think about building these systems.

Were trying to determine how many billions its going to cost through the first set of flight(s) so we can go to decision makers and say this is what it will cost, these are the benefits, Sheehy said. Its up to the senior-most people in the agency to determine whether its worth the cost of developing the system.

Its too early to say if any of the work on this rocket will happen in Houston, but if it came to fruition, it would impact the training of astronauts living and working in this city.

A more efficient alternative

The military began examining what it would take to use nuclear energy to power airplanes during World War II a concept that would, if successful, enable a plane to fly around the world for days and return to the U.S. without refueling.

But this proved impossible. The amount of shielding needed to keep crew members and the public safe from radiation would keep the plane from staying aloft.

U.S. officials regrouped. Could nuclear rocketry work for space travel?

They realized that it just might. With the right amount of shielding to protect the crew, nuclear rockets could be a more fuel efficient and lighter option, producing more power and speed than their chemical counterparts meaning missions into deep space would be much quicker, the Los Alamos National Laboratory stated.

They were also ideal for space, an area where the only people who needed to be protected were the crew members.

So in 1961, the Nuclear Engine for Rocket Vehicle Application (NERVA) program was born, a joint endeavor by the Atomic Energy Commission and NASA to build a nuclear rocket engine for space, according to a historical report on the program published in 1991.

Between 1964 and 1969, scientists built and tested a number of nuclear reactors and rocket engines in Nevada, according to NASAs Glenn Research Center in Ohio.

The tests were so successful that in August 1969, rocket pioneer Wernher von Braun proposed sending 12 men to Mars in the early 1980s using NERVA-developed rocket engines. This plan, of course, did not come to fruition.

As far as a vehicle goes, they didnt get very close at all because, early in the 1960s with the war in Vietnam and other things, Congress already had started cutting NASAs budget, said Bob Arrighi, an archivist at NASAs Glenn Research Center in Ohio.

The project was canceled in 1972 the same year human moon missions came to an end with Apollo 17 after President Richard Nixon decided to focus his space policy on low Earth orbit and the space shuttle program.

Sending humans to Mars was a lot more costly and there was a lot more involved long-term than the space shuttle, Arrighi said.

New life for an old program

Over the ensuing decades, attempts were made to jump-start the nuclear rocket project, Sheehy said, but the current initiative is the most promising hes seen.

So far, the work has been focused on designing the fuel elements and the nuclear reactor. Sheehy said researchers are drawing on what was developed in the 1960s.

NASA will spend the next year determining how much the program would cost and how long it will take and part of that is deciding where the elements would be tested to ensure everything is working properly.

Ground testing could happen on Earth, Sheehy said, but there are many more safety requirements now than in the 1960s. This means NASA would need to build facilities that would retain the radiation emitted if something went wrong an endeavor that could prove cost-prohibitive, he added.

So, personnel are exploring what it would take to test the reactor in space, Sheehy said, a move that would require NASA to launch the rocket engine far enough from Earth that no radiation would leech into the atmosphere if the reactor exploded.

Like the real launch with people onboard, this would involve launching the vehicle off the planet aboard a chemical rocket. The nuclear rocket engine would kick in after the vehicle departed Earths atmosphere.

He does not expect any negative impacts to the space environment.

The amount of radiation from a reactor like this would be very small in the grand scheme of space, Sheehy said. There really isnt any hazard to equipment or people who arent close to the reactor.

The correct amount of shielding for the crew and the electronics on board also would need to be determined. But Sheehy said any future launch of a nuclear rocket out of Earths atmosphere shouldnt pose a danger to the planet because it would be built so that, even if there was a rocket failure, radiation would not be released.

You could characterize everything were doing as risk reduction, he said. Ultimately, the agency has to decide what propulsion to use. Were just trying to give them the information to at least make an informed assessment.

Alex Stuckey writes about NASA and science for the Houston Chronicle. You can reach her at alex.stuckey@chron.com or Twitter.com/alexdstuckey.

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