NASA Keeping Nuclear-thermal Option Open For Mars

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Safer fuel and a new concept for ground testing have nudged NASA another tiny step in the direction of using hydrogen heated by a small fission reactor to hasten humans on their way to Mars. Nuclear-thermal propulsion (NTP) has been studied since the Apollo era because of the high specific impulse it offers for deep-space missions, but radiation fears and technical difficulties ultimately have blocked it. Now, with low-enriched nuclear fuel instead of bomb-grade material, and what may be a ...

http://m.aviationweek.com/space/nasa-keeping-nuclear-thermal-option-open-mars
 
For about a year or so there have been a few articles about this subject along the lines of "NASA is doing stuff on nuclear thermal." Unfortunately, this is 99% PR and 1% reality. I think it is a case of the Glenn Research Center having a few people doing a limited amount of research and hoping that they will get funding for more. But there's no push in the NASA budget to spend the required money--which is a LOT of money. So there's no there there.
 
hesham said:
We heard about that from 1980s.

Actually we heard that story in 1960s, 1980s, 1990s and 2004

In 1955 to 1973 it was ROVER/NERVA under Los Alamos, first USAF then by NASA
In 1985 to 1992 it was TIMBERWIND under Los Alamos by USAF
in 2000s NTP under NASA

but all of those machines never saw space or were used there
so what to do to succeed ?
First: stable Funding until Reactor In Flight Test
Second: a Space program that need this engine and keep it alive
Third: Ignore those Panicking Tree hugging Hippies from Greenpeace and love your Nuclear Engine...
 
I have always been a supporter of fission/fusion power for deep space missions beyond the solar system ever since I saw the BIS Project Daedalus in a space book I was reading back in the early 1980's, we need to keep this kind of technology alive so that those in the future can use it to colonize the stars.
 
blackstar said:
For about a year or so there have been a few articles about this subject along the lines of "NASA is doing stuff on nuclear thermal." Unfortunately, this is 99% PR and 1% reality. I think it is a case of the Glenn Research Center having a few people doing a limited amount of research and hoping that they will get funding for more. But there's no push in the NASA budget to spend the required money--which is a LOT of money. So there's no there there.

Stan Borowski and some of the other true believers at Glenn have been analyzing pretty much every conceivable variation of the core NERVA concept (pardon the pun) for many years now. For example, here's a recent take on a clustered 16.5K lbf option for cislunar and Mars operations:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150023036.pdf

I always thought clustering of NTRs was a no-no, but maybe that was when we were looking at 5000 MW and up for the reactors. The current thinking is a reactor around the 350 MW class and the size of a beer keg.

I got to meet Stan at an AIAA event at MIT right after the end of SEI. Smart guy and he graciously took the time to chat with a dweeb like me. I'll bet he would have expected to see one of his designs flying by now, sadly.
 
http://www.spacedaily.com/reports/NASA_taps_BWXT_for_spacecraft_reactor_design_999.html
 
George Allegrezza said:
I always thought clustering of NTRs was a no-no, but maybe that was when we were looking at 5000 MW and up for the reactors. The current thinking is a reactor around the 350 MW class and the size of a beer keg.

I got to meet Stan at an AIAA event at MIT right after the end of SEI. Smart guy and he graciously took the time to chat with a dweeb like me. I'll bet he would have expected to see one of his designs flying by now, sadly.

NTR like this need additional shielding if they Cluster, other wise there Neutron flux adding up during operation.
until chain reaction let to new Chernobyl, this time in space !
NTR Cluster need Beryllium shields (that stuff is very toxic) to prevent the Neutron hit other reactors.
 
Michel Van said:
NTR like this need additional shielding if they Cluster, other wise there Neutron flux adding up during operation.
until chain reaction let to new Chernobyl, this time in space !

Doubt it would create a larger nuclear holocaust than the Sun. ;)
 
The meltdown may not be an evironmental disaster in space but if you are halfway to Mars and you need the reactor to slow you into orbit, that may be a problem...
 
AndrewN said:
The meltdown may not be an evironmental disaster in space but if you are halfway to Mars and you need the reactor to slow you into orbit, that may be a problem...

if that happen, the crew will died fast, because the NTR run at maximum output for some second during melting.
With radiation levels beyond the protection shield specification...
 
http://www.world-nuclear-news.org/ON-NASA-to-test-prototype-Kilopower-reactor-1711174.html
 
AndrewN said:
The meltdown may not be an evironmental disaster in space but if you are halfway to Mars and you need the reactor to slow you into orbit, that may be a problem...

And that's different than any other potential power system how?
 
Michel Van said:
George Allegrezza said:
I always thought clustering of NTRs was a no-no, but maybe that was when we were looking at 5000 MW and up for the reactors. The current thinking is a reactor around the 350 MW class and the size of a beer keg.

I got to meet Stan at an AIAA event at MIT right after the end of SEI. Smart guy and he graciously took the time to chat with a dweeb like me. I'll bet he would have expected to see one of his designs flying by now, sadly.

NTR like this need additional shielding if they Cluster, other wise there Neutron flux adding up during operation.
until chain reaction let to new Chernobyl, this time in space !
NTR Cluster need Beryllium shields (that stuff is very toxic) to prevent the Neutron hit other reactors.

Clustered nuclear shuttles were a big part of the original post-Apollo Mars plans, I'm sceptical that neutrons from nearby piles were not factored in. In fact, the NERVA pile needed neutron reflectors to keep the pile critical. I'd hazard a guess that the inverse-square law and adjustments to the neutron reflector control laws would easily handle any excess neutrons from the other piles.
 
Nasa announces successful 'Kilopower' test of nuclear reactor for space

Nasa has successfully tested a nuclear reactor they will send to space.

The agency hopes that the breakthrough can allow future missions to the Mars and Moon to be powered with nuclear energy.

Tests conducted by Nasa seemed to suggest that the space-bound nuclear reactor was even more successful than it had thought.

https://www.independent.co.uk/news/science/nasa-kilopower-nuclear-power-space-reactor-latest-update-mars-moon-energy-a8332746.html
 
Demonstration Proves Nuclear Fission System Can Provide Space Exploration Power

NASA and the Department of Energy’s National Nuclear Security Administration (NNSA) have successfully demonstrated a new nuclear reactor power system that could enable long-duration crewed missions to the Moon, Mars and destinations beyond.

NASA announced the results of the demonstration, called the Kilopower Reactor Using Stirling Technology (KRUSTY) experiment,during a news conference Wednesday at its Glenn Research Center in Cleveland. The Kilopower experimentwas conducted at the NNSA’s Nevada National Security Site from November 2017 through March.

“Safe, efficient and plentiful energy will be the key to future robotic and human exploration,” said Jim Reuter, NASA’s acting associate administrator for the Space Technology Mission Directorate (STMD) in Washington. “I expect the Kilopower project to be an essential part of lunar and Mars power architectures as they evolve.”

​Kilopower is a small, lightweight fission power system capable of providing up to 10 kilowatts of electrical power - enough to run several average households - continuously for at least 10 years. Four Kilopower units would provide enough power to establish an outpost.

According to Marc Gibson, lead Kilopower engineer at Glenn, the pioneering power system is ideal for the Moon, where power generation from sunlight is difficult because lunar nights are equivalent to 14 days on Earth.

“Kilopower gives us the ability to do much higher power missions, and to explore the shadowed craters of the Moon,” said Gibson. “When we start sending astronauts for long stays on the Moon and to other planets, that’s going to require a new class of power that we’ve never needed before.”

The prototype power system uses a solid, cast uranium-235 reactor core, about the size of a paper towel roll. Passive sodium heat pipes transfer reactor heat to high-efficiency Stirling engines, which convert the heat to electricity.

According to David Poston, the chief reactor designer at NNSA’s Los Alamos National Laboratory, the purpose of the recent experiment in Nevada was two-fold: to demonstrate that the system can create electricity with fission power, and to show the system is stable and safe no matter what environment it encounters.

“We threw everything we could at this reactor, in terms of nominal and off-normal operating scenarios and KRUSTY passed with flying colors,” said Poston.

The Kilopower team conducted the experiment in four phases. The first two phases, conducted without power, confirmed that each component of the system behaved as expected. During the third phase, the team increased power to heat the core incrementally before moving on to the final phase. The experiment culminated with a 28-hour, full-power test that simulated a mission, including reactor startup, ramp to full power, steady operation and shutdown.

Throughout the experiment, the team simulated power reduction, failed engines and failed heat pipes, showing that the system could continue to operate and successfully handle multiple failures.

“We put the system through its paces,” said Gibson. “We understand the reactor very well, and this test proved that the system works the way we designed it to work. No matter what environment we expose it to, the reactor performs very well.”

The Kilopower project is developing mission concepts and performing additional risk reduction activities to prepare for a possible future flight demonstration. The project will remain a part of the STMD’s Game Changing Development program with the goal of transitioning to the Technology Demonstration Mission program in Fiscal Year 2020.

Such a demonstration could pave the way for future Kilopower systems that power human outposts on the Moon and Mars, including missions that rely on In-situ Resource Utilizationto produce local propellants and other materials.

The Kilopower project is led by Glenn, in partnership with NASA’s Marshall Space Flight Center in Huntsville, Alabama,and NNSA, including its Los Alamos National Laboratory, Nevada National Security Site and Y-12 National Security Complex.

For more information about the Kilopower project, including images and video, visit:

https://www.nasa.gov/directorates/spacetech/kilopower

For more information about NASA’s investments in space technology, visit:

https://www.nasa.gov/spacetech
 
Just to be clear: the kilopower reactor project is not the same as nuclear thermal propulsion.
 
Nuclear Propulsion for Space Applications

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130003317.pdf
 
A new type of nuclear reactor designed to power crewed outposts on the moon and Mars could be ready for its first in-space trial just a few years from now, project team members said.

A flight test is the next big step for the Kilopower experimental fission reactor, which aced a series of critical ground testsfrom November 2017 through March 2018. No off-Earth demonstration is on the books yet, but Kilopower should be ready to go by 2022 or so if need be, said Patrick McClure, Kilopower project lead at the Department of Energy's (DOE) Los Alamos National Laboratory in New Mexico.

 
Humanity's next giant leap could be enabled by next-gen nuclear tech, NASA Administrator Jim Bridenstine said.

During the sixth meeting of the National Space Council (NSC) today (Aug. 20), the NASA chief lauded the potential of nuclear thermal propulsion, which would harness the heat thrown off by fission reactions to accelerate propellants such as hydrogen to tremendous speeds.

Spacecraft powered by such engines could conceivably reach Mars in just three to four months — about half the time of the fastest possible trip in a vehicle with traditional chemical propulsion, said NSC panelist Rex Geveden, the president and CEO of BWX Technologies Inc.

 

"A new report from the National Academies of Sciences, Engineering, and Medicine offers some answers about two such ways. Conducted at the request of NASA, a broad-based committee of experts assessed the viability of two means of propulsion—nuclear thermal and nuclear electric—for a human mission launching to Mars in 2039.

"One of the primary takeaways of the report is that if we want to send humans to Mars, and we want to do so repeatedly and in a sustainable way, nuclear space propulsion is on the path," said Bobby Braun, director for planetary science at the Jet Propulsion Laboratory and co-chair of the committee that wrote the report, in an interview."

"In recent years, therefore, NASA has not asked for nuclear propulsion funding. Congress has appropriated money for the effort anyway. In the fiscal year 2021 budget bill, NASA received $110 million for nuclear thermal propulsion development.

Braun said it would cost substantially more—at least an order of magnitude—for NASA to work with the Department of Energy and other parts of the government to develop this technology and begin cargo flights to Mars in the mid-2030s. However, he said this is the kind of project that NASA would be well positioned to undertake.

"It's the kind of technology challenge that NASA was built for, and it's the kind of technology challenge that our nation expects NASA to be able to overcome," Braun said. "You know, going all the way back to the Apollo program, this is the kind of thing NASA was created for. So, I think they could do it.""
 
But this IS the private sector. Darpa is a creator of ideas for new advanced technologies funded by the government, but built by private companies, not the government. The government doesn't build anything. Just put the money. Those of the taxpayers.
 
What is the technical reason hydrogen is used as the reaction mass vice other gases? I'd have thought it harder to store than most any other liquified gas. For that matter, is there any reason you couldn't just use water? Probably far less efficient, but much easier storage. It could also form part of the radiation shielding before consumption.
 
Probably far less efficient
Exhaust velocity practically goes down by half.

Hydrogen, being the lightest element, gives the highest exhaust velocity of all the propellants for a given thermal rocket engine temperature; it is beaten only by monatomic hydrogen.

Given that solid-core NERVA barely gets 10km/s of exhaust velocity (it isn't much), cutting the exhaust with water will drop exhaust velocity down to 5km/s - barely better than hydrolox chemfuel rockets. NERVA loses a lot of its advantages (higher exhaust velocity) at that point. You can't go to Mars easily with 5km/s, for instance. As it was, they needed a multi-stage NERVA to get to Mars. The art always has drop tanks or stages or whatever. You need every meter per second you can squeeze out of that NERVA.

srvr.jpg
the-future-of-nuclear-rockets-for-space-travel_hero.jpg


The middle tank is under a saddle truss so they can drop it. It's a drop tank. NERVA limitations mean it's barely enough to get to Mars. These two concepts are separated by like 30 years. Top is from 1970, bottom is from the 2000s.
 
Given how long SLS is taking, god only knows how long it would take them to build this. Infinite time I suppose.
 
Thanks for the reaction mass explanation. I'd have thought water would make up for exhaust velocity by being more massive, but I'm in over my head physics wise.

I wonder if a new NERVA concept would allow for refilling the tanks with hydrogen processed from water on Mars. Though that might not be practical because I can't imagine a NERVA vessel being able to come down from orbit. Perhaps some hybrid of chemically powered 'slowboats' to deliver fuel to Mars orbit and NERVA to move astronauts back and forth quickly.
 
DARPA is not the government? When did this happen? A key component of air (and space) technical intelligence is to "avoid technological surprise."

Not to point fingers, but with China awash in American dollars from making cheap products, the US cannot afford to sit on its hands. The last thing anyone needs to see is "China announces launch of nuclear powered spacecraft for Mars."
 
Looking forward to this i guess.

and hope private sector also willing to look at this one.

Imagine "Space X, Nuclear Starship"
*knock on wood* they beat NASA or the Keldysh Center on 1st to getting to Mars. But switching to Nuclear is right now considered a must if they want to reach planets farther than Mars like launching submarine drones in liquid composed planets.
 
It’s a little surprising DoD is already concerned with ‘space awareness’ in lunar orbit. They clearly expect a Chinese military presence at some point.
 
Watching cut scenes of Chernobyl (2019) has me a little paranoid about sending anything nuclear related to our one and only moon. I have at least a preference for missions to Mars
 
Anything sent to the moon will likely be relatively small and unpressurized. Plus any pressure suit would keep you safe, so long as you didn’t track radioactive material into a habitat. I’m a lot more concerned by Russian attempts to build a nuclear engine for their missiles here on earth, several tests of which have already failed with fatalities.
 

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