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NASA's Kilopower nuclear reactor with Stirling converters (not an RTG) has passed key tests:
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.
The full system will generate 10 kW of power, but the prototype tested from November to March was designed to produce just 1 kW. The solid uranium-235 core is safe to handle.
The Kilopower Reactor Using Stirling Technology (KRUSTY) prototype exceeded almost all performance metrics.
Multiple units could power missions on the Moon, Mars, or other destinations:
"Kilopower's compact size and robustness allows us to deliver multiple units on a single lander to the surface that provides tens of kilowatts of power," NASA Associate Administrator Steve Jurczyk said in January.
Also at Beyond Nerva. 3m8s video.
Previously: NASA's Kilopower Project Testing a Nuclear Stirling Engine
Initial Tests of NASA's Kilopower Nuclear System Successful
(Score: 2) by HiThere on Friday May 04 2018, @04:44PM (3 children)
Yes, but eventually isn't now, and a manned mission had better have a repair tech available.
That said, Stirling engines are among the most reliable mechanical engines. For one thing, they can be sealed against contamination. So for the manned mission you'll need multiple generators, the ability to make parts, and the tools to open and repair individual failures. And those are going to be rare, so that can't be anybody's main job.
This thing, though, reminds me of vacuum tube computers. Just barely good enough. What the equivalent of transistors is, though, I have no idea. As you say, solar power looks dubious. MHD hasn't ever really panned out. Etc. Of course, I could be excessively pessimistic, but moving parts wear.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by dry on Friday May 04 2018, @10:59PM (2 children)
I'd guess by the time something like this is needed for manned missions, it'll be the mark 3 or so version. As well a Mars mission is going to use a mixture of solar and nuclear and may not usually depend on the nuclear.
(Score: 2) by HiThere on Saturday May 05 2018, @05:57PM (1 child)
Well, you need to remember that solar power falls off as the square of the distance from the sun. It's true that Mars' atmosphere is thin, and usually rather transparent, but solar power will be weaker than at earth's orbit even so.
earth orbit radius = 93 million miles (approx.)
mars orbit radius = 142 million miles (approx.)
93^2/142^2 = 0.43 (approx.)
So figure you'll need twice as many solar cells to generate a given amount of power on Mars than on Earth. This is *quite* rough, of course, but it should be in the ballpark.
IOW, it's quite likely that given that you're going to need nuclear power, adding the solar power wouldn't be worth it. Better to have redundant nuclear power, so if one goes down you can fix it. I just wish there were something better than a steam engine to extract the power with. OTOH, the lower average temperature on Mars should mean the steam engine is more efficient, and at least with a Stirling engine you don't need to keep replacing the working fluid.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 3, Interesting) by dry on Saturday May 05 2018, @06:26PM
Have to consider things like power distribution. Probably going to be a shortage of wire at first and a real shortage of poles. Then there's how long it'll take the nuclear plant to come on line. Then any power needs far from camp.
Needing twice the solar panels as Earth isn't that bad. With lack of cloud cover and a higher flux of UV should boost that 43% up a bit.