Composed of over 100 Viking Orbiter images, this mosaic of Mars shows the 1300-mile-long, 5-mile-deep Valles Marineris in the center of the photo, as well as the Tharsis thermal bulge that is causing volcanoes in the left-hand part of the photo and spreading the ice-cemented crust in the center. This opens the ice to the atmosphere which sublimes, triggering huge avalanches that widen these large canyons over time. The fine material, pulverized by a billion years of impacts, is blown by large dust storms to eventually settle in the higher latitudes. The ice does occasionally melt, during the slumping or during meteorite impacts, causing transient rivers and lakes which only last days to weeks before evaporating and snowing out at the poles.
The National Aeronautics and Space Administration (NASA) is developing a tiny nuclear reactor that is perfect for powering a colony on Mars or the Moon, fueling a large spacecraft to a distant star, or operating a mining operation in the asteroid belt.
In the Kilopower Fission Power Project, the reactors are designed to provide 1 to 10 kW of electrical power which could be used for more science instruments, to power electric propulsion systems, or to support human exploration or colonies on another planet. It would provide higher data rate communications with a smaller antenna, something that is more important than one might think.
NASA partnered with the Department of Energy’s National Nuclear Security Administration to develop the Kilopower reactor using existing nuclear facilities.
The prototype uses a solid cast U-235 reactor core the size of a paper-towel roll.
High-efficiency Stirling engines produce about 10 kW of electricity.
The Kilopower nuclear reactor will take advantage of active nuclear fission, passive sodium heat pipes and Stirling engines that convert heat into motion and then electricity, to increase its efficiency compared with previous power sources.
The Kilopower system has undergone several non-nuclear tests using an electrical heat source and a depleted uranium core to verify the complete non-nuclear system design.
Actual nuclear testing is ongoing at the Nevada Test Site.
In Nevada, the reactor will be fueled with the highly-enriched uranium core and re-tested using the nuclear heat source.
For the last 50 years, we have used radioisotope electric propulsion systems and radiothermal generators (RTGs) to power long missions far from the Sun, like the Voyager missions to Jupiter and beyond, or the New Horizons mission to Pluto.
Pu-238 is the best isotope, emitting steady heat from natural radioactive decay by emitting alpha particles that thermocouples then convert to electricity.
Its 88-year half-life means the missions can be long in duration.
But RTGs don’t supply enough power to support people on another planet.
It takes a lot of power to produce oxygen, water, heat, food, charge rover batteries, manufacture tools and special materials, and smelt ore for metals.
In 2010, NASA's Mars Global Surveyor took this image of Mars' ice cap, which measures about 1,000 kilometers (621 miles) across. The ice cap is made out of water ice with frozen carbon dioxide. The ripples are deep valleys covered in shadow
NASA/JPL-Caltech/MSSS
Space travel is all about mass.
You can’t travel through space without shooting out some mass really fast in the opposite direction, to get going.
Then you have to lose mass in the opposite direction to stop.
Maneuvering during the trip also takes mass.
Fuel for space travel, even to a nearby planet like the Moon or Mars, is usually the most critical aspect of any mission.
To set up an initial colony on a planet means taking even more mass if you’re going to stay any length of time.
Fossil fuels are very heavy, as is any chemical fuel.
Solar panels are not too effective with the dim light from the Sun at Mars and beyond so that many many tons of panels plus many many tons of batteries would be needed to power even a tiny colony.
On Mars, dust storms would periodically cover these panels with dust and maintaining them will be time-consuming.
They might work better for the Moon, as there is no blowing dust and it’s much closer to the Sun, but the Moon’s 336-hour-long night would require an awful lot of batteries.
There is no wind sufficient to turn turbines on Mars or the Moon.
Even with the high velocity storms on the Red Planet, the Martian atmosphere is too thin to turn anything remotely approaching a wind turbine, contrary to the well-done movie, The Martian, which had to take liberties with that particular subject to support the plot.
Although there is sufficient water for a colony on Mars, it is frozen as ice, and could not provide enough running water for hydro.
Biomass is a no-go as it will be difficult enough to produce food as the Martian regolith is not actually a soil. Lots of soil amendments will have to be taken from Earth to grow anything there.
While volcanism is still active in the Tharsis region of Mars (see figure above), there are no subsurface water convention cells needed to run a geothermal plant.
The best and only practical energy source is a small nuclear reactor.
Nuclear fuel is the most energy dense – 80,000,000 MJ/kg versus about 50 MJ/kg for petroleum, 30 MJ/kg for coal and less than 1 MJ/kg for batteries of any type.
The latter would have to be charged anyway.
This is why NASA is developing this very small nuclear reactor.
Solar and batteries will be used in conjunction, but the safety of a colony depends on having more than one energy source that is constant.
So a few Kilopower nuclear units, some solar panels and some batteries is an ideal mix (see figure above).
This artist’s concept shows four fission-based modular nuclear power stations powering a human outpost on Mars. The system could be supplemented with solar and battery arrays.
The space mining aspect of this technology is important as the commercial space sector continues to expand.
The United States Space Act (HR 2262) was unanimously passed by Congress in 2015 and recognized the right of U.S. citizens to own asteroid resources they obtain as property and encouraging commercial exploration and recovery of resources from them.
As for Mars, NASA is planning three expeditions of four to six astronauts for a stay of about 500 days.
Each expedition will land at a different location on Mars to explore the diverse terrain and environment.
The first expedition to arrive at the surface would be unmanned cargo landers, which house the power system, propellant production for getting off the planet, and the Mars Ascent Vehicle for returning to the orbiter.
The power system will initially be used to convert the Martian CO2 atmosphere into oxygen where it will then be cryogenically cooled and stored in the Mars Ascent Vehicle (MAV).
After sufficient propellant has been produced and stored in the MAV, and the Mars orbiting habitat fully checked out, the crew will leave Earth and rendezvous with a Mars Transfer Vehicle, beginning the 200-day trip to Mars.
After arriving in orbit around Mars, the crew will rendezvous with the habitat and begin the entry, descent, and landing to the pre-deployed cargo landers to start their surface mission.
Mars’ surface looks so much like Earth, it seems likely that humans will set foot on it. This photo by the Curiosity rover on September, 2015 shows a long ridge colored by the iron oxide mineral hematite. Just beyond is an undulating plain rich in clay minerals. Beyond that are a multitude of rounded buttes including Mount Sharp, all high in sulfate minerals. Liquid water, for some amount of time, billions of years ago, is needed to produce these rocks and minerals
NASA/JPL-Caltech/MSSS
There is an awful lot of logistics, technology and planning to be done before any mission could occur, but humans on Mars would be the greatest achievement of this century.
And nuclear power will be the energy that makes it happen.
James Conca , CONTRIBUTOR
I write about nuclear, energy and the environment
Dr. James Conca is an expert on energy, nuclear and dirty bombs, a planetary geologist, and a professional speaker.
Follow him on Twitter @jimconca and see his book at Amazon.com
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