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28 February 2019 Nuclear In Space - The NETS Meeting By James Conca Forbes |
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The NETS meeting is wrapping up today at the Pacific Northwest National Laboratory in Richland, Washington. The Nuclear And Emerging Technologies For Space is an annual gathering of people from NASA, National Laboratories, industry, and academia to discuss space nuclear power and propulsion as well as new and emerging technologies that make further space exploration possible, safe and economic. For future space missions, especially for establishing colonies on the Moon or Mars, we need new energy systems to power larger facilities and spacecraft. So far, NASA has done well with small nuclear systems that power our unmanned spacecraft to distant planets. On January 1st 2019, the nuclear powered New Horizon’s spacecraft flew by the most distant object ever observed up close - Ultima Thule, far beyond Pluto, in the region called the Kuiper Belt, outside the Solar System proper. It will continue on into the Oort Cloud, the outermost region of the Solar System remaining from the original nebula from which the Sun and planets formed, before it exits our Solar System completely.
The spacecraft could not have done so without nuclear energy. Solar energy does not work much beyond Mars and only in line-of-sight with the Sun. Chemical sources don’t work for very long as their energy density is too low and their weight is prohibitive on long missions. So as we gear up for more government and private commercial space exploration and development, we need conferences where we can discuss and exchange information in this area. NETS fills this role. It is a topical meeting of the American Nuclear Society (ANS), hosted by the Aerospace Nuclear Science and Technology Division and the ANS Eastern Washington Section. Papers presented at the meeting can be seen here. Everything was discussed, from Nuclear Powered Cryobots that can access the oceans of Icy Planets like Europa, to Nuclear Thermal Rockets, to developing special composite and polymer materials to withstand long times in space. Keynote speeches from former astronaut and entrepreneur Dr. Franklin Chang-Diaz, NASA Associate Administrator Steve Jurczyk, and John Kelly, the President of the American Nuclear Society set the stage for the meeting. As Dr. Christopher Morrison notes, synergistic sharing of information is essential now that the global space market is $400 billion/year. Presently 72 different government space agencies are in existence, although only 14 of those have launch capability, and only six have full launch capabilities which includes the ability to launch and recover multiple satellites, deploy cryogenic rocket engines and operate space probes. These six include the China National Space Administration (CNSA), the European Space Agency (ESA), the Indian Space Research Organization (ISRO), the Japan Aerospace Exploration Agency (JAXA), the National Aeronautics and Space Administration(NASA), and the Russian Federal Space Agency (RFSA or Roscosmos). Nuclear energy in space has come in and out of fashion over the decades. 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 the outer Solar System. 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. However, RTGs cannot achieve the high-power density needed for large remote applications and there is not enough supply to meet the kilowatt- and megawatt-scale power needs of human spaceflight and off-world bases. The next big step is to provide power for human settlements. These will require kilowatt and megawatt power systems for life support, propulsion of large payloads, and off-world industry. While solar energy works well in many locations for small loads, nuclear energy is necessary for large loads in locations far from the sun or places like the moon whose surface has long periods of darkness. An ideal solution is a combination of both power sources, but the survival of a group of humans will require the certainty and reliability of nuclear power. A recent analysis at MIT, corroborates this – we need more powerful, miniaturized nuclear engines to go farther and faster into space. This is not new. NASA launched a nuclear fission system called SNAP-10A in 1965, and Russia launched over 30 fission-powered spacecraft during the Cold War. In addition, in the 1960’s NASA successfully ground tested dozens of nuclear rockets in a program called NERVA.
More recently, NASA ground tested
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. Called the
Kilopower Fission Power Project, the reactors are
designed to provide 1 to 10 kW of electrical power, and
can be set up in coordinated modules, which could be used
for more science instruments, to power electric propulsion
systems, or to support human exploration or colonies on
another planet (see figure). It would provide higher data
rate communications with a smaller antenna, something that
is more important than one might think. Traditional terrestrial nuclear
reactor designs are big. A space reactor, with a power
level in the kW range, would be a million times lower
power than most reactors on Earth. This translates to
simplicity and low cost. For example, the Kilopower
reactor core is only the size of a roll of paper towels
and the entire system with all of its components and
shielding, is about the weight of a car. Until recently, putting anything
into orbit around the Earth was incredibly expensive. Any
object orbiting the Earth was worth its weight in 14 karat
gold. The international space station is the most
expensive object built in modern human history with a cost
of 100 billion dollars to build. These costs put space
travel strictly in the realm of governments. But that is changing. Designing,
building, and operating complex technology has never been
easier in all of history. The manufacturing, materials,
and computer codes are orders of magnitude better than
they were in the 1960s. This has dropped the cost of
developing space faring capabilities to a level cheap
enough to be at the finger-tips of private companies such
as
Blue Origin,
SpaceX, and even smaller companies like
Rocket Lab. The space market, now about $400
billion/year, is set to grow to between
$1 trillion and $4 trillion per year by 2040). Last
year, the market for electricity in the United States was
only $400 billion. So the economic push is great to evolve
these systems. Jeff Bezos (Blue Origin) and Elon Musk
(SpaceX)
started their companies with the mission of enabling
millions of people to live and work in space. SpaceX
launch vehicles have dropped the cost of spaceflight by a
factor of 15, and
that should continue to drop by another factor of 5. For fission power systems, this is
game changing. In the past, the launch cost was simply too
great to achieve the critical mass requirements necessary
for colonization. What held back humanity from pursuing
endeavors beyond Earth orbit was cost, and now that
barrier has been lifted. So the gateway to space is open in
the way that the internet was opened in the 1990’s. And
nuclear energy is the power that will get us through that
gate. When humans are ready to live and work in space,
nuclear energy must be ready as well. That nuclear power
is
the safest energy source on Earth doesn’t hurt. Dr. James Conca is an expert on
energy, nuclear and dirty bombs, a planetary geologist, and a
professional speaker. Follow him on Twitter @jimconca. |
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