Space nuclear propulsion: Humanity’s route to the solar systemANS Nuclear CafeMay 8, 2012, 6:00AM|Wesley DeasonPart III: Nuclear Thermal PropulsionToday's post is the final installment of a series concerning space nuclear propulsion (Part I) (Part II). Previous posts discussed nuclear reactor safety and nuclear electric propulsion. Today I will focus on the other extensively researched nuclear space propulsion method: nuclear thermal propulsion.Nuclear thermal propulsionNuclear thermal propulsion (NTP) involves the direct heating and expulsion of a propellant using nuclear power. To accomplish this, nuclear thermal rockets (NTRs) normally consist of three components: a propellant tank, a nuclear power generator, and a nozzle. As in nuclear electric rocket systems, the component that sets various NTRs apart is the type of nuclear generator used.Most systems that have been designed and tested have used a nuclear reactor to provide heat, while some others have examined the concept of radioisotope power. In the end, the determining factor for which nuclear power generator type should be used is the purpose for which the system was designed. If a nuclear thermal rocket is intended to power a mission to Mars or beyond, a nuclear reactor is a necessity as a power source.HistoryThe concept of the nuclear thermal rocket was first developed in the 1950s as a solution for safe and reliable travel to Mars. The research program subsequently developed in the late 1950s and 1960s was unprecedented for space nuclear technology. Through the program, many NTRs were designed, built, and tested. The test site for these systems was Jackass Flats, a location adjacent to what is now the Nevada National Security Site, which lies about 65 miles northwest of Las Vegas.Famous tests in the program included PHOEBUS 2A, the most powerful nuclear reactor ever to be operated, and NRX-A2, a reactor that was purposefully placed under a very fast power transient to prove its safety. Later NTRs were designed with a specific application in mind, as they were considered for the eventual final stage for the famous Saturn V rocket. Unfortunately, funding for the NTRs, and even the Saturn V rocket, eventually vanished due to a change in the nation's priorities after the Apollo lunar landings. Despite this change, the program is today considered a technical success, as the tests showed that a system could be safely built and operated.Some Reactors tested in Rover Program -- Space Nuclear Power by Angelo and BudenAdvantagesBut why choose nuclear thermal rockets-and nuclear propulsion in general-over chemical propulsion technology, which has been used for carrying payload from earth to space for over 50 years? The answer lies in the tremendous energy density present in nuclear power, and its inherent flexibility in application. NTRs are able to heat any propellant that is pushed through its core, unlike chemical rockets that must rely on the combustion of propellant for energy transfer. Because of this feature, NTRs can heat and expel the most efficient propellant possible, which is hydrogen gas, allowing for a large reduction in the overall mass that must be carried from earth's surface to orbit.In addition, all nuclear propulsion methods are inherently capable of providing long-term electricity production. Bimodal NTRs (BNTRs) can accomplish this by coupling a dynamic power conversion system to the reactor system. These systems are designed to run an additional coolant through selected channels in the reactor core, spinning a turbine, and producing electricity. Unlike solar power, nuclear power can operate independent of its location and orientation in space, providing electricity for energy intensive life support systems and scientific equipment.Humanity's route to the solar systemNuclear power offers an unmatched capability for producing the massive amounts of energy required to travel in and out of the gravity wells of our solar system. Whether nuclear power is applied as a means of heating a propellant, as in nuclear thermal propulsion-or as a generator of electricity, as in nuclear electric propulsion-nuclear power stands as humanity's route to the solar system._____________________DeasonWes Deason is a graduate student in nuclear engineering at Oregon State University working on the safety analysis of vented fuel systems for gas-cooled fast breeder reactors. He is a former summer fellow for the Center for Space Nuclear Research and the current student liaison for the Aerospace Nuclear Science and Technology Division of the American Nuclear Society.Tags:american nuclear societyspace applicationsShare:LinkedInTwitterFacebook
Trump leaves space nuclear policy executive order for Biden teamA hot fire test of the core stage for NASA’s Space Launch System rocket at Stennis Space Center in Mississippi was not completed as planned. The SLS is the vehicle meant to propel a crewed mission to the moon in 2024. Source: NASA TelevisionAmong the executive orders President Trump issued during his last weeks in office was “Promoting Small Modular Reactors for National Defense and Space Exploration,” which builds on the Space Policy Directives published during his term. The order, issued on January 12, calls for actions within the next six months by NASA and the Department of Defense (DOD), together with the Department of Energy and other federal entities. Whether the Biden administration will retain some, all, or none of the specific goals of the Trump administration’s space nuclear policy remains to be seen, but one thing is very clear: If deep space exploration remains a priority, nuclear-powered and -propelled spacecraft will be needed.The prospects for near-term deployment of nuclear propulsion and power systems in space improved during Trump’s presidency. However, Trump left office days after a hot fire test of NASA’s Space Launch System (SLS) rocket did not go as planned. The SLS rocket is meant to propel crewed missions to the moon in 2024 and to enable a series of long-duration lunar missions that could be powered by small lunar reactor installations. The test on January 16 of four engines that were supposed to fire for over eight minutes was automatically aborted after one minute, casting some doubt that a planned November 2021 Artemis I mission can go ahead on schedule.Go to Article
New U.S. space nuclear policy releasedAn artist's concept of a fission power system on the lunar surface. Image: NASAA national strategy for the responsible and effective use of space nuclear power and propulsion (SNPP)—Space Policy Directive-6 (SPD-6)—was released by the White House on December 16 as a presidential memorandum.Space nuclear systems include radioisotope power systems and nuclear reactors used for power, heating, or propulsion. Nuclear energy can produce more power at lower mass and volume compared to other energy sources and can shorten transit times for crewed and robotic spacecraft, thereby reducing radiation exposure in harsh space environments. SPD-6 establishes a road map for getting space nuclear systems into service and sets up high-level goals, principles, and federal agencies’ roles and responsibilities.Go to Article
NASA work on lattice confinement fusion grabs attentionAn article recently published on the IEEE Energywise blog heralds “Spacecraft of the Future,” which could be powered by lattice confinement fusion. While lattice confinement fusion is not a new concept and is definitely not ready for practical applications, it has been detected within metal samples by NASA researchers at the Glenn Research Center in Cleveland, Ohio, using an electron accelerator–driven experimental process.Go to Article
One small step for fission—on the Moon and beyondA reliable energy source is critical for long-duration space exploration. NASA, targeting launch readiness by the end of 2026, has teamed up with the Department of Energy and Idaho National Laboratory to solicit realistic assessments of fission surface power systems designed for deployment on the Moon that could, with little modification, be sent to Mars as well.Go to Article
Experimental Breeder Reactor I: A retrospectiveIn the not-so-distant 20th century past, our planet was in an uncertain new-world order. The second of two major wars had dramatically reshaped the landscape of the world's nations. It was not by any means assured that the extraordinary nuclear process of fission, which itself had been discovered mere years before the second war's end, would be successfully utilized for anything but the tremendous and frightening powers realized in thermonuclear warheads. In the years following, a humble project materializing out of the National Reactor Testing Station in Idaho was to challenge that assertion and demonstrate that nuclear fission could indeed be a commercial, peaceful source of electrical power for civilizations around the globe.Go to Article
Be the change you want to see in the worldWhat does it mean to be a leader? That question is at the heart of the Young Professionals Congress 2019 (YPC19).Go to Article
RadioNuclear 22: HBO’s Chernobyl: A Setback or Opportunity? Episode 22 of RadioNuclear is now available. In this episode, we discuss the recent miniseries "Chernobyl", which recently concluded on HBO. We debunk some of the more egregious articles written in the wake of the show (see links to these articles below). We also discuss good ways to engage with individuals who are captivated with the show, and not necessarily familiar with nuclear technology.Go to Article
Advocating for Nuclear with the NESDSometimes it feels like we're fighting an uphill battle for nuclear energy - and perhaps we are.Go to Article
Honoring Dr. Leona Woods - #HerstoryDuring March's Women's History Month, I honor Leona Woods by telling #herstory.Go to Article
New Year, New Committee, Diversity and Inclusion in ANSAs I write this, I'm excited to know the future of the American Nuclear Society will involve the activities and efforts of the newly formed Diversity and Inclusion in ANS (DIA) Committee. The DIA Committee was formed after the 2018 Annual Meeting by expanding the Professional Women in ANS (PWANS) committee with the inclusion of Nuclear Pride, a LGBTQA+ nuclear organization. It is dedicated to giving a voice to all underrepresented and marginalized groups within ANS, including, but not limited to, women, persons of color, the LGBTQA+ community, and people with disabilities. This new committee is the result of the combined efforts of several people over several years to ensure all of these groups, named and not named, have a voice.Go to Article