Sometimes, even with decades of research and testing, a project never gets off the ground. That has been the case for U.S. nuclear thermal rockets—so far. Research began in the 1950s and peaked with a series of rigorous ground tests for NERVA—the Nuclear Engine for Rocket Vehicle Applications—before the program was canceled in 1973. Five decades on, this technology has yet to make it to the launchpad. But while mission priorities shift, the physics is solid: Fission-powered nuclear thermal rockets (NTRs) still offer two to five times greater efficiency than conventional rockets.

This year the American Nuclear Society’s Nuclear and Emerging Technologies for Space (NETS 2023) conference, which will be held May 7–11, 2023, in Idaho Falls, Idaho, is focusing on powering the next era of space exploration through nuclear-enabled technologies and is sure to be the can’t-miss event of the year for those in the aerospace community.

A “resurgence of interest” in nuclear propulsion for space missions is described in a new article authored by science writer Jon Kelvey for the American Institute of Aeronautics and Astronautics’ (AIAA’s) Aerospace America website. The focus of Kelvey’s article is nuclear thermal propulsion (NTP), which, according to the Department of Energy, “could significantly reduce travel times and carry greater payloads than today’s top chemical rockets­—giving humans a great chance of exploring deep space.”

It’s Thursday, meaning it’s time to dig through the Nuclear News archives for another #ThrowbackThursday post. Today’s story goes back 60 years to the January 1963 issue of NN and the cover story “Review of Rover: A nuclear rocket” (p. 9), which reviews the first phase of the nuclear rocket program from Los Alamos National Laboratory.

Some quick digging online uncovers a lot of information about Project Rover, most notably, a short 20-minute film on the LANL YouTube page that reviews the project (Historic 1960s Film Describes Project Rover). The description of the video notes that the project was active from 1955 to 1973 and led to the design of multiple reactors suitable for testing, including Pewee 1, and that NASA has a modern nuclear thermal propulsion project based on the Pewee design. So it seems fitting to revisit Project Rover, given that there is today a lot of renewed interest in nuclear propulsion for space exploration.

The opening line from the January 1963 article seems to ring true today— “Provided the U. S. continues her space efforts, nuclear-powered rockets are inevitable”—although that probably didn’t seem likely to the nuclear community after the country’s attention shifted from the Space Race to the Vietnam War in the early 1970s when Project Rover was canceled. The introduction to the article lays out the argument for a nuclear-powered rocket and provides a review of the program since its launch in 1955.

The full article as it appeared in 1963 is reprinted below, but don’t forget, all ANS members have full access to the Nuclear News archives that has decades of great content about all topics on nuclear science and technology. Happy reading!

Just this last April, President Biden officially commissioned the USS Delaware, a new Virginia-­class nuclear attack submarine, the 18th built in that class and the eighth and final Block III Virginia-­class submarine. (The Delaware was administratively commissioned in April 2020, but the COVID-­19 pandemic caused delay of the ceremony for two years.)

Connecting nuclear engineers and scientists with space exploration missions has been a focus of the American Nuclear Society’s Aerospace Nuclear Science and Technology Division since its creation in 2008. One of the main ways those connections are made is through the Nuclear and Emerging Technologies for Space (NETS) conference, which the division supports in conjunction with the National Aeronautics and Space Administration.

The Naval Academy ANS student section, with support from the Washington, D.C., local section, held its semiannual dinner on March 29 in Annapolis, Md. The event was attended by more than 100 people, including midshipmen, professors from the U.S. Naval Academy, local ANS members, and ANS President Steve Nesbit.

The evening’s program was hosted by the student chapter president, Midshipman First Class Sara Perkins, and was headlined by the director of the Naval History and Heritage Command, Rear Admiral (retired) Samuel Cox.

NASA and Idaho National Laboratory have just opened a competitive solicitation for U.S. nuclear and space industry leaders to develop innovative technologies for a fission surface power system that could be deployed on the surface of the moon by the end of the decade. Battelle Energy Alliance, the managing and operating contractor for INL, issued a request for proposals and announced the news on November 19. Proposals are due February 17.

NASA’s Mars 2020 Perseverance rover took its first drive on the surface of Mars on March 4, traversing 21.3 feet and executing a 150-degree turn in about 33 minutes. The drive was one part of an ongoing check and calibration of every system, subsystem, and instrument on Perseverance, which landed on Mars on February 18.

The NASA team has also verified the functionality of Perseverance’s instruments, deployed two wind sensors, and unstowed the rover’s 7-foot-long robotic arm for the first time, flexing each of its five joints over the course of two hours.

With relatively little fanfare, the functionality of Perseverance’s radioisotope thermoelectric generator (RTG)—assembled at Idaho National Laboratory and fueled by the decay of plutonium-238—is also being proved. It is reliably providing the power that Perseverance’s mechanical and communication systems require.

In an article published on March 5, Axios reviews the ways the world’s maritime companies are trying to decarbonize. The maritime industry, “from ferries to freighters—is trying to navigate a once-in-a-century transition away from fossil fuels to new, cleaner means of propulsion,” the article explains.

Emissions from shipping: The article notes that the world’s economy relies on international shipping, with more than 90 percent of global trade traveling via maritime vessels. The issue, though, is that “the vessels burn about 4 million barrels of oil a day, accounting for almost 3 percent of the world’s carbon emissions.” The article then cites a United Nations report from 2018 that sets greenhouse gas reduction targets of 50 percent by 2050 compared to 2008 levels.

A 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 Television

Among 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.

A new research contract between the U.K. Space Agency and Rolls-Royce will see planetary scientists working together to explore nuclear power as an energy source for deep space missions in the decades to come. The effort is similar to one that the United States is undertaking through NASA.

"Space nuclear power and propulsion is a game-changing concept that could unlock future deep-space missions that take us to Mars and beyond," said Graham Turnock, chief executive of the U.K Space Agency, on January 12. "This study will help us understand the exciting potential of atomic-powered spacecraft, and whether this nascent technology could help us travel further and faster through space than ever before."

A “visionary view” of a nuclear thermal propulsion–enabled spacecraft mission. Image: NASA

Secretary of Energy Dan Brouillette and NASA Administrator Jim Bridenstine on October 20 signed a memorandum of understanding to continue decades of partnership between the Department of Energy and NASA and to support the goals of NASA’s Artemis program. These include landing the first woman and the next man on the moon by 2024 and establishing sustainable lunar exploration—using nuclear propulsion systems—by the end of the decade to prepare for the first human mission to Mars.

Brouillette

In remarks addressed to a meeting of the National Space Council on May 19, Energy Secretary Dan Brouillette said that the development and deployment of small modular reactors could provide sustainable power sources for space applications.