Space Reactor-1 Freedom (SR-1) is a proposed NASA spacecraft intended to be the first nuclear fission-powered interplanetary mission and to demonstrate nuclear electric propulsion in deep space.[1] Announced in March 2026, the spacecraft would combine a closed Brayton cycle fission reactor generating more than 20 kW of electrical power with the Power and Propulsion Element (PPE) previously developed for the Lunar Gateway space station.
 Rendering of Space Reactor-1 Freedom | |
| Mission type | Nuclear electric propulsion technology demonstration |
|---|---|
| Operator | NASA |
| Spacecraft properties | |
| Manufacturer |
|
| Power | >20 kW of electrical power from reactor |
| Start of mission | |
| Launch date | 2028 (planned) |
Proposed technical specifications
editThe fission reactor is to be fueled by high-assay low-enriched uranium (HALEU), using uranium dioxide fuel encased in a boron carbide radiation shield, and will use existing designs for the Department of Energy's research reactors.[2][3]
For propulsion, the PPE is equipped with four 6 kilowatt (kW) Hall-effect thrusters built by Busek and three 12 kW Advanced Electric Propulsion System Hall-effect thrusters developed by NASA and Aerojet Rocketdyne.[4][5]
Proposed missions
editSR-1 is proposed for launch in December 2028 on a trajectory to Mars.[3] It will demonstrate the technology to potentially reduce travel time, but will not at this size be significantly faster than previous probes.[6] At Mars it would deploy the Skyfall payload—an entry capsule carrying three Ingenuity-class helicopters to scout potential landing sites for future human missions and survey subsurface water ice.[7]
The mission, jointly sponsored by NASA and the United States Department of Energy, is intended to demonstrate nuclear propulsion and power technologies for sustained exploration beyond the Moon, including future missions to Mars and the outer Solar System. Data from SR-1 is also expected to support development of Lunar Reactor-1 (LR-1), a fission surface power system designed to provide continuous energy for a lunar base during periods without sunlight.[8]
Funding and management
editThe FY2027 presidential budget request gave little to no prominence to Space Reactor-1 Freedom; however, in an April 3, 2026 message to NASA employees, Administrator Jared Isaacman listed “launching SR-1 Freedom” among NASA’s priorities upon responding to that request, while Sen. Jerry Moran (R-KS), the chair of the Senate appropriations subcommittee that funds NASA, said he opposed proposed cuts to parts of NASA’s budget and would seek to fund the agency at FY2026 levels, particularly nuclear propulsion.[9][10][2] At the same time, the U.S. Office of Science and Technology Policy issued NSTM-3, the National Initiative for American Space Nuclear Power. The memorandum directed NASA to initiate a program for a mid-power space reactor with a lunar fission surface power variant and an option for a space variant for a nuclear electric propulsion demonstration, and to prioritize integrated FSP and NEP designs using common elements, including reactor hardware and nuclear fuel to be potentially used on SR-1 Freedom.[11] SpacePolicyOnline reported that the memorandum focused principally on FSP and NEP for NASA and directed work on common NEP/NTP components for initial use on a potential NEP demonstrator.[12]
In May 2026, the House Appropriations Committee's fiscal year 2027 Commerce, Justice, Science, and Related Agencies report recommended $50 million for nuclear electric nuclear propulsion development and stated that NEP would play a critical role in advancing Space Reactor-1 Freedom with $10 million.[13] Later that month, NASA Administrator Jared Isaacman said NASA would centralize authority for space nuclear activities under a Space Reactor Office, direct that office to prepare an integrated program plan for SR-1 Freedom and LR-1 within 60 days, and sustain common enabling technologies for SR-1, LR-1, NTP, and future missions.[14]
On June 2, 2026, NASA announced it is working on a streamlined management approach for its development, tailoring that to the needs to allow them to go faster.[2]
References
edit- ↑ Low, Lauren E. (March 24, 2026). "NASA Unveils Initiatives to Achieve America's National Space Policy". NASA. Retrieved March 24, 2026.
- 1 2 3 Foust, Jeff (June 4, 2026). "NASA working to streamline development of nuclear electric propulsion demo mission". SpaceNews. Retrieved June 9, 2026.
- 1 2 Caton, Ryan; Bergin, Chris (March 24, 2026). "NASA unveils Space Reactor-1 Freedom mission to Mars in 2028". NASASpaceflight. Retrieved March 25, 2026.
- ↑ Cassady, R. Joseph; Wiley, Sam; Jackson, Jerry (October 2018). Status of Advanced Electric Propulsion Systems for Exploration Missions (Report). Aerojet Rocketdyne. Archived (PDF) from the original on June 13, 2019. Retrieved March 26, 2026.
- ↑ "Maxar and Busek Thruster System for NASA Lunar Gateway Passes Critical Milestone". PR Newswire (Press release). Retrieved April 28, 2021.
- ↑ Chang, Kenneth (March 24, 2026). "NASA Sets Out New Plans and Timelines for Moon Base and Nuclear Mars Mission". The New York Times. Retrieved April 1, 2026.
- ↑ Clark, Stephen (March 25, 2026). "Here is NASA's plan for nuking Gateway and sending it to Mars". Ars Technica. Retrieved March 25, 2026.
- ↑ "America Underway in Space on Nuclear Power" (PDF). NASA. March 24, 2026. Retrieved March 25, 2026.
- ↑ Foust, Jeff (April 13, 2026). "Key Senate appropriator rejects proposed NASA budget cuts". SpaceNews. Alexandria, Virginia: SpaceNews. Retrieved April 14, 2026.
- ↑ Cowing, Keith (April 3, 2026). "Isaacman Letter To NASA On FY 2027 Budget". NASA Watch. NASA Watch. Retrieved April 14, 2026.
- ↑ "National Initiative for American Space Nuclear Power" (PDF). The White House. Washington, D.C.: Office of Science and Technology Policy. April 14, 2026. Retrieved May 24, 2026.
- ↑ Smith, Marcia (April 14, 2026). "White House Releases Space Nuclear Initiative". SpacePolicyOnline.com. Space and Technology Policy Group, LLC. Retrieved May 24, 2026.
- ↑ "Commerce, Justice, Science, and Related Agencies Appropriations Bill, 2027" (PDF). House Appropriations Committee. Washington, D.C.: United States House of Representatives. May 13, 2026. Retrieved May 24, 2026.
- ↑ Isaacman, Jared (May 22, 2026). "A Message From Administrator Jared Isaacman". NASA Workforce Updates. Washington, D.C.: NASA. Retrieved May 24, 2026.
External links
edit
Media related to Space Reactor-1 Freedom at Wikimedia Commons
