The National Aeronautics and Space Administration (NASA) will launch a nuclear-powered spacecraft to Mars for the first time. The goal is to verify whether a nuclear propulsion craft can be used for deep-space exploration. The nuclear propulsion craft plans to send three helicopters down to Mars.
NASA announced at its Washington, D.C., headquarters on the 24th (local time), "We will launch the nuclear-powered spacecraft 'Space Reactor-1 Freedom' to Mars before the end of 2028." Until now, a nuclear-powered spacecraft has never been launched.
◇Generate propulsion electricity with fission energy
A nuclear-powered spacecraft operates in the same way as a nuclear power plant. Nuclear power generation uses the enormous heat energy produced by the chain reaction of uranium fission to boil water and create high-temperature, high-pressure steam. This steam turns a turbine and drives a generator to produce electricity.
A nuclear-powered spacecraft uses the electricity produced in the same way to create electrically charged ions. Applying the opposite charge at the end of the nozzle makes the ions move in that direction, generating thrust. This is the so-called nuclear electric propulsion (NEP) method.
NASA said the Space Reactor-1 Freedom mission will demonstrate that nuclear propulsion can power a spacecraft and will invigorate the industrial base for future fission power systems. This could include exploration missions to planets or celestial bodies in the outer solar system.
Conventional spacecraft cannot explore such distant bodies. They cannot carry the enormous quantities of liquid fuel required. Only small spacecraft powered by batteries or solar energy, like Voyager or Juno, have been able to reach the outer regions of the solar system.
The unmanned probe Voyager, launched by NASA in 1977, is powered by a nuclear battery called a radioisotope thermoelectric generator (RTG). The heat produced as a radioisotope undergoes radioactive decay is converted into electricity through a thermoelectric module. A thermoelectric module is a device that generates current when its temperature changes.
Thanks to its nuclear battery, Voyager is operating even at the edge of the solar system, where solar panels are useless. The Jupiter probe Galileo, the Saturn probe Cassini, and the Mars exploration rover Curiosity also used the same battery. The nuclear-powered spacecraft announced this time differs in principle from a nuclear battery in that it uses the same method as a commercial nuclear power plant.
◇Collect data for crewed exploration sites with three helicopters
The nuclear-powered spacecraft plans to arrive at Mars and deploy the Skyfall payload carrying three helicopters. In 2021, NASA landed the Perseverance rover, which moves on four wheels, and the ultra-small unmanned helicopter Ingenuity on Mars. There had been Mars exploration robots before, but a helicopter flying in the Martian sky was a first. The rover is still operating, but the helicopter crashed in Jan. 2024 and its mission ended.
NASA said the helicopters to be sent by the nuclear propulsion craft will be modeled after Ingenuity. Ingenuity conducted 72 flights from April 2021 to Jan. 2024. While Ingenuity was for a technology demonstration, the Skyfall helicopter formation is expected to carry out concrete scientific exploration missions.
Earlier, U.S. space company AeroVironment said in a statement on July 24 last year, "We have designed Skyfall to deploy six reconnaissance helicopters on Mars," adding, "The helicopters will explore several sites selected as top-priority landing candidates for America's first Mars astronauts." According to the webcast NASA released that day, the number of helicopters carried by Skyfall has been reduced to three.
AeroVironment said, "Each helicopter will operate independently while exploring Mars," adding, "By transmitting high-resolution surface imagery and subsurface radar data to Earth for analysis, they will help ensure that crewed landers can safely touch down in regions richest in water, ice, and other resources."
◇Three-phase plan to build a crewed lunar base also unveiled
NASA Director General Jared Isaacman said the plan for the next 10 years aims to restore Americans' confidence in space exploration missions. NASA has resumed crewed lunar exploration, halted since Apollo 17 in 1972, through the Artemis program.
Artemis II, set to launch on the 1st of next month, will, for the first time, carry four astronauts on a test flight around lunar orbit. Earlier, in 2022, the Artemis I mission conducted an uncrewed test flight with the Orion spacecraft orbiting the Moon carrying mannequins.
Astronauts' lunar landing has been revised to 2028. Artemis III, which was originally scheduled to land astronauts on the Moon, will test docking with the lunar lander in Earth orbit in 2027, and the following year Artemis IV will land astronauts on the Moon. NASA said, "Starting with Artemis V, we plan to land a crewed lander on the Moon every six months."
NASA also said it will move in earnest to build a crewed lunar base. Director General Isaacman told space corporations, officials from space agencies of various countries, and lawmakers, "There will be an evolutionary process to build humanity's first permanent surface outpost beyond Earth."
NASA announced it will pursue a phased approach to secure a sustained human foothold on the Moon. As part of this strategy, it said it will temporarily pause the Gateway lunar space station project that had been underway and shift its focus to building infrastructure that supports continuous surface exploration of the Moon.
In phase one, privately led corporations will send lunar landers, rovers, and instruments. This includes nuclear batteries. Phase two will establish semi-habitable infrastructure and a regular logistics supply system to support astronauts' surface activities on the Moon.
At this stage, lunar rovers will shift from open to pressurized. The pressurized rover from the Japan Aerospace Exploration Agency (JAXA) is also included in phase two. In the past, Apollo astronauts rode rovers that only had wheels, but the Artemis pressurized rover being developed by Japanese automaker Toyota has a roof, allowing boarding without spacesuits.
Phase three is the process of establishing a full-fledged foundation for long-term stays. The lander will transport astronauts and cargo together to secure a sustained foothold on the Moon. This phase includes a multipurpose habitation module under development by the Italian Space Agency (ASI) and a multipurpose lunar rover from the Canadian Space Agency (CSA).
NASA (2026), https://www.nasa.gov/news-release/nasa-unveils-initiatives-to-achieve-americas-national-space-policy/
AeroVironment (2025), https://www.avinc.com/resources/press-releases/view/av-reveals-skyfall-future-concept-next-gen-mars-helicopters-for-exploration-and-human-landing-preparation