US government is developing a nuclear rocket to send satellites between Earth and the Moon

The US government is developing a nuclear rocket to send satellites into the vast area between the Earth and the Moon, in a renewed space race with China. 

The rocket, which is being developed for the government by the Defense Advanced Research Projects Agency (DARPA), will have a nuclear thermal propulsion engine.

The engine uses a small nuclear reactor to generate heat from uranium that is then transferred to a liquid propellant which expands into a gas and generates thrust after being shot through a nozzle at the back of the craft.

DARPA says the nuclear rocket will be used to move and position satellites between low-Earth orbit and the Moon, after being carried into orbit by a traditional chemical rocket.

According to a report by the Daily Beast, the goal is to have an operating spaceship in ‘cislunar’ space before China gets there with its own craft. 


NASA is working on a similar type of Nuclear Propulsion Engine that could be used to get humans to Mars in about 100 days


Nuclear Thermal Propulsion (NTP) systems have been around since the 1950s but are only now starting to come into their own. 

They allow for more efficient, lower weight and faster manoeuvring of satellites or spaceships.

The system involves placing a small nuclear reactor on the spacecraft to generate heat from uranium fuel. 

The thermal energy produced is then transferred to a liquid propellant such as liquid hydrogen. 

That then expands into a gas and is shot out through a nozzle at the back of the craft to produce thrust.

That thrust gets the exhaust moving very fast and moves the spacecraft forward. 

It would replace a similar thrust process in existing satellites and ships derived from chemical engines – but is able to go further, faster and with less fuel on board. 

DARPA has allocated $158 million (£122 million) for space technology research in 2021 – including the nuclear engine and robots to service satellites.

The development of the nuclear rocket comes from an allocated $21 million (£16million) to build the first components. 

A spokesperson for DARPA said the rocket will ‘enhance domestic operations to a new high-ground, which is in danger of being defined by the adversary.’ 

They say the nuclear engine will allow them to move satellites further, faster and with less fuel than conventional chemical engines currently on board the spaceships. 

This is the second year the agency has allocated funds to the nuclear engine program – in the 2020 budget they allocated $10 million for an early study. 

The engine has been called the Demonstration Rocket for Agile Cislunar Operations (DRACO) and the 2021 funds allow for the first components to be developed. 

DRACO will be developed and a test version built by DARPA before it is handed over to the US Air Force, who will operate it in space. 

A number of space agencies including in the US, China and Europe – as well as private companies – have been working on operations aimed at mining the Moon.

This will allow them to extract minerals that could be used to support longer missions including those to Mars and beyond.  

DRACO is almost identical to a NASA program that has been in development for the past few years aimed at making trips to Mars quicker and cheaper.

Copernicus, the theoretical NASA spacecraft, would speed up travel time between Earth and Mars and be lighter due to having to carry less fuel.

The type of rocket being developed by NASA and DARPA is described as a ‘high-assay low-enriched uranium nuclear-thermal propulsion system.’ 

This basically means a small nuclear reactor heats liquid hydrogen that expands and shoots out of the thruster – pushing the craft in the opposite direction.

‘We’re looking at nuclear thermal as a key technology because it can enable faster transit times,’ Joe Cassidy from Aerojet Rocketdyne, a company working on the lunar gateway space station told the BBC. 

‘If we can cut transit time [to Mars] down by 30-60 days, it will improve the exposure to radiation facing the crew.’ 

The engines won’t launch craft from the Earth’s surface – this will still be carried out by conventional chemical rockets. They are specifically designed for travelling long distances in space.  

In the nuclear engines a small nuclear reactor heats liquid hydrogen that expands and shoots out of the thruster - pushing the craft in the opposite direction

In the nuclear engines a small nuclear reactor heats liquid hydrogen that expands and shoots out of the thruster – pushing the craft in the opposite direction

The renewed space race between the US and China has been heating up recently and the Moon appears to be a target. 

In 2019 China landed the first-ever probe on the far side of the Moon and are working on possibly sending humans to the Moon within the next few years.

NASA are also working on having boots on the Moon’s surface within the next few years as part of the Artemis mission – that will see the first woman land on the Moon. 

If things go to plan Artemis will see an American land on the Moon in 2024 – more than 50 years after the last visit in 1972.

NASA is also working to build a $30 billion manned space station in cislunar space that would act as a staging post for return trips to the Moon – it is being built in collaboration with other space agencies including the European Space Agency ESA. 

DARPA says parts of DRACO could be launched into Earth orbit on top of traditional chemical rockets and then assembled in space.

‘Compared to chemical propulsion systems, the performance advantages of NTP can enable shorter total mission times and enhanced flexibility for crewed Mars missions,’ Clare Skelly, a NASA spokesperson, told The Daily Beast. 

For the US Military a nuclear propulsion engine provides more manoeuvrability in spy and military satellites – meaning they can be repositioned without eating through huge amounts of on board fuel, according to expert Dale Thomas.


NASA has been using nuclear material to power spacecraft for decades.

In 1960 a satellite programme called TRANSIT, used to guide missiles from space, was the first to use plutonium isotopes to create batteries.

These work by wrapping the plutonium with thermoelectrics, that turn the heat given off by the decaying isotope into electricity.

Nasa also used plutonium batteries on its failed Nimbus B1 satellite, which blew up on launch.

In 1972 and 1973 Nasa then launched its Pioneer space probes, which used 155-watt nuclear batteries to keep them powered as they travelled to the very edge of the solar system.

The Viking landers, which touched down on Mars for the first time in 1976, also used plutonium batteries to power their experiments.

The Voyager probes, which have become the first manmade objects to leave the solar system, also relied upon three plutonium-238 batteries that have allowed them to communicate with Earth for 36 years.

The Ulysses sun probe also used a nuclear battery to keep the spacecraft operating while it performed a slingshot around Jupiter.

The Galileo spaceprobe to Jupiter’s moons also used two nuclear batteries to give it 570 watts of power.

The Cassini space probe to Saturn carried the largest nuclear battery every launched, weighing 72lbs.

In 1959, Nasa began work with the US Atomic Energy Commission to develop a nuclear powered rocket to carry astronauts into space, but the project was ended in 1973 at the same time as the Apollo space missions.