Revolutionary nuclear fusion rocket could cut interplanetary travel time

British startup Pulsar Fusion has unveiled a bold concept for a nuclear fusion-powered space rocket called Sunbird, which could one day cut the journey to Mars in half. Backed by the UK Space Agency, the rocket would use fusion propulsion to reach speeds up to 500,000 miles (805,000 kilometers) per hour — surpassing any spacecraft built so far.

While fusion power remains elusive on Earth, Pulsar believes space offers a more natural environment for it. “Fusion doesn’t want to work in an atmosphere,” says Pulsar CEO Richard Dinan, noting that conditions in space resemble those where stars naturally undergo fusion.

Unlike nuclear fission, which splits heavy atoms, fusion combines light elements like hydrogen, producing four times more energy than fission and millions more than fossil fuels, with no dangerous waste. Pulsar plans to use helium-3 fuel, which generates protons instead of neutrons for thrust — making it ideal for propulsion, though not efficient for terrestrial energy production.

Still in early development, Sunbird’s first in-orbit fusion test is targeted for 2027, with full functionality expected four to five years later. The initial demonstration — a $70 million “linear fusion experiment” — will prove the core concept. Components will be tested in orbit this year.

The idea is to launch Sunbirds into orbit like reusable docking stations, where they could meet spacecraft, shut off inefficient engines, and use fusion propulsion for interplanetary travel. Dinan envisions stations near low Earth orbit and Mars to enable rapid back-and-forth missions.

While Earth-based fusion aims to produce more energy than consumed, spacecraft don’t need that threshold — any energy output is useful for propulsion. That simplifies requirements and may fast-track fusion use in space.

Pulsar sees huge potential: a Sunbird could deliver 2,000 kg (4,400 lbs) of cargo to Mars in under six months, send probes to Jupiter or Saturn in two to four years, and even complete asteroid mining missions in half the current time.

Other companies are in the race too. Helicity Space is building fusion engines with Lockheed Martin’s support, while General Atomics and NASA are developing a fission-based reactor for space testing in 2027.

Experts agree fusion propulsion could transform space travel. “Even a Moon mission could benefit,” says Professor Bhuvana Srinivasan of the University of Washington, noting its potential to deliver a full lunar base in one mission. The challenge lies in making fusion systems lightweight and compact enough for space — no small feat, given their current scale on Earth.

Fusion rockets could eventually power missions far beyond Mars, even helping unlock resources like helium-3 on the Moon. If successful, fusion propulsion would mark a game-changing leap in human space exploration.

By Tamilla Hasanova