As RAL astronomer and space scientist Barry Kellett puts it: "The engine is simple. The problem is getting the fuel."
The particle accelerator at the CERN complex in Switzerland can make anti-matter but only creates extremely small amounts. With current technology it estimates that it would take about a billion years to make a gram ... and at huge cost.
You can't store anti-matter in a can -- it would destroy the can -- so it would have to be captured and held in a magnetic field. Then you have to get it into space, and safely.
If those seemingly impossible barriers could be crossed then RAL scientist Bob Bingham estimates that a spacecraft might be able to reach half the speed of light.
"In other words, it would take eight years to get to the nearest star which is four light years away and then another four years for a signal to get back," he said.
The problem can be eased slightly by sending tiny robotic probes, which does away with the cost and complexity of looking after humans in space for considerable periods.
"If it costs $1billion for a robot camera why spend $100 billion to get someone to press the button for you?" said Kellett.
What other ways are there of powering a spaceship? Many have been proposed, including solar sails and photon laser thrusters.
NASA is encouraging new technologies with its Innovative Advanced Concepts program.
One of those studies focuses on PuFF -- pulsed fission-fusion propulsion system -- which NASA says aims to make a "radical improvement in our ability to explore destinations across the solar system and beyond."