While policy-makers discuss the benefits of manned spaceflight to the moon and beyond, scientists and engineers are considering how to protect astronauts from the harsh realities of space. During the Apollo era, when astronauts went to the moon, the sun emitted one of the largest bursts of energetic charged particles on record. Luckily, this occurred between the Apollo 16 and 17 missions, on 2nd August 1972; otherwise, if the astronauts had been on a moon walk, they would have received a life threatening dose of radiation. Today, solar energetic particle (SEP) events are recognised as one of a wide range of hazards affecting astronauts, spacecraft, aviation, and ground-based technology that is referred to as space weather.