In January, I was fortunate to attend a much-anticipated debate between astronomer royal Lord Martin Rees and Mars exploration advocate Dr Robert Zubrin. The event at the British Interplanetary Society took on the topic of whether the exploration of Mars should be human or robotic. In a recent book called The End of Astronauts, Lord Rees and co-author Donald Goldsmith outline the benefits of exploration of the solar system using robotic spacecraft and vehicles, without the expense and risk of sending humans along for the ride. Dr Zubrin supports human exploration.