Speaking at an Aerojet Rocketdyne plant, NASA administrator Charles Bolden said the program is looking into advanced propulsion technologies that can cut the current eight-month journey to Mars “in half.” Technologies such as solar-electric propulsion are definitely in the cards, but NASA may look towards more unconventional solutions such as nuclear rockets as well. The main problem with getting humans to Mars is that, with our current liquid-fuelled rocket engines, it takes a very long time to get there; about eight months or so. If we can cut the journey in half, we significantly reduce the amount of food and water needed—which in turn cuts down the weight of the spacecraft, which in turn reduces the amount of fuel needed, which in turn feeds a very positive feedback loop. Less time in outer space means astronauts will be bombarded by less radiation too.