Nasa

For all its real-life benefits and future potential for saving our entire civilisation, space travel is still a long-term effort. Current estimates from Nasa put travel time to Mars for humans at five months, at the absolute best. Slowing down once you're there in order to actually land is even harder.

Now Nasa engineers are wondering if there might be a way to solve that problem without even leaving Earth.


Philip Lubin, a scientist at Nasa, has set out one possible answer in a video for Nasa 360. Lubin proposes a system which uses 'photonic propulsion' that he says could get us to Mars in just three days. And which, put simply, is more or less a giant laser designed to push spacecraft to incredible speeds.

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Photonic propulsion, as it is properly known, is a theoretical system that would use particles of light to propel objects through space. Though particles of light have no mass, they do have energy and momentum -- and it's this energy that, when reflected off an object, is transferred into a push. With a large, reflective sail, Lubin suggests, it would be "possible to generate enough momentum to accelerate a spacecraft" via lasers pulsing light from the surface of the Earth. This could, he says, get a "100 kilogram robotic craft to Mars in three days". A craft occupied by humans would take slightly longer -- but at a month, it would still be significantly shorter than current transit estimates.

The added benefit is that very little fuel would be required on board the craft itself -- keeping weight, and cost, to a minimum.

Lubin supposes that the system could propel crafts to an "unheard of" 30 percent the speed of light. "There is no known reason why we could not do this," said Lubin.

Lubin notes that the system would work best on unmanned spaceships -- robots are better equipped to explore deep space, he says, and the systems would work better if they were "wafer thin". Sending AI to solar systems so quickly would still have "huge benefits", though. It's possible that we might be able to explore potentially habitable planets outside our Solar System -- though communicating with craft around even our nearest neighbouring star, Alpha Centauri (distance: four light years), would still pose enormous technical problems.


The photonic propulsion theory joins a number of other projects seeking to send us into space faster. Ryan Weed, speaking at WIRED 2015, detailed his plans to create an "antimatter rocket" which, according to him, could "loop Earth in three seconds" and reach Mars in a matter of weeks.

His plan is also to reach Alpha Centauri -- which, using traditional technology, would take 30,000 years.

Weed's antimatter rocket would power spacecraft with 'annihilation', which is the energy created when positrons and electrons come into contact. It could, he says, reach speeds of up to 72 million miles per hour.