Credit: Joe Raedle/Getty Images/AFP
FROM HIS CORNER office at Ad Astra Rocket Company's headquarters near Houston, Texas, president and CEO Franklin R. Chang Díaz hatches big plans.
He may be tucked behind a row of shops and restaurants on a suburban street, but his mind is wandering the cosmos.
He envisions multibillion-dollar mining operations extracting iron, cobalt and platinum from asteroids for use in cities on the Moon and Mars.
He dreams of space infrastructures so evolved that astronauts freely roam the moons of Jupiter and Saturn. He sees parallel societies, growing bigger and richer, with Earth gradually transformed into a grand nature preserve.
But first, he confides, he hopes to trade his comfy landing pad in Houston for an office on the Moon.
If anyone can help launch a spacefaring society, it'll be Chang Díaz. The former NASA shuttle astronaut has spent more than two months in space during seven missions.
Three times he has gazed down through his helmet's mirrored faceplate at his home planet. Now he's building the rocket engine that might make his dreams of space colonisation come true.
Decades ago, Chang Díaz - who holds a PhD in applied plasma physics - concluded that chemical rockets were a dead end, owing to their modest performance specifications and huge appetite for fuel.
Voyaging in a chemical rocket is the celestial analogue of drifting around the world on a yacht that got its one burst of speed by charging out of port like an angry elephant. It's heavy, it's inflexible and it breaks all the rules of sensible travel.
So in the late 1970s he began developing an alternative technology he calls VASIMR, for Variable Specific Impulse Magnetoplasma Rocket.
In its most ambitious form, VASIMR would be a nuclear-electric rocket engine - a fission reactor with a plasma thruster that could potentially push people to the planets and back using a fraction of the propellant and time needed for a chemical rocket.
With a power plant similar to the ones on nuclear submarines, his plasma rocket could carry several people from Earth to Mars in 39 days, as opposed to what would be at least a 180-day journey on a chemical rocket, Chang Díaz says.
The savings in food, water, air, tedium and cosmic-ray exposure would be immense. In 2012, Ad Astra plans to test a prototype - using solar power rather than nuclear on the International Space Station (ISS).
An astronaut will spacewalk out to attach the 200-kilowatt (kW) engine and, if all goes well, it will bump the station into a more attractive orbit with about five newtons of thrust.
The tests will begin to indicate whether VASIMR can figure in NASA's grand plans of shuttling people and cargo to the Moon, the asteroids and Mars over the next decades.
In particular, engineers will analyse two things: how efficiently the engine uses its electricity to produce plasma, and how fast its radiator can siphon away excess heat.
if this rocket success or 100 % safe
can shoot nuclear waste no need to store