HEY, HOT STUFF
Step aside, solids, liquids, and gases. Plasma has arrived, and former astronaut Franklin Chang Diaz, who has been to space seven times on conventional chemical rockets, wants to travel with plasma. "If you heat a gas enough, the atoms break apart, and you get plasma. It's a fourth state of matter that's really, really hot. Plasma is everywhere in space," he says. "It's what our stars and sun are, really."
The hotter the exhaust, the zippier the rockets. Right now, rocket exhaust is in the thousands of degrees. "That's a pretty cold fuel," says Chang Diaz. "Plasma exhaust will be millions of degrees hot."
He's talking about fueling an ionically souped-up engine that can shift gears through space and get humans to Mars in three or four months instead of the minimum 10 months projected for chemical rockets. Better travel speed could greatly reduce the wearying weeks of boredom, the bone weakening of weightlessness, and the dangerous levels of exposure to solar radiation that space travelers face on long trips.
The plasma rocket is too hot (by just a few million degrees) to launch from Earth. One idea is to assemble it in space, like the ISS. Current plans to heat the plasma are for the power source to be electrical - possibly converting solar energy for close to Earth and using nuclear reactors for deep space.
Rockets are what have gotten all those satellites, spaceships, andpeople to Earth's orbit and outer space in the past, so building abetter rocket is the most pressing concern, Chang Diaz believes.Harnessing plasma energy, he says, is one way "to give the UnitedStates a capability no one else has, and that will get us ahead ofthe game."
VASIMR (Variable Specific Impulse Magnetoplasma Rocket) wasresearched at MIT, found a home at NASA's Advanced Propulsion Lab,and is now in the creative custody of Chang Diaz's company, AdAstra (Latin for "to the stars"). Both NASA and Ad Astra will shareintellectual property rights in what Chang Diaz considers anall-win situation for government, the private sector, and hiscompany. Ad Astra is hoping their prototype business arrangementwith NASA will fuel not only future rockets but fasterimplementation.
"I think we are witnessing the birth of commercial spacetransportation," says Chang Diaz. "Something similar happened inthe '30s and '40s with the explosion of air travel."
Hundreds of years ago, sails caught the earth's winds to propel amajor era of exploration. Today, a growing group of people envisionsails propelling voyagers in a new age of discovery throughout theuniverse.
There is no air in the void of space, but light particles calledphotons can push against a very thin, reflective material. Unlike atraditional rocket's short bursts of thrust via heavy toxic fuels,sunlight applies a continuous thrust. Changing the angles of sailscan adjust attitude and direction. Proponents say initial speedswould be very slow, but a space sail craft could reach speeds of36,000 mph in a year, and 100,000 mph (2.4 million miles in a day)in three years.