updated 2/15/2011 8:18:29 AM ET 2011-02-15T13:18:29

Overcoming gravity is not easy. Conventional rockets are 97 percent fuel and tanks. Even NASA's mighty Saturn 5 moon launchers had just 3 to 5 percent available for payloads.

A new technology under study would use ground-based lasers or microwaves to zap a heat exchanger on the rocket, releasing more energy from the fuel. The heat exchanger works like a hot plate, spiking the temperature of the fuel to more than 3,100 degrees Fahrenheit (1,704 degrees Celsius), which significantly increases the rocket's thrust.

"The objective is to reduce the cost of getting into space. The way this rocket works, it has a more energetic propulsive system than one where you have fuel and oxidizer that release energy," Carnegie Mellon University's Kevin Parkin, head of the Microwave Thermal Rocket project at NASA's Ames Research Center in California, told Discovery News.

The biggest stumbling block is not technical, but financial. Startup costs to build the ground facility would be high, but supporters say overall launch costs would be sharply reduced.

"It only makes sense economically if you're going to launch a large number of payloads," said physicist Jordin Kare, who pioneered the technology while working at Lawrence Livermore National Laboratory.

"Some alternatives to conventional launchers really are highly desirable. It may be time to at least do some development work to see if this is at least potential," Kare, who is now an independent consultant based in Seattle, told Discovery News.

The technology is most suited to payloads weighing around 100 kilograms (220 pounds), but it would be capable of thousands of launches per year so larger spacecraft could be assembled and refueled in orbit. Think of it like a pipeline instead of a ship, Kare points out.

Thermal beamed systems also would be safer than today's rockets. First, the vehicles are very simple, so there is not much that can fail. Second, they are not explosive.

"The notion of the rocket where engines can be working but avionics fails doesn't exist. It can't go anywhere the laser isn't pointed. And it can't explode in the way that rockets occasionally do. There just isn't the energy onboard," Kare said.

"Also, because it's high rate launch system, you can do far more testing than you can on any other system," he added. "You can launch thousands of times before you launch a person or a high-value payload."

With only hydrogen as exhaust, the system is environmentally friendly, though there may be an issue with birds flying through the lasers or microwave beams as they track the rocket into space.

NASA's Glenn Research Center in Ohio is conducting a study to assess the viability of beamed energy propulsion for space launches. The study is expected to conclude next month.

© 2012 Discovery Channel


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