A team of scientists and researchers from UAHuntsville’s Department of Mechanical and Aerospace Engineering, Boeing and Marshall Space Flight Center’s Propulsion Engineering Lab are busy putting together a strange looking machine they’re calling the “Charger-1 Pulsed Power Generator.” It’s a key element in furthering the development of nuclear fusion technology to drive spacecraft.
The analysis of the Z-Pinch MIF propulsion system concludes that a 40-fold increase of Isp over chemical propulsion is predicted. An Isp of 19,436 sec and thrust of 3812 N-sec/pulse, along with nearly doubling the predicted payload mass fraction, warrants further development of enabling technologies.
Cortez likes to use a colorful analogy to explain the process. “Imagine using a 1-ton TNT equivalent explosive and putting it out the back end of a rocket. That’s what we’re doing here.”
Those pulses come from a bank of large capacitors, known as a Marx bank, which stores electrical charges for release on command. The wires, some composed of lithium 6 and others of lithium deuteride, provide the power pulses.
“We plug the wire array into this machine,” explains Cortez, “and a massive jolt of energy is fed into the array, which vaporizes into a plasma which we collapse into a Z-pinch.”
The Z-pinch effect, he explains, is the compression derived from the plasma’s own magnetic fields. Cassibry says the Z-pinch is “the equivalent to 20 percent of the world’s power output in a tiny bolt of lightning no bigger than your finger.”
Energy gain is another important factor in nuclear fusion propulsion where, Cortez says, “we need to get more energy from the reaction than we use to initiate it.”
That would be a major breakthrough, but Cassibry says an important milestone will be to simply achieve “break even” – the point where the energy derived from the pulse system equals the energy put into it.
Though the concept of nuclear propulsion has been around for decades, Cortez says it has only been recently that engineers have been able to create the needed reactions and control them.
“This has been the Holy Grail of energy propulsion technology. The massive payoff is that energy gain, where we get more energy out of the reaction than we put in. This is what everyone has pursued since the time we first started thinking about this.”
The researchers say Charger – 1 is an important tool that will help them ultimately achieve the goal of practical thermonuclear propulsion.
“Charger 1 won’t come close to break even, but will give us ability to conduct experiments that optimize fusion energy output,” says Cassibry. “Our ultimate goal is to build a break even fusion system that will propel humans throughout the solar system.”