A Spacecraft Could Get to Titan in Only 2 Years Using a Direct Fusion Drive
by Andy Tomaswick | Universe Today
Fusion power is the technology that is thirty years away, and always will be – according to skeptics at least. Despite its difficult transition into a reliable power source, the nuclear reactions that power the sun have a wide variety of uses in other fields. The most obvious is in weapons, where hydrogen bombs are to this day the most powerful weapons we have ever produced. But there’s another use case that is much less destructive and could prove much more interesting – space drives.
The concept fusion drive, called a direct fusion drive (or DFD) is in development at the Princeton Plasma Physics Laboratory (PPPL). Scientists and engineers there, led by Dr. Samuel Cohen, are currently working on the second iteration of it, known as the Princeton field reversed configuration-2 (PFRC-2). Eventually the system’s developers hope to launch it into space to test, and eventually become the primary drive system of spacecraft traveling throughout our solar system. There’s already one particularly interesting target in the outer solar system that is similar to Earth in many ways – Titan. Its liquid cycles and potential to harbor life have fascinated scientists since they first started collecting data on it. And if we properly utilized the DFD, we could send a probe there in a little under two years, according to research done by a team of aerospace engineers at the Physics department of the New York City College of Technology, led by Professor Roman Kezerashvili and joined by two fellows from the Politecnico di Torino in Italy – Paolo Aime and Marco Gajeri.
Though still under development, the engine itself utilizes many of the advantages of aneutronic fusion, most notably an extremely high power to weight ratio. The fuel for a DFD drive can vary slightly in mass and contains deuterium and a helium-3 isotope. Even with relatively small amounts of extremely powerful fuel, the DFD can outperform the chemical or electric propulsion methods that are commonly used today. The specific impulse of the system, which is a measure of how effectively an engine uses fuel, is estimated to be comparable to electrical engines, the most efficient currently available. In addition, the DFD engine would provide 4-5 N of thrust in low power mode, only slightly less than what a chemical rocket would output over long periods of time. Essentially the DFD takes the excellent specific impulse of electric propulsion systems and combines it with the excellent thrust of chemical rockets, for a combination that melds the best of both flight systems.