The Direct Fusion Drive That Could Get Us to Saturn in Just 2 Years

According to experts, the right kind of propulsion technology might transport spacecraft to Saturn in about two years. The direct fusion drive (DFD), a concept being explored by Princeton Plasma Physics Laboratory, would cover the nearly billion miles between Earth and Saturn in record speed.

According to the researchers, the Princeton field reversed configuration-2 (PFRC-2) drive might be the key to feasible travel inside our solar system.

Titan, Saturn’s moon, was chosen as an appropriate target by the study team. The #1 moon in our solar system has a great deal of scientific interest because of its surface liquids, and the fact that they’re hydrocarbons means Titan could even become a refueling waystation in some far future space highway system.

Universe Today reports:
“[T]he engine itself exploits many of the advantages of aneutronic fusion, most notably an extremely high power-to-weight ratio,” a press release reads. “The fuel for a DFD drive can vary slightly in mass and contains deuterium and a helium-3 isotope. 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.”

In a way, this is a lot like how hybrid consumer vehicles are designed. There are times when electric gives the best, most efficient push, and other times when fossil fuels remain the best option. The PPPL direct fusion drive is being researched in two modes: one where it thrusts continuously, and another where, like a Prius, it thrusts just to get up to speed. The trip to Titan changes from about 2 years to about 2.5 depending on the mode.

Even a bigger spacecraft in our current vision is far smaller than family homes or enterprises on the earth, thus the reactor is quite small. “DFD employs a unique plasma heating system to produce nuclear fusion engines in the range of 1 to 10 MW, ideal for human solar-system exploration, robotic solar-system missions, and interstellar missions,” PPPL researchers wrote in 2019.

The plasma within is heated to performance temperatures by radio waves, and the design, like other rocket engines, is open on one end to generate thrust as energy rushes out extremely quickly.

For now, this design, as Universe Today jokes about all of nuclear fusion, is about 30 years away. That’s because the next favorable window for visiting Saturn’s satellites is in 2046, providing PPPL scientists a precise timeframe to aim toward. Their DFD design also has another significant advantage: it can power the ship’s interior systems.

That means the ship’s propulsion and steering, as well as life support and research, will all be driven by the same energy-efficient drive.

It will still be decades before anyone travels to the moons of Saturn. But when they do, the achievement will be . . . Titanic.