Do you really want to spend the next 501 days locked in a tiny room with your spouse, hurtling toward the Red Planet just to take a few snap shots from 100 miles away? What about competing with 10,000 people to build the first Martian colony on a “Big Brother”-style reality TV series?
What if you could just go for a few months to do some research? What if you could not only get there quickly but without any of the radiation dangers from fission or even from burning deuterium-tritium fuels?
The Direct Fusion Drive (DFD) is a novel system that we have been developing with the Princeton Plasma Physics Lab, and two weeks ago we filed a thrust-augmentation patent for the DFD. Propellant gasses such as deuterium and helium can be pumped into a gas box and weakly ionized. These flow out along the magnetic field lines of the scrape off layer and pass around the closed-field region of the field-reversed configuration. Fusion products fly out into the scrape off layer at 25 millions meters a second and collide with the propellant, heating it up (and therefore speeding it up), and then everything gets ejected through the magnetic nozzle.
If propellant wasn’t added, then the fusion products would give the spacecraft a velocity of around 25 million meters per second but would provide only a fraction of a Newton. By adding propellant, the exhaust velocity drops directly proportional to the thrust. An exhaust velocity of a few dozen km per second is sufficient for many missions and therefore tens and even hundreds of newtons of thrust can be achieved.