Humanity has been in space for a while, but we really haven’t managed to go very far. Carl Sagan once said that “the surface of the Earth is the shore of the cosmic ocean, and recently we’ve waded a little way out, maybe ankle deep” — that was in 1980, and we haven’t risked testing the water any deeper since then.
One of the main reasons for that, though, is that space is so frustratingly massive. Voyager 1 is the fastest man-made thing ever, but 10.5 miles per second is a piffling fraction of the speed of light. Even getting to one of our nearest neighbours, Mars, would take six to eight months using conventional spaceship engines. Ideas like warp drives are still theoretical, and unlikely to be seen within our lifetimes. However, it might be possible to cut that trip to Mars down to as few as three months using a form of fusion fuel — “dilithium crystals.” Yep, just like Star Trek.
It’s not quite the same, of course. In the sci-fi series, the crystals are a rare substance that the crew spend an inordinate amount of time searching for, and their engines can use it to travel faster than the speed of light. This engine, currently under development at the University of Hunstville by a team working in collaboration with Boeing, NASA and the Oak Ridge National Laboratory, would by comparison be about twice as fast as the best current technology.
According to Txchnologist, General Electric’s online tech magazine, this fusion reactor would be fueled by “a few tonnes” of deuterium (a heavy isotope of hydrogen) and lithium-6 (a stable molecule of lithium) in a crystalline structure — hence the “dilithium crystal” claim. Technically, dilithium is a molecule with two covalently bonded lithium atoms, while lithium-6 features six bonded atoms, but we can forgive them for the temptation of using a little poetic license. When the deuterium and the lithium-6 are forced together under high pressure they undergo a fusion reaction — a process which they’re still trying to turn into a net producer of energy. While fusion isn’t yet a viable fuel source, recent developments in the field seem to indicate that we can’t be far away.
The engine, dubbed the “Charger-1 Pulsed Power Generator”, would be constructed in space along with the rest of the spaceship to avoid the tricky engineering difficulties of getting all that delicate fusion equipment up through the atmosphere — just like the International Space Station. Once ready, the reactor would be engaged, and millions of amps are passed through super-thin lithium wires in 100 nanosecond pulses — this could generate up to three terrawatts of power. Those wires vaporise into plasma, which is collapsed onto the core of deuterium and lithium-6, inducing a fusion reaction.
The energy from that would be forced out the back of the ship in a so-called “z-pinch” using a “magnetic nozzle”, a component which the team are also developing. The engine’s potential top speed? Over 100,000km/h. That’s roughly the same speed at which the Earth orbits the Sun.
However, as Business Insider points out, it’s likely that any commercial or scientific use of the technology will only be if the US army allows it, as the research is being conducted using equipment repurposed from military projects. And, again, that depends on developing a fusion reactor that generates more power than it consumes.
The dilithium of Star Trek was not merely a molecule with two atoms of lithium, though — it was always described as its own element, and a periodic table seen in one episode listed it as having atomic weight 87 (which would place it between Rubidium and Strontium if its atomic number followed normal convention, but we can probably assume that dilithium is a bit unusual and obeys laws of molecular physics as yet unknown to our primitive science).
Hopefully those astronauts trained to maintain and run these dilithium crystal fusion reactors will not suffer the ignominy of their colleagues asking that they give status reports in Scottish accents. Even if it would be quite funny.