Could starships use cold fusion propulsion?

Voyager 1 is now leaving solar system, making it the first manmade probe to enter interstellar space. That’s quite an achievement, and it only took 30+ years. But if we’re going to get serious about boldly going where no man has gone before, and send humans beyond the solar system, we’re gonna need a cheap and plentiful energy source to help us get there.

Exactly how much energy are we talking about? Well, back in January, a paper appeared on the arXiv by Marc Millis, a former head of NASA’s Breakthrough Propulsion Physics Project, calculating the costs — in terms of energy — of a truly interstellar manned space mission. And it wasn’t good news.

For one scenario, he assumed a 500-person space ship on a one-way trip to establish a human colony on some distant exoplanet. That would require an exajoule of energy, or 1018 J, i.e., just about the same amount of energy consumed by everyone on Earth in one year.

An unmanned mission to Alpha Centauri would be even more of an energy hog, because of the need for more complicated maneuvers (deceleration, etc). That would require 1018 J. Millis figures we won’t have the ability to generate that kind of energy until 2200 for the passenger ship, and 2500 for the unmanned probe.

Scientists are mulling all kinds of options, of course, including harnessing the power of the stars, i.e., nuclear fusion (as opposed to the nuclear fission underlying nuclear power plants). As Carl Sagan once noted, «Every time you look up at the sky, every one of those points of light is a reminder that fusion power is extractable from hydrogen and other light elements, and it is an everyday reality throughout the Milky Way Galaxy.»

There’s just one problem. We can achieve hot nuclear fusion, but recreating the intense temperatures and pressures that exist inside stars currently requires more energy than it gives back, so it’s economically unfeasible, and pretty much an energy sinkhole for the time being.

If only we could achieve fusion at room temperatures! That’s the claim of proponents of so-called «cold fusion,» a field that has languished on the fringe since its alleged discovery almost 20 years ago. Back in 2000, TIME magazine listed cold fusion as one of the «worst ideas» of the 20th century.

Prevailing scientific opinion is still that the vast majority of cold fusion research falls under the rubric of «pathological science»: the results are always on the verge of a stunning validation. Whenever said validation fails (again) to materialize, there is always a handy rationale for why it isn’t really a definitive failure — and why the naysayers are just closed-minded tools of the scientific establishment, conspiring to keep these unsung geniuses down.


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