Travelling to Another Star? Unfortunately Starship Fuel Economy Sucks

The Daedalus star ship, proposed in the 1970s, would propel itself forward using controlled fusion explosions (Nick Stevens, www.starbase1.co.uk)

On writing the Universe Today article Bad News: Interstellar Travel May Remain in Science Fiction yesterday, I couldn’t help but feel depressed. So far, in all my years of science fiction viewing, I have never thought that travelling to another star would be impossible. Although I knew it would be hard, and something we won’t be able to consider for a century or so, I always assumed it could be possible. Well, in a recent meeting of rocket scientists at the Joint Propulsion Conference in Hartford, Connecticut, they concluded that even the most advanced forms of propulsion would require gargantuan quantities of fuel to carry a starship over the few light years to the nearest star. Suddenly I realised I had been looking at the question of interstellar travel in the wrong light; it’s not that it would take a stupid number of generations to get from A to B, we would require 100 times the total energy output of Earth to make it there. Where’s Captain Kirk when you need him…

If you thought the current cost of running your car was sky-rocketing, spare a thought for our future interstellar travellers. To be sure they have enough energy to travel the 4.3 light years to Proxima Centauri (although that destination is open to debate, Proxima is a flare star and therefore a little inhospitable for us humans), starships would require at least 100 times more energy that is currently generated by the entire planet. So that begs the question: where could we get the fuel from? Some suggestions include mining the outer planets, asteroids and comets. Others suggest a “short” hop to the outer Oort Cloud (thanks alan) to re-fuel and then make the possible two-light year interstellar flight to Proxima Centauri’s theorized Oort Cloud (that’s if the Oort Cloud exists in the first place). Unfortunately, interstellar travel would require a cosmic mining effort, possibly an impossible feat.

They said putting a man into space was impossible; Uri Gagarin did that in 1961. They also said that about putting man on the Moon; Neil Armstrong and Buzz Aldrin nailed that endeavour in 1969. Now we have our sights set on Mars, and there’s a real chance we’ll see that happen within the next 30 years. Nothing appears “impossible” within the confines of our Solar System. But that’s the issue, we are confined within the heliosphere, literally an island in the middle of a vast ocean we call interstellar space. Flying to a planet is one thing, getting to another star system is a challenge we can only begin to come to terms with.

“Impossible” is not a word we like, but the use of current (and advanced) technology to travel to Proxima Centauri simply cannot cut it. So we have to start looking deep into the possibilities of more bizarre theories that have recently hit the headlines. As previously discussed on Astroengine, many years of research have been devoted into the science behind the warp drive (more commonly associated with Star Trek, as a means to ensure the starship Enterprise can potter around in more than one star system per season) and the web has been abuzz with this possibility. Warping space-time (whilst assuming the existence of microscopic dimensions permeating throughout the Universe) is becoming an accepted possibility (albeit rather extreme).

But there’s a problem. You guessed it. How would you fuel such a starship? To even think about creating a “warp bubble,” the warp drive would require an energy output of 10⁴⁵ Joules, that’s the same energy as if you converted the whole of Jupiter into its equivalent mass-energy.

Again, the fuel simply isn’t there. I think we need to start thinking out of the box on this one and probe deep into the quanta so we can begin to unravel what makes the cosmos tick. So from the very big, to the very small; perhaps experiments like the Large Hadron Collider (LHC) will be able to help us out by seeing if there really are tiny dimensions extra to the four we already know about. From there we might be able to devise new theories about how they could be used for long-haul space travel.