As Douglas Adams said, “Space is Big. Really Big." And that’s the major obstacle for traveling between the stars. But a new proposal published in the Journal of the British Interplanetary Society promises to shrink that distance just a bit. Physics and technology consultant Richard Obousy claims that an antimatter starship that creates its own fuel from the vacuum of space itself would be capable of making a return journey to the nearest star and back within one lifetime.
Sometimes it’s a bit difficult to grasp just how vast space is. The American space probe Voyager 1 was launched in 1977, yet is only now reaching the edge of our Solar System despite hurtling along at 38,000 mph (61,000 kph). At its present velocity, it would take 70,000 years to reach the nearest star – and it’s not even pointed in the right direction. Even NASA’s Solar Probe, a mission to study the Sun’s corona that will use an interplanetary slingshot maneuver to reach record speeds, would take 6,450 years. Needless to say, the odds of getting funding for a mission that will take longer to reach its destination than the whole of recorded history aren't that great.
What’s worse, a mission to another star won’t be worth much if it doesn’t produce any tangible results. Even if you could build a probe capable of reaching another system, a flyby mission isn’t going to be worth much if the probe blurs through it inside of a few hours at speeds too fast to see anything. Not to mention that all the data and samples aren’t going to be worth a bean if Mission Control doesn’t receive the results. That means any interstellar craft has to be fast enough to get to the next star, slow down and orbit the star long enough to do the science and then return to Earth with the results.
The upshot is that such a mission would require incredible amounts of energy that even some sort of fusion drive would have trouble delivering. Based on current science, the only energy source that has a shot of throwing a starship across the void and back in a reasonable time, say 50 years, is antimatter. That’s the idea behind Obousy’s VARIES proposal: Vacuum to Antimatter-Rocket Interstellar Explorer System.
The principle behind VARIES is as simple as it is theoretically cutting edge. It’s based on something from quantum mechanics called a “Schwinger pair production." According to quantum theory, particles in a vacuum don’t exactly exist. They’re only “sort of” there as an expression of probability. We don’t notice this on our scale because the probabilities balance themselves out. However, on a quantum scale, it’s a different story. One upshot of this is that it’s believed that if you tip the scales of probability by subjecting a vacuum to a powerful electric field, it will cause particles of matter (or antimatter) to spontaneously appear.
If this phenomenon pans out, VARIES would exploit it by way of an unmanned starship with huge solar panels that would collect the sun’s rays. These would, in turn, power banks of x-ray free electron lasers to charge the vacuum and create antimatter, which would then be collected and stored aboard as fuel for the journey.
This sounds very simple, but the engineering would be herculean, to say the least. In addition to building the solar power system and the lasers, the starship would also need magnetic bottles to store the antimatter. Otherwise, one instant of contact between ship and antimatter would vaporize both in a flash of gamma rays. Then magnetic nozzles would be required to handle the fuel as well as radiation shielding and all the other precautions needed to protect a craft flying through interstellar space at speeds where striking a dust mote is like hitting an atom bomb.
If all of these obstacles can be overcome the VARIES mission would proceed in stages. After fueling up in solar orbit, the ship would accelerate to a fraction of the speed of light. It would then coast, studying the interstellar medium as it traveled. After a few years, the ship would turn tail and decelerate until it reached its destination. It would then go into orbit around the star and conduct its exploration program while refueling in the new sun’s rays. Then it would leave the for home, accelerating, coasting and decelerating as before.
At present, VARIES is still merely a proposal with a long research shopping list attached, but if things work out, the path to the stars might be a little closer to reality.
Obousy's paper can be downloaded here as a PDF.