The problem with going interstellar is that the distances involved are huge. Couple that with the fact that our friend Albert Einstein imposed an annoying speed limit on the universe, and going even to the nearest star at light-speed is going to take 4.3 years, Earth time.
That’s always supposing you can get your rocket to lightspeed in the first place, which is incredibly difficult (it’s to do with mass ratios and energy).
It gets worse. Space isn’t exactly empty – you’ll be running into hydrogen atoms and other particles. Because you’re moving at lightspeed, and they’re not, they’ll rip through the spacecraft, and you, like very hard radiation.
Even an unmanned probe is a challenge. Project Daedalus, envisaged in the early 1970s by the British Interplanetary Society, involved a monstrous two-stage probe of 50,000+ tons mass, fuelled with deuterium mined from Jupiter, which could get to Barnard’s Star in 50 years. The maths worked out. The practical engineering – well, it wasn’t so simple. Or cheap.
Recently somebody figured out that it’s possible to build a relatively small solar sail, shine an Earth-based laser at it, and whip the thing up to about 25 percent of lightspeed. Apparently the system will get a 1-gram payload to Alpha Centauri within about 16 years. Naturally there’s no way of slowing it (much), and how much useful science could be got while scorching through the Centauri system at 20-25 percent C is questionable. Then there’s the problem of getting the instrumentation and transmitter for the interstellar broadcast back to Earth to fit inside the 1-gram mass limit.
Science fiction writers have been tackling these problems for decades. The usual method involves waving the hands vigorously, which causes devices such as the ‘Hand Wave Drive’ to come into existence, neatly circumventing annoying physics problems (it also creates artificial gravity on board and makes hot waffles for Sunday breakfasts).
When I wrote my interstellar story ‘Missionary’ I ran into exactly this issue. My take – which is the fairly standard answer – is that practical space-flight is always going to be ‘interplanetary’. And the type of ship for that was essentially defined in the 1950s by Arthur C. Clarke. Curiously, not Heinlein – whose ‘atomic rocket analog’ was closer to a seagoing ship.
Clarke rightly recognised that a space-to-space ship didn’t need a full hull. More on that in another post. The problem is getting that ship to another star. I came up with the idea of a drive that instantly switched ships from one system to another – but only where Einsteinian space-time was flatter, well away from the star. I didn’t devise the details because the key plot issue was the need to get to flat space-time (‘Minkowski Space’) and the drive itself didn’t need explanation beyond that for this particular story. I also wanted to keep the amount of hand-waving down – this story was based on real physics (apart from the silly star drive) and I did a lot of maths to work out orbital velocities, accelerations, periodicities and so forth.
The idea that ships travel to a point away from the planets and ‘jump’ to an equivalent point in another star system has been well used in science fiction. Heinlein introduced it in his 1953 ‘juvenile’ novel Starman Jones. And there’s Niven and Pournelle’s Alderson Drive. Both were limited to ‘congruence’ points. I didn’t envisage my star-drive being framed that way, it doesn’t work closer to space-time distortion but there are no other limits. A friend suggested that the degree of space-time distortion might affect the accuracy of the journey – something that opens up plots for future stories.
Meanwhile, if you want to check out the story, it’s been published as part of the first Endless Worlds compilation – out now on Amazon.
Copyright © Matthew Wright 2015