ONE SOLAR SYSTEM? WHAT GOOD IS THAT? by John M. Ford<\/p>\n
(This article originally appeared in ROLEPLAYER #11.)<\/p>\n
John Ford wrote this as commentary\/contribution for GURPS Space – but <\/p>\n
unfortunately, as we fought to get the final manuscript down to “only” 128 <\/p>\n
pages, it didn’t make it. So here it is . . . some comments and suggestions <\/p>\n
for the GM who wants a science-fiction campaign set in a single solar system.<\/p>\n
* * * * *<\/p>\n
Space opera usually spans vast interstellar distances, with dozens or <\/p>\n
hundreds of inhabited worlds. But it doesn’t have to. The exploration of one <\/p>\n
solar system – ours, or another reached by colony ships – is material enough <\/p>\n
for centuries of epic adventure.<\/p>\n
The one-system background is excellent if the GM and players prefer a <\/p>\n
“hard science” story. FTL travel is not needed; if the system is not <\/p>\n
Earth’s, it was reached the hard way, by a generation ship, or perhaps by a <\/p>\n
ship traveling so close to light speed that only a short time passed aboard. <\/p>\n
Or perhaps FTL exists, but is so expensive that it can only be used to send <\/p>\n
colonists on one-way trips. Or stargates go only one way. Or the colonists are <\/p>\n
exiles and can’t go home.<\/p>\n
The whole campaign can be set at the top end of Tech Level 7. Still, with <\/p>\n
developments of present-day science technolgy, this could include better hand <\/p>\n
weapons, clean fusion plants, a “beanstalk” space elevator from planetary <\/p>\n
surface to orbit. In particular, this campaign needs breakthroughs in space <\/p>\n
propulsion. To go somewhere, you must still accelerate a reaction mass and <\/p>\n
throw out the back of the ship. The mass may be bulky and cheap – water <\/p>\n
flashed to steam by a nuclear reactor – or dense and expensive – heavy metals. <\/p>\n
The result is the same: the faster you want to get where you’re going, the <\/p>\n
more of the ship’s mass is taken up with fuel.<\/p>\n
The cheapest, slowest way to get around in-system is along a Hohmann <\/p>\n
transfer orbit, an ellipse with foci at the origin and destination worlds. <\/p>\n
Hohmann data for the Solar System is available in reference books, including <\/p>\n
the CRC Handbook of Chemistry and Physics, or “Rubber Bible.”<\/p>\n
Notice we said “slow.” A one-way Hohmann trip from Earth orbit to Mars <\/p>\n
orbit takes about 260 days – and the launch window for a trip this short <\/p>\n
occurs only once every two years. To travel any faster, or at another time, <\/p>\n
requires a lot more energy. If the characters aren’t to spend most of their <\/p>\n
lives either on one world or in transit (not that that would be a bad idea), <\/p>\n
you may want to allow the “torchship,” with a highly efficient system that <\/p>\n
produces 1-G thrust for as long as necessary. 1-G thrust is wonderfully fast; <\/p>\n
with a mid-course turnover (accelerating halfway, decelerating halfway; it <\/p>\n
feels just the same aboard ship) you can get from Earth to Mars in less than <\/p>\n
four days. But this requires power and materials we don’t (yet) have, or any <\/p>\n
useful idea how to make, so it’s TL8 at a minimum.<\/p>\n
Instead of a star map, the one-system campaign uses an orrery – a set of <\/p>\n
orbital tracks with markers to show the planet’s locations. Move the planets <\/p>\n
at intervals appropriate to their year; Earth might move every 10 days, <\/p>\n
Jupiter every year or so. Planetary motions can also be programmed on a home <\/p>\n
computer, with any level of precision you choose. (One advantage to using the <\/p>\n
real Solar System is the huge amount of very precise data available, <\/p>\n
especially for the inner planets.)<\/p>\n
One common SF theme is “mining the asteroid belt.” This is usually <\/p>\n
compared to the California gold rush, with lots of lone-wolf miners in their <\/p>\n
one- or two-person ships, wandering through a cloud of space rocks, staking, <\/p>\n
digging and jumping claims. Unfortunately, the reality is very different. The <\/p>\n
asteroids are at least half a million miles apart, invisible from one another. <\/p>\n
And once you get there, most of them are just rock, and most of the rest are <\/p>\n
just iron. If civilization needs a lot of asteroidal iron, the cheap way to <\/p>\n
get it will be to send one mission to find a big lump, and set up a mass <\/p>\n
driver to bring it slowly home.<\/p>\n
If you still want a Belt civilization, you could set up a system with a <\/p>\n
much denser asteroid belt, or just “salt the mine” with something widely <\/p>\n
scattered (justifying all those little missions) but very valuable. Metals <\/p>\n
like iridium, for instance, are much more common in space material than in <\/p>\n
Earth’s crust. Larry Niven posited that “magnetic monopoles” might be the <\/p>\n
remnants of an inhabited planet, with alien artifacts scattered through it. <\/p>\n
(Incidentally, our own Belt is almost certainly not a shattered world; there’s <\/p>\n
not enough matter there. Sometimes science is a real spoilsport.)<\/p>\n
Given all these restrictions, what sort of adventures can you have in one <\/p>\n
system? The same sort that real explorers and settlers have always had: The <\/p>\n
excitement of trying to survive in a strange new environment, making society <\/p>\n
and government work under new circumstances, and every now and then finding <\/p>\n
something that no one ever saw before. That’s at least as exciting as <\/p>\n
slaughtering aliens with particle beams.<\/p>\n
Quit, List, or number to read :<\/p>\n
