Capital Ship Combat, part 2
by Dan Repperger

The Unique Nature of Space Combat

Elite, Space Rogue, Wing Commander, Freespace.  I’ve always been a fan of space fighter sims.  Unfortunately, most of them have the feel of World War 2 games that just so happen to be set in space.  You zip around in very close proximity to your target, flying on physics that imply the presence of air, blasting away with streams of untargeted lasers until your enemy goes down.

These games are a ton of fun, but let’s be honest about their accuracy.  Space flight has far more in common with a math problem than a dogfight, and many of the ground rules (excuse the pun) we subconsciously accept regarding terrestrial combat simply don’t apply once you’ve left your planet behind.

First, there is no atmosphere or omnipresent gravity.  We can expect ships and weapons to move farther, faster, and more accurately than anything we employ on Earth.   Spacecraft will not operate on aerodynamic principles, because there is no air.  And unless you’re very close to a planet or star, nothing will be tugging you toward the ground.

Let’s use the following illustration.  Take out a piece of paper and make a paper airplane.  Now, throw it in such a way that it will fly.  Obviously, you will throw it with the nose forward and wings aloft.  If you try to throw it forward while the plane is parallel to your body, the wings will press back against your hand and the whole mess will promptly drop to the ground.

Anyone with a basic understanding of physics can see what’s going on here.  If you throw it correctly, wind resistance is minimized, and the shape of the plane will allow it to carry aloft for a time before the air slows it down and gravity pulls it to the floor.  If you throw it incorrectly, the air works against you immediately, and gravity wins that tug-o-war a whole lot faster.

None of this is true in space.  A paper airplane will fly just as well if you throw it from any angle.  You could hold it parallel to your body, push it forward, and expect it to fly just fine.  And unlike its terrestrial cousin, it may never slow down, stop moving, or fall.

We can apply these same ideas to more sophisticated ships and weapons in space.  Ships do not need to face the direction they’re traveling, nor will simply turning the nose be enough to change its direction.  They will not need wings.  You will not slow down or stop after turning off your engines.

In atmospheric flight, the facing of your craft is directly related to its vector of movement.  In space flight, the two can conceivably have nothing to do with each other.  A burst of thrust will start you moving in a direction.  You can spin the craft around or do anything else you like, but nothing will change your movement until you exert another burst of thrust.

Second, we’re fighting over a much larger area.  The circumference of the Earth is roughly 40,000 kilometers.  In other words, even if we follow the surface of the Earth (no subterranean shortcuts), the farthest you can be from anyone else on Earth is about 20,000 kilometers.  Most battles tend to be fought over areas much, much smaller than that.  For example, the modern-day XM2001 Crusader artillery piece has an unassisted range of just 30 kilometers (up to 50 with enough help).

Put such notions aside when talking about space.  If we had a war between Earth and its closest neighbor — the moon — our enemies would be about 384,000 kilometers away.  In August of 2003, Mars moved the closest to Earth it’s been in 50,000 years, putting it 56,000,000 kilometers away.  These examples are both for relatively close bodies, so you can imagine how quickly the distances go up if fleets are slugging it out from any two randomly selected points in a solar system.

Sure, but won’t ships close that gap before fighting?  Possibly not.  As I’ve already explained, missiles, bullets, and lasers alike will no longer be working against gravity and air.  They can fly for incredible distances with little opposition.  And, depending on the type of weapon, they may traverse great distances and strike home just fine.  (We’ll talk about weapons more in the next installment, so hold your objections regarding target prediction and such until then!)

Third, there is very little terrain.  The vast majority of space is effectively empty.  Of course, the places worth fighting over tend to have bodies of mass in them such as planets.  But even planetary orbit is considerably more open than a city block, forest, or mountain range.  Objects that are “dangerously close” may still be thousands of kilometers away.  So putting aside a running battle through an asteroid belt, you can generally expect ships to see each other quite plainly across vast distances.