Space ship concepts: Combat in space

Here we go again. Having digested my first post on this subject, I've decided to look at military star ships in popular media.


First up is a personal favourite: USS Sulaco. Named after a town in the book 'Nostromo' by Joseph Conrad, this is a design by none other than Syd Mead himself (with help from James Cameron and Ron Cobb). When it comes to designing the future for the big names in sci fi cinema, you don't get bigger than Mead. The name of the ship is a nod to Ridley Scott's first film in which the spacecraft was called Nostromo. Click on the above image for more views of a model of this ship.

This is the US Marine's star ship in which Ripley returns to battle the aliens in James Cameron's film 'Aliens'. (Video 2) We can assume the USS Sulaco is an interstellar warship given that its carrying both marines and weapons from one star system to another. Like the HMS Camden Lock, it has the utalitarian look about it which gives it an aura of realism (deserved or otherwise). As far as I am aware, this is the most thought through 'war ship' design yet presented in a science fiction movie though originally Mead envisioned the ship as being a sphere radiating hundreds of sensor spines. The weapon systems shown in the film (rail guns and cannon) are obvious, but unobtrusive, the ship does not engage in 'space battles' but carries marines to a mission and at no point do we see evidence of energy shields or weapons (thus keeping within the parameters of known science). Of course the idea that this ship could travel between stars at all is unrealistic, but at least when it does, the crew are in a form of stasis. Not a very good stasis I'll admit, but still the concept is there. According to the Wikipedia site devoted to this ship it carries numerous other weapons systems but I've ignored these as they are never revealed in the film. What essentially makes this ship work (for me) is the fact that it never actually engages in combat. It remains aloof, an orbital weapons platform rather than a 'battleship in space'.



Compare the USS Sulaco to the recent TV space ship design in Battlestar Galactica and several points of comparison become evident.


BSG as its most often called, has a few interesting points of interest, but for a true sci fi fan, its just another space opera. The Galactica is a sort of 'carrier in space', obviously conceived with current US aircraft carriers in mind (more so in the reincarnated series) and apparently utilising human piloted fighters as its primary weapon system, backed up by rail guns and nuclear weapons. It is obvious fro the get go that this design is meant for fighting other ships.

The idea of human piloted fighters participating in space combat is anachronistic and deeply flawed. Space combat would most likely take place at ranges which required enourmous acceleration, with very high g forces to reach the target before being destroyed by enemy counter measures. Conceivably, warring space ships would detect each other whilst still millions of kilometres apart and barring long range energy weapons, would launch drones as soon as possible. Rail guns on the opposing ships would then try to destroy any incoming projectiles before these could hit. In TV and movies, battles (with WW2 style dog fights) take place with opponents within hundreds of metres of each other. Often in Star Trek 'weapons range' is so close the ships are almost colliding!



This sort of thing makes for dramatic art, especially when Hans Zimmer is provinding the score, but its hardly realistic. Drones would rip human piloted fighters to shreds. They'd be faster, react quicker, be much better able to handle radiation and wouldn't care about dying.

I haven't seen all of BSG, but I do recall the Galactica surviving a nuclear blast in one early episode. Here is a description of how a nuclear warhead would act upon a space craft. Its the last bit in particular that gets my attention.

A nuclear explosion in space, will look pretty much like a Very Very Bright flashbulb going off. The effects are instantaneous or nearly so. There is no fireball. The gaseous remains of the weapon may be incandescent, but they are also expanding at about a thousand kilometers per second, so one frame after detonation they will have dissipated to the point of invisibility. Just a flash.

The effects on the ship itself, those are a bit more visible. If you're getting impulsive shock damage, you will by definition see hot gas boiling off from the surface. Again, the effect is instantaneous, but this time the vapor will expand at maybe one kilometer per second, so depending on the scale you might be able to see some of this action. But don't blink; it will be quick.

Next is spallation - shocks will bounce back and forth through the skin of the target, probably tearing chunks off both sides. Some of these may come off at mere hundreds of meters per second. And they will be hot, red- or maybe even white-hot depending on the material

I imagine space combat, that is to say combat between two or more warring space vessels beginning with an intial phase of ECM and ECCM probing. 'cloaking' or hiding would be near impossible in the monotone void of space so obscuring one self behind a blur of white noise and static would be SOP. This would mean targetting systems would be partly or completely paralysed, so targetting and tracking drones would be launched first. These systems would be path finders for numerous other drone types which would fan out into multiple approach trajectories. Drones would carry their own submunitions, missiles and secondary defensive weapons. In some Peter F Hamilton novels these are refered to as 'Combat wasps'. As this was happening the ships would start firing long range hyper velocity projectiles at each other. The initial phases of space combat between two war ships of comparative strength would be very fast with computers making lightning fast computations and decisions and with all munitions accelerating at formidable rates.

Any missile, drone or hyper velocity projectile that hit its target would likely destroy it and its crew. Armour against weapons in space would not be very effective as we can read from the description above of a nuclear warhead hitting a space ship. Anything designed to kill at such long ranges is going to do a horrendous amount of primary and secondary damage with the radiation levels cooking anything unshielded. Even a hyper velocity projectile would like as not completely destroy anything it hit. From the Atomic Rocket site:

Rick Robinson's First Law of Space Combat states that "An object impacting at 3 km/sec delivers kinetic energy equal to its mass in TNT." In other words there are 4,500,000 joules in one kilogram of TNT (3,000²m/s * 0.5 = 4.5e6). This means a stupid bolder traveling at 2,000 km/sec relative has about 400 kilo-Ricks of damage (i.e., each ton of rock will do the damage equivalent of 2e12 / 4.5e6 = 400 kilotons of TNT or about 20 Hiroshima bombs combined).

Ricks = (0.5 * V²) / 4.5e6

where:
V = velocity of projectile relative to target (m/s)
Ricks = kilograms of TNT worth of kinetic energy per kilogram of projectile

So a projectile moving at 200 km/sec (20,000 m/s) would have about 4,000 Ricks (4 kilo-Ricks) of damage, approximately the same as a standard one-kiloton-yield nuclear weapon. By that I mean it has the same damage per kilogram as a nuke, counting all the nuke's framework, electronics, fissionable material, and whatnot. (for the projectile to do the same damage as a standard nuke, it would need to be the same mass as a standard nuke, about 250 kilograms) A projectile moving at 3,500 km/sec would have about one mega-Rick, which is the same damage per kilogram as the ultra-compact 475-kiloton-yield W-88 nuclear warhead.

.