[Spaceships]/[UT] Launching life pods, drop capsules, and stealth capsules

[Agemegos]

Life pods, drop capsules, and stealth capsules are small, one-use re-entry vehicles described in GURPS Ultra-Tech, on p.232. Each has a loaded weight of one ton, besides which the life pod will carry four people and half a ton of cargo, a drop capsule will carry 2 people and half a ton of cargo, and a stealth capsule will carry one person and 0.3 ton of cargo. Despite having half the capacity in the same loaded weight, the stealth capsule is "more cramped than the drop capsule": this is because the stealth capsule includes ECM equipment, decoys, and an extra parachute which allows it to "jink", i.e. to change its course unpredictably by expending a parachute.

I suspect that a stealth capsule is large enough for a drop trooper in commando battlesuit (UT, p.183), a [military] cybersuit (UT, p.185), a warsuit (UT, p.185) or any other armour that does not increase SM, but that a drop capsule would be necessary for a drop trooper in armour that increased SM, such as the heavy battlesuit (UT p.184), HEX suit (UT p.184), or dreadnought battlesuit (UT p.185), and that there would only be room for one armoured trooper in such a capsule. I don't know about powered combat armour (UT p.183, B.285)), which is seven feet tall but not noted as SM +1.

Drop capsules are listed as consumables in Spaceships (on p.47), with a reference to Ultra-Tech p.232. The term is used in Spaceships 2 on p.20, with the interesting information that the 24-cm missile launchers on the Hermes-class courier are intended to launch drop capsules—but merely for delivering packages from orbit. They are mentioned in Spaceships 5 (p.37) as a means of covert landing on a planet. "Re-entry capsules" are mentioned in GURPS Mass Combat (p.38), in connection with "airborne" troops that can be dropped from orbit. But unless there is something in Spaceships 4 (which I don't have) there is no statement of what is actually required to launch life pods, drop capsules, or stealth capsules. They can be launched through a missile launcher, but it is not clear how large a missile launcher is required.


One thing to observe is that a life-pod, drop capsule, or stealth capsule has a loaded weight of one ton, which is the weight per shot for 32-cm missiles (Spaceships, p.47). A 32-cm missile launcher can be carried as a spinal mount by a spaceship of SM+7 (~300 tons), as a major battery by a spaceship of SM+8 (~1,000 tons), or as one of several weapons in a battery by a spaceship of SM+9 (~3,000 tons) or larger. That's a 50-ton missile launcher including about 20 loaded capsules (20 tons of capsules). That seems reasonable.

On the other hand, if I scrunch up as much as I can, I am 50 cm across the shoulders, and space marines or drop troopers presumably include men who are broad-shouldered and muscular. Allow a few centimetres on either side for their armour and a few either side for the walls of the pod, and it seems unlikely that you will be about to fit them into a 56-cm capsule. 64-cm would seem to be the smallest possible diameter for a stealth capsule, and it would seem that drop capsules and life pods must be even larger. But the smallest spaceship you can get a 64-cm missile launcher into is SM+11 (30,000 tons, about the size of a WWII battleship), where it is a spinal battery (15% of the ship, 1,500 tons of missile launcher). And a one-ton loaded drop capsule with cramped space for one man is perhaps small compared with a 7.5-ton, SM+3 64 cm missile.


Life pods, drop capsules, and stealth capsules might alternatively be launched through hangar bays (see Spaceships, p.18). Hangar bay capacity is noted in tons, so it is not necessary to know the SM of a life pod, drop capsule, or stealth capsule for this purpose (though it would be nice to know when we are shooting at them). An SM+5 spaceship (30 tons) could carry a single life pod or drop capsule in a single hangar system. An SM+7 could carry a squad SM+8 a platoon, SM+9 a company, etc.

So it looks as though hangar bays are the way to go when launching life pods or drop/stealth capsules. The only hint of doing it otherwise is the Hermes-class courier's packet delivery missile tube. Why am I unhappy about that?

Well, UT (p.232) and Spaceships (p.47) agree that drop capsules "have small rocket engine clusters that provide limited maneuverability, but careful landing is a matter of good navigation. De-orbiting takes two or three rotations around a planet with an Earthlike atmosphere (more for a planet with a thinner atmosphere, such as Mars). During this time, radio, radar, and all passive sensors will be blinded due to plasma effects." That makes them very tactically limited. Two orbits around an Earth-like planet take three hours. And if plasma effects blind radar, radio, and all passive sensors, then the capsule is going to be a very conspicuous object, a brilliant fireball that circles the planet twice. The planetary defences might not be able to shoot a stealth capsule in re-entry, but they get plenty of warning to put all their military facilities on full alert. This isn't a Starship Troopers-style surprise raid. Neither is it a good way to covertly insert a first-contact team (Spaceships 5, p.37).

So I'm looking for a way to land drop troopers much more quickly and discreetly. That means less reliance on aerobraking and considerably sharper decelerations.

• One approach would be to equip each capsule with a drive with sufficient acceleration and delta-v to use engine braking. But that threatens to make the capsules far too expensive for non-reusable items (I already have qualms on that front).
• Another would be to use the ship's main drives to cancel most of its orbital velocity, launch the pods with a much smaller braking task, and then boost the ship back to orbital speed again. That sounds rather like a hair-raising manoeuvre to me, besides being expensive in propellant/delta-v and pretty conspicuous.
• Hoping to get a result that looks more like Starship Troopers, I'm thinking of launching the capsules from the ship at some velocity to kill part of their orbital speed. Sadly, it isn't a very promising approach. Supposing the drop troopers could stand ten gees and recover consciousness before landing it'd take 81 seconds to cancel their orbital velocity for a drop on Earth and require a launch tube 320 km long.

Is it possible for drop pods and particularly stealth pods to make a steeper re-entry and to aerobrake harder? Orbiting the planet twice in the course of aerobraking implies deceleration at only 1/25 of local gravity.