What real use are escape pods?

[rinku]

I just looked at real life escape pods and the B58 fully enclosed ejection seat is an eye opener. Taking up no more space than needed for the normal seat it is pressurised allowing ejection at high altitude and contains survival gear and supplies (sufficient for 3 days on the arctic ocean completely unsupported). From that it looks like a 0.5 DTon escape capsule should be able to have similar performance (the air requirement is higher but life support in Traveller is quite low impact). We can be more efficient than 1960's tech.

Setting aside an additional DTon per stateroom is not beyond credibility. The cost is also negligible amortized over the life on the mortgage. The biggest hit would be the opportunity cost of the loss of 1Dton of cargo. There would be no ongoing life support costs as the pod will only need replenishing if it is used (and then it will likely need complete replacement anyway).

I think a full dTon is excessive, given that the overhead for a fully functional breakaway hull is only 2%. Earlier in the thread I suggested 1 ton per 10 staterooms to make staterooms ejectable.

Aside from "most commercial starships are usually 100D from habitation", the other situation where ejecting may be better than staying would be in a fleet situation, where timely recovery is possible. Naval fleets are also more likely to face immanent ship destruction, although even so staying with the ship or getting to the small craft would usually be best.

 

[Maxijohndoe]

Probably the most realisitic lifeboats were from the Aliens movies.

Basically a lifeboat needs to be able to sustain live long enough for rescue to be a possibility. In space that might be a really long time.

So a couple of weeks won't be worth it. If you are in a system where you are likely to encounter other spacecraft a rescue ball will do if staying with the ship becomes impossible.

But what if you are in a system where rescue could be weeks or months away?

Basically you need emergency cold berths. A small craft stuffed with multiple cold berths and enough power to run them long term might preserve life long enough for rescuers to come across you and thaw you out.

So a lifeboat should basically be a number of cold berths. Of course that requires the time to access them and go into hibernation but maybe you just slide in and hope that whoever opens the pod has a good medical skill.

 

[swordtart]

I think a full dTon is excessive, given that the overhead for a fully functional breakaway hull is only 2%. Earlier in the thread I suggested 1 ton per 10 staterooms to make staterooms ejectable.

Aside from "most commercial starships are usually 100D from habitation", the other situation where ejecting may be better than staying would be in a fleet situation, where timely recovery is possible. Naval fleets are also more likely to face immanent ship destruction, although even so staying with the ship or getting to the small craft would usually be best.

My 1DTon was based on two escape capsules at 0.5 Dton each per HG.

Breakaway hull might not require much in the way of tonnage, but a stateroom is generally not considered self sufficient. You either need to take the power plant, drive and "bridge" from the stateroom space or add it and make the stateroom bigger. Now per the small craft book these could all take up less than 1 DTon in total (the bridge would have to be virtual). Each stateroom having its own life support would be an attractive safety feature in it's own right even if it were not detachable.

Now you could basically build each stateroom as a small craft. Once you can do that you effectively have a shuttle with a stateroom as it's only payload. It would need to be capable of landing to fulfil the functions of an escape pod so thrust 1 minimum (but that could be very short duration reaction drive). It would need some sort of streamlining or it will break up on landing and that will either need increasing the hull volume or again eating into the space in the stateroom. The ability to dock with other escape pods might be a useful option to share resources and allow access to other passengers with specialist skills. You could build a small enclosed town if that was useful outcome either in space or on a less hospitable planet.

The issue is a 4Dton small craft would need 5 DTon for the bay. If it assumed that the 1 DTon for a bay is largely for access perhaps it could be waived as the access to the small craft is the front door to the cabin. I hadn't considered breakaway hull to reduce the overhead but that is entirely sensible as we have to assume a bay allows docking and an escape pod doesn't necessarily need to re-dock in the same way as a shuttle or air raft would.

It does tend to make the air raft look a little large if you can get a hotel room with more space, better duration and (as long as you have an m-drive) better mobility into the same bay.