Escape pods for interstellar spacecraft.

[RedDwarfIV]

I'm trying to persuade someone on the OOC thread for my RP Safe Haven on the TwoKinds forums about the uselessness of having escape craft on a city-sized Alcubierre and NERVA driven spacecraft designed for recreational visits to sites of interest in other star systems.

The ship, Sanctuary, is in a star system that is devoid of planets, in a low orbit of a star with unusually low brightness, heat and gravity despite its mass [This is intended as one of only two parts that are anything below Speculative Fiction on the Moh's Scale of Sci-Fi Hardness.] The Santuary is equipped with a fusion generator, solar panels, a coldsleep cryonics bay with chambers for all crew and passengers. The ship is designed to be as unsusceptible to problems as possible.

I say that it wouldn't have them because they take up weight, they leave you with a less powerful distress transmitter, they leave you with less resources, they aren't large enough to hold coldsleep chambers [including all the bumf like life support computers and life process control drugs that go with them,] and there are already all-purpose personnel shuttles that could fit a similar role if neccesary.

The other part of the RP that is below Speculative Fiction on the Moh's Scale are that the rescue ships have hyperdrives instead of Alcubierre drives, allowing them to arrive in only a few weeks.

The person I'm trying to persuade insists that it should have escape ships because of 'mundane problems causing disasters', that he would rather 'be jumping out of a damaged airplane with a parachute than remain on board', and 'If I were trapped on a spaceship with superheated gas monsters, I would rather leave in an escape pod than face them when I don't know how to kill them'

The gas monsters are canon, but they are not superheated after their heat conducts to the hull and surroundings in the outer layers of the ship, and the designers of the Sanctuary would not have known about them at the time. Neither would being on an escape craft make its occupants any less of a target for the gas monsters.

Edited October 4, 2012 by RedDwarfIV

[The Stinger]

To use the parachute analogy; Why use a parachute if there is no place to land?

[RedDwarfIV]

To use the parachute analogy; Why use a parachute if there is no place to land?

I said something similar. He said he would still rather be using the parachute.

[Aescwulf]

this is how i see future of space travel for when you know we are traveling throughout the galaxy.

giant spaceships that's either doing tours of the solar system or traveling to other star systems wouldn't have a escape craft because well if you've got i don't know thousands of people on board then you would need a huge escape craft. a future huge spaceship would possibly have long range communications system which could be used for sending out a distress signal but if your stuck in deep space and not in a universe where spaceships can instantly move from one location to another its a pointless feature. Or possibly would have a small detachable craft that contains all information from the ship from the moment of launch to moment of incident and sent in the general direction of nearest place where people would be kind of like a black box of some sorts.

But as you said its a alien creature then in fear of it being in contact with the rest of your species then you would effectively quarantine the ship no one leaves no one comes out.

this person said that he would rather jump out of a plane with a parachute .... if its a passenger jet it wouldn't happen because your 30 thousand feet up and the plane is pressurized to sea level and anyone can guess what happens there.

[NIN3]

this person said that he would rather jump out of a plane with a parachute .... if its a passenger jet it wouldn't happen because your 30 thousand feet up and the plane is pressurized to sea level and anyone can guess what happens there.

Well, wouldent that just blow your ears out? and give you the bends? better to be deaf then dead.

I agree with not having escape pods, since anything that damages the main ship would probably doom any escape pod.

But for a good arguments sake, I shath play the bad guy. heres my best escape pod argument:

If the ship was to hit somthing, and punture the hull, an escape pod could save anyone who could get to them in time, and keep them alive till help arived. even if the escape pod had no warp/long distance travel/propelent, help could arive assuming it had a distress signal, or the main ships distress signal was still operation. (little lack of oxigen never hurt no robot)

[Accelerando]

The problem with escape pods is that in order to be worth having, they have to be at least as capable as the mothership is at delivering the crew to another planet in another solar system... the parachute analogy does not work because a damaged aircraft is at least guaranteed to crash somewhere, and anyone parachuting out is guaranteed to either land or at least crash somewhere as well, and even if their chutes don't deploy they still have a marginal chance of surviving (as long as the airplane isn't traveling faster than the speed at which point the surrounding air is too fast relative to any human to allow breathing). An escape pod in the worst case, by contrast, will find itself on an intercept course with a star or into deep interstellar space near a star without planets. In either case, it will need engines and FTL drives on the order of capability of the mothership's in order to be useful as a means of escape, and even if only the case of using the escape pod in a system with planets is considered, it still has to be powerful enough to manage interplanetary transfers on its own while keeping the crew and passengers alive (or at least frozen) for what could be months. Since space travel can be very slow, this would ideally be accomplished in just one flight  a task which could require thousands of tons of consumables and organics to constitute a robust life-support system for a city-sized spaceship, plus thousands of meters per second of delta-v to account for planetary transfers, orbital braking + capture burn, and/or landing if necessary.

Without powerful engines and an equally robust life support system to the mothership, casting off in an escape pod to get away from the mothership only cuts you off from your only possible hope of navigating safely to safety without the help of someone else; and if the escape pod is powerful enough for such a task, it might as well be the mothership itself. The original mothership would become a boost stage and secondary consumables reserve, with which there is nothing essentially wrong, but if we assume a constant payload then this new mothership would find itself scaled drastically out of proportion. Assume an interplanetary escape pod scenario and say that the pod would require 10km/s of delta-V: Atomic Rockets states that a hydrogen-propelled NERVA vehicle with around 11km/s of delta-V will have a ratio of total mass to dry mass of four. In other words, accounting for reinforced structure, the new mothership would require at least around four times the mass of the old mothership just in propellant to allow the escape pod to make it safely to another planet in what isn't even the worst case scenario.

That doesn't begin to account for the increased antimatter fuel cost to account for increased volume the warp drive must bubble up, and if the escape pod can't safely make it to another planet, then it has very little chance of making it there at all in uninhabited space. If it misses the transfer burn by a little bit, it will zoom past the planet (most likely) or greatly risk burning up in its atmosphere (much less likely due to the small size constituted by any given planet) unless it has a very powerful heat-shield. At best, it would drive up the price of a ticket significantly; at worst, it would make the tourist line completely nonviable. And if the gas monsters are capable of intercepting an interstellar spacecraft with sufficient delta-V capacity for interplanetary operations in more than one solar system, then whether or not an escape pod can outrun other gas monsters is uncertain at best.

What if the escape pod were merely a cryosleep truck or a hab module with no significant engines and a distress beacon  i.e., existing sections of the ship, wired together and beefed up with a little more structural support, just in case of any mundane disasters that disable the ship's systems? Then the pod would probably confer even less benefits than an escape pod that could perform interplanetary transfers. As before, the value of an escape pod without transfer-capable engines is dubious in the context of a possible interplanetary gas monster attack, and escapees would be cutting themselves off from the mothership's resources, leaving them without any hope of salvaging the engines and/or life support and electronics and getting home in the worst case scenario. Any well-designed spacecraft will have pressure bulkheads that can be sealed automatically, or manually, in emergencies to prevent the loss of immediate life support to any compartment that isn't damaged beyond hope, so at least if the crew could fend off the monsters for the time being, they would have some chance of restarting the spacecraft and limping home. In an engine-less escape pod, they would be even bigger sitting ducks than they would be aboard the damaged mothership.

Maybe, like a parachute, the escape pod is designed only to save a relatively small number of people  the personnel, the "VIP" passengers, whoever can manage to get in and cast off, or some combination of the three. Ignoring the possibly extreme unpopularity of such an option, what then? As before, the escape pod still needs to be able to support people for as long as it takes to make interplanetary transfer, meaning that for an escape pod capable of carrying one person to safety it needs to carry at least a fraction of a ton of consumables and recycling equipment to fulfill the person's material needs for some time, not counting the potential psychological trauma of being cooped up in a tiny <1-ton capsule for a period of what could be months or years (we can say it's a cryosleep casket). A NERVA engine itself + radiation shielding masses at least several tons, and the mass of propellant tanks and maneuvering systems would constitute several additional tons at least, putting the minimum mass of a 1-person interplanetary escape pod at somewhere between 80-160 tons at a rough guess. Even if this would not take up a huge amount of the mothership's payload capacity, it would still drive up the price of a ticket, and would not even be the safest possible way for one person to get away.

Edited October 5, 2012 by Accelerando

[Khrissetti]

Escape pods only make sense if there is a reasonable chance of rescue in a fairly short time, or if they can parachute to safety. For instance, if it is a well-trodden shipping line with a ship going past every week or so, then it might make sense to have some escape crafts to keep people alive.

In your scenario, though. It makes more sense to have a more modular spacecraft so that if one section of the ship is damaged/invaded it can be easily sealed off or ejected to keep the rest of the ship safe.

The obsession with having escape pods on spaceships is an extension of the fallacy of equating space travel with sea travel and is fairly well ripped-apart at TV Tropes.com

http://tvtropes.org/pmwiki/pmwiki.php/Main/EscapePod

Edited October 5, 2012 by Khrissetti

[RedDwarfIV]

The obsession with having escape pods on spaceships is an extension of the fallacy of equating space travel with sea travel and is fairly well ripped-apart at TV Tropes.com

http://tvtropes.org/pmwiki/pmwiki.php/Main/EscapePod

I mentioned that, too.

[pwnedbyscope]

just my two cents, having a lifeboat/escape pod on any deep space craft, meaning any ship that is more then a month or so away from a habitable planet would be like jumping into a life raft, raft not boat, from a cruise ship in the middle of a class 3 hurricane

[AeroPelican]

The escape pod could jettison and stay near the craft until drones can fix the problem, when the humans can come back onboard.

[RedDwarfIV]

The escape pod could jettison and stay near the craft until drones can fix the problem, when the humans can come back onboard.

Thing is, you might as well stay on the craft while drones and the crew fix the problem.

[Nibb31]

Then why separate from the craft at all? What you need in that case is a shielded safe haven module on the ship.

[RedDwarfIV]

Then why separate from the craft at all? What you need in that case is a shielded safe haven module on the ship.

And that's exactly what the Sanctuary has.

Problem is, people still saying it should have escape pods simply because people want them.

[nhnifong]

Sorry if I hit a sore spot, but it seems you are coming to the KSP forums to justify the opinions you have already decided upon, because we are more likely to agree with them. While you can do this all you want on the Net, it will only result in your tolerance of others becoming distorted because of your selectivity. Be careful not to become hardened and righteous from this. I'm not really into RP but I think you need to share the decision making process more if you want them to participate. This ship is designed for humans anyways, it's not going to be a perfect machine, it's going to have all kinds of whacky features because we are fickle, and have a discordant collective identity.