What Are Realistic Mid-Journey Disasters in Interstellar Travel?

[256bits]

Or rather: Why send ten ships with lasers only on one end, if you could send five with lasers on both ends? Especially since the latter increases the chance of survival for the individual crews? After all, human beings are K-type strategists, not R-type.

K and R life history theory deals with species as a whole, not the specific individual of the species.

If K live in stable environments, then it would follow that the species itself would not seek adventure into uncharted territories, et humans do, as k-type, as they have done throughout history, as that entails a risk to offspring and survival of the offspring which do need a stable environment to mature and continue the species.
Individuals of a species shouldn't be labelled as K or R type.
The entrepreneur, whatever he would get out of the endeavour himself, is actually acting as an r-type, spreading his many children ( the occupants of the generation ship even if they are not genetically immediately linked as kin ) out into space in the hope that they will survive and continue, if one wishes to go there.

In any event, can we be so sure that the group onboard the generation ship will continue to act as a K-type. Perhaps a closed group in a closed environment becomes super k-, as has been mentioned, with one result that they discontinue all resources towards reproduction, and the group dies off on its own accord. the venture would be doomed from the very beginning. We, on ferma terra, do just not know how groups will function for long periods of time.

 

[Strato Incendus]

Yes, I was referring to the entirety of the crew here as if they were a (new) species, since they are going to be the first colonists of the new planet. And at one point in the story, they even have a reason to believe they might be the only ones left of the species (because life on Earth just took a serious hit, and all communication has been disrupted - meaning in reality, this happened over ten years ago already). So if anything happened to that single ship at that point, as far as they know, it would indeed be the end of the species.

The main thing I was getting at with my comment, though, was that, because the human species as a whole is K type, we hold the life of the individual in higher regard. Meaning, if you told the crews that you're sending 10 ships, but the chance of survival for the individual crew is lower than if you sent 5 ships with lasers on both ends, most human beings would find that unacceptable, especially given the alternative option. The 10-ships-fewer-lasers strategy wouldn't just factor in the death of more people, it would also make those deaths more likely than the competing 5-ships-more-lasers strategy.

 

[Drakkith]

The 10-ships-fewer-lasers strategy wouldn't just factor in the death of more people, it would also make those deaths more likely than the competing 5-ships-more-lasers strategy.

It's also more like 10 ships with dual laser arrays vs 11 ships with single laser arrays, unless the cost of the array is half the cost of each ship.

 

[Strato Incendus]

That’s why I was saying it was unbelievable to begin with that there would be more ships, but fewer lasers. Meaning, if they had the budget for 10 ships, but not enough to equip at least five of them with dual laser arrays, that would suggest the project planners had very strange priorities .

 

[Strato Incendus]

Okay, I've realised one major problem with the two-engines design: The gravity that would be created as a result of that acceleration would then also point in the respective direction. This would influence how the central trunk of the ship is designed on the interior (which we discussed in the parallel thread).

Now, in my ship's case, these g forces are pretty low (0.048 m/s²). But it's more than nothing, so it still creates a "floor" during the time frame of the acceleration / braking sequence.

If the ship has to turn around, the central trunk / pipe can be structured like a classical "skyscraper ship" (with all floors pointing towards the rear end of the ship). If however the ship accelerates from the rear during acceleration, and accelerates from the front during breaking, the former ceilings of the rooms in the central pipe would now become the floors.

Depending on how those rooms are structured on the inside, all objects that are attached to the floor would have to be attached to the ceiling (loose objects are to be avoided anyway). But there may be some things that must be integrated in the floor or ceiling. So those would have to exist as doubles, if the ship were to have two engines.

This is still important in my story, as in the second book, they use the aforementioned lasers to create a black hole out of light (a singularity drive) in one of the spheres. The much higher energy output of this drive, compared to nuclear fusion, allows them to achieve a higher coasting speed - but to get there within a reasonable time frame, they will also have to accelerate at higher percentages of g.

The most extreme requirement, if the ship could actually accelerate all the way up to light speed via constant acceleration at 1 g, would be for the crew to spend an entire year just in the central, "skyscraper-like" trunk. So far, though, I've merely postulated that the ship gets up to 0.77 c with the black-hole drive.

 

[DaveC426913]

the rotation only takes a couple of seconds

Wait,what???

How long do you expect it should take to rotate a ship this size??

 

[Strato Incendus]

I went with 20 seconds, but I don't recall exactly how I got to that number. I was only re-reading this thread today - I guess you looked into it again because I liked one of your previous posts today? ;)

I can easily extend the time frame to several minutes or hours, but I would have to adjust the range of the deflector lasers accordingly. Meaning, the longer it takes to rotate the ship, the further ahead the lasers have to clear the path of dust and debris, before the rotation sequence is initiated.

 

[DaveC426913]

I went with 20 seconds, but I don't recall exactly how I got to that number. I was only re-reading this thread today - I guess you looked into it again because I liked one of your previous posts today? ;)

I can easily extend the time frame to several minutes or hours, but I would have to adjust the range of the deflector lasers accordingly. Meaning, the longer it takes to rotate the ship, the further ahead the lasers have to clear the path of dust and debris, before the rotation sequence is initiated.

I think you'd be jeopardizing plausibility for plot.

Figure out the unchangeable first: how long would the 180 degree rotation of a ship of this tonnage - and this extended - take to turn? I particular, what rotational g-forces can it plausibly withstand with minimal risk? I would expect the rotation to plausibly take hours. Then figure out how they would manage to clear the space long enough to do it.

 

[Strato Incendus]

Can I use the same calculator for this that I used to calculate the size of the rings (SpinCalc)? For example, if the ship is 3 km long, then rotating it at g forces bearable for humans would be like getting a ring habitat with 3 km diameter to rotate at a speed that would create 1.05 g (I went with 1.05 instead of 1, since that’s the gravity of the destination planet, Teegarden b).

For the rings, with a diameter of 500 m, we’re talking about 1 to 2 rotations per minute here. So for a ship with a length of 3 km (=radius of 1.5 km), according to SpinCalc, it would be 0.79 RPM. SpinCalc also says all of these values would be within the comfort zone.

So by this logic, a full rotation around the ship’s axis should take 1 minute (79% of the full rotation) plus a 5th of a minute (for the remaining 20%), i.e. 1 minute 12 seconds. But since the ship only needs to perform half a rotation to face backwards, it should take half that long (72 seconds : 2 = 36 seconds).

Of course, rotating the ship at 1.05 g would result in the people getting pushed against the walls on the rings, towards the spheres at both ends of the ship. So potentially, the ship should be rotated at much less than 1.05 g.

 

[Grelbr42]

Realistically? Every body changes their minds.

It is a plot aspect of a novel by Robert Sawyer.

https://www.amazon.ca/dp/B06XBLDWC9/

The ship is under constant acceleration. They are about to reach the point where reversing thrust and going back to Earth takes the same ship-board time as continuing to their destination. They have a plebiscite to decide whether to go home or continue. A range of dramatic things proceed from that.

 

[EventHorizon]

I have some ideas:
- Running out of fuel before reaching the next Jupiter-like planet for fuel.
- Battles between spaceships (assuming multiple ships).
- Meteor showers/difficulties
- Objects that are out of the ordinary that the people on the ship detect.

 

[Strato Incendus]

Thanks for your ideas! I’ve only seen your post now, hence my late response. A few of these have already been discussed here; I was re-reading this thread yesterday, and I’m currently considering the fire-on-board option again, which I’d like to explore in a little more detail below. Quick summary / refresher:

Running out of fuel before reaching the next Jupiter-like planet for fuel.

The ship can’t slow down to pick up anything — as much as I myself would have liked a scene where the ship dives into the upper atmosphere of a gas giant to pick up fuel (I indeed had such a scene in mind at one point).

There’s also the problem that the ship is headed for Teegarden’s Star, and there is no nearer star in the constellation of Aries between that one and our own sun. Thus, there shouldn’t be any planets on the way either, unless there happens to be some rogue planet on the way that we can’t see from Earth.

Battles between spaceships (assuming multiple ships).

Not applicable in my case, since the ship is the first manned interstellar vessel, is on its own (in contrast to the setting in “Braking Day”), and there are no aliens either.

(Well… there’s the Tic-Tacs we keep hearing about in the news recently; but they are evidently so far above the level of technology even my fictional generation ship has that they still don’t bother engaging with the ship, much like they only seem to be watching our current military technology while actively trying to avoid contact.)

Meteor showers/difficulties

This is indeed the current idea; however, “meteor” has been reduced to “speckle of dust”. This dust particle is missed by the deflector lasers, penetrates several of the rings of the ship and some of the tanks in the aft sphere. Among others, it passes through a quarter on the habitat ring, killing the couple residing within it.

However, the particle alone does not lead to the number of casualties that is required at this point of the story. So while I can still stick with the particle causing the initial damage, what damage exactly it causes to the ship is still left to determine (see below).

Objects that are out of the ordinary that the people on the ship detect.

If you are talking about black holes, clouds of dark matter etc., those are also options we’ve considered. The problem here is that they are so massive you’d either be bound to detect them early enough to evade — and if somehow you don’t, due to some system failure, you would notice so late that it would already be too late to save the ship.
Now, going back to the idea of a fire breaking out on board:
As I’ve stated before, the most damage a fire could do would be somewhere where there is a lot of hydrogen. Meaning, in the aft sphere, where the drive is, and where I’m planning to send the crew members anyway (of which many are going to be among the casualties).

The sub-tanks in the aft sphere, however, would not contain pure hydrogen — not only given how hard it is to contain, but also because the architects of the ship obviously remember what happened to the Hindenburg. Instead, what the sub-tanks need to contain is actually water, in order to shield the central trunk and rings from the radiation coming from the front (and back, after the ship has turned around).

Thus, if one of the sub-tanks gets pierced by the particle, it would lead to water slowly leaking into the surrounding bigger sphere (which is there to prevent it from escaping directly into space). But this will probably just be a spray of water, so that it disperses itself into lots of tiny drops, rather than forming one large bubble in zero gravity that somebody or even a bunch of people could drown in.

At some place in the ship, however, the water would have to be converted into hydrogen / deuterium that the fusion drive could use. And that might be a vulnerable spot where a fire could break out.

Now, with nuclear fusion not even being functional as a source of energy on Earth yet, how exactly a nuclear-fusion reactor would work in a zero-g environment is even harder to foresee for me.

Just brainstorming some ideas:

1) Could I have a lot of crew members climb into the deactivated fusion reactor to fix something? Then, from somewhere in the supply systems, hydrogen might start leaking into the chamber, and a little spark might be enough to ignite it, killing everyone currently still working on the reactor. (If we go with this scenario, then the question is what could fail inside a nuclear-fusion reactor that would require about 70 pairs of hands to fix.)

2) In the other scenario we’ve considered, it would not be the reactor that fails, but the drive — since that is what we need for the other half of the twist, where the ship loses its ability to brake in time. Here, I had the idea that, because of the drive not reaching its full capacity, they first try to fix them; for this purpose, they retract the exhausts into the ship hull to work on them (since spacewalks at 0.125 c, as we’ve established, aren’t possible). The drive sits in one of the spherical sub-tanks, the one closest to the rear end of the ship. Then something could go wrong and the lid covering on of the holes through which the exhausts were retracted into the ship might open while a bunch of people are still inside the spherical room.

 

[Drakkith]

Unless the primary systems are redundant, any significant explosion in a crucial area of the ship, such as a main reactor or part of the propulsion system, is likely going to completely cripple the ship. Think Apollo 13 without the lunar module as a backup.

Your best bet, in my opinion, is something going wrong in a non-crucial part of the ship. An arc-flash in a backup battery compartment for example. Maybe a coolant leak from a heat exchanger where the coolant is either poisonous or flammable. Like I've said before, fires are exceptionally dangerous. Not only can people be killed through direct contact with flames and burning material, the fire can poison them with its byproducts, asphyxiate them through consumption of oxygen, and it can blow open a sealed compartment by heating the inside air to a high temperature, leading to decompression issues. The Apollo 1 command module fire ruptured the inner wall within 15-20 seconds as the pressure quickly rose above what the spacecraft was designed to handle.

Fires are also easy to make believable and easy to justify. Equipment failures, personnel mistakes, and sabotage are all readily believable. And fires also spread easily and can rapidly cause problems in other areas. Exactly the scenario you're looking for if you want an emergency to quickly kill off a substantial number of people.

A non-primary system is also easy to make a problem as you can always justify the accident as being caused because people were focused on keeping the primary systems operational and neglected the 'unimportant' ones. If you have limited manpower and expertise, what are you going to focus on? Maintaining the engines and reactor that are absolutely crucial to your survival, or backup battery room number four? In real life a huge number of incidents occur in exactly the same way.

1) Could I have a lot of crew members climb into the deactivated fusion reactor to fix something?

Sure. But, like you said, what's going to make several dozen or more people climb into a reactor? I'd expect that many people to be needed to disassemble the entire reactor perhaps, but you're unlikely to do that while the ship is in-flight.

Unless, of course, such a disassembly and reassembly is necessary. It might be that the ship has more than one reactor and they each have to be disassembled, cleaned, pieces replaced or recalibrated, and other such necessities before being reassembled.

2) In the other scenario we’ve considered, it would not be the reactor that fails, but the drive

Also a possibility. Though I don't think simple decompression would be the best choice here. If I have a work team working anywhere around a possible sudden decompression risk I'm certainly going to require emergency respirators or something if I have them. You don't send 50+ people into what is essentially an airlock without proper safety equipment unless you're incompetent or you just don't have the safety equipment. Both of which are plausible plot points, however, if you want them to be.

 

[Algr]

Real life disasters are often the result of a complex string of events. Here is a good example:

In succeeding years, much of the blame settled onto KLM’s captain, Jacob van Zanten, who began his takeoff roll before receiving air controller clearance. But nearly a dozen mistakes and coincidences had to line up with dismaying precision in order for the disaster to happen.

A single event being unplanned for is rather implausible. But a complex issue where figuring out what went wrong is part of the story could be quite interesting and suspenseful.