space crash how could it happen?

[Jo Zebedee]

Ok, so I had a space ship crash caused by coolant leaking; the incident which caused it happened in the hold.

The action in the scene has now changed to the cockpit/ control room but I still need the same outcome, and I'm stumped.

So the ship, cargo ship quite small, has just left the atmosphere, about 15 mins out when incident happens. It has to survive the atmosphere on return, so I reckoned that ruled out puncture damage, and last for about 10 mins, and still be able to steer at least a little.

I could go for a systems failure but if so I think it should be from the action/fight. It's quite a detailed scene, so I don't think I can wing it in terms of what caused the crash. I'm pretty stuck.

Can I say if I ever become a mega selling author I will thank everyone profusely and throw a slap up party

 

[Interference]

Lured by the thought of a party, I just wonder if there should be an investigation later which will determine cause of the crash to be something really simple and stupid, like a loose rivet or something. Then the big question: Is it saboutage?

Or, something dodgy in the air supply, only the heroic skipper manages to remain conscious long enough to steer to a wobbly landing.

Or, meteor/debris strike affecting steering/comms/computers.

Or, radio interference affecting navigation, caused by a Pirate TV Station broadcasting on an illegal frequency.

Or, stay with the cargo bay and have an explosion caused by two types of contraband being brought into volatile proximity with each other - an accident, but two smugglers have to be tracked down, now.

Or, look for something else in your plot that could refer back to this moment and cause the near-disaster.

 

[Jo Zebedee]

Ty Inter, no matter what the outcome you are definitely invited to my party. Apart from anything else, you might be able to find where it is; the pub across the road from the castle do?

 

[Interference]

That'll do nicely

 

[Ursa major]

I'd suggest a widespread O/S is the cause, but legal action might prevent me from getting to that party.


(All the eights. )

 

[Jo Zebedee]

Well, Ursa, you'd be very welcome in this neck of the woods; we're very accepting, and a bear should be no problem.. There is the small matter of me becoming a multi selling author first, so there's plenty of time to plan it..

 

[Langadune]

Tribbles

 

[mosaix]

Some kind of guidance computer failure caused by the coolant leak interfering with the electronics requiring a difficult manual landing which is, of course, for this kind of craft /crew quite difficult and they're lucky to get it down at all?

 

[Jo Zebedee]

That would certainly be more believable than I have now; I suspect coolant has to escape for more than 15 mins to cause a crash, but it could interfere with the electrics. Ty all.

 

[chrispenycate]

Depends vastly on what is being cooled. If it were life support, sure, I expect that even in the thermos flask of space, as long as atmosphere was being circulated, fifteen minutes would not cause excessive discomfort. If, however, it was liquid helium cooling a superconducting core in a multiprocessor navigational computer then I'd expect the thermal protection to drop in after less than a second; quite possibly in a millisecond or so. Similarly, if you had superconductive coils maintaining the magnetic bearings that kept the living quarters rotating frictionlessly, and they heated and jammed, then control of the ship's direction could become suitably haphazard; the sort of problem a computer would balk at, but a living organism might attempt by intuition, if sufficiently immersed in space navigation (one raised with planetside reflexes would invariably get it wrong).

If the sip were flying 'forwards' (as accelerated by the drive), hit something in orbit, rotated through 180° so the drive was slowing it, rather than increasing speed, when it hit atmosphere it would be the 'tail' that came in first. With a conventional reaction drive the 'exhaust' (thrust gasses) would push back the planetary atmosphere (so it didn't force back up the rocket tubes) and put the main frictional heating well outside the vessel's skin. This would mean that even a fairly major rip near the 'bow' would not tend to tear the skin back, or heat the living quarters to tens of thousands of degrees K.

Playing off the decreasing horizontal velocity with the ever increasing vertical velocity, and arriving at the planetary surface with none of either is merely vector analysis. Well, no; wind speed comes into it somewhat, too, and the thrust increasing as the atmosphere becomes denser, or the solid surface being close enough that there is thrust reflected from it…

A nice bit of continuous feedback.

 

[Jo Zebedee]

Thanks Chrispy, so in the interest of my simple mind, let me see if I've got this right. If there is a problem on the ship and it reaches the atmosphere the ship will start to fight against gravity and start to pull vertical, and even as the pilot adjusts horizontal to the gravity the pressure will keep forcing him vertical. Is this right, or completely wrong?

So, could he steer at all? Even in a limited sense, or is this a straight down scenario?

Memo to self, a crash course in aeronautical design needed.

 

[chrispenycate]

The only ways the ship can 'fight against gravity' are a) with its main drive or b) using atmospheric friction.

The problem with b) is that at escape velocity or near it, the amount of heat generated will be excessive, and will need to be dissipated. It the craft is designed for it, like the shuttle with its ablative tiles, fine; although even there plasma and turbulence effects are not negligible. But a designed space craft won't have any aerodynamic surfaces, any flaps or rudders, and it will have considerably greater fuel reserves than any atmosphere vessel. So steering will either be through secondary sideways thrust jets (rockets, reaction engines, call them what you will) or by rotating the craft – gyroscopes seem the most energy effective technique – until the main thrust axis is lined up with the direction you want to push.

While taking off, you want the thing to get as fast as possible while getting as high as possible (slightly different with a spaceplane, but they are essentially surface to orbit designs, rather than interplanetary anyway), so as to get the minimum of atmospheric drag. Now, you're out of atmosphere, and something goes wrong enough that it seems wiser to go back home than try and continue.

You are not out of the planet's gravitational field. If the main motor is cut off you experience weightlessness because you and the craft are falling at the same rate. If you are in a stable orbit, you will miss the planet as you fall, but you are still undergoing an acceleration of nine hundred cm/sec/sec, or whatever (depending on your altitude and the gravitational field of the planet) and you are travelling at a speed relative to the surface of the planet (and thus the bulk of its atmosphere) dependent on your altitude; at geostationary, almost nothing.

But you don't want to be in orbit; you want to go back – let's call it "down", OK? So, if you are below geostationary, you rotate your ship so the main drive is slowing you down, and start to synchronise with the planet's surface. Now the gravity acceleration will bring you into a spiral that will hit the surface of the planet, but you'll reach the atmosphere with a horizontal speed low enough that you don't burn up like a meteor. But unfortunately you're gaining hundreds of cm/sec vertical velocity, which will do the same thing, so you need to tilt the ship a little so the drive is cancelling this out as well; that's where your vector analysis comes in; gravity is changing all the time, and if you know how high the top of the atmosphere starts, you want to hit it with as little speed in the two axes as you can manage.
Now, you've got two choices. If your craft is aerodynamic, you play of atmospheric friction against gravitational force, and land it like an aeroplane. If it's a 50s rocket ship, you stand it upright as soon as soon as atmospheric horizontal velocity has been reduced to negligible, then blast towards the planet, at first without enough force to compensate for gravity (otherwise you hover there), later with a bit more to eliminate the speed you've gained in the first place. <as you approach the surface your drive becomes more efficient, so continuous feedback; easier with electronics, but a human could do it, relying on monkey reflexes and not calculations.

I wouldn't like to try, though.

How does your drive work?

 

[Jo Zebedee]

My drive? I'm sure there's a name for this somewhere, but I don't know what it is, but I thought the ship would thrust from the planet and then move to a cruise in space with thrust applied again to get through the atmosphere and land. I don't think the gyroscope approach would work for this.

In terms of the crash, the aerodynamic style craft fits best, and the pilot does a bail out, so it's okay if ultimately the ship crashes.

the ship retains power during the approach, the decision to turn back is taken as the lesser danger, so the pilot should have limited control.

 

[alchemist]

What kind of weapons are being deployed in this cargo hold? Lasers, grenades, bullets, conkers? Could they take out some critical circuitry, damaging the computer systems they need to jump into hyperspace, so that return is the only option. And they have to return manually.

 

[Jake Reynolds]

Bringing it back to what causes almost all the world's problems, I'd say human error is your best bet. Someone showing off a pulse rifle to their prospective girlfriend accidentally fires and breaches the hull. You don't get that realism much in sci-fi, where people so often think that because it's 'the future' everyone is super professional, highly trained and educated, super smart and capable. One of the reasons Firefly was so awesome was because it's characters were flawed and realistic.

 

[chrispenycate]

For getting out of atmosphere we offer a range of different drives, some of which would also work for interplanetary work. Otherwise, if you want to use one vessel for multiple tasks you need to carry different drive systems for different times, and as they are generally a largish percentage of the mass, at each change of functoin you are carrying dead weight (unless you leave bits in a parking orbit and go back for them).

With presently existing technology we have the chemical rocket. This is adequate for surface to orbit transfers and could, I suppose, go to the moon, but as the reaction mass is entirely the fuel, and as you are restricted to chemical specific impulses (and physical containment, which limits both maximum temperature and pressure useable), normally you'll throw away ninety percent of your starting mass getting into orbit (the original equations that 'proved' that chemical energy could never accelerate anything to escape velocity {who coined that term? It's escape speed, a scalar quantity, not velocity, a vector} forgot about all that mass that was going backwards, so didn't need accelerating). Saturns, Soyus, shuttles have all chosen to leave a fair percentage of their structure behind to save carrying extra mass. Could probably be improved; with modern materials SSTO (single stage to orbit; what you need for most adventures) are theoretically possible, but they wouldn't have much fuel for bombing around the solar system later.

Still here and now scramjets. gain on efficiency by using the air around them as their reaction mass, but only while they're in atmosphere; totally useless in space. So you'd need a separate drive system for low gee vacuum work, probably a low acceleration, long push system like an ion drive. Furthermore, the engines only work while they're moving, so you'd need some kind of catapult or tow to get you started (yes, of course I'm in favour of a linear accelerator, but that's between me and Laithwaite). Which means takeoffs restricted to specialised facilities; if you came down in the wrong place, you'd have to be trucked to the launch pad.

It might be possible to hybridise a scramjet and a rocket, feeding in reaction mass and oxidiser as the atmosphere got too thin to support combustion, but I haven't seen a potential solution yet; mechanically complicated and working in incredibly adverse conditions it seems a source of potential problems somewhere you really don't need one.

Electrohydrodynamic. If you have a source of massive quantities of energy, say a fusion reactor on board, you can heat the atmosphere in front of you to plasma, then manipulate it with mobile magnetic fields. That's right, very much like a linear accelerator When you're in space you eject some matter into the right place for the plasmolising system to correct it. No contact between solid and plasma, so you can use much higher temperatures, and if you've got a working fusion reactor you're probably quite experienced with controlling fluids with fields. Yes, it will cause a bit of electronic interference, like blank off satellite TV for Great Britain every time one of these gains altitude, but omelettes and eggs…

Orion. Big, heavy ship with a big, solid heavy plate mounted behind on springs. Explode an atomic bomb behind the plate, it will jump in the air; when it starts to fall, another bomb. The spare bombs can be carried in the ship itself, or fired to the relevant position with a cannon – or a linear accelerator. Somewhat polluting, and implies a world with enough plutonium hanging around available to fuel a transport system, making terrorist A-bombs almost commonplace.

Fusion rocket. If you can persuade a small capsule of hydrogen to fuse, perhaps by zapping it with a multi-gigawatt laser, you can do a smaller version of the Orion, much less environmentally unfriendly. Should work between planets, too.

Laser launcher. Not very good for swashbuckling, as the government controls your motive force (at least while you're close to Earth) The lasers in question are on the ground, and you project the base of the ship into their beam. It looks a bit like the Orion plate, but much lighter. Air is heated, and rushes out backwards, driving the ship up. When there is no more air, the laser starts to vaporise the plate as reaction mass. When completely over the horizon you detach the remains of the plate and fire up your high efficiency interplanetary drive.

Orbital tower (space elevator, beanstalk) Very unromantic. You crawl up a vertical railway line at a mere hundred miles an hour for a day or two, until you reach the huge counterweight at geostationary. Then you continue; the centre of gravity of the tower has to be at the counterweight, so it will extend outwards probably as far as in. You feed your braking power bac into the system, as you get out, and hang on to the end until the computer informs you that if you let go – wait for it, wait for it – now, you will reach the same point in space as asteroid G8569 at the same time it does. Then your engines give occasional tiny course corrections for the next fifteen months, when it's time to deploy the fishing net…

Ferris wheel – as above, but smaller, and you have to get to the very top of the atmosphere befor it picks you up.

Esoterics I can't tell you what antigravity, or orbital loops, or geomagnetic pulse drives will do without a glance at their basic theory (which doesn't yet exist) Remember, energy on its own does you no good unless you repeal the law of conservation of momentum; and that is dangerous (Heinlein did it a couple of times and got away with it; not many others. I do not recommend baskets pulled by swans, or giant cannons, and if you want a really big linear accelerator the end of it has to be quite a lot higher than Everest; sort of ambitious building project.

I'm bound to have forgotten something, but there's a reasonable starting point here.

 

[Phyrebrat]

This seems a little redundant in light of Chris's comprehensive help but I'll pitch in just for the invite

In my past life as a ledger assistant, I used to get horrendously frustrated with simple formatting problems in spreadsheets where the data in a cell would be auto-formatted differently to those in the rest of the workbook or spreadsheet and this would cause havoc, especially with multiple currencies. Apply this to a flight system's software or operating system (without mentioning Bill Gates, of course) and you may be able to use it in a way that causes a mass fuel dump or some critical deployment (a la 'un-commanded slat deployment' in Michael Crichton's Air Frame) within the ship.

Change Excel or Word to bespoke flight system software and all it needs is an inattentive flight officer and an over zealous auto-formatting tool and hey presto; crash-u-like

 

[Jo Zebedee]

Ty everyone, this has all been really helpful, and can I wonder out loud to the mods' if there might be room for a technical thread; Chrispy's detailed input in this, which went beyond the detail I needed for this scene is something I'll keep referring back to.

With sci fi being an arena where winging it is difficult, I've had a couple of threads and have read several others which are more than useful and I'll keep referring to, but with them being about technical capacity and future capability seem a little different to a general writing discussion.

Alternatively, I'm mad, in which case please feel free to ignore.

 

[chrispenycate]

You could always just copy them onto your own computer – I doubt whether anyone else is ever going to need them. Alternatively, I could move them down into science and nature (where I am officially caged).

which went beyond the detail I needed for this scene

Yes, others have noted this problem with a Chrispy; it's not getting them started that's difficult, but shutting them off when you've got enough (and they start misspelling Soyuz)

But going mad can neither be considered a drawback or an excuse on this website.

 

[Jo Zebedee]

You could always just copy them onto your own computer – I doubt whether anyone else is ever going to need them. Alternatively, I could move them down into science and nature (where I am officially caged).


Yes, others have noted this problem with a Chrispy; it's not getting them started that's difficult, but shutting them off when you've got enough (and they start misspelling Soyuz)

But going mad can neither be considered a drawback or an excuse on this website.

The caging within a thread is limited and yes madness seems to be the default.
I'm not sure about the first point, okay this was about a specific query, but a lot of what went in to the thread was more generic/ cross over.

To be fair, you did warn me that by bamboozlement you often were, quite literally, last person in lot's of threads

Or maybe we should have a default Chrispy section where the level of detail is there for anyone who needs to explore further, or wants to know more.