Could you, theoretically, "land" a warship in an emergency?

[JA Baker]

Ok, so I'm re-watching Star Trek Beyond, and it's got me thinking about an old theory of mine.

Let's say you're on a WarShip that's heading towards a planet. Between your delta-vee, the planets gravity well and damage you've taken, you can't just break away or even make orbit. But the planets got a nice, big ocean right there, and you have at least some power to your in-system drive.

Could you, theoretically speaking, reorientate the ship so you could use the in-system drive to slow your reentry to something survivable, using your armour and structural integrity as a heat shield? And then slow your in-atmosphere speed to the point where the ship doesn't just exploded like a dropped pumpkin upon hitting the water?

I'm not saying that this is something I'd want to do through choice, but it's essentially a scaled-up version of what happened in Mercenary's Star. Just, you know, with a WarShip and not a DropShip. I can't help but think it's make an interesting bit of fluff to have some random world where a small port town grew out of the washed-up wreckage of a WarShip that made an impromptu water landing.

[Frabby]

In the absence of rules, a GM could spin such a tale - if the WarShip has enough thrust. Being a nasty GM here, I can think of the following reasons why it probably still wouldn't work:
- The thrust engines are designed for vacuum operation and might just blow apart in an atmosphere;
- You'd have to land a large unstable scyscraper without gyro control;
- With a soft landing impossible, you have to cut the engines shortly before landing (even if they won't simply blow apart) and your many hundred meter tall tinfoil skyscraper will topple, a bad crash even into water;
- WarShips aren't designed to operate in a gravity well and may prove structurally unsound if their thrust axis isn't parallel to the gravitational pull;
- the attitude thrusters or whatever turns a WarShip around similarly may rip the structure apart in a gravity well and/or work poorly in an atmosphere (just like the main thrusters);
- There simply aren't many if any exits, so even when crashing into sufficiently deep water instead of a hard crashlanding, most survivors will drown.

It's a mightmare scenario all around, but I guess a handful of people might survive...

[JA Baker]

In the absence of rules, a GM could spin such a tale - if the WarShip has enough thrust. Being a nasty GM here, I can think of the following reasons why it probably still wouldn't work:
- The thrust engines are designed for vacuum operation and might just blow apart in an atmosphere;
- You'd have to land a large unstable scyscraper without gyro control;
- With a soft landing impossible, you have to cut the engines shortly before landing (even if they won't simply blow apart) and your many hundred meter tall tinfoil skyscraper will topple, a bad crash even into water;
- WarShips aren't designed to operate in a gravity well and may prove structurally unsound if their thrust axis isn't parallel to the gravitational pull;
- the attitude thrusters or whatever turns a WarShip around similarly may rip the structure apart in a gravity well and/or work poorly in an atmosphere (just like the main thrusters);
- There simply aren't many if any exits, so even when crashing into sufficiently deep water instead of a hard crashlanding, most survivors will drown.

It's a mightmare scenario all around, but I guess a handful of people might survive...

Oh, you'd need Chuck Yeager at the controls, but you could turn the engines up at high as they'll go: it's not like you're going to need them again, so melt them if you need to. Just get the ship down in enough of one piece that you at least have a fighting chance of finding an airlock and getting out before it sinks.

Hell, depending on the shape and damage, it could end up bobbing along like a cork!

And wouldn't the drive plume evaporate some of the water? Could that soften the impact?

[Fireangel]

Some time back, during a clan v. clan capital naval battle on a map edged by high-altitude hexes over a planetary surface, my opponent miscalculated his vectoring and ended up with a Sovetskii Soyuz cruiser on the interface hexrow.

Knowing that he didn't have the thrust to make it out, he just pointed the tail to the ground and continued the fight from that hex, surrendering only when its escort was destroyed.

The plan then became: "how to save she ship before its fuel ran out?"

The conclusion was to lighten the ship as much as possible in order to, through fractional thrust numbers, combined with the less-than-1g gravity of the planet, achieve the necessary thrust of 4 in order to escape the interface hex.

All the cargo was evacuated or dumped, all ships launched, all ammo dumped or fired at the ground, panels of armor jettisoned, cargo doors cut away… a skeleton crew was left behind to open up the afterburners and dump the fuel reserves in the herculean effort.

The calculations wend down to kilograms – literally – with the crucial thrust number coming up only when there was one turn of thrust left.

In other words, it came down to a single piloting roll: the biggest lawn dart check in history.

The dice were rolled…


… and a passage in the Remembrance of all clans was earned when the ship cleared the atmosphere!  [rockon]


A few years later, It was my turn; this time with an Aegis. When calculations showed that it simply could not lose enough weight to hit the magic number, it was decided to evacuate it and attempt to lean it against a canyon wall.

Man… snake eyes suck…   #P

[cray]

Prior discussion:
In-depth: http://bg.battletech.com/forums/index.php?topic=17350.0
Formal rules references: http://bg.battletech.com/forums/index.php?topic=54315.0

[cray]

Let's say you're on a WarShip that's heading towards a planet. Between your delta-vee, the planets gravity well and damage you've taken, you can't just break away or even make orbit.

You need a lot less thrust to escape orbit, and only about 41% of the delta-V to escape orbit, as to safely land.

Could you, theoretically speaking, reorientate the ship so you could use the in-system drive to slow your reentry to something survivable,

Not with the stated damage. You'd need at least 2 thrust points to do that, and would need to slow to about 0 velocity from orbital velocity because - per the link with rule references I gave above - WarShips take hideous damage if they're moving during reentry.

If you have 2 thrust points and the required ~40 fuel points for an Earth-ish planet then you could much more easily stabilize your orbit (1-2 fuel points) or escape orbit (~10 fuel points).

If you want to land anyway, see the rules reference I provided above, and the lengthy discussion when this topic last came up.

[JA Baker]

You need a lot less thrust to escape orbit, and only about 41% of the delta-V to escape orbit, as to safely land.

Not with the stated damage. You'd need at least 2 thrust points to do that, and would need to slow to about 0 velocity from orbital velocity because - per the link with rule references I gave above - WarShips take hideous damage if they're moving during reentry.

If you have 2 thrust points and the required ~40 fuel points for an Earth-ish planet then you could much more easily stabilize your orbit (1-2 fuel points) or escape orbit (~10 fuel points).

If you want to land anyway, see the rules reference I provided above, and the lengthy discussion when this topic last came up.

Are there any circumstances under which a WarShip could find itself forced into attempting a landing, and still, again, theoretically be capable of pulling it off?

Because it feels like something I'd like to have a go at writing.

[cray]

Are there any circumstances under which a WarShip could find itself forced into attempting a landing

Sure. Failing life support, and broken KF drive, and no shuttles or DropShips to land the crew safely, and no chance of rescue add up to a recipe to try it.

and still, again, theoretically be capable of pulling it off?

The rules are too hostile for anything less than a Leviathan 2 to pull of a landing, which would end with it (at best) toppling on its side and being destroyed. See prior posts.

[Tyler Jorgensson]

Not to really beat that dead horse some more but...

Is it theoretical that you could create a custom design Warship to do exactly that? All armor all engines and all structure with minimal everything else: IDK some boondoggle Amaris or the SLDF built to test the theory?

Just thought from the gallery...

[worktroll]

From the other thread, one could if it was a priority - with the Fox as a good starting place. Thrust well in excess of 2/3, lots of fuel, and it'd probably be a good thing to load up on SI and rear armour.

Just it's a really inefficient thing to do, and at any point returning to orbit would be quicker, simpler, and safer than continuing to land.

Also non-canon ;)

[worktroll]

PS - don't try taking off again. You just landed in molten rock, and firing off the engines for liftoff will be not unlike doing an Orion recreation, but without the springs ;)

[Col Toda]

You would want to aim for a river or river delta .  The running flowing water will transport the hot engine waste heat down stream . Sinking into soft river bottom silt which quickly turns to ridged glass may be a good thing .
Jumping battle armor may permit almost instant egress to shore with Zip Line Mission equipment to disembark the mobile crew members . After the water cools  the area and the radiation is mitigated by time and flowing water a more extensive salvage job may be done as the ship at this point can only leave in pieces and most of those could not be used again except as refined materials to remake the component as too many stress factors would be in it to just plug it in again . This seems more of " A Time of War " Scenario than a Battletech one . To do this a small craft or aerospace fighter would have to go ahead to find the best location on the 1/4 hemesphere to land on and have the computers number crunch for the landing .  If you are lucky enough that a good enough landing site is available in the time window of your closure due to the planets water land ratio if it has water at all .  Then you have to make a huge piloting check at the atmosphere / space interface . Then you hope no massive weather complications . In a " Time of War "  you can burn edge ( Luck Points ) to actually get this done if you are veteran or elite to begin with .

[Amaris Fan Club]

Hmm, forget about landing the big warships, could a subcompact warship be built with dropship-style landing gear?  They're as small as dropships, it should be theoretically possible.

While obviously the ship cannot jump anywhere near a planet is there anything about the KF-Drive that prevents it being taken into a gravity well?  The drive probably isn't designed for anything but zero-g and might not be able to handle the stress, but then again given how much they cost you'd think the engineers would put in a few extra brackets (and warships do maneuver quite a bit.)

I had in mind a scenario where a group of Lostech prospectors discover the ultimate prize:  Jonathan Cameron's one-of-a-kind private jump-yacht more or less intact on a planet.
- The first joke for the players would be that the Goliath Scorpions discover it too, and you know how they feel about lost SL relics (they'd probably end of worshiping the thing if they got it.)
- The second joke is that the ship is so valuable and rare that I don't know how they'd ever sell it.

One other question:  If this is possible what would be the design rules for such a thing?  A 28X final cost multiplier like a dropship?  (I think the thing might end up costing the GDP of the Lyran Commonwealth!)

[Dragon Cat]

Maybe instead of on a planet inside a planetoid or in a huge crater on a moon

[Kovax]

Now, if a warship somehow manages to survive atmospheric entry and set down on its tail, and then topple over, the result would look a bit odd.  The tail section, not having fallen far, would likely hold relatively together, just badly bent and mangled.  As you go further up the hull, there would be appreciably more "splatter" to the sides, with an ever-increasing debris field heading at an angle away from the impact point.  By the time you reach the nose, the debris will be scattering almost entirely away from that impact point, with everything completely shattered.

Having just fallen the better part of a mile as the ship toppled over, and the nose section slammed the ground hard, there would almost certainly be no survivors on the bridge, and nothing but twisted and scattered wreckage left of it.  There may be a fair number of survivors toward the tail end, and some small salvageable pieces of more durable equipment, provided that there are no explosions, fires, or releases of toxic materials that wipe out anyone who doesn't die in the impact. On the other hand, getting out may prove difficult for anyone too close to the tail end, as the surrounding ground will have been heated into molten glass, and will take some time to cool before anyone can safely cross it, while hopefully not broiling in the dispersing heat in the mean time.

If that doesn't sound at all pleasant, that's probably not being harsh enough.  While a few survivors are possible, they're not likely to be in anything resembling "functional" condition, and if anyone actually WALKS out, that would be a miracle.

[JA Baker]

Now, if a warship somehow manages to survive atmospheric entry and set down on its tail, and then topple over, the result would look a bit odd.  The tail section, not having fallen far, would likely hold relatively together, just badly bent and mangled.  As you go further up the hull, there would be appreciably more "splatter" to the sides, with an ever-increasing debris field heading at an angle away from the impact point.  By the time you reach the nose, the debris will be scattering almost entirely away from that impact point, with everything completely shattered.

Having just fallen the better part of a mile as the ship toppled over, and the nose section slammed the ground hard, there would almost certainly be no survivors on the bridge, and nothing but twisted and scattered wreckage left of it.  There may be a fair number of survivors toward the tail end, and some small salvageable pieces of more durable equipment, provided that there are no explosions, fires, or releases of toxic materials that wipe out anyone who doesn't die in the impact. On the other hand, getting out may prove difficult for anyone too close to the tail end, as the surrounding ground will have been heated into molten glass, and will take some time to cool before anyone can safely cross it, while hopefully not broiling in the dispersing heat in the mean time.

If that doesn't sound at all pleasant, that's probably not being harsh enough.  While a few survivors are possible, they're not likely to be in anything resembling "functional" condition, and if anyone actually WALKS out, that would be a miracle.

Wait to see which way if starts to topple, the fire the insanely powerful manoeuvring thrusters to slow the fall to something more survivable.

[Frabby]

Wait to see which way if starts to topple, the fire the insanely powerful manoeuvring thrusters to slow the fall to something more survivable.

Since both the main thrusters and the maneuvering thrusters on WarShips were designed for vacuum operation I expect them to work poorly in an atmosphere. They'd just blow apart.
It's a bit like operating a passenger aircraft with rocket motors underwater. Wrong environment, funny effects.

And that's not even taking into account how gravity will warp, weaken and shred the structure by pulling it in all the wrong directions...

Really, WarShips are fighting not one but two mortal enemies in this scenario.

[cray]

Since both the main thrusters and the maneuvering thrusters on WarShips were designed for vacuum operation I expect them to work poorly in an atmosphere. They'd just blow apart.

They'd be inefficient. Maybe rapidly destroyed by oxidation. But not blow apart. Rocket engines designed for vacuum have operated in atmosphere, and vice versa.

And that's not even taking into account how gravity will warp, weaken and shred the structure by pulling it in all the wrong directions...

An SI of 50 can endure 25Gs. It won't be warped by gravity from laying at an off-angle. When it falls over or is baked by its own drive, that's another issue.

However, I think your chances of making enough successful rolls and having enough armor to survive the process is unlikely.

****************************************

You would want to aim for a river or river delta .  The running flowing water will transport the hot engine waste heat down stream .A

A 3500-ton Union-class DropShip releases several kilotons per second of energy at 2 thrust points in tactical mode. WarShips are going to be releasing megatons per second in drive energy. A flowing river is going to be a bit short of heat capacity to keep the environment cool.

******************************************

Hmm, forget about landing the big warships, could a subcompact warship be built with dropship-style landing gear?

Not by the rules, but as you noted they're in the correct tonnage range.

One other question:  If this is possible what would be the design rules for such a thing?  A 28X final cost multiplier like a dropship?  (I think the thing might end up costing the GDP of the Lyran Commonwealth!)

x28 for a Spheroid-type shape would be reasonable for your home rules.

[I am Belch II]

I would love to see Warships land, but I think it would make the game and the rules condfusing.

[idea weenie]

It won't be landing in lava, as the thrust from the engine will blow away any liquified rock.  Now after the engine shuts down and the massive amount of propellant isn't accelerating the surrounding rock vapor to supersonic speeds, you will have heat issues to worry about.

Though since the heat sinks were capable of cooling the ship in a vacuum of space, I'd argue they are capable of dumping heat into the local atmosphere much faster.  So your ship would be at the center of a rising column of air, meaning that all the vaporized rock will be blown back towards the ship, this means any evacuees might have to worry about silicosis (rock dust getting into the lungs, absorbing moisture, and hardening into xeno-concrete).

[Bartholomew bartholomew]

double post. meh

[Bartholomew bartholomew]

I think that it surviving could be probable. Not so likely for the crew. But a lost tech scavenging settlement springing up around the landed wreckage of one would be a near certainty. Especially during the succession wars era. And would make an interesting story line for a campaign.

[JA Baker]

I think that it surviving could be probable. Not so likely for the crew. But a lost tech scavenging settlement springing up around the landed wreckage of one would be a near certainty. Especially during the succession wars era. And would make an interesting story line for a campaign.

This is kind of my take on it: it's not something any sane person would want to attempt, and 99 times out of 100 it'll end... badly for all involved. But from a pure lore prospective, it'd be all kinds of awesome!  8)

[Cryhavok101]

You could have the crew start jumping out with parachutes on the way down. That way they aren't killed by the force of impact or the ship collapsing all about them. Even without parachutes they have a better chance of surviving their own impact than the warship's.

[Fireangel]

You could have the crew start jumping out with parachutes on the way down. That way they aren't killed by the force of impact or the ship collapsing all about them. Even without parachutes they have a better chance of surviving their own impact than the warship's.

The drive plume might be an issue...

I keep seeing Engineer Olson from Star Trek (2009).

https://www.youtube.com/watch?v=eY4fJToqGbE

[Cryhavok101]

The drive plume might be an issue...

Yeah, you would need to clear some distance before you fell too far, but then, if you were to do this, as the majority of the crew jumped, you could just kill the drive and let the monster fall.

[Dragon Cat]

Yeah, you would need to clear some distance before you fell too far, but then, if you were to do this, as the majority of the crew jumped, you could just kill the drive and let the monster fall.

An uncontrolled descent and a big explosion follows

[Cryhavok101]

An uncontrolled descent and a big explosion follows

And the falling crew can ride the thermals to saftey  :D ;D

[Intermittent_Coherence]

I don't think it's that the drives won't work in an atmosphere. Warship drives are, after all, just scaled up versions of dropship drives. The bigger problem is distribution of weight. Even if you could point drives straight down, the warship is long and slightly top heavy. In theory they should work as well as spheroid dropship drives. In practice, I suspect the fact that dropships tend to have low height to width ratios plays a significant number in its stability as it enters the atmosphere.

[jimdigris]

Suppose that the warship has suffered no hull breeches when it enters the atmosphere.  If the entire crew put on their pressure suits and pumped all the air out of the ship lowering it's mass, what would it do to the ship's density compared to the air surrounding it?  Would it meet the ground with considerably less force?