Tonight, I very nearly had an attempt to drop a transport ship into a gravity well. The intent was to then activate the warp drive inside the atmosphere, near the surface, to wipe out a possibly corrupted Hive city shell... I think the RT is now keeping this in mind as a possible backup plan for a future situation.

What kind of tests would you require to pull this off, and what would happen?

I would just flat-out not allow it. It's such an absurdly effective tactic if it were possible that Chaos would've wiped out the Imperium by now it it were possible. In much the same way that you can't warp jump into orbit, I believe that Imperial (as well as Chaos) Warp Drives literally cannot activate inside of a solar system.

Orks annoyingly have the ability to "aim" warp jumps, but if this were possible then any enemy would put one transport on Silent Running, send it into system and destroy every planet you've ever been on.

Where I have seen people try to start up Warp drives in orbit the ship blows up. Not a Warp Drive failure, just the ship. Plasma drive explosions should be possible...

Regarding my understanding of warp drive uses inside star systems

The warp is mad inside star systems due to the planetary bodies counterparts inside it.

I think its stated more than once that ships actually need to use a jump point outside the system's gravity wells or else they'd be destroyed by the massive dense warp energy currents after completing translation.

I believe however, that if you translate into and back really quick, the chances of being caught in the storm is much less likely. (see navigator "blink" ship combat action in Navis Primer)

This makes Emergency Geller Fields tremendously less interesting unless you are fighting in the outermost reaches of a system or you have no other option besides throwing yourself in the unforgiving currents of the warp inside a gravity well...

Regarding using the warp drive as a weapon

The transport would be immediately destroyed after translating - you are not even close to a grav well, you'd be INSIDE one - the tear in reality would bleed off tremendously corrupting warp energy into the planet where the ship's own geller wouldn't be protecting it anyhow. No, the hive wouldn't be entirely destroyed. Horribly mutated and corrupted, raped by demons, yes.

Now, if you are planning on sitting the transport on the ground, and detonating the Warp Drive into a Warp-Rift.

Well, that would probably mean: 1) Exterminatus (from raging warp currents tearing it apart) 2) New Daemon Planet (if the planet manages to hold together long enough to be completely sucked into the warp, or to be completely transformed by it)

Personally, I would just prefer standing in orbit for 1-2 days and shooting it with any weapons I got than to use a valuable voidship. Or else, if there isn't absolutely time for anything else, ram the hive with the transport with the PLASMA drive set to overload (which would be 1/2 Exterminatus I think).

A -9000 Navigate (Warp) Skill Test and an -9000 Operate (Voidship) Skill Test.

There's a reason you can't even jump INTO areas that are within the gravity well. The warp gate would vex and wane and tear the ship apart, nevermind when you try to jump out of there, pulling not only yourself, but half the crust of a planet with you.

Sure, Imperial ships can take a beating, and sure they are big, but have you ever tried to dodge Olympus Mons heading towards you at near-relativistic velocities?

have you ever tried to dodge Olympus Mons heading towards you at near-relativistic velocities?

I laughed hard at this.

A -9000 Navigate (Warp) Skill Test and an -9000 Operate (Voidship) Skill Test.

There's a reason you can't even jump INTO areas that are within the gravity well. The warp gate would vex and wane and tear the ship apart, nevermind when you try to jump out of there, pulling not only yourself, but half the crust of a planet with you.

Sure, Imperial ships can take a beating, and sure they are big, but have you ever tried to dodge Olympus Mons heading towards you at near-relativistic velocities?

What I can't get past is what was mentioned above. If its so dangerous, why hasn't some enterprising Chaos warlord gone and done it to half a dozen forge worlds? I'm tempted to say that the warp core devours itself that close to a planet. There might be a highly localized warp storm that peters out after a bit, but the gravity well prevents the core from getting a true 'hold' on the warp. That way, the ship might still do some local damage, but not on the scale of a Warp Drive Implosion from the catastrophic damage table.

Also, I should mention, the RT was pretty sure that the Hive and planet were already corrupted beyond saving, and he was looking for a 'kill it with fire, now!' Option. He relented into simply bombarding the surface from orbit with a fleet for a day.

Planetary Bombardment: The cause of, and solution to, heresy. Forever.

I actually think that the Warp Engine self destructs due to the incredible stress of trying to punch through to the Warp in an area with so much disruption. That causes the ship to explode (Warp Engines are a good part of the ship, and them blowing up is going to pop the ship apart).

Ship weapons should be fine for killing a hive unless the hive is well enough armed to make that prospect dangerous. My players once glassed a 500km+ wide area to destroy a debased Eldar Webway that had become a minor portal to the Warp. They considered it a prudent and reasonable action.

Sounds like he was trying to pull off a Battle of New Caprica moment, without recognizing the huge differences in FTL mechanics between Battlestar Galactica and 40k.

It sort of depends, at least to me, how warp travel works in 40K. In Star Wars and Star Trek, the ship would move into subspace, and the acceleration of the ship's colossal mass, moving so fast, is what would eat a planet, and probably the ship, in the aforementioned gravity well, which might save the planet. In 40K, though, do you do the same, or simply enter a portal into the warp? If you just move from one reality to another, without high velocity being an issue, you wouldn't cause any disturbance, to your ship, or to the planet; you'd just poof-vanish. If you don't have "get up to 88 mph", to use a Back to the Future reference, you won't leave fire trails to ruin the planet. Gravity wells would also thus not hinder you.

Still, whether it is velocity-based (your ship will give before a planet will), or portal-based (the planet waves good bye as you go, but is otherwise unmoved), I'd say that this isn't going to be a great doomsday weapon for you to use.

The comic supplied with the original BFG box shows some sort of portal on exit, I think.

I also believe I've seen several sources mention a visual "blink" upon transition, though that could easily just be cherenkow radiation.

There is an actual portal upon travel, but contrary to what Venkelos suggests, you don't just "poof, vanish".

Opening a portal to the warp is a major thing, and no matter it's exact nature, it's not something you just do; I'm with CaptainRemiVandigrath - it can't actually be done within the gravity well. At least not with regular warp engines.

And if it *can* be done, it would wreak all kind of hell on the planet below, in more ways than one.

I had some players take an emergency warp "skip" while in low orbit around a (technically) uninhabited planetoid. The results were catastrophic.

The planetoid, already weakened by a web of fissures, ripped itself apart, its pieces following the vessel into and through the warp. Upon translation to material, the vessel was bombarded with gargantuan chunks of the destroyed planetoid, effectively a close-range attack with a macro broadside infused with warp residue. The vessel was crippled, off course in BFE, and the PCs/crew had some considerable warp manifestations to purge.

The vessel had been used exclusively for intra-system passenger/pilgrim transport (a luxury liner, sort of), and the PCs were Inquisitorial Acolytes investigating Cold Traders. As they took the Vagabond's captain into custody, his totally amoral superior was detected on an intercept course. Outgunned (their Vagabond-class versus a Dictator-class), caught with their pants around their ankles (no Navigator), and following desperate successful attempts to ignite the warp drives and waken the machine spirits of the Gellar field, the senior Acolyte issued the command to translate.

The shock wave resulting from the planetoid's destruction caused only minor damage to the Cold Trader's vessel due to it still being fairly distant and using stellar "terrain" for shelter.

The big no-no to the translation possibility in the gravity well is the most elegant way of saving your game from planet (hell: star) destroying orion clippers.

About the translation into warp for some time I tend to visualize it like on few you tube animation: ship is basically flying/get sucked by rift in front of it. It ties smoothly with gravity stuff as at given moment part of the ship is in warp and part is not, so intermolecular forces keeping the hull together got plenty of time to go south.

I have a question then...

How useful are emergency gellers then? How often are you fighting outside the system`s gravity well?

And what happens with that "blink" navigator hability from Navis Primer?

I have a question then...

How useful are emergency gellers then? How often are you fighting outside the system`s gravity well?

When a ship is totally destroyed, there is a risk of a warp rift forming and sucking you in (it's the bottom result in the crit table).

I believe this to be the purpose of the emergency geller field.

My (one) group's senechal had it uninstalled and sold it (to finance a Warpsbane Hull) recently. Without telling the RT.

I was just reading Star Of Inequity, and there is a sidebar on pg. 18, titled Operating Within A System. It suggests that translating too far in-system from a jump point could result in Gravity Riptides difficulties (Gravity Tides, Rogue Trader core, pg. 227)- you could have the PCs and their vessel deal with those prior to making a translation into the warp from a planet's orbit (or within relatively close proximity).

I was just reading Star Of Inequity, and there is a sidebar on pg. 18, titled Operating Within A System. It suggests that translating too far in-system from a jump point could result in Gravity Riptides difficulties (Gravity Tides, Rogue Trader core, pg. 227)- you could have the PCs and their vessel deal with those prior to making a translation into the warp from a planet's orbit (or within relatively close proximity).

Good find, but I think there should be quite a diffrence between translating - let's say - in a middle of distance between Earth and Mars (still, unquestionably deep in-system) and warp-jumping from orbit or within atmosphere.

This all just gave me an idea.

A -10 Navigation-Stellar followed by a -40/-20 option for Navigation-Warp test for a Navigator to find an ideal Lagrangian point where translation in-out of the warp would be possible within a gravity well.

It also needs to take into account the size of the star and planets nearby, as their correlative in warp-space could smash the ship anyhow when it translates, so being able to do this should be rare.

For example: a system with a dim small white star that has 2 planetary bodies could have two Lagrangian point. But using the one closer to the start would inflict a -40 instead of -20 on the warp nav test due to the increased amount of warp anomalies/reefs representing being closer to the core.

After some thinking on that subject I'd like to point out that there should be a major diffrence between jumping into uninhabited system, inhabited one and one with sentient life.

It's because, aside from mundane gravity stuff, there must be huge impact reflacting state of warp. I assume that planet with sentient life generates some currents in the warp, those currents will increase in case of i.e. war raging on the planet, hive city-wide celebrations or Iron Maiden gig. Navigator can more or less calculate the date of transition from the warp but she/he should almost never be aware of what is/will be going on the planet. Maybe some previous divinations or something would do the trick.

That way PC would be warned from jumping into Scintilla orbit which would prevent game from raider-class-torpedo-scenario, yet still they can jump into uninhabited system with only moderate risk of being turn into chaos spaaaa....

I don't think one planet, even covered in people, affects the local Warp that much, or should have that much cause-and-effect influence on the warp. It took the entire War in Heaven to corrupt the Warp as a whole into its current state. It took the entire Eldar species' depravity to birth Slaanesh.

That way PC would be warned from jumping into Scintilla orbit which would prevent game from raider-class-torpedo-scenario, yet still they can jump into uninhabited system with only moderate risk of being turn into chaos spaaaa....

What prevents the raider/torpedo scenario is the notion of the "hyper limit" and also Battlefleet Calixis on a general quarters picket, where ships leaving Warp need a minute to bring their non-warp systems online and adjust their bearings.

I see a Black Crusade mission in which a few minions are sent on a suicide mission to have cause a ship to warp jump in a planet atmosphere. The resultant death and destruction would destroy the ship, probably destroy the planet and tear open a warp rift. I think the reason Chaos hasn't tried this before is because most seek daemonhood not martyrdom. But influence a bunch of loony cultists and who knows what they might do.

Seriously, what ever happened to death from above (from falling asteroids)? If it was good enough for the dinosaurs, it's good enough for some random planet that needs killing.

Also, why not just bombard the thing? Even with Thunder Macrocannon a hive should be relatively easy pickings.

Seriously, what ever happened to death from above (from falling asteroids)? If it was good enough for the dinosaurs, it's good enough for some random planet that needs killing.

Also, why not just bombard the thing? Even with Thunder Macrocannon a hive should be relatively easy pickings.

In general, I think you're right (and I personally endorse giant rocks from orbit if you don't need the planet for a few years).

In this specific case, Tobias Caine got really paranoid when he saw the Chaos forces rebelling in the system, and found the rumblings of a large warp artifact on the surface. He needed a last ditch, everything-must-die option with as much collateral damage as the God-Emperor would allow.

Caine's response to most situations is actually orbital bombardment.