The Titan question (and some other older threads on this forum) made me ponder some more about the use of ships versus planets. To simplify matters, let us first discuss the use of ships. There will be others, and we could use more modern concepts. The concepts of strategic and tactical use of airpower have been far further refined. But they should do for now.

- To start with there is the 'naval' blockade. Ships can blockade a planet and ensure no large amounts of cargo/people/troops enter or exit a planet. It will be hard if impossible to stop anyone entering/exiting a planet without smothering the Void around a planet with ships (of which a few should be carriers), but a steady patrol can stop most communications. Depending on the target planet, this can be quite pointless or devastating. A hive world needing constant food supplies would face starvation very soon and might be amenable to reason. A feudal world will be absolutely unimpressed (even if the few astromancers will be amazed at that odd new star in the skies).

- Then, there is the 'Strategic Air' scenario. This necessitates a ship to enter low orbit, from which it can rain down destruction on a vast scale. Cities, industry, army bases...all are viable targets. In this case, think of the Allied bombing campaigns against germany and Japan in WW II. A protracted campaign can inflict untold harm on any society, and especially civilised societes seem vulnerable. Bombing back Savage Orks to the stone age will be a bit tough. But making a Governor of a luscious civilised planet quail in fear might be quite a bit easier.

- Finally, there is the 'Tactical Air' question. A ship in low orbit bringing its devastating firepower to bear on a battlefield itself. Artillery is the God of War, and what gives more "oomph" then macrobatteries and lances? Problem here is of course, that devastating might not be limited to the enemy alone.

Now, how to rule all of this.

- The Naval Blockade: Basically, this depends on preventing getting stuff in and out of a planet. I suppose one ship can only guard one half of a planet at the same time, but if it flies in an orbit around earth it should be able to make the full circle around a planet in a number of hours (Low Earth Orbit is about 90 minutes in comparison). The crux here seems to be on detecting attempts to get in and out of the system. Quick fast shuttles making a run for it when a ship is on the other side of a planet should have a good chance, big lighters taking off might be easy targets. For an efficient blockade, two or more ships seem to be the best option. The biggest advantage for a Rogue Trader of a blockade is that it can be mounted at distances where he should be impervious to planet based defences. The problem is, as with all blockades and embargoes, that it normally takes a long time before its effects are felt.

- Strategic Bombardment: Now we get more violent. A lot more violent. I should probably mention that the first question here is a moral one, but luckily we are in the WH40k Universe here and we all know morals have been superseeded by Faith in the God-Emperor, just as the only good rebel/heretic/xenos is a dead one. So, we can happily go on with the technicalities, knowing that consigning millions or more to a fiery oblivion is a virtuous act if it serves the Imperium of Man. And killing millions is certainly a possibility here. According to the rules in BFK, we talk off utter annihilation within square kilometres. One ship in low planet orbit sailing by can map out its targets and give each a taste of lance and macrobattery fire as it passes...or worse, enter stationary orbit and rip half a continent apart, carefully working over the ground knocking out any big enough target to warrant attention. Obviously, civilised systems will have defenses against such a threat, so we will might see an interesting fight between the defenses and the space ships, just as we have the real world duels between air defences and air power. Here we have fighter and bomber aircraft attacking the ships, planet based missile silos unleashing their torpedos and well dug in lance and battery weapons hammering at shield and hulls, while at the same time the ships (and their ordinance) try to knock out the defences, jam, disrupt, feint....the possibilities are endless.

- Tactical Support: This is quite a bit more difficult. If it doesn't really matter that you miss a Hive Spire during your Strategic bombardments (hell, the idea is bringing destruction), missing your foes in a battle can be a serious problem. Especially as you hit your own troops at the same moment. The rules in BFK give an interesting start here, and I dug in my library to get some interesting rules from Epic Armageddon as well. Different system, I know, but I see no reason not to use it as an inspiration. Interestingly enough, you can use ships weapons in Epic battles, even if they are less all destrcutive there then they are in RT. Bascily, a ship can launch a predermined macrobattery barrage (you have to announce before the battle where and how it will land...I see the logic of a ship cresting the planets horizon, augur arrays scanning the ground and fire control plotting the barrage), launch a preplanned assault from space (again, lots of plotting to be done) and use its lances for 'pin point' attacks (who happen to be Titan killers by the way). I specifically like the preplanning of the battery fire and the assaults. It gives a very Imperial rigidity to warfare and allows for interesting planning and enormous **** ups ('My Lord Captain! The enemy retreated and we took the hill. The victory is ours! What did you say my Lord Captain? Retreat...yes...but...ooh Nooo").

All in all, ships versus planets give a load of interesting game possibilities. As most of the aspects mentioned here can give epic RP moments. Are you capable of breaking the will of the defending oligarchs after you have destroyed their Orbital defence stations? Do you succeed in your commando raid on the main Augur array coordinating the torpedo and lance batteries of Retzivan VII? Can you draw in that ork advance on the preplanned killing zones? And will they notice the hidden transponders guiding your Arc Light mission?

Friedrich van Riebeeck, Navigator Primus, Heart of the Void

Both Battlefleet Koronus (Rogue Trader) and Rites of Battle (Deathwatch) have rules to involve a space ship into combat with the surface. As for the blockade, you don't need more than 8-12 ships to cover a planet's access with a 99% success. After all, it's not about being into a position to hit the target, but to intercept it. Four ships would be the bare minimun to blockade a planet, however.

Also, Battlefleet Koronus has rules for the application of bombers into the battlefield.

Well, a blockade can obviously have different levels of intensity. The easiest one to maintain is a distant blockade, where it is rather the void around a planet rather then the planet itself that is blockaded. The main effect of this would be to block inter system traffic and most system traffic, but would not severely affect the close traffic around a planet . Compare this to the distant blockade of Germany by Great-Britain in WW II. Very hard to impossible to reliably realise crossoceanic trade, some blockade runners, plenty of coastal and inner sea traffic. This is a matter of gaining void supremacy in the system and intensive patrolling and hunting down of enemy ships.

The next step would be close blockade of a planet. This would involve gaining direct void control over the orbit of a planet. Depending on the foe, this might involve intense battles with the orbital defences and any ships that might have retreated within their cover during the esthablishment of the distant blockade. Once an enemies orbital defences have been destroyed, it will be very hard for a planetbound opponent to do anything about it. Planetary defences will only be efficient against ships entering the near orbit, and the close blockade can easily maintained outside their reach. Planetbound defence systems will only come to their own when ships start later phases, such as a strategic campaign (see above) or direct planetary assaults. How many ships are needed will probably depend on the size of the planet as well (even if humanity capable planets will be in a comparable range, as the gravity of huge planets seems to make human habitat there very hard). If you wish to prevent any serious communications with the outside world, a few ships should suffice. To cut off any contact, you will indeed have to smother the space around the planet to ensure not one small craft escapes and heads for a hidden raider to carry it out of the system.

Mind you, this is written from the side of the attacker, but makes of course great material for defence adventures as well. Running the Ork Blockade, an orbital battle againts Karak Vall's Raiders or getting a vital person from a Thulian besieged planet make for great adventures.

FvR

There is also the "Total Annihilation" scenario.

This scenario requires the use of a specific class of weapon - specifically the Nova Cannon. Depending on the exact term of the Rogue Trader's warrant, some Rogue Traders are empowered, if not obligated to eliminate threats to humanity's expansion outside the borders of the Imperium.

Sometimes the Rogue Trader will find a resource laden world that is already populated but hostile to the Imperium. Maybe its infested by Xenos or Chaos worshipping humans. Assuming the resources of the planet can be harvested after Nova Cannon shelling (eg mineral resource rather than ecological), Total Annihilation becomes a viable option, which is in fact much safer than Strategic or Tactical Air as the ship does not have to expose itself in Low Orbit.

A shell from a Nova Cannon is an imploding charge with an area of damage 2.5 times the diameter of the planet Terra. On a direct hit, any planetary structure or geological structure within approx 5,000 km the source of impact is totally destroyed. Within the area of damage (approx an additional 5-10,00km), all structures will receive massive structural damage and geological structures will suffer heavy damage. On a planet with an atmosphere, the actual structural damage from the shell is lessened somewhat but is compensated by the supersonic windstorm created as a side effect by the imploding nature of the charge. Should a shell penetrate the surface deeply enough on a planet with a molten core, it is possible that planet wide seismic activity will be triggered. In short - a single Nova Cannon shell can be considered an extinction level event, multiple shots can be used as a crude form of Exterminatus.

You're forgetting one thing when it comes to nova cannon shots and planets. A starship, which is a lot smaller, is not guaranteed to be killed by even a direct nova hit. Granted, more of the explosion will strike the planet. But unless it's a pretty small planet, it'll still be there albeit with horrendous damage to the atmosphere. Shielded facilities, especially on the other side of the planet, are likely to survive. There's also the matter of the locals fighting back and what happens when masses of debris are loosened in the event of success. That patch of space would become hazardous to shipping *very* quickly.

To be honest - as with all fights, its a matter of choosing who to fight and how you do it.

Anyone without ship grade materials and armor isn't going fare well against a Nova Cannon. However, even a world with no warp travel tech but has a fleet of intersystem monitor ships is going to be hard to conquer or subjugate.

This tactic is most useful when the planet in question has a huge population and few space defenses (say Earth's current state of technology). Feral ork worlds and Eldar Exodite can be dealt with this way once you disable the orbital defenses left behind by their more advanced kin. As can pre-stellar Xenos race you come across.

Alternatively this can also be used as gunboat diplomacy - fire off a shot at a smaller settlement to show how much force you can bring to bear - then negotiate.

Other ways to conquer a much larger army is to use the conquistador method of allying with locals and destroying the army in portions.

My suggestion? Use a virus warhead. Must be a planetkiller type though.

1: Destroy all biological matter within a few hours.

2: ???

3: Profit.

Nova Cannons are truly problematic. They range from plasma warheads which are akin to a simple nuclear explosion on a much larger scale. The Archeotech version fires off a vortex round.

Both can heavily damage a ship as per rules but have problems destroying one outright, unelss you get lucky (or unlucky).

But what would happen if you fired a Vortex shell at a planet? Planet vanishes within the warp? Part of it?

OTOH a plasma warhead would knock off 10% of the planetery matter; more; less? It could let you harvest the planetery resources in a more expensive (send in the mining ships) but a more complete (mine the planetery core as well) method.

On the more general matter of attacking a planet.

1. You try to achieve orbitgal supremacy. You do not bombard city centers, since ín the galaxy of 40k there is no surrender. Since this is 40k, quite often you will failt to achieve true orbital supremcy (see 3rd Armageddon war or The Frozen reches)

2. You land troops at prepared locations. These can be places which have been saturated by macrobattery fire. Maybe you only send in a wing or two of marauder bombers clearing a landing zone. First you send in the shock troops and regular tank regiments. Later on you will land superheavy tanks/titans and mroe importantly the artillery regiments.

3. You are now ready to root out the enemy positions. Orbital or atmospheric bombardement is available for shock tactics against strong enemy locations. Enemy void shielded fortresses and underground locations will be either leveled with intense lance strikes leaving an area totally useless afterwards (think major landscaping); otherwise you send in those precious troops you have.

4. Space Marines can truly shine with these tactis, since they are essentially siperheavy paras. Using these elite supersoldiers you can circumvent the primary problem of all paras, the lack of heavy equipment.

Now if you are the defender:

1. You will try to get your stupid leader of a planetery governor to allow the spaceborne assets to fight a sweeping battle of mobility. (see: Mansteins bachhanded blow) A total blockade is too much like WW1 style warfare, only asking fo rhigh losses on both sides. Using thses tactics you can hope to let the enemy try to get his transport vessels towards the battle in an escort style. At this moment you will strike his only asset worth attacking. His troops. (Space marines also shine here. They have huge oversized vessels to get them towards the planet with little losses)

2. Once the landing operations begin, you will use atmospheric assets to catch dropships and bombers before they can do too much damage.

3. Depending on the sitation in orbit. You either have lost all hope of orbital balance and will try to fight it out regardless. Or maybe you have achieved orbital balance and can fight without the worry of lance strikes and macrobattery fire.4. If you lost the battle in the void totally, you will now scatter your forces to smaller formations, and fight guerilla style. This does not mean that ground forces will only fight platoon sized, as even larger formations will be able to hide from orbital sensors (mountains or forests). You will try to fight as close to the enemy as possible. Lance strikes are precise (within a few dozen metres; see: 40k tabletop and if you can hit a ship at 15 VU you can hit a big house on a planet) but friendly fire can happen and no one wants to have lance explosions continually rolling over your own troops.

4. Once the ground troops are destroyed, you have to hope void ship reinforcements have arrived, or the enemy has no interest in burning your planet down to the ground.

Small distraction of orbital bombardement.

Accuracy is NOT a problem. A Lanceshot is energy (AFAIK) which will not be deflected much by the atmosphere.

It can hit a raider (cobra) going 20 VU per hour (200'000 km/h) which is only 1.5 kilometres long at a range of 24 VU (Godsbane lance; thats 240'000 km). Why would it miss as much as 1 kilometre at a range of 300km? Assuming the problems for long range and orbital fire are about the same (so i dont have to guesstimate additional penalites), hitting the cobra at around the 800 times farther range means we get to divide the target radius (750metres) by that number. So your Godsbane lance just hit the target within less of a metre.

Sry have to go for lunch, further musings will follow.

So picking up with our lance strike accuracy.

If we take less extreme examples, we still can only agree that lances must be quite precise, taking less accurate (shorter range lances) we still hit an accuracy of a few metres. Coupled with potential divergence of the beam by the atmosphere, we can maybe agree on a few dozen metres.

Unless lances do not create explosions reminiscent of small nukes (which they do) we get the problem, that lances are more accurate than the ensuing explosion radius.

If a lance obliterates everythign within a hundred metres of the target, you will still get a kill on said target.

Now lances do have the problem, that a void shielded target will be able to survive. A lance puts its power into too short a timeframe; the void shield will not break down, regardless how much power you pack into such a short punch. Solutions are to use either a lance battery (Admech Gothic class cruisers have 5 lances for bombardement) Or aquire an archeotech longburst (fires long enough that void shields break down after a while) lance.

Next possibilty: Torpedoes (Nova cannons have been doen i think ^^)

A torpedo is nothing but a plasma (melta/virus) explosion. Anythign within the impact will be vaporized. If a torpedo does 2d10+15(-armour) damage against a ship, no human can survive. Carries nothing comparable to naval armour (even Space marines dont have as much armour as the metres of adamantium a Lunar has).

We do have the problem of accuracy due to atmosphere though. Guidance systems are designed for the void after all. No stabilization fins exists. But does it need some? Problematic would also be the cogitator systems, which have been optimized to track HOT (plasma drives) targets. You are effectively dumbfiring (+ a little precalculated flight path maybe) them.

So accurcay might prove to be a problem (aim whole ship, no cogitator bonus); but firepower should definitely be more than what DW suggests (only gives krak missile damage).

Macrobatteries (last but not least; especially if you use no house rules):

The same problems that lances have, also applies here. And finally to all you nonbelievers: A ship in orbit does not fire at relativistic speeds! The atmosphere does NOT burn up those precious macroshells. Thats why its called an orbit.

Beyond that, macrobatteries are probably the one solution that has you laying waste to a whole area, but you also have the smallest explosion effect per shot. basically you are firing stuff witgh the firepower of Mininukes (nice but a few dozen to a few hundred metres) which can only be balanced by firing more shells. Sunsears would be at the short end of the explosion radius or other smallish weapon systems, with bombardement cannons being on the far end explosive firepower.

A single Meltashell destroys a whole hab block for example. (Nightbringer novel)

So this is from me, on orbital destruction by the militant Rogue Trader.

Hope you like it .

I like it, I only would never bring in an invasion fleet before achieving Void Supremacy or at least dominance. Just as the British did in the Falklands, first ensure the hostile fleet is out of action (by destroying it or chasing them back to port), then bring in the landing ships and disembark. Fighting through a landing force against main opposition is both very dangerous and only needed if time is of the essence. Otherwise, just take your time. As soon as you dominate the void around a planet, there is very little the planetside opposition can do against you until you enter orbit.

As for the defending side, to take a naval comparison to the brilliant Manstein (in my opinion the absolute master of manoeuver warfare in WWII), it is of importance to keep a 'Fleet in Being'. As long as you have the voidships to strike your foes, they will have to take them into account. Slugging it out with orbital defences or bringing in a landing force can become a debacle if an enemy strikefleet hits you when you are at your most vulnerable. So, again, first win that battle for Void Supremacy or have a vastly superior force ready.

FVR

Was thinking of torpedoes myself - the problem with torpedoes is that they are 1) armor piercing and 2) tracking

1) Armor piecing will make torpedoes very very bad against soft targets. Because they do not explode on impact, against anything that is not made from at least meters thick metal, a torpedo will penetrate far too deep into the earth before exploding. But then macrobatteries will chew those types of targets up anyway.

2) Tracking might be very problematic if there are many large metallic targets in the area besides your primary target. Without knowing how torpedoes actually track its hard to comment on this.

Hmmm what about torpedo bombers?

Undoubtedly, the Imperium will have made torpedoes for Orbital bombardment, but they will very likely differ from the void vrs void anti ship torpedoes. But with the vast amount of launch tubes an Imperial Fleet had, it is unthinkable they would not have made provisions to use them to attack and conquer planets. Things to consider are indeed:

- Different guidance systems. The cogitator scanning the void for the profile of voidships will in all probability have no chance to securely home on a planetside target unless it has the size and profile of a hive city. Against which a classical torpedo might be devastating by the way, an armour pirecing plasma warhead detonating in a hive can't be good.

- Different range. The vast range of 60 VU is not needed, so more place can be given to a warhead or speed, probably even both.

- Different warheads. Although here one is limited because if memory serves the plasma drive of a torpedo is part of its warhead. But against an area target, you wish to have a vast blast effect that would only scorch the outside paint of a voidship.

FvR

Yes there might be more types of torpedoes, but explode on impact would be kind of rare given their limited use since they do have very limited use (they will be very very vulnerable to being shot down for example.)

That being said, I tend to favor macrocannons (especially laser ones), lances & space/atmosphere capable aircraft - for versatility and logistical purposes. Even for mass combat, I favor laser weaponry (yes they are usually torchlights, but multi-lasers and lascannons are really big ones) over SP or bolt weapons. For limited ammo support, I favor grenades and missiles as they are very common as opposed to most other heavy weapons. For ground vehicles, I really like the Sentinel. It can serve as a weapon platform as well as a cargo unloading vehicle.

While love torpedoes in BFG, the limitations of stocking and storing torpedoes in RT, puts me off using them. The limited number of salvos (4-8) they can fire (even a nova cannon carries 20 shots) really limits them especially in RT where the theme is on long range missions such as exploration and restocking is not something you will be doing often. On the other hand, if I did obtain an escort/transport fleet for maintaining trade routes, I would not be adverse to equiping these ships with torpedoes as these ships do resupply frequently.

The nova cannon attracts me for totally different reasons. Its the BFG of spaceship combat, it huge, very destructive and is not hidden even if powered down. This makes it a weapon of intimidation as well as a weapon of destruction. Its difficult to use and so you can get by combat without firing the cannon even once and it would still be considered a threat. The versatility of the Nova Cannon is not so much what it will do but what it CAN do.