?

Brigade XO wrote:Forts do have some mobility but that is both mostly station-keeping and ability to move around for maintenance or other reasons. The Junction forts for the MWHJ rotate duty, which I had taken to mean that they repositioned when coming off a week to a month or so of being on-station and then changing the guard so they could be off line.

Having a steathed for planetary defense sound great but what do you do when you have to rotate crew and/or do resupply? The shuttles and cargo lighters would also have to be stealthed which would be interesting for Astro Control. There would be a bunch of "restricted" areas in the navigable areas around the planet that would highlight that something was there that someone didn't want anyone going near. Then there is the movement of people that would entail. Sure, the shuttle's (at least) would be leaving from the military areas of your orbital station but that would be good blocks of people coming and going at regular intervals not associated with ship movements.

penny wrote:It should be impossible to see anything orbiting the planet with wedges down. That is the entire point that Jonathan made upstream where I agree. There is nothing as stealthy as an object without a wedge. That is natural stealth. Going dark. That fact is responsible for Admiral Courvosier's death.

Jonathan_S wrote:But something the size of a fort orbiting near a planet should be a lot easier to pick up optically (or via IR emissions) than a ship, or remote platform, way off in the depths of space. And it's even more obvious if the fort happens to transit the face of the planet while you're looking at it.

ThinksMarkedly wrote:

Jonathan_S wrote:But something the size of a fort orbiting near a planet should be a lot easier to pick up optically (or via IR emissions) than a ship, or remote platform, way off in the depths of space. And it's even more obvious if the fort happens to transit the face of the planet while you're looking at it.

Right, the problem is that there's no such thing as perfect stealth. You have to depend on the other side not scanning too closely in the volume you're in: any stealth can be defeated with enough scanning, close enough scanning, or the right type of scanning (or more likely, a combination of all of them). You can't hide a fort because it's too massive and in an obvious location: around a target that must be protected.

Honor could see the ones in orbit of Galton because they weren't trying to hide in the first place. And there's no point in hiding because she would have seen them eventually when the first or worst second drone shell arrived.

A command and control station that doesn't fire anything and therefore does not need to be close to anything in particular, is another story. That's what the Mycroft is.

penny wrote:I still withhold my vote. A massive fort in orbit is much less metal than a massive fleet; which storyline says cannot be seen until their wedges come up. If aggressive scanning can detect a fort, it should be able to detect a massive fleet as well.

Chapter 10 wrote:For all intents and purposes, surprise was total.
Commodore Yeargin's crews were still scrambling frantically to their stations when the first wave came in. Of her six heavy cruisers, two never got their point defense on-line at all. Three more managed—somehow—to bring their laser clusters up under computer control, but only Enchanter got off a single salvo of counter-missiles. Not that it made much difference. One hundred and six incoming missiles were picked off before they reached attack range; the other eight hundred and sixty-two raced in to twenty-thousand kilometers and detonated in rippling succession.
Nuclear explosions pocked space, each one generating a thicket of bomb-pumped X-ray lasers. It wasn't even a massacre, for there was nothing—absolutely nothing—between those lasers and their targets. It took less than four seconds for all eight hundred-plus warheads to attack. Sixteen seconds later, Shannon Foraker's second salvo streaked down on the stunned, mangled survivors, and when the last of them detonated, the Manticoran Alliance had lost six RMN heavy cruisers, three RMN and seven GSN light cruisers, and nine destroyers . . . without getting a single shot off at their attackers.

tlb wrote:

penny wrote:I still withhold my vote. A massive fort in orbit is much less metal than a massive fleet; which storyline says cannot be seen until their wedges come up. If aggressive scanning can detect a fort, it should be able to detect a massive fleet as well.

That is NOT correct, story-line is that passive scans have trouble finding ships until their wedges come up. You forgot that Shannon Foraker set up an attack at Adler that killed a bunch of ships with their wedges down. From In Enemy Hands:

Chapter 10 wrote:For all intents and purposes, surprise was total.
Commodore Yeargin's crews were still scrambling frantically to their stations when the first wave came in. Of her six heavy cruisers, two never got their point defense on-line at all. Three more managed—somehow—to bring their laser clusters up under computer control, but only Enchanter got off a single salvo of counter-missiles. Not that it made much difference. One hundred and six incoming missiles were picked off before they reached attack range; the other eight hundred and sixty-two raced in to twenty-thousand kilometers and detonated in rippling succession.
Nuclear explosions pocked space, each one generating a thicket of bomb-pumped X-ray lasers. It wasn't even a massacre, for there was nothing—absolutely nothing—between those lasers and their targets. It took less than four seconds for all eight hundred-plus warheads to attack. Sixteen seconds later, Shannon Foraker's second salvo streaked down on the stunned, mangled survivors, and when the last of them detonated, the Manticoran Alliance had lost six RMN heavy cruisers, three RMN and seven GSN light cruisers, and nine destroyers . . . without getting a single shot off at their attackers.

There are some other things that you have not included in your guess:

1) "Tourville's officers had known their drives and defensive systems would be needed, and they'd been at standby for over fifteen hours, but even with hot impeller nodes, they would need at least another thirteen minutes to bring their wedges up." A fort would take longer to bring up its defensive wall.

2) If a prankster takes your soccer ball and a bunch of your golf balls and throws them in the rough, you are going to have a much easier time recovering the soccer ball than getting ALL of the golf balls.

The sheer size of the fort makes it harder to hide and it is a much more expensive piece of equipment that most of the ships of the fleet. Therefore you cannot afford to have the sidewalls down on all of your forts, because a stealthed enemy could find and destroy them before their defensive walls could come up.

penny wrote:But I was under the impression that Shannon had already scouted the system and saw the ships with drones. The same way I assume Honor was aware of Galton's forts is from the scout's reports. But just knowing they are there doesn't mean you can lock them up to fire on them. Or can fire on them before they are locked up. Not that I am correct, but it is my take on it.

At any rate, why would an attacking fleet use passive scans???

tlb wrote:They knew that ships would be present, because Manticore had recently taken over Adler; but there was NO other scouting, not even by drones. They knew where they were once active scanning started and at that point they could lock and fire.

Any fleet is going to use passive scans, until they are in range to use active scans; because passive is FTL and the other is only light speed.

penny wrote:At any rate, why would an attacking fleet use passive scans???

Jonathan_S wrote:

penny wrote:At any rate, why would an attacking fleet use passive scans???

In part because active scans (aka radar) will be seen by the enemy, thus announcing that the attacking fleet is present and roughly where it is. And (thanks to that pesky inverse square law) if both sides have equally sensitive radar receivers the defenders can pick up the attacker's radar transmissions at over 10 times the distance at which the attackers can see the radar return off the defenders (and that's ignoring any radar reducing features of the defedder's ships).

So not only is active sensors (radar) slow, like ThinksMarkedly points out, but it announced your presence. So an attacking fleet would use passive grav (FTL) and optical/IR sensors both because they've longer effective ranges and because they don't highlight the attacking fleet's location.

Generally an attacking fleet would only fire up their active radar when either they knew they'd been spotted and are now looking for things trying to sneak up on them, or they're already in attack range and trying to use its higher level of precision to nail down a better target lock.