How easy is it to hide in deep space?

[Korzon77]

I was thinking about the idea for dropship tenders, probaly using the 1/2 speed you see on the Aquilla.

So if one of these jumped in, then decided to "hide" in deep space, how hard would it be?  After all, a tender doesn't want to get into the thick of things (well not always) and so the logical idea is to keep in touch with teh fleet via laser or some other directional system and then try and make it impossible for the bad guy to find them.

[Mendrugo]

Strategic Operations has a whole section on detecting objects in space. 

Jump signatures are detectable from quite a distance, so it's hard to disguise the fact that something just popped into the system if the local defenders have enough tech to look for that sort of thing.  That being said, the detection range isn't infinite, and if you jump in far enough from the system and are willing to spend a while getting to the target with maneuvering drives, you could make a stealth insertion.

You'd want to keep your engines pointed away from the enemy at all times, though, since the light and other emissions from the drive flare are also detectable from a fair distance.  This makes the whole 'accelerate to the midpoint, flip over, and then decelerate the rest of the way' technique somewhat non-stealthy.

And then, of course, you'd want to maintain radio silence and shut down your active sensors.

If you do that, you're a cold, silent needle in a very big haystack.  During the...War of 3039?...a FedSuns Fortress-class DropShip got lost during an assault.  Dozens of ships combed the system for weeks looking for it, with no luck.  And that ship would've been trying to be found.  Another example - the Blakist base at Gabriel, in the Odessa system, maintained operational secrecy for centuries, moving ships in and out of the asteroid shipyard in the remote reaches of the system without anyone detecting their presence.

[cray]

So if one of these jumped in, then decided to "hide" in deep space, how hard would it be?  After all, a tender doesn't want to get into the thick of things (well not always) and so the logical idea is to keep in touch with teh fleet via laser or some other directional system and then try and make it impossible for the bad guy to find them.

Do you have Strategic Operations? Sensor detection ranges are presented there.

As Mendrugo said, jump signature detection is at very long ranges: 10AU or more, depending on how many collars your DropShip has.

The sensor with the next longest range is a drive plume detector with a range of tens of millions of kilometers.

After that, you have radio triangulation, radar, IR and optical with ranges of under a million kilometers, give or take a bit.

So if you're willing to stay hours away and keep your engines off, then you can be pretty stealthy fairly close to a planet.

[ShadowRaven]

so useing our own Solar System for an example, how far out from earth would you have to be when you jump in to avoid detection? Jupiter? Beyond Pluto?

[Moonsword]

I'm assuming you're talking about detection from Earth as a hypothetical.  Call it about halfway between Saturnian and Uranian orbit for a reasonable safety margin on the detection ranges, which also has the fringe benefit of evading Martian observation points.  Keep in mind that a system may well have detectors at the zenith and nadir points.  Coming in at the position I mentioned will also evade those.

You can also, assuming only one point of detection (not a safe assumption in many cases), simply arrive on the side of the star opposite the target's orbital position and use its emissions to hide your own.

Note that in BattleTech, you've got to come in significantly farther out - the Belters apparently maintain their own detection environment as part of their autonomy from interference by ComStar or the Word of Blake.  This extends the detection envelope around the system periphery quite a bit and not necessarily predictably.

[Arkansas Warrior]

The BattleCorps stroy "Grand Masters" is a great little story that uses this exact concept (remaining hidden in space) as a central tenet.  Suffice to say I hope your crew packed for a Tharkad winter, because it's going to get cold.

[Korzon77]

Another thing, if you look at hte speeds you can get under constant acceleration, even moving at jumpshiop station keeping drive speed (which probably makes it harder to see than a h7undred mile long blowtorch), gets you a long, LONG way from your jump poing pretty quickly.

[Moonsword]

I think you mean station-keeping acceleration (0.1 G).

[ShadowRaven]

yeah, forgot about them Belters. Still, that gives a good idea, and it amkes things like pirate points, and secret insertions, and ships like the Bug Eye a lot more understandable

[cray]

so useing our own Solar System for an example, how far out from earth would you have to be when you jump in to avoid detection? Jupiter? Beyond Pluto?

Earth's orbit = 1AU radius.
Mars = ~1.5
Jupiter = ~5
Saturn = ~10
Uranus = ~20
Neptune = ~40
Kuiper Belt = 40-80

Jump signatures are 10-15 AU in radius. With that sort of radius, you don't need a lot of satellites to monitor for arriving jumps out to, say, 40AU from the star. Most folks probably wouldn't bother beyond 100AU unless they live in a star system with a particularly bright star.

Note that in BattleTech, you've got to come in significantly farther out - the Belters apparently maintain their own detection environment as part of their autonomy from interference by ComStar or the Word of Blake.  This extends the detection envelope around the system periphery quite a bit and not necessarily predictably.

I agree since I wrote the Belters and put them in the Kuiper Belt and Oort Cloud, but where're their sensor capabilities published?

[Moonsword]

There weren't any specifics.  I'm making a guess that they maintain at least some capabilities along those lines based on this line in JHS: Terra, "Other than to maintain the system’s isolation, ComStar asked little of the Belt[,]" as well as mention of their aerospace defenses being formidable.  Since a lot of the Belters live in places where very close proximity jumps are possible, having at least some emergence detectors seems likely, and it would assist in deterrence.  How many and where, on the other hand, I wouldn't care to hazard a guess.

EDIT: I'm also not going to claim that this is the only interpretation of the evidence, especially not to the guy who wrote the lines.  It just seems like something at least some of the outer system Belter colonies would do.

[greatsarcasmo]

How far (ball-park) are Nadir and Zenith jumpoints in AU? I think my now lost Battlespace rulebook had it in there, but...

[Mendrugo]

How far (ball-park) are Nadir and Zenith jumpoints in AU? I think my now lost Battlespace rulebook had it in there, but...

It really depends on the star.  There are tables in AT2 and Strategic Ops (even all the way back to DropShips and JumpShips), as well as BattleSpace.  The bigger the star, the farther away you have to go to get out of the gravity well.

[Arkansas Warrior]

I think he was asking specifically about the Sol system.

[Weirdo]

Can't remember where it's written, but Sol's jump point distance is about 10 AU from the star, or roughly Saturn's orbit. Obviously jumping near Saturn itself would be made difficult by the gas giant's gravity(and possibly the other giants if they're nearby along their orbital paths), but you could probably jmup in relatively close to it. Explains all the shipyards built over Titan. You could build a JumpShip or WarShip there, and once complete you'd only have to burn for a short distance before you could jump at will.

[cray]

How far (ball-park) are Nadir and Zenith jumpoints in AU? I think my now lost Battlespace rulebook had it in there, but...

Any book (DS&JS, Battlespace, Explorer Corps, AT2, AT2R, SO) with the chart of distance to proximity jump points will tell you because the zenith and nadir are special case proximity points. In the case of Sol, they're about 10AU from the north/south poles of Sol (and Earth, for that matter, since Earth is proportionately quite close to the Sun).

Red dwarfs can cut that to 1AU, while the brightest stars exceed 100AU.

There weren't any specifics.

I always figured that any well-developed system would have a constellation of satellites in the outer system (and, in fact, several shells of them) looking for JumpShip traffic. I'm sure the Belters have their own systems, too, but the default system defenses would fall on Terra/Comstar/WoB.

[Moonsword]

I understand why you'd include it for the sake of completeness, but would you care to speculate on why someone would want to be hanging around a class O hypergiant other than scientific curiosity?

[Weirdo]

To make sure there's no Tetatae. You can never be too sure. ;)

[Moonsword]

To make sure there's no Tetatae. You can never be too sure. ;)

Nukes, orbit, large planetoids diverted for major collisions, etc.

[cray]

I understand why you'd include it for the sake of completeness, but would you care to speculate on why someone would want to be hanging around a class O hypergiant other than scientific curiosity?

...where did that question come from? O-type giants aren't even on the proximity point table.

[Moonsword]

...where did that question come from? O-type giants aren't even on the proximity point table.

Response to this right here:

Red dwarfs can cut that to 1AU, while the brightest stars exceed 100AU.

I was just wondering if you had any idea why someone would want to do that.

[Arkansas Warrior]

They're pirates.  What?  No one would think to look there, and they use pirate points. O0

[Moonsword]

That applies to being in any uninhabited system or really anywhere else you wouldn't expect them to be.

[cray]

I was just wondering if you had any idea why someone would want to do that.

Even bright F and A class stars have nearly 100AU proximity limits, to say nothing of B class stars. So I don't understand where the O-class stars came into the discussion. Did you look at the proximity point distance table?

[Moonsword]

Even bright F and A class stars have nearly 100AU proximity limits, to say nothing of B class stars. So I don't understand where the O-class stars came into the discussion. Did you look at the proximity point distance table?

I thought I'd said "no" in response to that the first time around, but evidently it got lost somewhere.  I'm kind of dubious on B class stars, honestly, let alone the Os I thought you were referring to.

[cray]

I'm still completely lost. How does any of this apply to detection limits? Please, be verbose because the previous few posts have left me in a state of confusion.

[Moonsword]

Ah, okay.  It didn't have anything directly to do with it - I was responding to your point about the brightest stars with curiosity as to why someone would want to be hanging around a star like that (even a B-type star), detected or not.  They just don't seem to have a lot to recommend them for most purposes.  I suppose the sheer brightness (and consequent ability to plot them) might make them useful for navigation in some circumstances...?

My apologies for causing any confusion.

[cray]

Ah, okay.  It didn't have anything directly to do with it - I was responding to your point about the brightest stars with curiosity as to why someone would want to be hanging around a star like that (even a B-type star), detected or not.  They just don't seem to have a lot to recommend them for most purposes.  I suppose the sheer brightness (and consequent ability to plot them) might make them useful for navigation in some circumstances...?

Ah, okay.

The answer is: because BT puts habitable planets around such stars. Not O-class, but there is one or two B-class stars with habitable planets and some A-class. Plenty of F's, too.

[Moonsword]

I'm not even going to ask how a viable biosphere emerges around a star like that despite the short lifespan.  I'm just going to repeat the MST3K Mantra and enjoy the stompy robots.

[Jackmc]

It really depends on the star.  There are tables in AT2 and Strategic Ops (even all the way back to DropShips and JumpShips), as well as BattleSpace.  The bigger the star, the farther away you have to go to get out of the gravity well.

Sol's is 10 AU out.  If you jump in ~16 AU (allowing a margin of error for the max 15 AU detection range) from both Sol and the Zenith or Nadir, that'd put you about 22.7 AU which is approximately 14 days out from Terra on a 1g burn.   

-Jackmc