Destroying Gravitic Arrays

munroburton wrote:Can gravitic arrays scan through a star? If the star creates a blind spot, then inevitably systems must invest in at least two separate arrays in locations far enough apart that there isn't a combined blind spot.

The text says that there is more than one array. It doesn't say how many there are, but we can be certain that the local star(s) don't block them all.

I expect that there are defenses in or near the system gravitic arrays. Any attack on the arrays would have to contend with them.

JohnRoth wrote:I've always imagined them to be something like the recent mission that mapped the lunar gravity field - two really simple satellites that used a laser ranging device to detect the subtle shifts in relative orbital velocity due to unevenness in the gravitational field.

There are advantages to having a few thousand relatively simple and relatively dumb nodes separated by hundreds if not thousands of kilometers and connected only by the beams of the ranging lasers.

Given sufficiently sophisticated analytical software, their positioning doesn't have to be all that good, either. In fact, there are real advantages to just sticking them in orbit and leaving them there until they have to be picked up for servicing.

Comparison to the lunar gravity mapping mission isn't bad, but probably not quite right. Since we know that a single ship, even a small ship, can detect gravitic signals, detection clearly does not require multiple independent detectors. A closer analogy is probably the Very Large Array, the array of radio telescopes in New Mexico. Hundreds or thousands of individual elements, each of which is a complete gravitic detector, combining their signals together to obtain a resolution equivalent to a single detector as wide as the farthest points of the array. It would not have the sensitivity (signal strength) of a single detector that large--the signal strength would only be the sum of the signals from the individual elements. But the array would be able to pinpoint the signals it detects with the accuracy of a detector that large.

SWM wrote:I expect that there are defenses in or near the system gravitic arrays. Any attack on the arrays would have to contend with them.

Maybe, but it's like having an AWACS orbiting the VLA. The megawatt radar will tend to reduce the accuracy of your sensors.

kzt wrote:

SWM wrote:I expect that there are defenses in or near the system gravitic arrays. Any attack on the arrays would have to contend with them.

Maybe, but it's like having an AWACS orbiting the VLA. The megawatt radar will tend to reduce the accuracy of your sensors.

Why would you think that? How much gravitic noise would a few shoals of mines, some missile pods, and some radar/lidar active detectors produce? If the defenses go active, that will produce lots of noise, sure. But under normal operating conditions there shouldn't be a problem.

SWM wrote:

kzt wrote:Maybe, but it's like having an AWACS orbiting the VLA. The megawatt radar will tend to reduce the accuracy of your sensors.

Why would you think that? How much gravitic noise would a few shoals of mines, some missile pods, and some radar/lidar active detectors produce? If the defenses go active, that will produce lots of noise, sure. But under normal operating conditions there shouldn't be a problem.

Since the arrays are sensors with warning bells of their own, they might automatically "shut down" and turn on localized search systems if something is too close. They probably have defensive wedge block buoys like the stations had, but I doubt they are kept at "hot" conditions like the station buoys - for obvious reasons.

Theemile wrote:Since the arrays are sensors with warning bells of their own, they might automatically "shut down" and turn on localized search systems if something is too close. They probably have defensive wedge block buoys like the stations had, but I doubt they are kept at "hot" conditions like the station buoys - for obvious reasons.

No, they were stated to be blind to things within a light hour.

kzt wrote:

Theemile wrote:Since the arrays are sensors with warning bells of their own, they might automatically "shut down" and turn on localized search systems if something is too close. They probably have defensive wedge block buoys like the stations had, but I doubt they are kept at "hot" conditions like the station buoys - for obvious reasons.

No, they were stated to be blind to things within a light hour.

I was about to say that the arrays could cover each other, but all of them are within a few light minutes of each other, aren't they.

Pretty much everything in a system is within a light hour of a star, so there must be a separate detection system for close in security and policing.

SWM wrote:

JohnRoth wrote:I've always imagined them to be something like the recent mission that mapped the lunar gravity field - two really simple satellites that used a laser ranging device to detect the subtle shifts in relative orbital velocity due to unevenness in the gravitational field.

There are advantages to having a few thousand relatively simple and relatively dumb nodes separated by hundreds if not thousands of kilometers and connected only by the beams of the ranging lasers.

Given sufficiently sophisticated analytical software, their positioning doesn't have to be all that good, either. In fact, there are real advantages to just sticking them in orbit and leaving them there until they have to be picked up for servicing.

Comparison to the lunar gravity mapping mission isn't bad, but probably not quite right. Since we know that a single ship, even a small ship, can detect gravitic signals, detection clearly does not require multiple independent detectors. A closer analogy is probably the Very Large Array, the array of radio telescopes in New Mexico. Hundreds or thousands of individual elements, each of which is a complete gravitic detector, combining their signals together to obtain a resolution equivalent to a single detector as wide as the farthest points of the array. It would not have the sensitivity (signal strength) of a single detector that large--the signal strength would only be the sum of the signals from the individual elements. But the array would be able to pinpoint the signals it detects with the accuracy of a detector that large.

I think we're talking about the same thing, essentially. I ignored the shipboard gravitic sensors because I doubt if they have the reach, and, like the fusion reactors, I don't know if they'd scale up. What I'm actually thinking of is the experimental gravity wave detectors like LIGO and Virgo, but scaled up for use in space. See Wikipedia (http://en.wikipedia.org/wiki/Gravitatio ... e_detector ). See LISA and DECIGO.

JohnRoth wrote:I think we're talking about the same thing, essentially. I ignored the shipboard gravitic sensors because I doubt if they have the reach, and, like the fusion reactors, I don't know if they'd scale up. What I'm actually thinking of is the experimental gravity wave detectors like LIGO and Virgo, but scaled up for use in space. See Wikipedia (http://en.wikipedia.org/wiki/Gravitatio ... e_detector ). See LISA and DECIGO.

Yeah, I figured LIGO is what you were picturing mentally. And it might be something like that. But gravitic signals do not behave at all like gravitational radiation. The physics is clearly unrelated. And since even drones can carry gravitic detectors that work for ranges up to many light-minutes, it seems unlikely that gravitic detection requires measuring a differential between separate sensors. That would make the arrays more like the VLA than the LIGO. But we don't know enough to be sure how the detectors work. With either the VLA or the LIGO model, larger size means greater resolution, so it works either way.