tlb wrote:Bill Woods wrote:Two-way video communication takes multiple megabits per second; that's high bandwidth. For fire control, do you think the data going one way and the commands going the other take more than a small fraction of that? I don't. Sure, since they've got it, they don't have to be fussy about compressing data, but that doesn't mean they need it.
Perhaps you and KZT are correct that high bandwidth is a convenience rather than a requirement, I do not have the technical knowledge to be definitive.
This is how I see the process. The Apollo computer collects the information from the sensors it controls and sends it to the SD computer for analysis. The unknown is how much data that entails. Raw sensor data from each missile could easily be several megabytes (one picture from my digital camera is easily that today). So we could have 8 or 9 sensor images times the number of bytes per image times the number of bits in a byte divided by the bit rate of the transmitter giving the time to generate the message. But maybe the Apollo computer can do some preliminary analysis to reduce this (we expect it must be able to do that, because it can direct the missiles it controls if the FTL link is lost). What is the resulting compression factor? After sending, it may wait 4 seconds until any answer can come back due to FTL delay. Ideally we want time to generate the signal to be much less than the time to travel to the ship, but is that a requirement or a convenience? How often is this process repeated and can it happen due to changes in target status before a response from the ship?
There is some truth to that. You are missing or
badly underestimating the degree to which the Mark 23-E analyzes, synthesizes, and compresses
on its own where the data feed from its slaved attack missiles is concerned.
The telemetry stream is denser than just "Go Here. Shoot
that ship," and the bandwidth
now available is enough for even the densest data stream. That was not the case at the time Apollo was first being designed, however. That degree of capability was still somewhere in the future, and they couldn't know how long it would take them to break through to it. The point that's been made by some of the other readers about the nature of the data transmission necessary to make Apollo
workable however, are completely valid. An Echo launches with an entire hierarchy of attack plans and profiles and the AI on board is capable of doing a lot of sorting and interpretation/interpolation to map the 3D battlefield all on its own. This means that the launching ship doesn't need to digest all the info coming at it from the Echo; it comes largely predigested, and all the mother ship needs to do is to combine the feeds from a dozen or so Echoes to fill in their mutual gaps. That done, it doesn't try to tell each Mark 23 how to attack. It tells its Mark 23-
Es what category of targets to attack and which penetration plan to use, and the AIs then sort out the details of applying those plans. It also explains why Mark-23 MDM salvos are at least as accurate
outside their maximum telemetry range as SLN SDMs are at
minimum range.
The launch ship can, indeed. send orders to attack specific targets identified by emission signatures or maneuvers. In many cases, that is precisely what the attacking CO would like to do. He just doesn't
need to do it that way, because of the capabilities the Echo bestows upon him.