From: mikkelhaaheim@gmail.com   
      
   Le lundi 24 octobre 2016 02:54:00 UTC+2, Rick Pikul/Chakat Firepaw a écrit :   
      
   > Interplanetary flights involve months, if not years, of floating out    
   > where the only control required is watching for course deviations.     
   > Computers are really good at spotting such deviations.   
      
   Computers are good at spotting such deviations IFF they have sufficient   
   processing power to handle the workload, AND IFF detectors are sensitive   
   enough to provide the required information.   
      
   >    
   > You _might_ have a single live communication each day or so, but even    
   > that is likely to be largely automated.   
      
   This is ture, but irrelevant.   
      
   >    
   > > The best military software in existence allows a single operator to   
   > > track perhaps a dozen or so targets. Most systems will only track about   
   > > half that much, and some can only track two targets at a time. I am not   
   > > even talking about projecting courses, here. I am talking about tracking   
   > > the path they have already flown.   
   > > So, yes, it is a hard task.   
   >    
   > Your high number is for a fighter's targeting radar, (and low even for    
   > them, the AN/APG-63 that the F-15 uses could track 14 targets with the    
   > version that was in use 20 years ago and has been improved twice since    
   > then), not for area surveillance.   
      
   Yes. Those systems have improved somewhat. As of ten years ago they could   
   track 16 targets. I would not be too surprised if todays systems can track to   
   dozen.   
   OTOH, I should have specified that I was refering to single operator, combat   
   capable, systems. The larger systems found in Sentry and JSTARS type platforms   
   can handle up to 600 targets, assuming they are travelling against precisely   
   mapped terrain    
   backgrounds.   
      
   >   
   > They are also doing the two things you need to do to avoid detection:     
   > Not thrust and generate no waste heat.   
      
   OTOH, they are not controlling solar reflection nor heat rejection from solar   
   absorbtion. Since they are taking no active measures, they are FAR easier to   
   detect. They also tend to stay in predetermined orbits... until they drift   
   through a planet's    
   gravitational sphere of influence.   
      
   >   
   > Changing your course is also called "making yourself very noticeable."     
   > This is because you either have a nice bright exhaust plume, a nice hot    
   > reactor, (possibly both), or large amounts of solar panels or solar sails.   
      
   Not necessarily. There have even been testbed NTR thrusters that operated on   
   20°K exhaust. Yes, that is 20° KELVIN, NOT centegrade. These testbeds were   
   certified for flight testing... unfortunately, the programmes were shelved   
   before flight models were    
   actually flown.   
   Ion or electrothermal engines might make slower corrections, but they are   
   equally useful. Their exhaust plumes are barely detectable, even from within   
   their testing chambers.   
      
   >    
   > Remember that you don't get to go days between scans.  You are going to    
   > be scanned multiple times per hour.     
      
   This is incorrect. Under ideal conditions, the scan will take 1 day. The   
   estimate you are referring to had been corrected.   
      
      
   > And "knowing what everyone else is doing," is an important part of that    
   > budget.  This only becomes more important when just about every ship out    
   > there is a weapon of mass destruction.   
      
   But the ugly reality is: THERE ARE ALWAYS TRADE-OFFS. Intelligence NEVER gets   
   everything they want, nor even everything they actually need. Neither do the   
   ground pounders or flyboys.   
      
      
   > First of all, let me tell you of a little truism:  Quantity is a quality    
   > of its own.  Even if we assume that a military sensor platform is half as    
   > likely to detect something as a scientific one, you only need three or    
   > four to be more likely to get a detection.   
      
   Quite a bit more, actually. Half the sensitivity actually means 1/4 the   
   detection range. That greatly increases the number of platforms required to   
   fill in the gaps.   
      
   >   
   > Furthermore, remember that the sky scan numbers are for what you or I    
   > could buy off-the-shelf over twenty years ago.  Even if we were to assume    
   > that the military, (and civil traffic control), is using outdated gear    
   > that still means that they are going to be using stuff better than anyone    
   > can get today.   
      
   except that these numbers were based on faulty info.   
      
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