From: eripe.dk@gmail.com   
      
   On Thursday, June 16, 2016 at 1:43:14 AM UTC+7, Mikkel Haaheim wrote:   
   > Le mercredi 15 juin 2016 15:31:28 UTC+2, eripe a écrit :   
   > > > >    
   > > > > To go anywhere you will need to turn your drive on, and then people   
   will know your trajectory, and they will be able to calculate it very   
   precisely, so even if they can’t see you, they will still know where you   
   are.    
   > > >    
   > > > This is not so easy as the AR crew would have us believe. All   
   observation is essentially 2D. In order to determine the trajectory, you need   
   3D information. For example, is that 2km gas cloud travelling laterally to   
   your location? is it at an angle (   
   which means it is considerably longer than 2km)? Is it the entire cloud, or is   
   part of it being obscurred?   
   > > > Next, the detectors that can extract such precision data are extremely   
   narrow field. You need to now exactly where the target is in order to use it.   
   Burnsides 4 hour scan can only provide resolution of 1225 km^2/pixel at 1   
   AU... and that is    
   assuming you actually know the distance. At such low resolution, at such   
   intervals of detection, it will not be possible to maintain a position lock   
   long enough to bring the precision equipment into play.   
   > > >    
   > > >    
   > >    
   > > For this one, a few other detectors in say, Earth-Sun Lagrange points,   
   would let you triangulate.   
   > > Considdering how important it would be to have the intel of where all   
   dangerous vessels are, im sure we can do better than a 4 hour scan time. Just   
   spend 100 times the money, and your down to 144 seconds. (Im assuming the is   
   still small compared to    
   the cost of any spacecraft, and peanuts compared to a surprise visit from an   
   angry torchship)    
   >    
   > The triangulation will only work if two different observation posts happen   
   to be scanning the same zone at the same time, and happen to detect a   
   simultaneous reading. Even then, resolution is a big problem, because the four   
   hour scan, even if you    
   reduce the scan time through redundant observation posts, will not permit   
   accurate size measurements. You only know that there is something within about   
   a 40 000 km^3 swath... assuming that the distance from each observation post   
   is less than 1 AU.   
      
   For 99% of the sky, thats fine. If you get a blib, you can dedicate more   
   sensor resourses to that area.    
      
   > So, two problems here: low res, and very small likelihood that two   
   observation posts will actually be scanning the same patch of space at the   
   right time. This latter becomes even more difficult because in a future with   
   high volume space traffic, scans    
   from any single detector are going to identify potentially hundreds of   
   targets, which means you have to try to match the targets from the two   
   observation posts. This is even more difficult if you have dense traffic   
   patterns.   
      
   But not impossible. All legal vessels will be carrying transponders allowing   
   you to match them up with the blibs. If you get a blib without a transponder   
   you can put a kee   
      
   > Another consideration is the amount of money you are talking about, and the   
   strategic/political environment. For the former, you might think that 100 time   
   the cost of a small observation satellite is negligible... until you consider   
   that you have to    
   deploy that platform in space. In order to reduce the scan time by a factor of   
   100, you need to increase the volume (and mass) of equipment by a factor of   
   100. Interplanetary probe space flights cost tens of MILLIONS of dollars (or   
   much more... the    
   current count for the two voyager probes is reported at over $800 million, in   
   1970s currency). Multiply this by a hundred times,   
      
   Each ship in your own fleet will cary such a sensor package.    
      
    then multiply that by a few thousand times to get reasonable 3D coverage,   
      
   I think 3-4 would do.   
      
    then multiply THAT by at least a several thousand times to get useful   
   resolution.    
      
   No, we dont need full resolution for the whole sky.   
      
   Then factor in the strategic/political environment. In a time of war, you can   
   either use the money to buld observation platforms, or you can use it to build   
   warships. As useful as observation is, wartime is too late. The military is   
   going to want to    
   maximise offensive and defensive capability. In a time of peace, you have to   
   convince the population that there is a credible threat that will warrant such   
   costs, and lots of the public are going to be rather nervous about having all   
   those spies deployed.   
    The public simply won't condone such an expense to spy on forces that are not   
   even a threat (yet), especially if they consider that the enemy might some day   
   be themselves.   
      
   Today, to public accepts the NSA, spying on every email. The US army is   
   developing system for total battlefield awareness, along with cruise missiles   
   and GPS guided bombs, specifically to hit the target. They know that you cant   
   hit what you cant see.   
      
   > In our age, nuclear power is reserved for warships. But in days of   
   interplanetary travel, nuclear power will be a requirement for virtually all   
   commerce and enterprise. ALL interplanetary vessels will have at least fission   
   power. Many colonies will    
   have civil fusion reactors, if anyone actually gets them to work. Some level   
   of fusion drive will be available to anyone who has the resources.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)