XPost: sci.space.policy, sci.astro   
   From: j.halpenny@rogers.com   
      
   Terrell Miller wrote:   
   >   
   > dexx wrote:   
   > > Is it true that Huygens ceased transmission less than 2 hours after   
   > > touchdown? Whilst it was a magnificent achievement to travel so far and   
   > > land perfectly, it seems a great shame that the probe was so short   
   > > lived.  I'm suprised the designers didnt make it rugged enough and   
   > > powered enough to survive several days.   
   >   
   > one design limitation factor was the length of time that Cassini would   
   > be "over the horizon" wrt the lander. Huygens doesn't have powerful   
   > enough transmitters to relay the datastream directly to Earth, so having   
   > longer batt life wouldn't do anything but waste money and resources if   
   > it couldn't see its mothership and thus transmit data.   
   >   
   > Building enough transmitter power to send to Earth directly would very   
   > likely have major scalability issues, which in turn would have a direct   
   > impact on other mission profiles (maybe they could have had a powerful   
   > transmitter but little or no instrumentation to feed it data, f'rinstance).   
   >   
   > Mission planning for any tpye of space vehicle is a series of tradeoffs   
   > between various things: time, money, propellant, payload, *type* of   
   > payload, mission duration, mission capability, etc. etc.   
   >   
   > Bottom line: for any launcher and any vehicle and any mission profile,   
   > there's only so much you can include. Add more of thing X and you have   
   > to take away from things Y, Z and A'.   
   >   
   Perhaps more importantly, the more things you put in, the more effort to   
   integrate it all, the more effort needed to shave weight, and the more   
   potential for a mission-threatening screwup. How many missions have   
   failed, or even failed to get funded, because they were too ambitious?   
      
   --   
   		John Halpenny   
      
      
   A cluttered desk is the sign of a cluttered mind.   
   I’m so glad my desk isn't empty.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)