Notices
Results 1 to 12 of 12

Thread: Cosmic Navigation

  1. #1 Cosmic Navigation 
    Forum Freshman
    Join Date
    Oct 2017
    Posts
    27
    From what I understand, the Apollo missions used a sort of "radio echolocation" with a radio base on Earth to determine their position and orientation, relative to the earth.
    However, I see a few major flaws with this design moving into a future in which a, ships become more common, and b, they become privately owned.

    1. One would need to construct thousands of new radio bases on Earth, to account for extra vehicles and the rotation of the planet, in order to maintain contact at any time. This does not account for planets and satellites that we can't build on.

    2. Radio, fast as it is, becomes really slow in the perspective of deep space. Not so much an issue for earrh-to-moon missions, but further out becomes a problem.

    You also have to consider exploration, in which a ship would be flying into new territory, meaning no ground stations have been built. Is this the best system we can do, or is there a better way we can develop, maybe something self contained within the ship, independent of planetary infrastructure?


    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Professor
    Join Date
    Jul 2008
    Location
    New York State
    Posts
    1,027
    How far away are you thinking about?


    Reply With Quote  
     

  4. #3  
    Genius Duck Moderator Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    11,588
    Quote Originally Posted by Jason Summer View Post
    1. One would need to construct thousands of new radio bases on Earth, to account for extra vehicles and the rotation of the planet
    Not really.
    It's not a case of "one base station per vehicle": any base station's signal will be accessible to each and every vehicle. (And the Earth rotated even during the Apollo missions).
    You also have to consider exploration, in which a ship would be flying into new territory, meaning no ground stations have been built. Is this the best system we can do, or is there a better way we can develop, maybe something self contained within the ship, independent of planetary infrastructure?
    Astro/ celestial navigation...
    Last edited by Dywyddyr; July 2nd, 2019 at 04:48 PM.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  5. #4  
    Forum Freshman
    Join Date
    Oct 2017
    Posts
    27
    Quote Originally Posted by mathman View Post
    How far away are you thinking about?
    I'm thinking if we could get it right the first time we won't have to constantly change it as we work out way out. We obviously won't be jumping immediately from Mars missions to regular passenger service across the solar system. So to answer your question "how far?", as far as we plan to go, which is anything between interplanetary to intergalactic
    Reply With Quote  
     

  6. #5  
    Forum Freshman
    Join Date
    Oct 2017
    Posts
    27
    Quote Originally Posted by Dywyddyr View Post
    Yes, but this method only works on Earth because the stars are (relatively) fixed. Moving through space, I'd think this would get more inaccurate. This also is subject to human error, unless we can teach AI to see and navigate stars.
    Reply With Quote  
     

  7. #6  
    Genius Duck Moderator Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    11,588
    Quote Originally Posted by Jason Summer View Post
    Yes, but this method only works on Earth because the stars are (relatively) fixed.
    The stars are "relatively fixed" for any "short" period of time, regardless of location.
    Moving through space, I'd think this would get more inaccurate.
    Nope.
    This also is subject to human error
    Not really a problem. Given the distances involved and travel speeds there's plenty of opportunity to take multiple readings to reduce errors.
    unless we can teach AI to see and navigate stars.
    AI not really needed. It's already in use for ICBMs and some cruise missiles1.

    1 Implemented in the Soviet Burya cruise missile in the 50s and the US SM-62 Snark of roughly the same period.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  8. #7  
    Forum Freshman
    Join Date
    Oct 2017
    Posts
    27
    So you are suggestion that we have cameras on the ship and it just uses stars?
    Reply With Quote  
     

  9. #8  
    Genius Duck Moderator Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    11,588
    Quote Originally Posted by Jason Summer View Post
    So you are suggestion that we have cameras on the ship and it just uses stars?
    It works, ergo it's useable.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  10. #9  
    Forum Radioactive Isotope zinjanthropos's Avatar
    Join Date
    Dec 2005
    Location
    Driving in my car
    Posts
    4,799
    Only because I remembered seeing this on NOVA.

    From NASA (wiki):
    Like mariners of old, Cassini navigators also used the stars to understand their ship's position. The spacecraft’s cameras collected "optical navigation" images of Saturn's moons against a background of stars whose positions are well-known from astronomical measurements. But Cassini’s position was never nailed down with absolute certainty. “We can never know exactly where the spacecraft is,” Roth said. "But we've managed to do some amazing things flying the spacecraft with the knowledge we have.
    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
    Reply With Quote  
     

  11. #10  
    Genius Duck Moderator Dywyddyr's Avatar
    Join Date
    Jan 2013
    Location
    Scunthorpe, UK
    Posts
    11,588
    Maybe they were tight on available space.
    I read that has having a limited number of cameras that were all essentially looking in the same direction. If that's the case then I'm not surprised that they didn't get a definite fix of position.
    "[Dywyddyr] makes a grumpy bastard like me seem like a happy go lucky scamp" - PhDemon
    Reply With Quote  
     

  12. #11  
    Forum Radioactive Isotope zinjanthropos's Avatar
    Join Date
    Dec 2005
    Location
    Driving in my car
    Posts
    4,799
    Quote Originally Posted by Dywyddyr View Post
    Maybe they were tight on available space.
    I read that as having a limited number of cameras that were all essentially looking in the same direction. If that's the case then I'm not surprised that they didn't get a definite fix of position.
    Close enough to do some amazing things but when you watch NOVA episode it was obvious there was many an anxious moment waiting for Cassini’s response signal to arrive. In fact the mood seemed to dominate almost every maneuver. 30 year old technology and here we are chatting through a device light years ahead of what mission control had to deal with. 30 years ago I was teaching myself Basic, but I don’t know if my Atari 400 could have flown
    All that belongs to human understanding, in this deep ignorance and obscurity, is to be skeptical, or at least cautious; and not to admit of any hypothesis, whatsoever; much less, of any which is supported by no appearance of probability...Hume
    Reply With Quote  
     

  13. #12  
    Brassica oleracea Strange's Avatar
    Join Date
    Oct 2011
    Location
    喫茶店
    Posts
    16,679
    Quote Originally Posted by Jason Summer View Post
    So you are suggestion that we have cameras on the ship and it just uses stars?
    Modern space probes do this pretty much automatically.

    https://en.wikipedia.org/wiki/Star_tracker

    They also use the Deep Space Network as a sort of space GPS.

    https://www.scientificamerican.com/a...-probes-navig/
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
    Reply With Quote  
     

Similar Threads

  1. Replies: 74
    Last Post: February 21st, 2013, 04:50 PM
  2. Cosmic pong
    By Boing3000 in forum Physics
    Replies: 3
    Last Post: November 5th, 2012, 03:37 PM
  3. China launches two more Beidou navigation satellites
    By Ascended in forum In the News
    Replies: 0
    Last Post: May 3rd, 2012, 11:55 AM
  4. Navigation Guided Missile Systems
    By Hoang Nguyen in forum Military Technology
    Replies: 3
    Last Post: December 16th, 2010, 05:39 PM
Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •