4 ms·

I once found a manual describing the machine code for the Voyager computers (can't find it anymore). Recently there was a flipped bit in memory which caused ser

by vbtemp 15y ago

I once found a manual describing the machine code for the Voyager computers (can't find it anymore). Recently there was a flipped bit in memory which caused serious problems: http://www.jpl.nasa.gov/news/news.cfm?release=2010-151 http://www.jpl.nasa.gov/news/news.cfm?release=2010-151 One of the things I find most fascinating about the mission are the RF systems -- the antenna on voyager is approx 40 watts yet the ground systems can read something on the order of kilobits per second -- and they are billions of miles away. This is an interesting read too: http://books.google.com/books?id=yws55Rx1orEC&pg=PA28&lpg=PA28&dq=voyager+mission+error+correction+codes&source=bl&ots=V2oS9O2t9d&sig=OBnExaOWkHvHZlZLpJf7p9FgUJk&hl=en&ei=tAmnTcD9NNCbtwftkOCFAQ&sa=X&oi=book_result&ct=result&resnum=4&ved=0CCgQ6AEwAw http://books.google.com/books?id=yws55Rx1orEC&pg=PA28&#3...

iwwr 15y ago
Potentially, optical (laser) transmitters have a lot more bandwidth, but need very fine aiming control. At those distances, a high-gain antenna would have to be too large to be feasible, even with an extensive upgrade of ground-based receivers.
- stewiecat 15y ago
  In the book "Voyager : seeking newer worlds in the third great age of discovery" they said that as the crafts got further out they had to use large radio antenna's in Spain, Hawaii, and Australia to lock onto the signal, creating an Earth-scale virtual antenna. Truly amazing stuff.
  - vbtemp 15y ago
    These are part of NASA's Deep Space Network, used to communicate with the fleet of interplanetary spacecraft (as well as plenty of satellites and the ISS). The you mentioned the three largest ones, each with a 70 meter dish.
    - mturmon 15y ago
      And here's the pic: http://deepspace.jpl.nasa.gov/dsn/images/picture_70_bw_lg.jpg http://deepspace.jpl.nasa.gov/dsn/images/picture_70_bw_lg.jp...
    - jules 15y ago
      Now that we're talking about big telescopes I can mention LOFAR: http://en.wikipedia.org/wiki/LOFAR http://en.wikipedia.org/wiki/LOFAR It's interesting in that it consists of 15.000 small antennas and they are using computers to combine the signals which effectively gives you a 1 square kilometer "dish".

by vbtemp 15y ago

iwwr 15y ago

Potentially, optical (laser) transmitters have a lot more bandwidth, but need very fine aiming control. At those distances, a high-gain antenna would have to be too large to be feasible, even with an extensive upgrade of ground-based receivers.

stewiecat 15y ago
In the book "Voyager : seeking newer worlds in the third great age of discovery" they said that as the crafts got further out they had to use large radio antenna's in Spain, Hawaii, and Australia to lock onto the signal, creating an Earth-scale virtual antenna. Truly amazing stuff.
- vbtemp 15y ago
  These are part of NASA's Deep Space Network, used to communicate with the fleet of interplanetary spacecraft (as well as plenty of satellites and the ISS). The you mentioned the three largest ones, each with a 70 meter dish.
  - mturmon 15y ago
    And here's the pic: http://deepspace.jpl.nasa.gov/dsn/images/picture_70_bw_lg.jpg http://deepspace.jpl.nasa.gov/dsn/images/picture_70_bw_lg.jp...
  - jules 15y ago
    Now that we're talking about big telescopes I can mention LOFAR: http://en.wikipedia.org/wiki/LOFAR http://en.wikipedia.org/wiki/LOFAR It's interesting in that it consists of 15.000 small antennas and they are using computers to combine the signals which effectively gives you a 1 square kilometer "dish".