1. Standard membermenace71
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    15 Jul '13 02:24
    http://eyes.nasa.gov/


    very cool app and seems to be real time

    Manny
  2. Cape Town
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    15 Jul '13 08:51
    Originally posted by menace71
    http://eyes.nasa.gov/


    very cool app and seems to be real time

    Manny
    I'm still exploring, but its really nice so far.
    The spacecraft I looked at, have their solar panels facing the sun, but their dishes do not face the earth. Does anyone know if they re-orient every time they wish to transmit?
  3. Cape Town
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    15 Jul '13 12:37
    Have a look at 216 kleopatra. Its shaped like a bone.
  4. Standard membermenace71
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    16 Jul '13 03:44
    Originally posted by twhitehead
    I'm still exploring, but its really nice so far.
    The spacecraft I looked at, have their solar panels facing the sun, but their dishes do not face the earth. Does anyone know if they re-orient every time they wish to transmit?
    I'm not sure I would think the arrays or antennas have to face generally towards earth not sure.

    Manny
  5. Standard membermenace71
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    16 Jul '13 03:50
    Dawn's solar Panels are facing the sun but the array is facing down or 90° almost


    Manny
  6. Cape Town
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    17 Jul '13 09:20
    Does anyone know how they reorient? Is it done with gyroscopes, or rockets?
  7. Subscribersonhouse
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    17 Jul '13 10:40
    Originally posted by twhitehead
    Does anyone know how they reorient? Is it done with gyroscopes, or rockets?
    They use microburster rockets and gyro's but some forms of gyro's don't use moving parts but rely instead on doppler shifting light beams inside fiber optic cables that produce a change in frequency related to changes in orientation.
  8. Cape Town
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    17 Jul '13 11:282 edits
    Originally posted by sonhouse
    They use microburster rockets and gyro's but some forms of gyro's don't use moving parts but rely instead on doppler shifting light beams inside fiber optic cables that produce a change in frequency related to changes in orientation.
    Those are gyros to detect orientation. Do they ever use gyros to actually move the spacecrafts orientation? I am just thinking that the fuel requirements would be significantly lower if you could use electric power from the solar cells rather than microbursts of fuel.

    I guess I should do my own research. This is what I have found so far:
    http://en.wikipedia.org/wiki/Reaction_wheel
    http://en.wikipedia.org/wiki/Control_moment_gyroscope

    Another interesting one:
    http://en.wikipedia.org/wiki/Magnetorquer
  9. Standard memberDeepThought
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    20 Jul '13 13:28
    Originally posted by twhitehead
    Those are gyros to detect orientation. Do they ever use gyros to actually move the spacecrafts orientation? I am just thinking that the fuel requirements would be significantly lower if you could use electric power from the solar cells rather than microbursts of fuel.

    I guess I should do my own research. This is what I have found so far:
    http://en.wik ...[text shortened]... /Control_moment_gyroscope

    Another interesting one:
    http://en.wikipedia.org/wiki/Magnetorquer
    The Kepler spacecraft was put out of commission by reaction wheel failures. They talk about this on the Wikipedia page in the section Spacecraft history. I think the advantage over rockets is that you get fine control.
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