Kepler telescope in trouble.

Discussion in 'science, nature and environment' started by ffsear, Apr 11, 2016.

  1. ffsear

    ffsear Well-Known Member

  2. TheHoodedClaw

    TheHoodedClaw acknowledging ur soup leg

    CNT36 likes this.
  3. Pickman's model

    Pickman's model Every man and every woman is a star

    nothing to see here
     
    lizzieloo and bi0boy like this.
  4. NoXion

    NoXion Eat leaden death, demon...

    The story's not over yet. They still haven't determined why Kepler went into emergency mode.
     
  5. editor

    editor Taffus Maximus

  6. editor

    editor Taffus Maximus

  7. fishfinger

    fishfinger تپلی

    About 170,000 stars to the gallon :thumbs:
     
  8. cybershot

    cybershot Well-Known Member

    What? They didn’t design it run on solar power!
     
  9. ricbake

    ricbake working out how

    PV powered what to orient a satellite?
     
  10. Crispy

    Crispy The following psytrance is baṉned: All

    Reaction wheels. Big gyroscopes that are "pushed against" to turn the spacecraft. But reaction wheels get "saturated" over time; they reach their maximum RPM and can no longer provide torque safely, so they have to fire the thrusters to counteract the "desaturation" torque from braking the gyroscopes. 2 of Kepler's 4 reaction wheels had already failed by 2013, limiting it to pointing at stars that lie roughly in line with the disc of our solar system.

    It's still a pitifully small sampling of the galaxy though.

    LombergA1024.jpg

    Extrapolated to the rest of the galaxy, there are something like 11 billion earth-sized planets orbiting in the habitable range of sun-like stars.
     
    a_chap likes this.
  11. ricbake

    ricbake working out how

    I understand the limited view relates to being able to re orientate to point data back to earth with only half of the gyroscopes working and it is limited by the thruster rocket fuel - just 3 gallons but with an expectation of lasting just a year. Had they been more optimistic about is longevity and usefulness perhaps electric Ion thrusters would be more efficient but presumably weaker and still needing propellant. There is still the problem of fixing or rebooting the gyroscopes.
    Also if it had a much wider view with such detail wouldn't there just be too much data to process?
     
  12. 2hats

    2hats

    What was clever was how they used solar radiation pressure with the remaining two reaction wheels to maintain sufficient spacecraft fine pointing to support the K2 observing campaign.
     
    ricbake and Crispy like this.
  13. Crispy

    Crispy The following psytrance is baṉned: All

    The data was not particularly complex; it's just the varying brightness of stars. It's instead a matter of sensitivity. A wider field of view means a dimmer signal, and a more sensitive sensor would be needed to tease out the signal of a transiting planet against the background noise.

    Kepler's successor, TESS, launched in April and will conduct an almost-whole-sky survey, with just such an improved sensor. Its range won't be much better than Kepler, but it will survey many, many more stars. It also has a special occluder for blocking the light of the target star that will allow direct imaging of ice/gas giant planets.
     
    ricbake likes this.
  14. Ponyutd

    Ponyutd Greebo likes this....r.i.p.

    Can't believe they didn't see that coming.
     

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