December 21, 2016 Zimmerman/Batchelor podcast

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Embedded below the fold. We spent some time talking about the James Webb Space Telescope, and the terrifying possibility that it might not work.



  • Hi Bob,

    great show, is there a link to the chinese images from the moon? thanks.

  • StarGazer: Do a search on Behind the Black for Chang’e-3. The most recent post gives a link to a story that provides that link.

  • James Fincannon

    You stated that the James Webb Telescope would be in the eclipse of the Earth at the Lagrange Point. This cannot be true. For one thing, the telescope is solar powered and it would be difficult to gather the 2 kW of power from the Sun if the spacecraft we sitting in the eclipse all the time. Also, a spacecraft at the Lagrange Point must orbit it. Finally, it has a “Sunshield” which would not be necessary if it sat in an eclipse all the time.
    “At the L2 point Webb’s solar shield will block the light from the Sun, Earth, and Moon. This will help Webb stay cool, which is very important for an infrared telescope. As the Earth orbits the Sun, Webb will orbit with it – but stay fixed in the same spot with relation to the Earth and the Sun, as shown in the diagram to the left. Actually, satellites orbit around the L2 point, as you can see in the diagram – they don’t stay completely motionless at a fixed spot.”

  • James: Ah, thank you. You are right.

    I do remember however hearing or reading somewhere that the reason they were aiming for the Lagrange point a million miles farther from the sun was to use the Earth’s shadow to block the Sun’s light. As you note, this really makes no sense since they need the sun to power the spacecraft.

    I wonder where I heard this, and why. Could it be they are using the Earth’s shadow during the trip out to cool the spacecraft?

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