• teft@startrek.website
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    11 months ago

    Hubble is essentially a Keyhole satellite so I assume if they flipped it around we’d have really clear photos of earth similar to the one trump got in trouble for showing on live tv.

    • QuinceDaPence@kbin.social
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      11 months ago

      Those spy satellites are focused at the distance of earth. Hubble is focused at infinity or near-infinity.

      You’d just get some really blurry images.

    • Pons_Aelius@kbin.social
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      11 months ago

      Not really. Hubble is set up to image objects light years away and moving relatively slowly.

      Keyhole stats as set up to image the earth’s surface that is only hundreds/thousands km away and moving quite fast.

      Two different missions would lead to two different designs.

      • teft@startrek.website
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        11 months ago

        That would lead to different focal lengths not different designs completely. Both optical systems for HST and KH were designed by Perkin Elmer so I’ll stick with my first thought that they would be very similar in capabilities.

        • Pons_Aelius@kbin.social
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          11 months ago

          Did you watch the video?

          The tracking problems Hubble would have imaging the earth surface are a direct guide to what differences the design would be.

              • mkwt@lemmy.world
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                11 months ago

                And the angular momentum is conserved.

                Your choices are basically RCS thrusters or reaction wheels. Thrusters burn limited fuel. Reaction wheels are flywheels inside the satellite that you spin in the operator opposite direction to where you want to rotate. They are limited by the mass and size of flywheel, and the maximum speed you can spin it up to.

                • Madlaine@feddit.de
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                  11 months ago

                  They have to rotate it fast enough, and hubble is not built to rotate that fast

                  • schmidtster@lemmy.world
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                    11 months ago

                    Is it an actual limitation of the hardware or a software safety limit? The designs are similar it more has to do with limitations put on it.

                    They mention they can’t because the gyro vibrates, so it does sound like it’s capable of spinning faster it’s limited for specific reasons. Now are those reasons detrimental to its use or would they just have to get fancier.

                    These can’t be answered.

          • teft@startrek.website
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            11 months ago

            Did you finish the video where they essentially say what I said in my first comment? Hubble and spy satellites share a lot of the same technologies. I wasn’t aware of the speed issue but other than that they are similar like I said.