• Hexamerous [none/use name]@hexbear.net
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    2 days ago

    The Znamya 2 was a 20-metre wide space solar mirror. […] when illuminated, produced a 5 km wide bright spot, which traversed Europe from southern France to western Russia at a speed of 8 km/s. The bright spot had a luminosity equivalent to approximately that of a full moon.[3] Although clouds covered much of Europe that morning, a few ground observers reported seeing a flash of light as the beam swept by.

    For reference: the Sun is about 400’000x brighter than the Moon.

    • DasRav [any, any]@hexbear.net
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      2 days ago

      I mean…that is not a lot. It moved at 8 kilometers per second as well? How is this useful to anyone?

      It occurs to me that if they want this to be geostationary, it will need to be at 60.000km height, which is 100x what this test thing was at.

    • Kazumara@discuss.tchncs.de
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      1 day ago

      But if you widen a 20m diameter mirror to a 5km diameter illuminated area you get 250*250 = 62’500 times less light energy per area, compared to the same spot in direct daylight. Or only 6.4 times brighter than the moon, calculating from your factor of 400’000.

      For the stated goal of solar power, this would be completely useless. Well not completely, just 62’500 times worse than during daytime.