Talk:Batteries in space

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Factual mistakes: orbit & shadowing

A satellite near the Earth will be shadowed for half of each orbit

This is incorrect. The terminator (day/night border) on a planet --- assuming the light rays are (almost) parallel to each other --- will be about half the planet. However, if you have a high tower or a plane at the terminator, the top of the tower will still be lit while the bottom is already dark, and the plane can well be seen, lit by sunlight, straight above even as the terminator has left you in darkness.

So obviously, the closer a satellite is to a planet (or moon or asteroid), the larger a part of it's orbit --- still strictly less than half --- it will be in shadow. The time spend in shadow, however, is not linear due to different speeds at different distances. With non-circular orbits the situation changes somewhat. An inclined orbit will have seasonal variations (extreme example: polar orbit perpendicular to Earth-Sun is 100% sunshine. But 3 months later --- the orbit being in line with the Earth-Sun axis --- it does get the "regular" time in shadow.).

See: ^[1], ^[2] and ^[3]

80.6.22.83 (talk) 16:32, 23 January 2018 (UTC)[reply]

References

[1] Worst Case Orbit Shadow Analysis

[2] shade-per-orbit How long will a 500 km altitude satellite spend in Earth - shade per orbit

[3] Orbit darkness time (Kerbal Space Program Wiki, also deals with non-circular orbits)

[1]

[2]

[3]