Re: [lojban] Re: Lojban Kids Show - location

[CosmicRay <cr@cosmicray.co.uk>]

OK we've had two compelling votes to place Lojgugde at Earth-Moon L4/L5, which for all practical reasons are ideal.  Can anyone tell me how frequently and for how long Lojgugde at one of these points may be in Earth's or the Moon's shadow?  The Moon's orbital period is ~27 days and is off Earth's equatorial axis by ~5°.

From the story's perspective it's less ideal; placing the station at those points would make it visible to the naked eye at certain times.  When the station is just past parallel to, through to behind the Earth (relative to the Sun) and back again, the spinning mirrors would glint, causing a pinpoint of flashing light in the sky with a frequency of about 30 seconds.  For a little under half its orbital period the flash may be visible from Earth at dawn and dusk and would certainly be easy to see at night.

For the story, which has Lojgugde hidden from Earth, it would need to be cloaked.  Perhaps there can be a very large black panel (maybe a square 50km along each side) between the station and Earth that obscures it from view.  The panel would likewise screen Earth from Lojgugde, so that the bright globe spinning past Lojgugde's window segments doesn't cause dizziness or interrupt the occupants' night phases.

To complete the illusion Earthside, the panel could be comprised of 5-10 metre square-shaped dishes, which can independently light up, forming an enormous TV screen of sorts.  A camera pointing out into space just ahead of Lojgugde's orbital path feeds to the screen, with a slight delay adjustment, such that from Earth all that appears to be seen when looking in the direction of Lojgugde are the usual stars.

Keeping the panel in place would be problematic - at its speed and height from Earth it should share the same centre of gravity as Lojgugde, and would try to fly off into an elliptical path.  It would also seriously attenuate signals between Earth and Lojgugde.  It would need a constant power supply too.

All of these problems are perhaps solved by Lojgugde pointing some multi-megawatt (or even multi-gigawatt?) lasers at it.  The lasers supply energy to power the light elements, provide a repulsive force to the panel (in effect allowing the station and panel to act as one mass in orbital calculations), and are modulated to carry Earthbound comms signals.  The Earth-facing dishes of the panel double up as satellite-dish style transceivers, and another set of modulated lasers from the back of the panel pass incoming datastreams back to Lojgugde.

How does this monumental feat of engineering seem, is it feasible enough?  I mean, if we have O'Neill cylinders then the cloaking panel should be relatively trivial, yes?

kozmikreis

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