*Satellite Eclipse* OK2, every time a satellite goes around the earth it is eclipsed by the earth. That is, it flies through the night, just like a 747 does, but at a higher altitude. When the orbit is full frontal to the sun, which happens twice a year, the eclipses are brief for a 70 degree north to 70 degree south orbit like Globalstar, and nil for a polar orbit like Iridium's.
I suppose they want to reduce the duration of the first satellite eclipse for some arcane reason like perhaps they use lots of power when positioning them in orbit and want heaps in reserve. The photovoltaic panels on the satellite only generate electricity in sunshine, so I suppose that's why. By launching the satellite half an hour later, they say they got more sunshine and less night-time in the first orbit, which must have been good for them.
I'm a layman too don't forget, so make these things up as I go! Then the real experts send me email [as with the GPS topic] to tell me what REALLY happens. Which I then post here with an "ooops, sorry, but this is the REAL oil'. [Which incidentally is getting cheaper again day by day].
Maurice
PS: The orbits of the satellites stay constant in space and the earth rotates under them. So as the earth goes round the sun, at one stage, the orbits are edge on to the sun, but as the earth and satellites go round the sun, the orbits gradually become face on to the sun so the satellites are in sun all the time. The satellite controllers have to orient the photovoltaics to face the sun to keep the panels collecting the light, while maintaining the radio signal beams pointing at the earth. It must be a bit tricky.
I bet a lot of you can't visualize that 3D combination!!
[Pierre, sorry, I've just got back to your question now: "Maurice, since you're closer to that neck of the woods - what time is it at launch site. I'm guessing around 10:00 pm - about five hours to launch. Is that close?" I have no idea. Also, it's probably a bit academic now! Dispensing should have happened. Celebrations are done. Waiting for the acknowledgement in the markets now!] |
