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December 11, 2009

Comments

RobiNZ

You're not paranoid, they are out to get you!

Would there be enough resolution from satellite data? Presume land contours but they could buy that for NZ to within a few metres. I thought higher detail stuff was still flown closer to the ground, or driven?

nomad496

You might be seeing the ESA Cluster group of satellites. They are a synchronized set of four satellites investigating the magnetosphere surrounding the earth. There is also a pair of NASA satellites, I forget the mission name, investigating gravitational variations in the Earth. I have seen the NASA ones here in Oregon, USA.

Earl Mardle

Thanks Steve, I didn't even know there were synchronised low-orbit jobs about. This cluster is definitely three and in a triangle both times. Is it possible one of them has dropped out?

I'll Google them and see if I can find out some more.

Earl Mardle

Got it, the four are in a tetrahedron which means one will be outside the plane. Separations vary from 100 to 1,000km.

What I can't get my head around is how you could synchronise the 4th satellite which must be in a different orbit from the other three. The higher the altitude the longer the period so synching with the other three must be a computational nightmare.

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