Lunar Observatories: Grand Plans vs. Clear Problems

On Dec 05, 2006, at 22:34 UTC, Lucio_de_Souza_Coelho wrote:

> > Why do you feel that similar (or larger) baselines couldn't be
achieved
> > with space-based telescopes?
>
> Satellite geographic positioning systems (like GPS) have error margins
> orders of magnitude larger than the wavelength of light, therefore the
> error in the relative positions of those space telescopes would render
> any attempt of interferometry useless.

Well yes, if you intended to use GPS for your formation flying.
Obviously you wouldn't do that; the satellites would have direct
measurements of their spacing (most likely using interferometry, in
fact), and use that to control their position.

If you can do it for satellites 40 m apart, I see no reason why it
would be any harder for satellites 1000 km apart. The problem (and
solution) are exactly the same. Station-keeping is station-keeping, as
long as the satellites are within line-of-sight of each other.

Best,
- Joe

Joe Strout -- joe@...