[progne]

> A low Earth orbit with a separation of approximately 0.1 km may be suitable for experimental purposes.

Wouldn't that also suit an Earth surveillance array with unprecedented resolution?

[1letterunixname]

In general, the smaller the separation, the smaller the synthetic aperture.

Precise ranging and relativistic corrections are what permit large scale experiments like LIGO and LISA to work as a device the size of the complete aperture.

[yodon]

The GP was presumably thinking about downward looking optical sensors. An 0.1km aperture in the visible at LEO would have quite significant resolving power.