Planetary orbit dynamics via trilateration: Prospectus for an interplanetary scale ring laser gyro with nominal area of 1 square AU

We present motivation and preliminary plans for an interplanetary scale laser ranging system, which would measure all 3 legs of the Earth, Venus, Mars triangle, in both directions, and thereby also function as a laser ring gyro, with enclosed area of order 1 AU2. The difference between round-trip light times, for prograde and retrograde circuits, can be as large as ±0.3 ​s (10⁵ km range) and can be measured with an accuracy of 0.3 ​ns ​(10 ​cm range), yielding a signal-to-noise ratio of order 10⁹. The primary motivation for this instrument would be to improve knowledge of solar system dynamics.