Asteroid Tracking with a Phased Array

Please take a look at my proposal to track the orbit of an asteroid to an accuracy of about 1 micron per second in velocity, and a few meters in range, in a single measurement. Such a measurement would take a few minutes, and not months of observation and celestial-mechanical refinement. Therefore, subtle variable effects, such as the pressure of sunlight (Yarkovsky effect) can be monitored.

The proposal is based on the idea of placing a phased array of radio transponders on the surface. Initially after landing, the transponders are in random, but fixed places. They are linked with glass fibers for precision timing synchronization. After receiving a signal from Earth, the array determines the locations of its constituent units, and can then return a signal as a phased array.

The proposal text, originally written for a competition by the The planetary society, gives detailed calculations of radio power requirements, precision, launch mass, etc.