Very interesting article on a technology being developed by DARPA: a micro-satellite:

Microsatellite deployment in GEO raises serious concerns. At such distances, ground-based detection via visual observation or radar is extremely difficult if not impossible. Currently, only the US Space Surveillance Network is capable of detecting these satellites reliably. This effectively gives MiTEx stealth capability. MiTEx is classified as a technology demonstrator, and it may be simply that. However, the possibility remains that the satellites are intended to do much more than demonstrate technology. Either way, the technologies used on MiTEx have substantial implications.

The MiTEx technologies detailed under the parent MiDSTEP program are applicable to a wide variety of military missions. The propulsive and lifetime capabilities of the NRL Upper Stage enable the satellites to go anywhere in GEO, and even perform proximity operations around other satellites. Such proximity would enable detailed reconnaissance of a satellite: identifying weaknesses, taking photographs, and collecting all the satellite’s incoming and outgoing radio traffic. More hostile acts, such as denying ground communications, depleting propellant reserves, and even inflicting permanent damage to the satellite cannot be ruled out.

Watch out VALIS…