Casimir force is the result of virtual particles and could be related to inertia and gravity.

DARPA is soliciting innovative research proposals in the area of Casimir Effect Enhancement (CEE). The goal of this program is to develop new methods to control and manipulate attractive and repulsive forces at surfaces based on engineering of the Casimir Force. One could leverage this ability to control phenomena such as adhesion in nanodevices, drag on vehicles and many other interactions of interest to the DoD. H/T to Nanowerk.com

A specific goal of this single-phase DARPA program is to demonstrate the ability to manipulate and engineer the Casimir force including the ability to neutralize the Casimir force.