Abstract: A digital computer for guiding the flight of a ballistic missile through instrumentation of a Q Matrix. The computer may be described as being the digital counterpart of a mechanical differential analyzer in that it is made up of a number of appropriately interconnected integrators which generate the solution of the particular equation or set of equations being solved. An initial value of velocity-to-be-gained is inserted into the computer and then by means of accelerometer outputs, multipliers, adders and integrators, samples of the missile's velocity are compared with the velocity-to-be-gained to generate output signals to control or guide the trajectory of the missile during its powered flight.