DULLES-Va.--Northrop Grumman's [NOC] Mission Robotic Vehicle (MRV) is to launch this summer on a SpaceX Falcon 9 rocket, as the U.S. Space Force looks to refueling, maneuver, and repair and upgrades--all on orbit--as part of the service's future mission. Northrop Grumman officials, as well as one from the Defense Advanced Research Projects Agency (DARPA) and one from the Naval Research Laboratory, briefed reporters on Tuesday here at the company's satellite manufacturing plant. The MRV will be the first robotic service…