WASHINGTON — Citing delays with its original launch on a SpaceX Falcon 9 rocket, the U.S. Defense Advanced Research Projects Agency is trying to launch an experimental small satellite mission on a Polar Satellite Launch Vehicle from India. DARPA had originally planned to launch a mission called EXCITE, or eXperiment for Cellular Integration Technologies, on a secondary payload adapter called Sherpa that Seattle-based Spaceflight expected to launch on a Falcon 9 in 2015. But the continued delay of that mission forced Spaceflight this March to seek out alternatives for Sherpa customers. Speaking at the Milsatcom USA conference here June 29, Jeremy Palmer, program manager for DARPA’s Tactical Technology Office, said the agency is now pursuing a launch opportunity with the Indian Space Research Organisation (ISRO).