The Proteus is a high altitude research platform, which can carry different types of payloads, it is seen carrying the Multi-Platform Radar Technology Insertion Program (MP-RTIP), an USAF project led by contractor Northrop Grumman to develop the next generation of airborne air-to-air and air-to-ground radar systems. Proteus can reportedly be operated remotely from the ground, but for this test flight a crew was on board.