Interesting Flyover Today

Checking the Mode S logs today, I saw something new. Tail #N404PA, a highly modified Boeing 707 which flew as a passenger plane for Pan Am for many years before being purchased by the Air Force. The aircraft is based at Hanscom Air Force Base, is a joint venture between the Air Force's 350th Electronic Systems Wing and M.I.T.'s Lincoln Labs. The aircraft, known as the "Paul Revere", always goes by call sign MTH4PA, and is "used to test and experiment with airborne battle management, command, control and communication technology and concepts"

Check out the plane in all it's bulgy glory in the photo below: