X-17

The US Air Force / Lockheed X-17 was a three-stage solid-fuel rocket used to test re-entry payloads on missiles. Among the numerous technologies it tested were ablative materials for re-entry vehicles, re-entry vehicle configurations (pioneering blunt nose cone design) and re-entry vehicle dynamics. Twenty-six X-17s are known to have been built and tested. The vehicles were 40 feet long and had a wingspan of more than eight feet. The first flight occurred in September 1956.