Lockheed X-23A "PRIME"

First Flight:  December 31, 1966
Mission: 
Test ablative coatings, re-entry control surfaces and lift body characteristics
Major Accomplishments: 
First craft to demonstrate re-entry maneuverability. Research from the X-23 lead to the development of the X-24 series and, eventually the Space Shuttle.
Power Source:
 None, launched by Atlas ICBM
Wing Span: 
4'
Length:
 5' 9"
Maximum Achieved Speed:
Approx. 90 miles
Maximum Achieve Altitude: 
16,500+ MPH 

Additional Information:  4 X-23A's "PRIME" (Precision Recovery Including Maneuverable Recovery) were built and 3 were flown on re-entry test flights. The first 2 were lost before they could be recovered, the 3rd was successfully recovered and the 4th was never flown (as was apparently scrapped). The 3rd craft is on permanent display at the US Air Force Museum in Dayton Ohio.