NF-104A "NF-756" and "NF-760" on the Edwards AFB flightline during the evaluation period from March 1965 until April 1967 Three aircraft were modified from existing Lockheed F-104A airframes and served with the Aerospace Research Pilots School between 1963 and 1971. The first NF-104A (USAF 56-0756) was accepted by the USAF on October 1, 1963. It quickly established a new unofficial altitude record of 118,860 ft (36,230 meter) and surpassed this on December 6, 1963 by achieving an altitude of 120,800 ft (36,800 meter). It suffered an in-flight rocket motor explosion in June 1971. Although the pilot was able to land safely, the damaged aircraft was retired and marked the end of the NF-104 project. This aircraft was reported as scrapped. The second NF-104A (USAF 56-0760) was accepted by the USAF on October 26, 1963. After retirement, this aircraft was mounted on a pole outside the U.S. Air Force Test Pilot School at Edwards Air Force Base and can still be seen there today. copyright © Mühlböck collection