only using jet power. It was the second prototype that first made use of the rocket motor during April 1957. During flight testing, a maximum speed of was attained at an altitude of, even without using the extra power of the rocket motor; this rose to 1667 km/h at 11,800 m while the rocket was active. A total of 45 test flights were performed prior to work on the programme being terminated. At the request of the French Air Staff, the French aircraft company SNCASO also developed its own point defence interceptor, the SNCASO Trident. It was primarily powered by a single SEPR-built rocket engine and augmented with a set of wing-tip mounted turbojet engines; operationally, both rocket and turbojet engines were to be used to perform a rapid climb and interception at high altitudes, while the jet engines alone would be used to return to base. On 2 March 1953, the first prototype Trident I conducted the type's maiden flight; flown by test pilot Jacques Guignard, the aircraft used the entire length of the runway to get airborne, being powered only by its turbojet engines. On 1 September 1953, second Trident I prototype crashed during its first flight after struggling to gain altitude after takeoff and colliding with an electricity pylon. Despite the loss, the French Air Force were impressed by the Trident's performance and were keen to have an improved model into service. On 21 May 1957, the first Trident II, 001, was destroyed during a test flight out of Centre d'Essais en Vol (Flight Test Center); caused when highly volatile rocket fuel and oxidiser, Furaline ( C13H12N2O) and Nitric acid (HNO3) respectively, accidentally mixed and exploded, resulting in the death of test pilot Charles Goujon. Two months later, all work was halted on the programme. The advancement of the turbojet engine output, the advent of missiles, and advances in radar had made a return to mixed power unnecessary. The development of Soviet rockets and satellites was the driving force behind the development of NASA's space program. In the early 1960s, American research into the Boeing X-20 Dyna-Soar spaceplane was cancelled due to lack of purpose; later the studies contributed to the Space Shuttle, which in turn motivated the Soviet Buran. Another similar program was ISINGLASS which was to be a rocket plane launched from a Boeing B-52 Stratofortress carrier, which was intended to achieve Mach 22, but