The New Millennium
As we enter the new millennium, it is interesting to note how the X-15 has shaped aeronautics and astronautics. Indeed, when the X-33 program began during 1996, it was surprising to find that many of the younger contractor engineers were totally unaware of the X-15, and that most thought the SR-71 was the fastest aircraft that had ever flown, discounting the Space Shuttle. Interestingly, the young engineers at Dryden remembered the program, and when it came to setting up the instrumentation range (which extends all the way to the Dakotas), lessons learned from the X-15 High Range were used.53
The most obvious difference today has absolutely nothing to do with the technology of hypersonic flight. It is the political climate that surrounds any large project. The NASA Administrator, Daniel Goldin, told an X-33 all-hands meeting that it was “okay to fail”—a reference that many times in order to succeed, you first have to experience problems that appear to be failures. But this is not the climate that actually exists. Any failure is often used as an excuse to cut back or cancel a project. In most cases the only way to totally avoid failure is to completely understand what you are doing; but if you completely understood something, there would be no point in building an X-plane!
The X-15 is usually regarded as the most successful flight research program ever undertaken. But the program had its share of failures. The XLR99 destroyed the X-15-3 before it had even flown; but the aircraft was rebuilt and the XLR99 became a very successful research engine. On several occasions the X-15s made hard landings, sometimes hard enough to significantly damage the aircraft; each time they were rebuilt and flew again. Mike Adams was killed in a tragic accident; but less than four months later William Dana flew the next research flight. Yes, the X-15 failed often; but its successes were vastly greater.
Perhaps we have not learned well enough.