It Was 50 Years Ago Today

The all-important X-15. From NASA.gov:

Fifty years ago in 1959, test pilot Scott Crossfield threw the switch to ignite the twin XLR-11 engines of his North American Aviation X-15 rocket plane and begin the storied test program's first powered flight.

"The drop from the B-52 carrier aircraft was pretty abrupt, and then when you lit that rocket a second or two later you definitely felt it,” said Joe Engle, another X-15 test pilot and member of the same exclusive fraternity of flyboys that included Crossfield and the eventual first man on the moon, Neil Armstrong. All took the X-15 to speeds and altitudes that extended the frontiers of flight.

Engle credits the X-15 for laying the foundation for many of the operational techniques of the space shuttle, and for providing designers with confidence that certain design and control concepts for the winged orbiter would work:

• With similar flying characteristics, the X-15 proved the shuttle could re-enter the atmosphere and glide to a precision landing, in part relying on a maneuver known as Terminal Area Energy Management where speed and altitude are carefully controlled so the vehicle can reach the runway instead of falling short or overflying it.
• Using technology developed and tested on the X-15, pilots learned how to transition control smoothly from reaction control jets at high altitudes or in space to wing- and tail-mounted control surfaces in the atmosphere closer to the ground.
• While not a benefit to the space shuttle alone, the X-15 was the first flight test program to make extensive use of simulators to work out certain problems and train pilots before going up—a practice since employed for nearly every flight test program.
• The X-15 flights proved the usefulness of having chase aircraft follow a test vehicle during its approach to the runway to make sure, as Engle put it: "Everything that is supposed to be up is up, and everything that is supposed to be down is down."