Flight Research and Space Flight

Before the X-15, high-speed research air­craft flown at Edwards could be monitored and tracked from Edwards. The trajectory of the X-15 extended much farther from

Edwards than those of the previous research aircraft, requiring two up-range stations where tracking, communications, and telemetry equipment were installed and inte­grated with the control room back at the FRC. Along the X-15 flight route, program personnel also surveyed a series of dry lakebeds for emergency landings and tested them before each flight to ensure they were hard enough to permit the X-15 to land.22 In many ways this parallels the tracking and communications network and the transat­lantic abort sites used by the Space Shuttle.

The opportunity to observe pilot perform­ance under high stress and high g-forces indicated that an extensive ground training program was needed to prepare pilots to han­dle the complex tasks and mission profiles of space flight. The result was a simulation pro­gram that became the foundation for crew training for all human space flight. The pro­gram depended on four types of simulation.

Prior to the first X-15 mission, the abil­ity of the pilot to function under the high g-forces expected during launch and reentry was tested in a closed-loop, six – degree-of-freedom centrifuge at the Naval Air Development Center, Johnsville, Pennsylvania. This project became the prototype for programs set up at the Ames Research Center and the Manned Spacecraft Center at Houston (now the Johnson Space Center).23

A static cockpit mockup provided the means for extensive mission rehearsal— averaging 20 hours per 10 minute flight. Such preparation was directly responsi­ble for the high degree of mission success achieved as pilots rehearsed their pri­mary, alternate, and emergency mission profiles. Similar, but much more elabo­rate, rehearsals are still used by astro­nauts preparing for Space Shuttle flights.

X-15 pilots maintained proficiency by flying an NT-33 or JF-100C variable – stability aircraft whose handling charac-

teristics could be varied in flight, simu­lating the varied response of the X-15 traversing a wide range of velocities and atmospheric densities. Much of this training is now conducted in advanced motion-based simulators, although the Air Force still operates a variable-stabil­ity aircraft (the VISTA F-16).

Pilots practiced the approach and land­ing maneuver in F-104 aircraft. With landing gear and speed brakes extended, the F-104’s power-off glide ratio approximated that of the unpowered X-15. Shuttle crews continue this same practice using modified Gulfstream Shuttle Training Aircraft (STA).

Astronaut “capsule communicators,” (cap – comms) were a direct outgrowth of the X-15’s practice of using an experienced pilot as the ground communicator for most X-15 mis­sions.24 This practice existed through Mercury, Gemini, and Apollo, and continues today on Space Shuttle missions. It is still believed that a pilot on the ground makes the best person to communicate with the crew, especially in stressful or emergency situations.25

Subsequent flight test work at Edwards relied heavily on the methodology developed
for the X-15. There are no fewer than three high-tech control facilities located at Edwards today; the facility at Dry den, the Riddley Control Center complex at the AFFTC, and the B-2 control complex locat­ed on South Base. Each of these control cen­ters has multiple control rooms for use dur­ing flight test. The X-33 program has built yet another control room, this one located near the launch site at Haystack Butte.26

The X-15 program required a tracking net­work known as “High Range.” Operational techniques were established for real-time flight monitoring which were carried over to the space program. The experience of setting up this control network became something of a legacy to Mercury and later space projects through the personnel involved. Gerald M. Truszynski, as Chief of the Instrumentation Division at the FRC, had participated in set­ting up the High Range, as had Edmond C. Buckley, who headed the Instrument Research Division at Langley, The Tracking and Ground Instrumentation Group at Langley had the responsibility for tracking the Mercury capsules, and it was headed, briefly, by Buckley.27

Buckley soon transferred to NASA Headquarters as assistant director for space
flight operations, with Truszynski joining him in 1960 as an operations engineer. Both con­tinued to be involved in instrumentation and communication until a reorganization under NASA Administrator James Webb created an Office of Tracking and Data Acquisition with Buckley as director. Buckley named Truszynski as his deputy, and in 1962 appointed him to lead the Apollo Task Group that shaped the Apollo tracking and data net – work. JK Much of this same infrastructure was used early in the Space Shuttle program.

Meanwhile, Walter Williams, who had headed the NACA operations at the HSFS/FRC since 1946, was reassigned as Associate Director of the newly formed Space Task Group at Langley in September 1959. He eventually served as the Director of Operations for Mercury, and then as Associate Director of the Manned Spacecraft Center. He also served as operations director in the Mercury Control Center at Cape Canaveral during the Mercury flights of Alan Shepard, Gus Grissom, and John Glenn in 1961 and 1962.2’

Experience from the NASA 1 control room undoubtedly influenced the development of the Mercury Control Center at Cape Canaveral, and perhaps more distantly, even the Mission Control Center (MCC)30 at Houston.31 However, the spacecraft control rooms and their tracking and data acquisition systems drew on many other sources (includ­ing the missile ranges which they shared),32 although the experience setting up the High Range and operating the NASA 1 control room undoubtedly provided some opera­tional perspectives.

An often overlooked area where the X-15 influenced Space Shuttle operations is in the energy management maneuvers immediately prior to landing. By demonstrating that it was possible to make precision unpowered landings with vehicles having a low lift – over-drag ratio, the X-15 program smoothed the path for the slightly later lifting-body program and then for the space shuttle pro­cedures for energy management and landing.

The techniques used by X-15 pilots consist­ed of arriving at a “high key" above the intended landing point. Once he reached the high key, the pilot did not usually need or receive additional information from the con­trol room; he could complete the landing using visual information and his own experi­ence with practice landings in an F-104 con­figured to simulate an X-15 landing. With considerable variation on different missions, the pilot would arrive at the high key on an altitude mission at about 35,000 feet, turn 180 degrees and proceed to a “low key" at about 18,000 feet, where he would turn another 180 degrees and proceed to a landing on Rogers Dry Lake. Depending upon the amount of energy remaining, the pilot could use shallow or tight bank angles and speed brakes as necessary.

Because of their much higher energy, the standard approach for the Space Shuttle con­sists of a variation on this 360-degree approach. As a Shuttle approaches the run­way for landing, if it has excess energy for a normal approach and landing, it dissipates this energy in S-turns (banking turns) until it can slow to a subsonic velocity at about

49,0 feet of altitude some 25 miles from the runway. It then begins the approach and landing phase at about 10,000 feet and an equivalent airspeed of about 320 mph some 8 miles from the runway.33 Early in the Space Shuttle program, a specially-configured T-3834 would accompany the orbiter on the final approach, much as the X-15 chase air­craft did at Edwards. Shuttle pilots practice in a specially-configured Gulfstream Shuttle Training Aircraft, much as the X-15 pilots did in the modified F-104.