An ejection seat ejects during a sled test run in adverse conditions. In the past, Holloman has conducted many tests on its grounds that have led to the development of pilot ejection seats, parachutes and seat belts. (Courtesy Photo)
Airman 1st Class Siuta B. Ika
49th Wing Public Affairs
(Editor’s Note: This is the first edition of a series that will provide an in-depth look at the Holloman High-Speed Test Track and the people who work there.)
HOLLOMAN AIR FORCE BASE – There are very few missions requiring years of planning and preparation, only to be accomplished in less than six seconds. There are even fewer facilities where such a mission can take place.
The Holloman High-Speed Test Track, operated by the 846th Test Squadron, is one facility that enables test scientists and engineers to meet both of the above criteria.
The test track is a 10-mile long, precision-aligned track that provides scientists and engineers a platform from which to conduct their various missions. Tests on the track provide valid data on problems which cannot be solved by other ground test means.
“The test track allows us to bridge the gap between laboratory developmental work and operational use,” said Lt. Col. David Dunn, 846th TS commander. “It provides for high-fidelity testing in a more realistic operational environment with better repeatability and high-bandwidth data collection, all at a much lower cost when compared to flight tests.”
The tests are conducted by securing the test item to a rocket-propelled sled and launching the sled to a speed identical to that of which it will encounter in an actual flight.
“For the most part, all of the tests utilize a pusher sled, which is used to accelerate the test article to the desired velocity, and a forebody sled which carries the test article,” Dunn said.
In the past, Holloman has conducted many tests on its grounds that have led to the development of pilot ejection seats, parachutes, nuclear missiles, and seat belts. Although the first sled test was conducted in 1950, Air Materiel Command had been looking for a site to house its testing operations a few years before the first sled launched.
In 1947, AMC announced that Holloman, then called the Air Force Development Center, would be its primary site for the testing and development of pilot-less aircraft, guided missiles, and other research programs, bringing the test community to its new home in the Tularosa Basin.
The basin provided the scientists and engineers the environment needed to succeed — good weather conditions and a supportive local community — while the Air Force provided the other resources. The base’s namesake, U.S. Army Air Corps Col. George Holloman, was an early experimenter with guided missiles and was also an early pioneer in pilot-less aircraft research.
“[The base] was shutting down as a training facility from World War II and thus was readily available,” said Kevin Rusnak, Air Force Research Laboratory historian. “It had a significant amount of open area for missile and pilot-less aircraft testing. The remoteness also helped with secrecy concerns.”
In the early 1950s, unique tests on the impacts of mach speed on the human body were done at the HHSTT. The goal of the research was to find out what would happen to a pilot’s body during extreme acceleration and deceleration in an actual flight.
On Dec. 10, 1954, Lt. Col. John Stapp became the “Fastest Man on Earth” when he rode a rocket-propelled sled at a speed of 632 miles per hour, in the process enduring more than 40 times the pull of the Earth’s gravity and suffering various injuries, including broken ribs and a temporarily detached retina. His sled run provided pivotal information on how gravitational stress affects the human body.
“Stapp’s record-breaking sled run was the final manned-run in a series of windblast and deceleration tests designed to understand human tolerance to high-speed ejections from aircraft,” said Rusnak. “Aside from the positive publicity the event garnered for the Air Force, it more importantly brought international recognition to Stapp’s mission to improve the safety of Airmen and pilots.”
In October 1982, the HHSTT became the fastest place on Earth when an unmanned rocket sled blasted a 25-pound payload to a target at a speed of 6,119 miles per hour. That record would stand for more than 20 years until another rocket sled delivered a 192-pound payload to a target at 6,453 miles per hour on the same track where the previous record was set.
The record-breaking sled run of April 2003 was a culminating event in the Hypersonic Upgrade Program. The program upgraded the HHSTT’s capabilities in many areas, including its ability to support various tests done at hypersonic speeds, and it added the ability to test payloads carrying the weight of full-scale aircraft at realistic flight velocities.
“The test track made significant advances in vibration isolation technology, slipper gouge mitigation coatings, and rocket motor propulsion technology during the life of the HUP,” Dunn said. “Achieving the extreme speeds required in anti-ballistic missile tests also would not have been attainable without the HUP.”
The primary mission of the HHSTT is to support the test and evaluation of Department of Defense material and non-material systems, such as aircrew escape systems, and navigation systems.
“Currently, our bread and butter is in egress-testing for both the Joint Strike Fighter and advanced cueing systems, as well as penetrator weapon tests for deep bunker-busting bombs,” Dunn said. “We are currently the only track in the world that can reliably and cost-effectively produce test velocities in excess of Mach 4.”
The HHSTT has played a significant role in U.S. and Air Force history in regards to the testing and development of weapon systems and aircraft safety instrumentation as well as many modern safety features found in automobiles and aircraft alike.
The latest project being worked on at the HHSTT is the development of a magnetic levitation track — essentially, a track system that would guide a levitating sled over its rails.
“Advanced electronics are extremely sensitive to the high vibration environment caused by the steel on steel interaction of the traditional sleds riding on the rails,” Dunn said. “As the MAGLEV system is completely suspended by magnetic forces, there is no contact between the sled and the rails, which gives the ability to produce high speeds at much lower vibration levels. This will allow testing of sensitive electronics at high speeds in an environment very similar to actual field conditions.”
Throughout its history, the test track has led to many engineering breakthroughs. In the next edition of the HHSTT series, an in-depth look at one family — that has immensely contributed to the track’s rich history — will be provided.