Holloman High Speed Test Track completes two recovery missions at over 5,000-feet per second Published Oct. 25, 2021 By Deidre Moon AEDC/PA HOLLOMAN AIR FORCE BASE, N.M. -- Since July 2021, the 846th Test Squadron at Holloman Air Force Base, N.M., successfully stopped two sleds traveling over 5,000-feet per second on a monorail as part of the Hypersonic Sled Recovery, or HSR, effort. According to Daniel Lopez, project manager for the test that was completed in July, the Arnold Engineering Development Complex Holloman High Speed Test Track, or HHSTT, is a unique Department of Defense test asset, as it is the only sled track capable of recovering sleds with test articles from velocities over Mach 5. “The HSR is a capability development effort being undertaken by the 846th to prepare for the increased need for hypersonic test and evaluation in support of the National Defense Strategy,” he said. “The project is multifaceted and covers development and resurrection of various braking methods, sled designs and thermal protection systems, as well as gaining proficiency in conducting recovered hypersonic missions.” Prior to this latest test, recovered hypersonic missions hadn’t been conducted at the sled track in nearly two decades. “Monorail testing is routine and common, but the unique aspect [of this type of testing] is the hypersonic velocity,” Lopez said. “The majority of hypersonic tests conducted at the HHSTT over the decades has focused on non-recovered impact testing.” If a customer needs the test article back for post-test analysis, then it must be recovered on the rail without damage. Therefore, recovered hypersonic missions entail using high-speed braking capabilities to slow down and stop the sled on the 9-inch monorail. These types of tests are limited to the monorail because at 10 miles, it’s the longer of the track systems. “The narrow gauge system, which is 3.8 miles, is too short to get the test article up to Mach 5-plus velocity and recover it,” Lopez said. “The narrow gauge system was used approximately 18 years ago to set the world land speed record of 9,465-feet per second, which equates to approximately Mach 8.4 or 6,453 miles per hour.” At this rate of speed, it would only take 51 minutes to travel from Los Angeles to London. In addition to recovery missions, the squadron provides customers relevant test data to verify lethality effects, impact survivability, aerothermal and weather effects, separation dynamics, guidance system performance, sensor performance and other key performance metrics. In the fall of 2020, the 846th TS, in conjunction with the Hypersonic Test and Evaluation Investment Portfolio, upgraded the rainfield capability for the sled track to improve weather effects testing. The squadron has studied natural rainfall in order to improve the simulation capabilities of the rainfield. As for what’s next with the Hypersonic Sled Recovery, Lopez commented that the goal is to further the recovery capabilities of the HHSTT. “The project will continue to expand the braking capabilities in order to recover sleds from Mach 6-plus,” he said.