https://peertube.dngr.us/videos/watch/b2226f34-239c-4b3b-b4a6-b0dcfe4c6d13 This silent film shows acoustic tests performed on a 6.4% scale model of the Space Shuttle Vehicle (SSV), made sometime between the first (STS-1) and second (STS-2) Space Shuttle flights, or sometime between 12 April to 12 November 1981. The tests also featured a scale vehicle launch pad equipped with an exhaust deflector and simulated duct. The background on this footage is this: the first launch of the Space Shuttle (STS-1) utilized what was known as the Sound Suppression Water System. This deluged the flame trench on the launch pad, in order to dampen the acoustics of the rocket engines firing. It was believed this would prevent damage to the Orbiter, External Tank (ET) and Solid Rocket Boosters (SRBs) during the first few seconds of lift-off. Data gathered from this first launch however, indicated that the acoustics were much worse than expected. Even with the water deluge, the sound waves literally bounced off the bottom of the flame trench and hit the rear end of the Shuttle stack. The resulting energy could have torn the whole assembly asunder. To address this critical problem before STS-2, NASA performed tests to determine a method of dampening acoustic effects to a safe level during the first few critical seconds of launch. The film shows one of these dampening tests. Engineers came up with the idea of a series of water-filled bladders across the openings to the flame trench. These would absorb the sound waves from the initial ignition of the engines, that would then be further dampened by the water being pumped into the trench itself. The end result was that sound effects to the stack were reduced, so that the stack could withstand for the first seconds and get pad separation. An article summary found online described the tests this way: "The SSV's engine‐generated acoustics and ignition overpressure environments have been long considered as severe dynamic inputs to a reusable aero‐frame structure with a payload located in close proximity to the propulsion systems. The definition of these environments and the noise suppression techniques that are required for SSV launch have been provided from a dynamically scaled hot propulsion model. The scale factor is 6.4% of the Shuttle with the vehicle launch facility with exhaust deflector and duct geometry being simulated. Water injection into the hot exhausts is also scaled for sound suppression for both on‐pad and liftoff cases. The environments measured on model are then scaled to provide launch vehicle environments for vehicle, launch facility, and farfield areas. Overpressure environments from SRB ignition are also acquired from over 100 measurements on the vehicle and launch facility. Suppression techniques are being investigated for Western Test Range (WTR) launchers and for thrust augmented configurations of the Shuttle." Date: 1981-11 Mirrored from Internet Archive: https://archive.org/details/6.4-space-shuttle-scale-model-acoustic-tests-nasa-sound-suppression-water-system-gg-50125 Wed, 15 Jul 2026 12:50:59 GMT https://validator.w3.org/feed/docs/rss2.html PeerTube - https://peertube.dngr.us https://peertube.dngr.us/lazy-static/avatars/ec5edb1e-3795-4978-be4f-c67e98fbc992.png https://peertube.dngr.us/videos/watch/b2226f34-239c-4b3b-b4a6-b0dcfe4c6d13 All rights reserved, unless otherwise specified in the terms specified at https://peertube.dngr.us/about and potential licenses granted by each content's rightholder.