{"id":39656,"date":"2014-01-28T22:27:51","date_gmt":"2014-01-28T14:27:51","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/smat-fires-up-to-open-sls-acoustic-testing\/"},"modified":"2014-01-28T22:27:51","modified_gmt":"2014-01-28T14:27:51","slug":"smat-fires-up-to-open-sls-acoustic-testing","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/smat-fires-up-to-open-sls-acoustic-testing\/","title":{"rendered":"SMAT fires up to open SLS acoustic testing"},"content":{"rendered":"

The Scale Model Acoustic Test (SMAT) \u2013 a mini-me version of the SLS \u2013 has fired up for the first time at the Marshall Space Flight Center (MSFC). The tests are focused on providing data to engineering teams who are tasked with designing the Sound Suppression System that will protect the Heavy Lift Launch Vehicle (HLV) from the acoustical energy of launch.<\/p>\n

SMAT Test:
\n<\/b>
\nFollowers of the Space Shuttle Program will be well versed in how one of the key events during the final seconds of the countdown was the flood of water being thrown over the Mobile Launch Platform (MLP).<\/p>\n

\"Z12\"Known as the Sound Suppression System, 300,000 gallons of water \u2013 stored in a 290-foot-high, 300,000 gallon tank \u2013 was released in stages, initially just prior to the Space Shuttle Main Engines (SSMEs) ramping up to full power and then at full flow at Solid Rocket Booster (SRB) ignition.<\/p>\n

The water flowed down the tower located at the pad complex and out through six 12-foot-high quench nozzles, known as \u201crainbirds\u201d, reducing acoustical levels within the orbiter payload bay to about 142 decibels, below the design requirement of 145 decibels.<\/p>\n

Without this system, the soundwaves of the engines firing would bounce back off the MLP zero deck and impact the orbiter, risking damage to the vehicle at the worst possible time.<\/p>\n

The Space Launch System (SLS) will also require the protection of the Sound Suppression System ahead of its launches from Pad 39B at the Kennedy Space Center (KSC).<\/p>\n

\"SMAT\"However, the system has to be tailor made for the monster rocket, with data being provided via the Scale Model Acoustic Test (SMAT) firings.<\/p>\n

\u201cWe can verify the launch environments the SLS vehicle was designed around and determine the effectiveness of the sound suppression systems,\u201d noted Doug Counter, technical lead for the acoustic testing.<\/p>\n

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\u201cScale model testing on the space shuttle was very comparable to what actually happened to the vehicle at liftoff. That\u2019s why we do the scale test.\u201d<\/p>\n

\"SMATPreparations for a series of SMAT tests began in 2012 at Marshall\u2019s test stand 116, with the construction of a working scaled down water-based sound suppression system.<\/p>\n

\u201cThis water system will be used during the planned hot fire testing series that is planned for SMAT, which utilizes small-scale solid rocket Boosters and Lox-Hydrogen thrusters,\u201d noted L2\u2019s rolling SLS updates at the time.<\/p>\n

\u201cBased on discussions with NASA\/KSC Ground Systems Development and Operations (GSDO) engineers, MSFC is satisfied that this properly represents the water flow rates and coverage of the full-scale system and will meet the test needs for SMAT.\u201d<\/p>\n

Click here for SLS Articles: http:\/\/www.nasaspaceflight.com\/tag\/sls\/<\/p>\n

As with the tests on the previous vehicles, the data will provide a good baseline ahead of the actual SLS firing into life later this decade.<\/p>\n

\"Z9\"The SMAT article itself is the most technically advanced sub-scale rocket ever to be used on such a test. It will provide an array of critical data to SLS engineers.<\/p>\n

\u201cIgnition overpressure (IOP) is a significant transient low-frequency pressure event caused by the rapid pressure rise rate of the solid rocket motor,\u201d opened an extensive presentation on the SMAT (L2).<\/p>\n

\u201cLift-off acoustics (LOA) noise is caused by the supersonic steady jet flow interaction with surrounding atmosphere and launch complex, persisting for 0-20 seconds as the vehicle lifts off.<\/p>\n

\"Z11\"\u201cScale Model Acoustic Test (SMAT) objectives: Verify predicted LOA environments, obtain data to update the lift-off acoustic environments.<\/p>\n

\u201cVerify predicted IOP environments, obtain data for use in IOP analytical models for updated environments, and improve IOP analytical models.<\/p>\n

\u201cVerify SLS deflector design. Characterize Ground Acoustic (GA) environments, provide data to support GA environment predictions. Obtain Spatial Correlation (SC) data for use in vibro-acoustic models. Obtain data for Computation Fluid Dynamics (CFD) validation, and evaluate water sound suppression systems, determine water suppression attenuation.\u201d<\/p>\n

\"Z6\"The tests will ramp up over time, with the opening SMAT firing \u2013 which lasted five seconds \u2013 involving an article that was without its twin imitation boosters.<\/p>\n

Instead, SMAT began testing with small thrusters of its aft, mimicking the RS-25D (Space Shuttle Main Engines) that will be placed on the core of the real life SLS.<\/p>\n

These thrusters \u2013 similar to vintage hardware originally designed in the 1960\u2019s and tested during the Space Shuttle program \u2013 successfully met all test objectives during Phase I scale model acoustic testing last year at Marshall\u2019s Test Stand 115.<\/p>\n

\"SMATFabrication then began for a \u201cfourthruster cluster\u201d set, mirroring the four RS-25s that will power all versions of SLS\u2019 core stage. They were fabricated by Aerojet Rocketdyne.<\/p>\n

\u201cHot-fire testing was initiated for the thrusters that will simulate the Core Stage Engines for the Scale Model Acoustic Test (SMAT). All four thrusters have been tested together for the first time in a single cluster in the same configuration that will be used for the Core Stage of the SMAT model,\u201d added SLS\u2019 rolling update section (L2) last year.<\/p>\n

\u201cTesting conducted at Test stand 115 in the Marshall Space Flight Center (MSFC) East Test area. The first start ignition test was conducted on March 7, 2013. Two low thrust main stage tests were conducted on March 8, 2013. All test hardware is in excellent condition so far and (will continue testing during the Spring).\u201d<\/p>\n

The test series will attempt to simulate a lift-off, without the SMAT model actually launching.<\/p>\n

\"Z7\"Also, as expected, the test vehicle is heavily instrumented, with five primary instrumentation suites resulting in over 325 sensors on the SMAT rocket.<\/p>\n

It is outfitted with B&K 4944-B microphones, pressure transducers on the tower\/mobile launcher \u2013 which is also a scaled model of the actual ML currently being converted from its role with Ares I to SLS.<\/p>\n

It includes far field measurement devices, accelerometers, thermocouples and strain gauges on vehicle, thermocouples, flow meters and chamber pressure instrumentation.<\/p>\n

Acoustic<\/b> Testing:<\/p>\n

SMAT continues the heritage of testing future launch vehicles at the scale model level.<\/p>\n

NASA engineers have test fired many versions of scaled rockets to gain data on the acoustic environments endured during ignition and launch.<\/p>\n

See Also<\/h4>\n
    \n
  • SLS Forum Section<\/li>\n
  • L2 SLS Section<\/li>\n
  • L2 FRR Section<\/li>\n
  • Click here to Join L2<\/li>\n<\/ul>\n

    The primary source of the acoustic field is the fluctuating turbulence in the mixing region of the rocket exhaust flow \u2013 known as Engine Generated Acoustics.<\/p>\n

    Engine generated noise is a function of the exhaust flow parameters, launch stand configuration, and to a lesser extent atmospheric conditions.<\/p>\n

    Preliminary estimates of the engine generated acoustics at a specified location on the vehicle can be determined by scaling measured acoustic data from previous launch vehicle programs, taking into account the above mentioned flow, configuration, and atmospheric parameters.<\/p>\n

    \"TheA better definition of the lift-off acoustic environment can be determined from hot fire testing of dynamically scaled models of the launch vehicle and stand.<\/p>\n

    During the Space Shuttle development program, a 6.4 percent scale model of the launch vehicle, propulsion system, launch stand, and exhaust duct system with water suppression was used to refine the analytical\/scaling estimates of the lift-off acoustic environment.<\/p>\n

    The resulting data provides a very useful template for the full scale rocket, although final verification of the environment is only fully provided by full static firings or launches of the actual vehicle.<\/p>\n

    Notably, the debut launch of the Space Shuttle Program (SSP) \u2013 with Columbia on STS-1 \u2013 showed the importance of understanding the acoustic environments, as the orbiter\u2019s heat shield was damaged when an overpressure wave from the SRBs caused a forward RCS oxidizer strut to fail. Her body flap was also pushed five degrees out of position.<\/p>\n

    \"STS-129The subject was also raised during STS-129\u2019s Flight Readiness Review (FRR), as a potential issue with a very small area of the orbiter \u2013 known as a stinger attach point between the RCS and OMS Pod \u2013 raised concerns that recent acoustic environment analysis of the Space Shuttle Main Engines (SSMEs) during ignition could cause stressing that potentially leads to cracks in the attach pins\/stinger.<\/p>\n

    Although those concerns were based on old and overly conservative data, managers showed their usual due diligence in gathering an array of updated information, via new computational models, borescope inspections on the fleet, and the installation of sensors in the area in question \u2013 all of which would be used to completely allay the potential fear of life fatigue on the stinger.<\/p>\n

    Click here for FRR Articles: http:\/\/www.nasaspaceflight.com\/tag\/frr\/<\/p>\n

    Notably, the FRR presentations noted they lacked key historical data, given the 6.4 percent model tested during the 1970s only fired motors that mimicked the Solid Rocket Boosters and not the SSMEs, while Main Engine Ignition (MEI) Acoustic & SSME Ignition Overpressure (IOP) Environment data was classed as \u201ccontinually evolving\u201d during the 30 years of the program \u2013 leading to the concern ahead of STS-129.<\/p>\n

    \"ASMATThe vehicle that was set to replace the Space Shuttle, Ares I, also underwent IOP testing \u2013 with the Ares I Scale Model Acoustics Test (ASMAT) tested during 2010.<\/p>\n

    Numerous tests, each using a different pad configuration \u2013 such as with and without water bags within the launch mount \u2013 were conducted at MSFC.<\/p>\n

    For the Ares I Scale Modelling Acoustic Tests, the vehicle model was set at a number of fixed elevations for individual test firings, these being 0, 2.5, 5.0, 7.5, and 10.0 feet. Based on the scale of the ASMAT, these distances corresponded to full-scale elevations of 0, 50, 100, 150, and 200 feet.<\/p>\n

    Quick look test results indicated that the overall noise levels measured on the vehicle were within predicted ranges and the data compared favorably between the firings. However, Ares I was cancelled shortly after the ASMAT firings.<\/p>\n

    \"SLSThe SMAT firings will continue over the coming months, with the vehicle soon to sport its two \u201cboosters\u201d, in the form of two ATK-built Rocket-Assisted Take Off (RATO) motors will simulate SLS boosters, with the test requirement calling for the motors ignite simultaneously, as the SRBs would during launch.<\/p>\n

    This testing will provide critical data about how the powerful noise generated by the engines and boosters may affect the rocket and crew, especially during liftoff, with a focus on how low- and high-frequency sound waves impact on the vehicle.<\/p>\n

    (Images via NASA and L2)<\/p>\n

    (NSF and L2 are continuing to provide the most extensive and exclusive SLS coverage. To join L2, support the site and access a huge database of content, click here: http:\/\/www.nasaspaceflight.com\/l2\/)<\/p>\n","protected":false},"excerpt":{"rendered":"

    The Scale Model Acoustic Test (SMAT) \u2013 a mini-me version of the SLS \u2013 has fired up for the first time at the Marshall Space Flight Center (MSFC). The tests are focused on providing data to engineering teams who are tasked with designing the Sound Suppression System that will protect the Heavy Lift Launch Vehicle […]<\/p>\n","protected":false},"author":1,"featured_media":30467,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[9034,624,9065,7806,8116],"class_list":["post-39656","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-hlv","tag-sls","tag-smat","tag-srb","tag-ssme"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39656"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=39656"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39656\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/30467"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=39656"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=39656"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=39656"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}