![\"2016-09-05-140231\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/09\/2016-09-05-140231-350x269.jpg\")
The B-2 test stand was originally constructed in the 1960s and first supported testing of the Saturn V first stage, the S-IC.<\/p>\nThe NASA and contractor workforce at Stennis Space Center are nearing completion of structural work on the B-2 test stand that will be used for the Green Run test of the Space Launch System (SLS) Core Stage before its first flight. In addition to SLS Core Stage testing, planning is now also underway for the stand to support a similar \u201cgreen run\u201d test of the Exploration Upper Stage (EUS).<\/p>\n
The Green Run:<\/p>\n
As structural modifications are finishing, work to activate the test stand is increasing and the test team is beginning work to define Green Run procedures.<\/p>\n
\u201cWe are near completion of what we would call restoration and buildout of the test stand \u2013 the removal and replacement of parts and existing structure,\u201d Travis Martin, Lead Systems Engineer for the SLS Green Run Test Project, said in an interview with NASASpaceflight.com. \u201cThat is coming to completion at the end of this fiscal year.<\/p>\n
\u201cAs far as activation is concerned, technically we started activation about six months ago, but that\u2019s at [the] subsystem level. Actual activation of the test stand is not slated to start until later this calendar year.\u201d<\/p>\n
The B-2 test stand was originally constructed in the 1960s and first supported testing of the Saturn V first stage, the S-IC.<\/p>\n
It was also used to test the Space Shuttle Main Propulsion Test Article (MPTA) in the late 1970s and early 1980s and in more recent times the Delta IV Common Booster Core in the 2000s.<\/p>\n
Buildout of the stand was required due to the length of the SLS Core Stage, which stretches to almost 212 feet from the top of the forward skirt to the exit plane of the four RS-25 engines at the bottom.<\/p>\n
In addition, the stand was configured for the off-axis, side-mounted Shuttle MPTA thrust; the MPTA thrust structure was therefore out of position for the inline SLS Core Stage.<\/p>\n
Astronomy (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n Rather than demolish the existing structure and build a new one, it was decided that it would be more cost-effective to move the existing MPTA structure about twenty-feet to an inline position and then renovate it. The move was completed in August, 2014.<\/p>\n Activation work:<\/p>\n While the structural work continues, Mr. Martin noted some of the subsystem activation work also beginning.<\/p>\n \u201cThe first item that we\u2019ll focus on when it comes to activation of the test stand is the data acquisition system,\u201d he explained.<\/p>\n \u201cSo that\u2019s the actual data acquisition system, recording hardware, all the sensing lines up into the interface boxes before we actually connect to a wire to the Core Stage. We started activation on the LOX vent system, that\u2019s a shared system between B-1 and B-2.<\/p>\n \u201cWe also have done some upgrades to the high-pressure industrial water facility, specifically we\u2019ve commissioned the use of a new 25,000-gallon per minute electric pump, which is needed to supply the extra acoustical damping we need for the Core Stage test.\u201d<\/p>\n Martin also noted that Stennis has completed renovation and activation of a Shuttle hydraulic skid they received from Kennedy Space Center (KSC) ground operations.<\/p>\n Green run schedule:<\/p>\n The B-2 test stand work is to get ready for a major development milestone for the SLS Core Stage, the Green Run test, which will essentially fly the Core Stage in place on the test stand through a nominal, eight-minute launch and ascent.<\/p>\n Green Run test activities will involve several firsts, including the first cold flows, the first full tanking, and the first hot fire of the four RS-25 engines integrated with the Core Stage propulsion system.<\/p>\n Given all the firsts, the plan is for the Core Stage to be at Stennis for several months.<\/p>\n \u201cWe still expect to see the Core Stage for September 2017 arrival and we expect to have the Core Stage anywhere between six to eight months,\u201d Mr. Martin said.<\/p>\n One of the first operations that will be done on the stage after arrival is what is called a \u201cmodal test.\u201d<\/p>\n \u201cThere are a number of ways to do it, but we haven\u2019t determined which method [yet] \u2013 whether we\u2019re going to do mechanical shakers or a calibrated hammer to actually ping the Core Stage while it\u2019s suspended inches above the test stand. That work will not be done by Stennis, it will actually be done by Marshall.\u201d<\/p>\n In a general overview of the Green Run operations with the first Core Stage, the outline also includes a key element of the Shuttle era, the tanking test, ahead of firing up the engines.<\/p>\n \u201cIn general, we advertise that we plan to do a modal test \u2013 a suspended modal test, a fill and drain test or \u2018tanking test\u2019 as we called it back on Shuttle, and then a hot-fire test \u2013 a full duration hot-fire test, which is approximately 480 seconds.\u201d<\/p>\n \u201cIf we deem it needed by analysis there afterward, we would do a second hot-fire test before removing the Core Stage from the test stand.<\/p>\n \u201cBetween modal test and wet-dress [fill and drain test], there are a number of subsystem checkouts, so we\u2019ll do thrust vector control checkouts [and] we\u2019ll do vehicle power-up checkouts.<\/p>\n \u201cBefore the tanking test, we\u2019ll go do a full simulated countdown and hot-fire demonstration test \u2013 there will be no fluids flowing, but through software simulation we will induce test conditions, induce faults, and practice our recovery [from those].\u201d<\/p>\n \u201cStarting in September, the Stennis operations team including myself and the Boeing operations team will start developing that integrated plan and procedure and we will in the future walk-through and go do simulations of [the plan],\u201d Mr. Martin noted.<\/p>\n \u201cThe actual simulations hopefully will coincide with some of the facility activations.\u201d<\/p>\n NASA is planning on a month\u2019s worth of refurbishment work on the stage at Stennis after the full-duration hot-fire, including standard engine servicing and making any repairs necessary to the stage\u2019s thermal protection system (TPS).<\/p>\n \u201cWe\u2019ve added additional personnel access structures to the engine servicing level for the Aerojet Rocketdyne personnel to do what they need to do to the engines \u2013 to refurbish, plug them up before we actually put it back on the barge,\u201d Mr. Martin noted.<\/p>\n \u201cWhen it comes to TPS, we actually have additional structures and access platforms for the Boeing personnel.\u201d<\/p>\n Pathfinder visit:<\/p>\n Prior to the arrival of the flight unit, Stennis will get an opportunity to practice handling a Core Stage when a pathfinder article arrives there on the Pegasus barge.<\/p>\n \u201cThe expected delivery date of the Pathfinder vehicle is July 2017, a few months before the advertised delivery date for the Core Stage,\u201d Mr. Martin said.<\/p>\n Currently under construction, the Core Stage pathfinder will have the same dimensions as the flight units, along with the same handling attachments and umbilical plate locations.<\/p>\n \u201cWe want to do three major things with the Pathfinder: we want to practice the lifting procedure, which is the lifting and breaking over of the Core Stage, we\u2019ll practice that with the Pathfinder multiple times. Also, inserting the Pathfinder in and out of the test stand itself, verifying structural clearances, at least three times or more.<\/p>\n \u201cWe also verify our umbilical carrier mechanisms \u2013 we want to check the alignment of those.\u201d The Core Stage has four umbilical panels where services are supplied to the different subsystems \u2013 one on the forward skirt, one on the intertank, and the two on the engine section.<\/p>\n A lot of cryos:<\/p>\n When it comes time to load the stage for the Green Run \u201cwet\u201d tests, it will take much of the infrastructure at Stennis that supports testing hydrolox engines and stages.<\/p>\n \u201cHere on site we have four LOX barges and three [liquid] hydrogen barges; all those barges plus a topping tank \u2013 that\u2019s a ground tank for liquid oxygen \u2014 will be needed to conduct the Green Run test,\u201d Mr. Martin explained.<\/p>\n When asked about supplying the stage with all the different commodities needed for a full-duration firing, Martin noted that the hot-fire is not the limiting case:<\/p>\n This includes not just the cryogenic propellant, but also things like hydraulics and purge gasses.<\/p>\n \u201cWe will fill every barge to their capacity or just above that to maintain margin. We will overfill our high-pressure industrial water reservoir, so we\u2019ll have margin there.<\/p>\n \u201cAnd we\u2019ve done modifications for the site-wide gas supply \u2013 for [gaseous] hydrogen, helium, nitrogen \u2014 to accommodate the increased usage of nitrogen to do purges, to warming the empty compartments \u2014 the forward skirt, the engine section, and the intertank \u2013 as well as engine drying and tank [inerting].\u201d<\/p>\n EUS Green Run in the future:<\/p>\n Plans are for the first two Core Stage flight articles to go through Green Run testing at Stennis.<\/p>\n Since EUS will fly on the second SLS launch, both hydrolox stages will need to be fired at Stennis before heading to KSC for launch processing; however, the timeline and order for that is still to be determined.<\/p>\n \u201cIt has not been determined if the upper stage will be tested in between Core Stage 1 and Core Stage 2,\u201d Mr. Martin explained. \u201cIf so, then the test stand will stay in an active status.<\/p>\n \u201cIf upper stage testing lags after Core Stage 2 testing, then the test stand will go into what we call an active standby status.\u201d<\/p>\n (Images: Via NASA and L2 \u2013 including Philip Sloss for NASASpaceFlight.com and SLS renders from L2 artist Nathan Koga \u2013 The full gallery of Nathan\u2019s (SpaceX Dragon to MCT, SLS, Commercial Crew and more) L2 images can be *found here*)<\/p>\n (To join L2, click here: \/\/www.nasaspaceflight.com\/l2\/)<\/p>\n","protected":false},"excerpt":{"rendered":" The NASA and contractor workforce at Stennis Space Center are nearing completion of structural work on the B-2 test stand that will be used for the Green Run test of the Space Launch System (SLS) Core Stage before its first flight. In addition to SLS Core Stage testing, planning is now also underway for the […]<\/p>\n","protected":false},"author":1,"featured_media":0,"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":[2363,624,8091],"class_list":["post-38968","post","type-post","status-publish","format-standard","hentry","category-news","tag-rs-25","tag-sls","tag-stennis"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38968"}],"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=38968"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/38968\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=38968"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=38968"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=38968"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"2016-09-05-142441\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/09\/2016-09-05-142441-350x225.jpg\")
\u201cCurrently, we have completed installation of all the new data acquisition hardware that is specific to B-2 and we\u2019re going to upgrade the rest of the site with the same hardware.<\/p>\nSee Also<\/h4>\n
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![\"2016-01-27-133641\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/01\/2016-01-27-133641-350x258.jpg\")
\u201cA modal test is, let\u2019s say, a vibration test to determine the resonant frequency of a structure or part,\u201d he added. \u201cWe\u2019ve already characterized the test stand and we want to insure that the Core Stage resonant frequency is not coupled with the test stand.<\/p>\n![\"2016-09-05-154625\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/09\/2016-09-05-154625-350x220.jpg\")
\u201cIf all goes well with that hot-fire test, then we plan to do the standard refurbishment needed to the Core Stage, defined by an integrated plan between [NASA] and Boeing, and then we\u2019ll put it back on Pegasus and send it on to KSC.<\/p>\n![\"2016-09-05-173622\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/09\/2016-09-05-173622-350x257.jpg\")
Work on the detailed operations plan for the Green Test began this month, which will be finalized via simulations of the test procedures.<\/p>\n![\"2016-08-24-170449\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/08\/2016-08-24-170449-350x238.jpg\")
\u201cWe intend to have the Pathfinder in our possession [for] about two weeks.\u201d<\/p>\n![\"2016-07-07-204204\"](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/07\/2016-07-07-204204-350x222.jpg\")
\u201cThe worst-case is not the hot-fire test, the worst-case is the tanking test, and that requires from start to finish about 22 hours of supplying of gases to the Core Stage,\u201d he added.<\/p>\n![\"Screen](\"\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2016\/03\/Screen-Shot-2016-03-10-at-10.55.13-350x241.png\")
With the EUS (Exploration Upper Stage) development beginning to proceed \u2013 with the preliminary design review is in December \u2013 the current plan is to modify and use the B-2 stand for that stage when the time comes.<\/p>\n