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<\/p>\nAs NASA showed off the first assembled Space Launch System (SLS) Core Stage to government stakeholders and media at the Michoud Assembly Facility (MAF) in New Orleans, prime contractor Boeing continued preparations to ship the stage to the Stennis Space Center in Mississippi as soon as they can. While the TV camera \u201cred lights\u201d were on during a live morning broadcast on December 9 at the beginning of \u201cArtemis Day\u201d event festivities held at MAF, similar \u201ctest in progress\u201d lights were on around the stage as Boeing and RS-25 prime contractor Aerojet Rocketdyne continued working to complete engine leak checks.<\/p>\n
In parallel, NASA and contractor teams at Stennis are wrapping up work at the B Test Stand there so the Core Stage can be installed in the B-2 stage test position there next month. Boeing is now estimating that the Stage \u201cGreen Run\u201d test campaign will last up to ten months before the stage will be ready to ship to Kennedy Space Center (KSC) in Florida for final preparations for a 2021 Artemis 1 launch.<\/p>\n
The centerpiece of the test campaign is an eight-minute long, flight duration \u201chot-fire\u201d of the stage in the B-2 stand, which could take place in the middle of the year; however, the extent of repairs and refurbishment of the stage after the first-time firing is an unknown and test managers are bookkeeping two to three months to restore the stage to a safe enough condition to travel to KSC.<\/p>\n
At MAF functional testing to verify that the systems of Core Stage-1 are connected and communicating with each other correctly is still in progress, and the tentative date for shipment to Stennis is now just after New Year\u2019s. Once testing is complete, final outfitting of the stage must be completed where it is currently lying in the SLS Final Assembly area, and then it will be moved for loading onto NASA transporters to roll out to the barge and head to Stennis.<\/p>\n
Stage shipping preps in parallel with completing functional testing<\/p>\n
NASA and Administrator Jim Bridenstine celebrated the completion of the first Core Stage at Michoud on December 9 and while all the working pieces are connected, prime contractor Boeing continues running through a final integrated functional test (FIFT) of the stage.<\/p>\n
\u201cWe\u2019re in functional testing, so we\u2019ve connected all the major pieces of the rocket, we\u2019re making sure they all talk to each other,\u201d Amanda Gertjejansen, Core Stage-1 Operations Manager for Boeing, said in an interview on December 9. \u201cOnce we\u2019re done with functional test we\u2019ve got to prep the vehicle to ship.\u201d<\/p>\n
<\/p>\n
Credit: NASA\/Bill Ingalls.<\/p>\n
(Photo Caption: Core Stage-1 provides the backdrop as NASA Administrator speaks during a live TV broadcast to begin the \u201cArtemis Day\u201d media event at MAF on December 9. Although assembly of all the mechanical and working parts of the stage is complete, Boeing still has a few weeks of work remaining to finish testing, outfitting, and closeout before the stage is ready to transport to Stennis for the Green Run test campaign.)<\/em><\/p>\n As seen during the media event on December 9, the stage is lying horizontally in the Area 47 footprint of the Area 47\/48 duplex in Building 103, where Core Stage Final Assembly takes place. With functional testing still underway, the stage is still missing several flight covers and remains surrounded by work stands.<\/p>\n Boeing still hopes to ship the stage from MAF as close to the end of the month as they can, and so the flurry of work to closeout the inside and outside of the stage is overlapping with the functional checks. \u201cIt\u2019s got covers, any of the test ports that we\u2019re covering up, some blankets around the engines, some covers across the systems tunnel we button that up,\u201d Gertjejansen said. \u201cWe have to back away the stands to do some rotations.\u201d<\/p>\n The stage is currently held in two Rotational Assembly and Transportation Tools (RATT) that allow it to be rotated; however, the stage has been in its current orientation since October to facilitate RS-25 engine installations. \u201cWe\u2019re at ninety (degrees) up so we\u2019ll rotate to put the boattail fairings on,\u201d she said.<\/p>\n The bottom of the boattail extends out slightly beyond the twenty-seven plus foot circumference of the stage to accommodate the powerheads of the four engines; the fairings help streamline aerodynamic flow during the early part of ascent. \u201cWe\u2019ll put two of [them] on in the orientation it\u2019s in now and then we\u2019ll have to rotate one-hundred eighty degrees and put the other two on.\u201d<\/p>\n The final assembly team is already working on shipping prep tasks where they can. \u201cWe\u2019re pulling ahead any we\u2019re calling it \u2018final outfitting\u2019 so we\u2019ve been putting on some of those covers now,\u201d Gertjejansen noted. \u201cAs we run the [last] test we\u2019re pulling whatever covers go over, this the last time we have to go hook up a connector to this area, we\u2019re putting covers on as we go.\u201d<\/p>\n As an example, she noted on the afternoon of the December 9 media day, \u201cwe just finished leak checks and we\u2019ll be looking to start the thermal blankets tomorrow.\u201d With the RS-25 engine leak checks completed, the engine-mounted heat shield (EMHS) blankets can be installed. The blankets provide thermal protection for the engine powerheads and the inside of the engine section and boattail.<\/p>\n Credit: Philip Sloss for NSF.<\/p>\n (Photo Caption: The covered nozzles of the four RS-25 engines are the most prominent feature of a heavily-obscured tail of Core Stage-1 on December 9. Upstairs on the second level, Andrew Rostron with Aerojet Rocketdyne sits next to Engine 2045 in the number one position, upper right. Boeing and Aerojet completed leak checks of the engines later that day.)<\/em><\/p>\n Once all of the outfitting is complete, a pre-ship review will be held about a week before the stage is rolled out to the Pegasus barge for its relatively short water voyage to Stennis. Mark Nappi, Boeing Green Run Test Manager, said in a media question and answer session on December 10 that the tentative schedule for the review was December 28.<\/p>\n That rollout will be the first time the stage has been transported outside and it will be placed in special NASA transportation equipment and moved by remotely-controlled \u201cself-propelled mobilized transporters\u201d (SPMT). Boeing has its own factory transporters for the shorter trips from one indoor work area to another and those will be used one more time to move the stage from its current location a couple of doors down to Building 110 to transfer it over to the NASA transporters.<\/p>\n Green Run outline<\/p>\n At Stennis, Boeing will begin the Stage Green Run for this first working Core Stage article that also doubles as the first flight vehicle. Now planned only to be conducted on this first unit, the test campaign is the first opportunity to run a Core Stage through a series of tests that will help validate analytical models of how the stage\u2019s mechanical and rocket hardware should behave during the phases of the countdown, ignition, liftoff, and ascent to orbit.<\/p>\n \u201cWe\u2019re setting up this thing so that we\u2019re essentially going to launch it bolted down, a full flight firing of that Core Stage over eight minutes bolted down,\u201d Nappi said during the December 10th Q&A session. \u201cThat\u2019ll satisfy a lot of our design objectives and make sure that that propulsion system is working like it\u2019s supposed to. Then we\u2019ll get it ready after the hot-fire and ship it to Florida.\u201d<\/p>\n \u201cIt\u2019s a big deal, it\u2019s a 24\/7 operation,\u201d he said. \u201cIt\u2019s just an extended launch campaign, actually; right now we (Boeing) probably have a dozen people here. In another thirty days, we\u2019re going to have two-hundred fifty to three-hundred people and we\u2019ll be working around the clock seven days a week, getting this vehicle ready for that hot-fire test.\u201d<\/p>\n The flight-duration \u201chot-fire\u201d of the stage, while it remains bolted into the B-2 stand, is the final major test in the Green Run Stage campaign; the firing serves as a \u201cGreen Run\u201d or acceptance test of the stage, but its primary purpose is to validate analytics that model the stage behavior.<\/p>\n Credit: Philip Sloss for NSF.<\/p>\n (Photo Caption: Core Stage-1 surrounded by work platforms in the SLS Final Assembly area at MAF on December 9. The lower level provides access to the -Z side LOX downcomer and adjacent systems tunnel. The upper level provides access to the tank repressurization lines and upper umbilicals for the forward skirt and intertank. Another set of platforms spans the +Z side of the stage.)<\/em><\/p>\n \u201cThe purpose of the Green Run is to satisfy design objectives, so we\u2019ve got really, really good models that are predicting how the vehicle is going to react once we load it with liquid oxygen, liquid hydrogen, and we do the hot-fire,\u201d Nappi explained. \u201cThe Green Run is to verify that yeah those models were right, and you only need to do that once and then you can depend on your models for any changes that occur.\u201d<\/p>\n The models also allow engineers to analyze how the stage would behave under a larger set of operating conditions, including outside the currently defined limits. Previously, NASA and Boeing had also planned on conducting an acceptance test of the second Core Stage; however, in the name of schedule the necessity of both months-long Green Run campaigns came into question.<\/p>\n \u201cIt\u2019s about ten months to get it all done and if we have a little bit of luck we could get it done a little sooner than that,\u201d Nappi said. If the stage arrives at Stennis in early January, that would put arrival at KSC in the October time-frame next year, implying that the Artemis 1 launch date target would be well into 2021.<\/p>\n A final decision in the summer was to perform the Green Run campaign once on the first flight unit; plans to do the same for the second unit were canceled.<\/p>\n Nappi provided an overview of the Green Run activities at Stennis: \u201cWhat\u2019s involved once the vehicle gets here is getting it in the stand and this is really a joint effort between Stennis and the NASA Marshall Stages Office and us as a contractor, Boeing, to get that vehicle in position where we can hot-fire it,\u201d he said. \u201cSo as soon as we get it in the stand we\u2019ll take about two or three weeks where we\u2019re going to do something called a modal, which is essentially just a response test to see how the vehicle reacts, again matching up those results with the models that we\u2019ve created to make sure that it\u2019s reacting like we expected it to.\u201d<\/p>\n As was practiced at Stennis with the Core Stage Pathfinder, the flight stage will be rolled off of the Pegasus barge that moves it from MAF to Stennis, lifted up with two cranes, rotated from horizontal to vertical, and then the primary test stand derrick crane will install the stage in the stand where it will be bolted down and the crane disconnected.<\/p>\n \u201cFrom the time the barge gets here it takes about three, four days and then it\u2019ll be in the stand,\u201d Nappi noted.<\/p>\n Credit: NASA\/Stennis Space Center.<\/p>\n (Photo Caption: The B Test Stand derrick crane lifts the Core Stage Pathfinder out of the stand\u2019s B-2 position on August 29. After installing Core Stage-1 into the stand in January, the crane will be used to lift the stage up out of the hold-down attachments to perform three separate modal test runs over a period of a couple of weeks. The modal tests are the first of many test cases to be run as a part of the Stage Green Run campaign.)<\/em><\/p>\n The modal test measuring the structural frequency response of the Core Stage by itself is three separate test runs where the derrick crane is reattached and the stage is partially lifted out of the stand so it is hanging on the crane to perform the test. \u201cWe lift it three times, so we take it, lift it up, do the modal test, put it back in the stand. Do some data analysis, come back again pick it up, do modal, put it back in the stand. Same thing, three times.\u201d<\/p>\n \u201cOnce we\u2019re done with modal then we\u2019ll bolt the vehicle down in the stand and we\u2019ll start getting access,\u201d Nappi explained. \u201cWe\u2019ve got to get access into the engine section, we have to get access into the intertank, we have to get access into the forward skirt so that we can start configuring the vehicle for test.\u201d<\/p>\n \u201cWe also have some work that we\u2019re going to complete from MAF, the LH2 (liquid hydrogen) feedlines still need to be connected so we\u2019re going to have about two or three months worth of work to get those feedlines connected so that when we start our power on testing we\u2019ll have the vehicle in flight configuration.\u201d<\/p>\n The LH2 feedlines and fill and drain line are positioned inside the engine compartment, but can\u2019t be secured while the stage is horizontal. Boeing, with NASA\u2019s concurrence, traded deferring that work to Stennis in order to buy back several months of time at MAF by completing the rest of the stage assembly in the horizontal.<\/p>\n \u201cWe\u2019ll do what we call power-up testing or confidence testing,\u201d Nappi explained. \u201cThis is the first time that this vehicle has been in this stand and has seen the software that we\u2019ve created to run these tests, so we want to take a really slow and methodical set of steps to make sure that that all works together properly so that when we do go do the \u2018wet dress\u2019 (Wet Dress Rehearsal) and the hot-fire everything is working like it\u2019s supposed to.\u201d<\/p>\n Special software will run on the stage\u2019s three redundant flight computers to account for the static nature of the eight-minute long test; otherwise, most of the stage\u2019s systems have to perform as they would during a dynamic ascent to orbit insertion. Boeing has also developed the Core Stage Controller (also known as the Stage Controller) package of ground software and avionics that manages that side of the Stennis testing.<\/p>\n \u201cThe tests are validating that all of our systems are working, that our avionics systems are working, our hydraulic systems are working, TVC systems are working, our Main Propulsion Systems are all working. We\u2019ll have people in our control room that will be monitoring all their systems as we bring every single black box up and we actuate every valve and we\u2019re checking to make sure that when we send the command that it works and the indications come back and they\u2019re coming back like they\u2019re supposed to.\u201d<\/p>\n \u201cSo we\u2019re going to take a couple of months testing everything with the software and the vehicle and the stand to make sure that it works right,\u201d he added. \u201cWhen we\u2019re done with that we\u2019re going to take a step back and say it\u2019s time to load this vehicle with LH2 and LOX (liquid oxygen) and see how it reacts.\u201d<\/p>\n Credit: Philip Sloss for NSF.<\/p>\n (Photo Caption: A view of the northern perimeter of the B Test Complex from Level 19 of the B-2 test stand position in December, 2018. The white-colored tubing to the right of the exhaust\/water deluge pathway that extends out from the flame buckets of both B-1 (left) and B-2 (right) positions is where LOX will be dumped after it is drained from the Core Stage after the Wet Dress Rehearsal. Any LOX residuals left in the tank following the hot-fire test will also be dumped here. Gaseous oxygen boiloff will be vented out a port on the stage\u2019s forward skirt.)<\/em><\/p>\n \u201cWe\u2019re going to do what\u2019s called a Wet Dress Rehearsal (WDR), load it with LH2 and LOX, make sure it doesn\u2019t leak, we\u2019re good. We detank it, these guys get us some more commodities so we can load that vehicle again and [then] we come back and we actually run the hot-fire.\u201d<\/p>\n Boeing anticipates a short turnaround from the WDR to the hot-fire; what amounts to a scrub turnaround between the WDR tanking and the hot-fire tanking is driven by the infrastructure at Stennis to supply propellant and other support commodities to the fluid-hungry stage. The cryogenic propellants are supplied to the hydrogen-oxygen test stands at Stennis by barges docked around them.<\/p>\n \u201cOur liquid oxygen barges here, each one of those holds about a hundred thousand gallons of liquid oxygen,\u201d Maury Vander, NASA\u2019s Test Operations Division Chief in the Stennis Engineering and Test Directorate, said. \u201cThose [liquid hydrogen barges] are about two-hundred, forty thousand gallons of liquid hydrogen.\u201d<\/p>\n \u201cThe vehicle holds five-hundred fifty thousand gallons of LH and about two-hundred thousand gallons of liquid oxygen so we\u2019ve got enough, but we don\u2019t have enough to try to recycle quickly. We\u2019re making the conscious decision after the wet dress we\u2019re going to discard the LOX and we\u2019re going to drain back the liquid hydrogen so we\u2019ve got to get trucks in here to replenish our barges and that\u2019s what drives the five-day turnaround between wet dress to hot-fire.\u201d<\/p>\n \u201cWhen we do the wet dress, we\u2019re just basically testing the health of the overall system,\u201d Nappi noted. \u201cAre we getting any leaks? Are the valves working properly? Is it a nominal type of tanking?\u201d<\/p>\n \u201cAnd detanking \u2014 it\u2019s real important to assure that we can detank this vehicle as safely as we tanked that, so those are two real important parts of the test. Then when we do hot-fire you\u2019re essentially just checking your flight readiness of all the main propulsion system and that it\u2019s working properly and we\u2019ll be watching it just like we would on day of launch.\u201d<\/p>\n Following the hot-fire, Boeing has set aside a long period for refurbishing the stage. \u201cIt takes about two to three months after hot-fire,\u201d Nappi said. \u201cWe haven\u2019t hot-fired it yet so when we\u2019re done we\u2019ll take a step back, we\u2019ll see what needs to be fixed before we put it on the barge.\u201d<\/p>\n \u201cFirst of all we have to do shipping preps, we have to get the vehicle ready to put on the barge. That\u2019s all known work, we know what kind of preparations need to be made.\u201d<\/p>\n Credit: Philip Sloss for NSF.<\/p>\n (Photo Caption: A view of the dual-position B Test Stand looking to the south on December 10. The B-2 stage test position is on the left, the single-engine B-1 test position is on the right. Both positions are fed propellants from barges docked around the stand, but the B-1 position has run tanks for the LOX and LH2 propellant commodities. For the SLS Core Stage Green Run propellant tests, the barges will be used to fill the stage and a day tank on the B-2 side will be used to maintain stable replenishment of LOX for the stage.)<\/b><\/em><\/p>\n \u201cThe second piece is the engine refurb, and the third piece is any damage that occurs during hot-fire,\u201d he added. \u201cThis thing is going to fire for eight minutes and it\u2019s going to be bolted down.\u201d<\/p>\n \u201cWe expect to see some TPS damage and so we\u2019re going to have to repair that, but we don\u2019t have to repair it all here. We can take a lot of that to KSC if we like and do it on a non-interference basis at KSC.\u201d<\/p>\n \u201cSo that work is undefined, we don\u2019t know what the damage is going to be yet,\u201d Nappi explained. \u201cWe suspect we know where some of it is going to be and we\u2019re preparing for it, but until we know what it is we won\u2019t be able to scope it.\u201d<\/p>\n Aerojet Rocketdyne will refurbish the RS-25s while Boeing works on the rest of the stage. \u201cThey\u2019ve come up with a minimal number of days that they need to essentially get the engines refurbished to a point where they\u2019re safe enough to put it on the barge,\u201d Nappi said. \u201cAfter hot-fire it\u2019s about two months.\u201d<\/p>\n \u201cWe\u2019re going to have a lot of instrumentation on the vehicle for this test so that instrumentation has to come off. That\u2019s again known work, we will be able to do that under the envelope of the engines being refurbished,\u201d he added.<\/p>\n There is also ground test instrumentation specific to the modal tests that will be conducted at the beginning of the campaign; Nappi said that instrumentation would be removed immediately after the modal tests are completed.<\/p>\n Pages: 1 2<\/p>\n","protected":false},"excerpt":{"rendered":" As NASA showed off the first assembled Space Launch System (SLS) Core Stage to government stakeholders and media at the Michoud Assembly Facility (MAF) in New Orleans, prime contractor Boeing continued preparations to ship the stage to the Stennis Space Center in Mississippi as soon as they can. While the TV camera \u201cred lights\u201d were […]<\/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":[1700,8891,3718,7866,624,8091],"class_list":["post-37784","post","type-post","status-publish","format-standard","hentry","category-news","tag-artemis-1","tag-b-2","tag-em-1","tag-maf","tag-sls","tag-stennis"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/37784"}],"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=37784"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/37784\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=37784"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=37784"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=37784"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}See Also<\/h4>\n
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\nAfter the LH2 Main Propulsion System (MPS) lines are secured, checked out, and final spray-on foam insulation (SOFI) closeout work completed, the power-up testing will start to verify that the stage is ready to be loaded with propellant and then fired; the cryogenic tanking and test-firing will be firsts for the SLS Program.<\/p>\n![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2019\/12\/P1120588.35pct.jpg\")
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