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Mobile Launcher-1 (ML-1) rolled out to Pad 39B last August, after Artemis I post-launch repairs, refurbishment, and installation of elements of a new emergency egress system (EES).<\/p>\n
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Credit: NASA\/Isaac Watson.<\/p>\n
(Photo Caption: The first slidewire basket is seen Jan. 24 during initial setups for validating the emergency egress system for crewed Artemis launches that begin with Artemis II.)<\/em><\/p>\n Before a launch, the pad workforce will be cleared from the area while SLS is loaded with propellants. However, as crewed flights begin, both the astronaut flight crew and closeout crew support team will be on the Mobile Launcher to help the astronauts board Orion. The egress system, which is similar to ones used for Commercial Crew and previous NASA crewed transportation systems like the Space Shuttle, will allow personnel at the pad to quickly get away from the vehicle and Mobile Launcher (ML) in case of an emergency.<\/p>\n Four baskets will be staged on the ML umbilical tower at the 274-foot level, which is where the crew access arm and \u201cwhite room\u201d are located for crews to enter and exit the Orion crew module. The baskets will run down slidewires to a terminus area on the west edge of the pad infield, where mine resistant ambush protected (MRAP) emergency transport vehicles will be parked that can be driven away from the pad.<\/p>\n Currently, EGS is setting up the first of the four slidewire baskets to begin verification testing. \u201cWe\u2019re fitting up that first basket to the rail system up on the Mobile Launcher tower,\u201d Lanham explained. \u201cWe\u2019ve got some software that we\u2019re finishing up over the weekend and we\u2019re looking right now at Monday [Jan. 29] to get into our drop testing with the baskets, where we\u2019re actually testing the baskets and the braking and the different systems that are part of that first basket run.\u201d<\/p>\n \u201cOnce we complete all that, then we\u2019ll get into the other three baskets and do similar drop testing with those.\u201d The first set of tests is being performed by the construction contractor, JP Donovan.<\/p>\n \u201cThat\u2019s called commissioning,\u201d Lanham noted. \u201cRight now, we\u2019re looking at finishing that up in the mid-spring timeframe to finish that testing, and then at the end of that testing by the construction contractor, we would then go into, with our operations contractor, the actual verification and validation testing for several weeks.\u201d<\/p>\n \u201cOnce that\u2019s complete, we get into another ISVV or integrated system verification and validation test where we\u2019ll actually bring the crew out, and that\u2019s called \u2018ISVV 1,’\u201d he added. \u201cWe\u2019ll run through, with the crew, the launch day sequence of events and also we\u2019ll be swinging the baskets down the tower.\u201d<\/p>\n The crew participated in an initial run of the launch day sequence of events last September; the next test run will add practice for emergency modes that might require quick evacuation. \u201cThey would come out of the vehicle, go down the walkway of the Crew Access Arm, across Level 274 of the Mobile Launcher over to where the baskets are. They\u2019ll practice that, they\u2019ll get familiar with the pathway, and then practice with the baskets,\u201d Lanham noted.<\/p>\n Credit: NASA.<\/p>\n (Photo Caption: Shuttle STS-109 mission pilot Duane Carey leads commander Scott Altman in evacuation practice during terminal countdown demonstration test activities in February 2002. The Artemis II flight crew will help commission the new emergency egress system by participating in similar practices between now and their launch, currently targeted for September 2025.)<\/em><\/p>\n Orion\u2019s launch abort system (LAS) will be available for the crew to use at the very end of the countdown, but up until then, the EES provides another evacuation route for both the flight crew and closeout crew if the latter team is still at the pad before launch.<\/p>\n Another important aspect of the verification and validation (V&V) testing at the pad is practice for setting up the system for launch. In contrast to the Commercial Crew launch pads and the Shuttle before them, Pad 39B is a clean pad, with no fixed crew access tower.<\/p>\n Access to the vehicle is more like the Saturn V vehicles that originally flew from the Launch Complex 39 pads over 50 years ago, with crew access on the umbilical tower of the Mobile Launcher. For SLS, the concept of operations is to roll the vehicle and ML out to Pad 39B a little more than a week before the planned launch date, which means that the EES slidewires and baskets will need to be set up as a part of launch countdown preparations.<\/p>\n \u201cThat\u2019ll all be a part of the [verification testing], that is where we practice setting up the system,\u201d Lanham said. \u201cWe\u2019ve got to run cables up to the tower from the terminus site, so we\u2019ll practice that, we\u2019ll time that, and that\u2019ll all roll into the launch countdown timeframe when we roll out, so that\u2019ll all be taken into account and worked.\u201d<\/p>\n \u201cAnd also any time we get the opportunity, like through the V&V phase of the testing, the COMET contractor will likewise be looking at those timelines as they put the system through its verification and validation.\u201d Jacobs Technology is the prime launch processing contractor for KSC\u2019s Consolidated Operations, Management, Engineering, and Test (COMET) contract.<\/p>\n Launch pad systems at 39B, such as the environment control system, have also been modified and upgraded between Artemis I and II, and those changes are being validated too. A major new capability being brought online beginning with Artemis II is a second, large liquid hydrogen (LH2) storage sphere to increase the original capacity at 39B to better support the needs of current and future SLS configurations.<\/p>\n The new sphere will increase the number of Orion\/SLS launch attempts that EGS can support, which should improve the chances of launching within the heavily constrained lunar launch periods that Artemis requires. One of the V&V tests that EGS is preparing for is to check out the LH2 loading system with both large storage spheres online and interconnected.<\/p>\n \u201cWe have what\u2019s called our integrated system verification and validation test four, which is a cold flow\/cryo flow of LH2 from that [new LH2 sphere] to the ML,\u201d Lanham said. \u201cWe have found some corrosion on some pipelines and on our vent lines and we\u2019re working to get that fixed.\u201d<\/p>\n Credit: Julia Bergeron for NSF.<\/p>\n (Photo Caption: The two, large LH2 storage spheres are seen in this image from a recent NSF flyover of the Kennedy Space Center. EGS will be validating that the new, larger sphere on the left is ready to support Artemis launches beginning with Artemis II. Plans call for the new sphere to be used to flow LH2 into SLS stages on the pad and for the original, Apollo-era sphere to be used for replenishment as necessary.)<\/em><\/p>\n \u201cWe\u2019re kind of building a contingency plan to go ahead and do a cold flow from the old sphere to the Mobile Launcher before we were to roll off the pad, in order to keep our schedule for Artemis II, and in the meantime we would complete that repair on that piping and then do a flow between tanks to allow us to complete that test in parts, which is perfectly valid as part of a certification program. So, right now we\u2019re thinking in the early to mid-spring timeframe we would be doing the Mobile Launcher portion of that cryo flow.\u201d<\/p>\n For tanking operations with the SLS rocket and Orion spacecraft, the plan is for the new, larger capacity LH2 sphere to supply the cryogenic fuel from the storage farm through the cross-county lines at the pad, into the ML plumbing, and eventually into the two SLS liquid-propellant stages. \u201cThe idea would be the old sphere is actually the replenishment sphere, back to the new sphere,\u201d Lanham noted. \u201cSo, we would load from the new sphere and use the other one to replenish.\u201d<\/p>\n A series of ISVV tests has been underway since ML-1 arrived at the pad last summer. One set of tests was just completed, fine-tuning the water flow from the Pad 39B water tank into the ignition over-pressure protection and sound suppression (IOPSS) system.<\/p>\n \u201cWe just finished, literally as I\u2019m talking to you, the last water flow, which is called ISVV 2,\u201d Lanham said in the Jan. 25 interview. \u201cThat was our final flow of water for that. That included ISVV 6, which is our high-speed imagery test.\u201d<\/p>\n \u201cWe did those in conjunction with each other, that final water flow plus that imagery test. We just completed that, so that\u2019s very good news.\u201d<\/p>\n SLS Boosters almost ready to stack, will wait for better schedule clarity<\/p>\n Over in the Vehicle Assembly Building (VAB) area of Launch Complex 39, EGS is completing Artemis II stacking preparations of SLS solid rocket booster (SRB) segment hardware in the Rotation, Processing, and Surge Facility (RPSF). Both sets of the two five-segment SLS boosters were transported by rail from Northrop Grumman\u2019s Promontory facility in Utah to KSC in late September.<\/p>\n Since they arrived at KSC, each of the ten fueled solid rocket motor segments has been offloaded and inspected. \u201cAll the segments are offloaded now and six of the 10 segments are in Surge 2, ready for stacking when we get to that point,\u201d Lanham said. All of the segments are offloaded in the RPSF Rotation building. After receiving inspections, eight of them are placed in one of the two \u201cSurge\u201d buildings for storage.<\/p>\n Credit: NASA\/Frank Michaux.<\/p>\n (Photo Caption: Four of the solid rocket motor segments for Artemis II are seen in the RPSF on Dec. 21. An unidentified center segment is to the far left as the left-hand center-center segment is rotated, post-offload. To the right, the two aft assemblies are seen in their build-up stands.)<\/em><\/p>\n The two aft segments are installed in buildup stands in the Rotation building, where each is mated to an aft skirt. A nozzle extension \u2014 also called an exit cone \u2014 is attached, along with the aft attachment ring that helps connect each booster to the SLS core stage. When fully outfitted, each is called an aft assembly.<\/p>\n \u201cWe have roughly about a month of work left,\u201d Lanham said about the aft assemblies. \u201cWe\u2019re doing the developmental flight instrumentation (DFI) work where we\u2019re routing some cables, wires, around that area of the attach ring and then we fill that area with cork, which is a lot of work going on right now.\u201d<\/p>\n \u201cWe finished our leak checks of the aft exit cones recently, so we have about a month of work left in that area, and towards the end of February we\u2019re expecting to have the segments ready for stacking.\u201d The other two segments that remain in the RPSF Rotation building are the center-center segments.<\/p>\n \u201cWhat we\u2019re doing there is just yesterday we completed our masking and outlining of the NASA worm logo, so they\u2019ll remain in the [Rotation building] as we paint on the worm logo to those segments, so you\u2019ve got six segments in Surge 2 and you\u2019ve got four in the Rotation building,\u201d Lanham added.<\/p>\n The SRBs have five motor segments: forward, forward-center, center-center, aft-center, and aft. A forward assembly on top includes booster avionics and a nose cone with one set of separation motors. The aft assembly includes the aft motor segment, exit cone, core stage attach ring, and the aft skirt that houses thrust vector control (TVC) systems and the second set of separation motors.<\/p>\n A systems tunnel runs vertically along the length of the booster, which is where the NASA worm logo resides on the center-center segment. As with the Artemis I boosters, most of the logo will be painted around the systems tunnel area in the RPSF now. After that, those two segments will be moved to the Surge 2 building for storage. The remainder of the logo will be finished after the systems tunnel covers are attached to the fully stacked boosters on the Mobile Launcher in the VAB.<\/p>\n Credit: Julia Bergeron for NSF.<\/p>\n (Photo Caption: The three main RPSF buildings are seen in this image from a recent NSF flyover of KSC. On the far left is one of the two storage buildings, Surge 2. In the middle, closest to the camera, the Rotation building is where all the SRB segments are offloaded and inspected; it is also where the aft segments, aft skirts, and exit cones are assembled into the booster aft assemblies. Immediately behind the Rotation building is the original Surge building. During the higher flight-rate Space Shuttle program, KSC ground operations might have been processing two or more sets of SRBs between the VAB and the RPSF and storing others in the Surge buildings.)<\/em><\/p>\n Although the SRB hardware could be ready to support the beginning of vehicle integration or \u201cstacking\u201d in the next several weeks for Artemis II, it is too early to start that with over a year and a half until the new target launch date. The new September 2025 target date was based on forecasts to resolve one of the issues, a redesign of a circuit within an electrical motor drive controller in the Orion environmental control and life support system (ECLSS). This issue will require taking some electronics out of the Artemis II Orion spacecraft and then retesting them after they have been replaced.<\/p>\n \u201cAt this point, we drove that September date based on the time we think it\u2019s going to take to do the removal [and] replacement of the [Orion] life support system electronics and the penalty testing required to do the integration on the way back out,\u201d Amit Kshatriya, deputy associate administrator for the Moon to Mars Program in NASA\u2019s Exploration Systems Development Mission Directorate, said in the Jan. 9 media audio conference where the delays were announced. \u201cWe\u2019re hopeful that the other findings that are as a result of abort loads on the battery, as well as the conclusion of all the tests required for the heatshield, is enveloped by that work.\u201d<\/p>\n Previously, the EGS and SLS programs were preparing to begin stacking the Artemis II vehicle early this year, starting with the SLS SRBs and followed by the cryogenic core and upper stages. With the new target launch date, the programs will be re-evaluating when to deliver the core stage, which is finishing its production at the Michoud Assembly Facility (MAF) in New Orleans.<\/p>\n The delivery schedule of the other SLS hardware \u2014 adapters that connect the stages and Orion \u2014 will also need to be reworked. Estimates had been that EGS would need at least eight months to prepare Orion from the point they received the spacecraft to the point of Artemis II launch readiness. If that were the case, Orion would need to resolve the issues, make all the necessary changes, and finish outfitting and retesting the spacecraft by the end of the year to make a September 2025 launch date.<\/p>\n In short, apart from the boosters, the pieces needed to support stacking are not in place and it\u2019s not yet clear when they will be ready. For now, as Lanham said, EGS is tentatively working towards bringing the Mobile Launcher back to VAB High Bay 3 around the end of the spring.<\/p>\n \u201cAt that point, we would get into a series of work, where we prep the VAB, we prep the Mobile Launcher, umbilicals, and get ourselves postured [to] start stacking the boosters,\u201d he said. \u201cI\u2019m using reference timelines, because we\u2019re still laying out the schedule, still working the details, but we\u2019re looking at the early summer to get into the booster stacking if all goes well.\u201d<\/p>\n Credit: NASA\/Frank Michaux.<\/p>\n (Photo Caption: The top of what would be an \u201cICPS Short Stack\u201d is seen from the Mobile Launcher umbilical tower cameras in 2021 during the Artemis I launch campaign. A tanking test of the Artemis II SLS vehicle\u2019s core stage and Interim Cryogenic Propulsion Stage (ICPS) with the Mobile Launcher and Pad 39B propellant systems will be conducted likely next year. Either the full vehicle with Orion will roll out to the pad for that test, or just the SLS Block 1 rocket elements with the ICPS on top.)<\/em><\/p>\n The SLS core stage is the centerpiece of the rocket and Lanham said that delivery of Core Stage-2 to KSC will be worked out between the EGS and SLS programs. \u201cCore stage delivery, from a hardware need date, is driven off of the stacking of the boosters, so what we do is we look at where that timeframe will fall, and then we back up to the left and we look at the work that we have to do in the transfer aisle on the core stage, and then we kind of say \u2018what\u2019s the margin we feel we need for that?\u2019 We kind of get an idea of the total timeframe that we need for [the] core stage and that puts us in the vicinity of a date out to the left that we then negotiate with the SLS program.\u201d<\/p>\n \u201cIn general, we try and do a \u2018just-in-time\u2019 delivery on the hardware, because when the hardware gets here, there is care and feeding of the flight hardware with our technicians and engineers, and having it here too early puts a burden on them that we try to avoid,\u201d Lanham added. He estimated that receiving the core stage about eight weeks before they expect to stack it with the SLS boosters would provide the work time and schedule margin needed.<\/p>\n Whether stacking could begin as early as summertime with placing the booster aft assemblies on the Mobile Launcher will remain a question while the Orion program works through their newly reported issues.<\/p>\n \u201cWhat will happen is, as we get closer to the date to start stacking, we\u2019ll have what\u2019s called a KMR,\u201d Lanham said. KMR stands for \u201ckey milestone review.\u201d \u201cWe\u2019ll get everybody, including our sister programs, together and we\u2019ll discuss \u2018Is everybody ready to start the stacking?’\u201d he added. \u201cObviously, things come up and we\u2019ll adjust accordingly.\u201d<\/p>\n The boosters are one of the \u201climited operational life items\u201d (LOLI) on the spacecraft and the rocket. They have a generic stacking life of 12 months and for Artemis I, extending that life required additional analytical work for each extension. Stacking of the Artemis I boosters was paused once for the SLS core stage Green Run, but the \u201cstack life\u201d still ended up being almost two years.<\/p>\n NASA leadership has previously said one of the lessons learned from Artemis I was to better \u201cprotect\u201d the standard 12-month stacking clock for the boosters. In addition, for Artemis II, Lanham said they are not planning to pause the booster segment stacking schedule after they start with the aft assemblies.<\/p>\n Looking at options for Artemis II tanking test, pad access<\/p>\n Once the Artemis II vehicle is stacked, there will be a tanking test conducted, where the vehicle will roll out on the Mobile Launcher to Pad 39B separately from launch. Following the test, it will be rolled back to the VAB to complete the remaining launch preparations. Only SLS is loaded with propellants on launch day itself; the Orion spacecraft is fueled for the mission months in advance. One of the questions for the test is whether or not to perform it with Orion integrated on top.<\/p>\n A tanking test working group was formed last year to take a look at the options. At some point in the future, after there is more certainty in Orion\u2019s schedule, a decision will be made by NASA leadership about using a full vehicle stack with Orion or a \u201cshort stack\u201d without Orion for the tanking test.<\/p>\n \u201cWe will do a tanking test, it\u2019s just a matter of what that configuration will look like,\u201d Lanham said. \u201cThe short stack configuration would be ICPS with a cover, and then the full stack obviously would be the entire vehicle with Orion stacked. But that\u2019s all still being weighed and looked at.\u201d<\/p>\n Credit: NASA\/Frank Michaux and Kim Shiflett.<\/p>\n (Photo Caption: VAB platforms, scaffolding, and test equipment are shown deployed around the forward skirts of the Artemis I SLS Boosters and core stage intertank in the main image taken in August 2021. Inset in the lower left, an image taken from the Mobile Launcher umbilical tower during the umbilical release and retract test in late September shows the location of yellow and red-colored access doors for the Boosters and core stage on the -Z side of the vehicle. EGS is studying the feasibility of whether safe access for launch team personnel could be provided to those access doors at Pad 39B to allow testing and reconfiguration of internal equipment.)<\/em><\/p>\n","protected":false},"excerpt":{"rendered":" At the Kennedy Space Center (KSC), NASA\u2019s Exploration Ground Systems (EGS) program continues to prepare for the Artemis II circumlunar mission that was recently delayed to September 2025. EGS is finishing certification of new ground systems to support crewed launches of the agency\u2019s Orion spacecraft with its Space Launch System (SLS) rocket beginning with Artemis […]<\/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":[304,5942,8347,4011,190,640,7933,624],"class_list":["post-24099","post","type-post","status-publish","format-standard","hentry","category-news","tag-artemis","tag-artemis-ii","tag-egs","tag-em-2","tag-nasa","tag-orion","tag-pad-39b","tag-sls"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/24099"}],"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=24099"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/24099\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=24099"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=24099"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=24099"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}See Also<\/h4>\n
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