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\u201c[The testing] included all of your pneumatics and avionics checkouts of the Core Stage,\u201d Florez said. \u201cThat [also] includes your flight readiness test of all four engines, especially after we replaced the engine controller on the number four engine.\u201d<\/p>\n
\u201cEverything checked out well, we did our checks on the thrust vector control system (TVC), all the actuators. [We] gimbaled the nozzles and then we concluded the test by closing out the hydraulic system for flight and also doing a spin test of the auxiliary power units that provide hydraulic power to the engines for both steering and also for engine control.\u201d<\/p>\n
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Credit: NASA.<\/p>\n
(Photo Caption: The aft end of the Artemis 1 SLS vehicle is seen from the zero-level of the Mobile Launcher during Core Stage functional testing on the night of January 12. The stage\u2019s hydraulic thrust vector control system was tested by moving the four RS-25 engines. The functional checks were the final part of Program Specific Engineering Tests on the Core Stage, which were completed that night.)<\/em><\/p>\n Resumption and completion of the remainder of the PSETs for the Core Stage occurred the week of January 10, with functional testing of the MPS pneumatics and hydraulics, along with the flight readiness test of the RS-25 engines being similar to the final pre-firing functional checkouts performed on the stage prior to its first tankings and test-firings at Stennis Space Center a little over a year ago as a part of the Green Run campaign for the stage.<\/p>\n With those functional checks complete, the Core Stage engine section can now be closed out for launch over the next few weeks. \u201cGetting that whole engine section closed out is a big milestone towards rolling out,\u201d Cliff Lanham, NASA Senior Vehicle Operations manager for EGS at KSC, said in the January 13 interview.<\/p>\n \u201cNow that PSETs [for the Core Stage are] over, we can get into our engine final inspection and then start closing out the engine section and then finally get into the engine blanket installations.\u201d A decision was made to have Core Stage prime contractor Boeing perform the installation of the engine-mounted heatshield (EMHS) blankets, which is the most time-consuming task in that part of preparations.<\/p>\n \u201cWe have engaged Boeing, they will be helping us out with the engine blankets now, so that work will be going on seven days a week and that pulled back our critical path by a few days,\u201d Lanham noted.<\/p>\n The powerheads of the four RS-25 engines fit into the engine section of the stage through large openings in the boattail; the EMHS blankets are a component of the thermal protection system (TPS), enclosing those openings to provide a thermal and environmental barrier between the engine section and the outside.<\/p>\n Boeing conducted and supervised vehicle operations during the Core Stage Green Run at Stennis, and has already performed the lengthy installation of the EMHS blankets as a part of preparations for both Hot-Fire tests that were performed in January and March, 2021. Boeing has been performing post Green Run refurbishment and modifications on the Core Stage at KSC on a seven day per week schedule since it arrived at the launch site in late April.<\/p>\n That post Green Run refurbishment \u201ctraveled work\u201d is also wrapping up. \u201cWe have one more leak check on a purge bag for the bleed [modification] that has to be completed, we\u2019re actually planning on doing that tomorrow,\u201d Lanham said during the January 13 interview. \u201cIn the intertank area there is some foam trimming that has to be done on the LH2 forward dome and we\u2019re looking at finishing that up next week, so from a traveled work standpoint we are 98-99 percent complete and plan to finish that up mid next week in total.\u201d<\/p>\n Final closeouts and TPS detailing work are also continuing around other areas on the integrated Orion-SLS Artemis 1 vehicle. \u201cWe\u2019re continuing with our [Solid Rocket] Booster closeouts, all systems tunnel covers are on both the left-hand and right-hand side now,\u201d Lanham said.<\/p>\n Credit: NASA\/Cory Huston.<\/p>\n (Photo Caption: The \u201cwhite room\u201d and Crew Access Arm on the Mobile Launcher is seen backed away to the left of the Artemis 1 Orion spacecraft during a recent retraction test of the arm in the VAB. Artemis 1 is an uncrewed test flight for both Orion and SLS, but the Crew Access Arm allows NASA to install late-stow payloads in the Orion Crew Module for this mission.)<\/em><\/p>\n \u201cWe\u2019ve been doing a lot of we call it RT-455 work, which is the cork material, so we\u2019ve been working on that on both [Boosters], there\u2019s a lot of effort there with our DFI runs, that all has to be closed out with this material, as well as the areas between the different systems tunnel covers.\u201d RT-455 is a room temperature vulcanizing (RTV) material that is applied to exterior seams as a weather seal and for thermal protection.<\/p>\n \u201cWe\u2019re looking to be done towards the end of January with the Booster closeouts, notwithstanding anything required [for] testing there,\u201d Lanham noted. \u201cWe continue to put RTV on the exterior of the Orion as we prepare for rollout for WDR, so that work is ongoing and that is time-consuming work as well, but that\u2019s going well.\u201d<\/p>\n Remaining tests and checkout before rollout and WDR<\/b><\/p>\n Getting the Core Stage PSET work completed has drawn engine section closeouts more or less even with the Integrated Test and Check-Out (ITCO) schedule to rolling out to the launch pad. \u201cOur critical path previously was running through our engine section with our blanket installation and final inspections and closeouts and then getting into confidence checks and then ultimately our final closeouts for roll,\u201d Lanham explained.<\/p>\n With Boeing working on the flight EMHS blanket installations seven days a week, Lanham said, \u201cthat pulled back off our critical path by a few days and our ITCO testing basically is now our critical path.\u201d<\/p>\n \u201cNow [that] we\u2019ve finished Core Stage PSET, [we have] ICPS (Interim Cryogenic Propulsion Stage) PSET next week, then we\u2019ve got a Countdown Sequencing Test Run 2, and then we get into our Flight Termination System Part 1 testing, and then we get into closeouts [for rollout] and that\u2019s kind of our critical path right now.\u201d<\/p>\n ICPS is the in-space second stage on the SLS Block 1 vehicle; functional testing was partially completed in early December before the remainder was temporarily deferred. \u201cWe\u2019ve run a lot of the tests, a lot of the guidance and flight control checks have been done,\u201d Florez said. \u201cWe [also] completed a big chunk of the electrical portion, which includes all the flight control tests.\u201d<\/p>\n \u201cThere was no issues [with the ICPS PSETs], but we had to get into [Communications] End-To-End testing,\u201d Lanham added. \u201cNow we\u2019re picking up the tail end of that back up.\u201d<\/p>\n The Communications End-To-End Test was conducted in mid-December; the test required reserving time with a large set of NASA\u2019s communications resources, which Orion in particular will engage during its trip from the Earth to the Moon and back on Artemis 1.<\/p>\n Credit: NASA\/Frank Michaux.<\/p>\n (Photo Caption: Members of the Artemis 1 Launch Team\u2019s Integration Console are seen during a day of launch simulation on December 13. The launch team will be conducting and overseeing final critical pre-launch testing in addition to the countdown operations for the Wet Dress Rehearsal and the Artemis 1 launch itself.)<\/em><\/p>\n \u201cThat\u2019s a very complex test, it requires multiple assets across the country,\u201d Florez said. \u201cIt requires the Deep Space Network [and] all those ground stations, as well as the Tracking Data and Relay Satellites on orbit, so trying to schedule that up is a monumental task on its own for the amount of time that we need to test. We prioritized that test and worked other things around it, due to the assets and the schedule constraints.\u201d<\/p>\n \u201cOnce we got into the test, everything went pretty smoothly for the Comm End-To-End test. We verified all the comm paths that we have. You\u2019re essentially simulating a mission profile, so you\u2019re making sure that you have data going through all the different legs, network legs, that you would for a mission with the different data rates and making sure that everybody that needs to receive the data and send commands can do that effectively.\u201d<\/p>\n As a part of the regular schedule reworking that goes on during a launch campaign, EGS and Jacobs rescheduled the remainder of the ICPS PSETs and that work is now expected to resume early the week of January 17. \u201cAs we got the engine controller changed out, we wanted to get into Core Stage PSET immediately, so that kind of pushed the ICPS PSET to the right some,\u201d Lanham noted. \u201cBut now we\u2019re ready to get back into it.\u201d<\/p>\n \u201cWe hadn\u2019t started the MPS testing, we\u2019re getting back into it now that we have some window [in the schedule],\u201d Florez said. \u201cWhat we\u2019re focusing in on now is the MPS\/Cryo tests and some of the reaction control tests.\u201d<\/p>\n One issue with the ICPS was seen late last year. A leak was discovered in a portion of a gaseous helium purge line on the forward end of the ICPS, but is not seen as a constraint.<\/p>\n A statement from the SLS Program emailed to NASASpaceflight by NASA spokesperson Tracy McMahan said: \u201cDuring checkout and testing, engineers detected a larger-than-anticipated amount of helium in the cavity between Interim Cryogenic Propulsion stage (ICPS) and the Orion stage adapter. Follow-on testing and analysis identified a helium purge line in the ICPS vent system as the probable source of the helium.\u201d<\/p>\n \u201cThe purge line is part of the ground support used to purge the ICPS on the ground,\u201d the statement continued. \u201cAt this time, the team does not believe any flight hardware action is required nor will this issue impact the wet dress rehearsal schedule. The team continues to assess test data and will closely monitor the situation during ongoing tests and checkouts.\u201d<\/p>\n After the ICPS PSETs are completed, the second run of the Countdown Sequencing Test is currently scheduled for around January 24. The first run was performed on December 20.<\/p>\n \u201cYou\u2019re essentially performing a launch countdown but inside the VAB, so you\u2019re simulating some things, you obviously don\u2019t have any [cryogenic propellant] and fluids onboard the vehicle so you have to simulate those tasks, but a lot of the [command and control computer] sequencing [is what] we\u2019re checking out,\u201d Florez said. \u201cThe intent there is to make sure that the software and the command and control system between the ground and the vehicle systems are talking to each other and are in sync.\u201d<\/p>\n The test runs through the critical, terminal launch countdown sequence, which is executed by computers as the volume and speed of necessary, coordinated actions and verification checks increases to very high levels. The first test cutoff a few seconds earlier than was desired.<\/p>\n \u201cThe test went very well, we learned a lot of critical things, but towards the end of the test we learned something new that prevented us from going down further in the count,\u201d Florez said. \u201cThe way the vehicle emulators that we use for software testing are built they behave a little bit differently [than the actual vehicle], so that\u2019s what we learned, and due to that we\u2019re changing the process and the procedures and [performing] the second run of the test.\u201d<\/p>\n Credit: Stephen Marr for NSF.<\/p>\n (Photo Caption: The Core Stage intertank is seen flanked by the forward skirts of the two Solid Rocket Boosters in VAB High Bay 3 on December 20. Access inside those three areas is needed to perform final installations of Flight Termination System components and verification that the safety system is fully functional. Testing inside the intertank and forward skirts will be one of the final tasks in the VAB before the Artemis 1 vehicle rolls out to the pad, prior to both the Wet Dress Rehearsal and launch.)<\/em><\/p>\n The Ground Launch Sequencer (GLS) controls the terminal countdown until about 30 seconds before liftoff, when control of the countdown is divided between the SLS flight computers and the GLS. The SLS flight computers take over control of the vehicle at that point, but the GLS not only continues to monitor the vehicle performance, but also continues to control and monitor ground systems.<\/p>\n During the Countdown Sequencing Test the GLS was run against the real, fully-integrated Artemis 1 Orion and SLS vehicle. Emulators were still used to simulate a \u201cwet\u201d vehicle with the SLS stages loaded with their LH2 and LOX propellant, but the ground sequencer was working with an otherwise real set of flight computers, spacecraft and rocket hardware, and instrumentation.<\/p>\n The first test run didn\u2019t quite make it through the handoff of vehicle control from the ground to the vehicle. \u201cWe got within four seconds of where we wanted to terminate the test,\u201d Lanham said.<\/p>\n \u201cAnd I think the fact that we did not do that handoff is exactly why, for the most part, we want to go and re-run the test, as well as picking up [changes to] the LCC (Launch Commit Criteria) limits and to get the software changed and accommodate those LCC limits.\u201d<\/p>\n The highest fidelity test of the terminal countdown sequence will be performed as a part of the Wet Dress Rehearsal (WDR), where the vehicle will be fueled and prepared for ignition and liftoff just as it will be on launch day, with the countdown being stopped only a couple of seconds before engine start.<\/p>\n The last major ITCO test before the first rollout to the launch pad will checkout some parts of the Flight Termination System (FTS). For Artemis 1, the final installations and checkout of the FTS are divided into two parts, with first part performed before the first rollout and the WDR and the second part done back in the VAB just before launch.<\/p>\n Once the FTS system is fully certified with an end-to-end functional test during the second part, that signifies the beginning of a 20-day period of time where it can be used for a launch before needing to be recertified; the system won\u2019t be fully active for the WDR, so only part of the installation and testing will be performed before the first rollout. \u201cAfter we connect ordnance, we do the resistance checks and all the checkouts required on the ordnance system to make sure that it was installed correctly but it\u2019s not necessarily the certification for launch,\u201d Florez said.<\/p>\n Although the ordnance is put in place during the first part of installation, Florez explained that it is not fully connected or integrated into the system until the second part of the checkout. \u201cYou leave the ordnance installed, but it\u2019s not connected to the vehicle, to the firing lines,\u201d he said. \u201cThe [second part] really certifies the FTS system for launch, and that\u2019s a test where we have live communications with the [Eastern Test] Range where we make sure that the signals are coming across.\u201d<\/p>\n Credit: NASA\/Cory Huston.<\/p>\n (Photo Caption: An engineer (left foreground) performs closeouts on the left-hand Solid Rocket Booster for Artemis 1 in the VAB on January 10. The vehicle will be outside in the weather out at the launch pad and then experience an extreme thermal environment from combustion and aerodynamic heating; room temperature vulcanizer is being applied in the gaps between the large-area\/acreage thermal protection system coverings on the exterior of the vehicle.)<\/em><\/p>\n The first part of the final FTS install and checkout requires access to areas inside the Solid Rocket Booster (SRB) forward skirts and the Core Stage intertank; once that work is complete, which would be in early February on the current schedule, EGS and Jacobs can configure those internal volumes for rollout and start getting into final preparations to roll the Mobile Launcher with the vehicle out to Launch Pad 39B.<\/p>\n There are a few other tests that the processing team plans to work into the schedule before launch. \u201cWe have one other small test that we\u2019re doing which is a test that checks out the data acquisition units \u2014 the DFI (Development Flight Instrumentation) network per-se \u2014 on Orion, ICPS, the Core Stage and Boosters, which we\u2019re planning on running right after the Countdown Sequencing Test,\u201d Florez said.<\/p>\n Another is a Launch Vehicle Stage Adapter acoustic impulse test. \u201cThat\u2019s really a test of opportunity which is not so critical for Artemis 1, it\u2019s critical for further missions from a data collection perspective, but we are still planning on running that,\u201d Florez said. \u201cWe\u2019re targeting that after we come back from WDR, we\u2019ll be in a better configuration to run that prior to launch.\u201d<\/p>\n Another task on the schedule that will be worked in parallel with critical path activities is the swap of the ICPS flight computer and batteries. Lanham said that the timing of that depends on when the flight units are delivered: \u201cOur plan would be to get that in before WDR, but if not, then obviously we would do it post WDR, but the plan is still to swap out that box.\u201d<\/p>\n Setting a launch date coupled to WDR demonstration<\/b><\/p>\n The Artemis 1 vehicle stacked on its Mobile Launcher will first be rolled out to Launch Pad 39B for the Wet Dress Rehearsal. The Mobile Launcher has made multiple trips to the pad on its own for different phases of Multi-Element Verification and Validation (MEV&V) and the upcoming trip to the pad is in essence the final phase of integrated testing that brings in the Orion-SLS vehicle for a full launch countdown demonstration test between the vehicle and ground elements.<\/p>\n Following resolution of the power failure in the RS-25 engine controller, current estimates of the soonest that the hardware could be ready to roll out to the pad for the WDR are mid-February, with the soonest that the hardware could be ready for launch in mid\/late March. SLS can only launch Orion on Artemis 1 when the Moon is in the right position in its orbit around the Earth, but launch readiness is a measure of when the hardware and the people are ready to go.<\/p>\n Estimates of the soonest that the hardware could reach major milestones like the WDR and launch have moved around significantly. NASA also has estimates that factor in the schedule risk, given this is a new system being prepared for its first flight, which reflect additional time to deal with issues that could come up.<\/p>\n The risk informed estimate hasn\u2019t changed as much; although it doesn\u2019t predict when issues like the engine controller power failure will occur, it projects how much additional time would be needed to resolve them. That risk assessed readiness estimate has more consistently pointed at mid April, because it included many weeks of extra time to work through hardware issues and learning curve situations such as with the first Countdown Sequencing Test.<\/p>\n Credit: NASA\/Cory Huston.<\/p>\n (Photo Caption: The aft end of the Artemis 1 SLS vehicle is seen in the VAB on January 10. This view of the -Z side of the vehicle is seen from the perspective of umbilical tower of the Mobile Launcher. The systems tunnel and tank pressurization lines for the Core Stage can be seen flanking one of the liquid oxygen \u201cdowncomer\u201d feedlines that run from the LOX tank into the engine section.)<\/em><\/p>\n NASA will not set a launch date until after the WDR is completed and they can factor in any additional tasks with already-known work. \u201cWe\u2019ve continually said that until we get through WDR we won\u2019t set a launch date, so us getting out in mid-February for WDR allows them to look at March and April as opportunities,\u201d Lanham said.<\/p>\n \u201cI really can\u2019t put my finger on it again until we come back from WDR and see if we have any issues there that we\u2019ve got to go correct.\u201d After the WDR test, the vehicle and Mobile Launcher will be rolled back to the VAB for final pre-launch maintenance and servicing.<\/p>\n When the vehicle arrives at Pad 39B for the WDR, EGS and Jacobs will begin countdown preparations, since the test is a full launch countdown minus the last 10 seconds before liftoff. With the vehicle being prepared just as it will be for launch, NASA will have to reserve a spot on the busy Eastern Test Range calendar for the test just like the other launch providers do for hazardous operations such as launches and WDR tanking tests.<\/p>\n Finding a spot on the Range calendar may be another complicating factor in the overall pre-launch schedule, as planning for the Comm End-To-End test was. When NASA is ready to perform the WDR, the Range\u2019s launch calendar may be relatively open and easier to schedule or it may be heavily booked and harder to reserve a spot.<\/p>\n (Lead image credit: NASA\/Cory Huston)<\/em><\/p>\n","protected":false},"excerpt":{"rendered":" NASA\u2019s Exploration Ground Systems (EGS) program and prime launch processing contractor Jacobs are performing final installations, functional checks, and buttoning up the Artemis 1 vehicle in the Vehicle Assembly Building (VAB) at the Kennedy Space Center (KSC) in Florida before rolling it out to its seaside launch pad for the first time. Rollout to Launch […]<\/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":[304,1700,8347,3718,190,640,624],"class_list":["post-24726","post","type-post","status-publish","format-standard","hentry","category-news","tag-artemis","tag-artemis-1","tag-egs","tag-em-1","tag-nasa","tag-orion","tag-sls"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/24726"}],"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=24726"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/24726\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=24726"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=24726"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=24726"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2022\/01\/KSC-20220110-PH-CSH01_0063large.jpg\")
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