EGS, Jacobs working to finish testing in time for Artemis 1 rollout in mid-February - NASASpaceFlight.com - NASASpaceflight.com

NASA’s 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.

In addition to finishing functional checks and closing the Space Launch System (SLS) Core Stage engine compartment out for launch, EGS and Jacobs are also preparing to re-run a countdown sequencing test to verify that the ground-based launch sequencer is ready to conduct launch countdowns for the integrated Orion and SLS vehicle.

The first vehicle trip to the pad will be to conduct a full launch countdown demonstration test called the Wet Dress Rehearsal.

Closing out Core Stage aft compartment after engine controller replacement.

With the broken Core Stage engine controller replaced over the New Year’s holidays, EGS and Jacobs were able to finish functional checkouts of the most complicated part of SLS on the evening of January 12.

SLS is derived from the Space Shuttle vehicle and the Core Stage combines the launch systems from the reusable Shuttle Orbiter and disposable External Tank into an expendable, in-line, ground-started sustainer stage.

The most complicated part of the Core Stage is the engine section where the cryogenic liquid hydrogen (LH2) and liquid oxygen (LOX) propellant is fed by the stage to the RS-25 engines.

The functional checkouts of the Core Stage Main Propulsion System (MPS) and RS-25 engines verified that they are again configured and ready to be loaded and fired, this time for launch.

The functional testing was the last part of Program Specific Engineering Tests (PSET) on the base elements of the new launch vehicle.

(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’s 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.).

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.

With those functional checks complete, the Core Stage engine section can now be closed out for launch over the next few weeks.

“Now 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.” 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.

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.

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

“Now [that] we’ve finished Core Stage PSET, [we have] ICPS (Interim Cryogenic Propulsion Stage) PSET next week, then we’ve 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’s kind of our critical path right now.”

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

(Photo Caption: Members of the Artemis 1 Launch Team’s 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.)

“As 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,” Lanham noted

After the ICPS PSETs are completed, the second run of the Countdown Sequencing Test is currently scheduled for around January 24

“You’re essentially performing a launch countdown but inside the VAB, so you’re simulating some things, you obviously don’t 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’re checking out,” Florez said

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

(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.)

During the Countdown Sequencing Test the GLS was run against the real, fully-integrated Artemis 1 Orion and SLS vehicle

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

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’t be fully active for the WDR, so only part of the installation and testing will be performed before the first rollout

(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.)

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

“We have one other small test that we’re doing which is a test that checks out the data acquisition units — the DFI (Development Flight Instrumentation) network per-se — on Orion, ICPS, the Core Stage and Boosters, which we’re planning on running right after the Countdown Sequencing Test,” Florez said

Another is a Launch Vehicle Stage Adapter acoustic impulse test

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

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

(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 “downcomer” feedlines that run from the LOX tank into the engine section.)

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