{"id":37354,"date":"2020-10-24T01:39:59","date_gmt":"2020-10-23T17:39:59","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/sls-core-stage-nearing-home-stretch-for-green-run-tanking-test\/"},"modified":"2020-10-24T01:39:59","modified_gmt":"2020-10-23T17:39:59","slug":"sls-core-stage-nearing-home-stretch-for-green-run-tanking-test","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/sls-core-stage-nearing-home-stretch-for-green-run-tanking-test\/","title":{"rendered":"SLS Core Stage nearing home stretch for Green Run tanking test"},"content":{"rendered":"

Final preparations are in work to ready the first Space Launch System (SLS) Core Stage flight article for its first-ever propellant loading in the B-2 Test Stand at NASA\u2019s Stennis Space Center in Southern Mississippi. Prime contractor Boeing is leading the Green Run test campaign for the central component of the space agency\u2019s new launch vehicle as the test team approaches the critical Wet Dress Rehearsal (WDR) now tentatively targeted for early November.<\/p>\n

The WDR is the seventh of eight Green Run test cases and the precursor to a full-duration Hot-Fire test of the stage once the tanking test is completed. Final closeouts of the stage to configure it for its first live countdown will take up much of the remaining time before the full Green Run team meets for a Test Readiness Review (TRR); the meeting is planned two days before the test to verify that the vehicle, the test stand, and the test team are ready to proceed.<\/p>\n

In the WDR, the Core Stage will be prepared for ignition exactly as it will for the Hot-Fire and for a launch, activating all its systems to run together and meet all their firing criteria before the countdown is stopped several seconds before engine start.\n<\/p>\n

Post-hurricane status, road to WDR<\/p>\n

A couple of days after the Green Run test team completed the series of simulation practice runs that made up most of test case six in early October, Hurricane Delta became the fifth tropical weather system to disrupt the work schedule at Stennis.<\/p>\n

Coupled with a two-month standdown from March to May due to the COVID-19 pandemic, natural causes are expected to stretch the Green Run campaign out to a full year; the stage arrived on NASA\u2019s Pegasus barge at Stennis on January 12, 2020, and the current plan has Pegasus departing with the SLS Core in mid-January, 2021, assuming things go well with the last two Green Run tests.\"\"The Mississippi space center returned to normal hurricane status on October 10 and back on-site, final preparations for the big Wet Dress Rehearsal and Hot-Fire tests resumed. \u201cThe next thing that we had to go do was load the new version of Stage Controller software, so that\u2019s behind us and now what we\u2019re doing is doing the last set of safing checks that basically validate that the new load of software is working just like the old one did,\u201d Mark Nappi, Boeing Green Run Test Manager, said on October 15.<\/p>\n

The safing checks were originally run earlier in the test campaign as test case three, but were executed again now that the ground control system\u2019s software is updated for the big, fueled tests. \u201cIt is almost identical to test three, you\u2019re just going to go through and check all that stuff again and make sure it\u2019s still working right with the final check of the big red button, which is our cutoff button,\u201d he explained.<\/p>\n

\u201cWe\u2019ve already run these tests once before but we\u2019re doing it as a confidence-builder since the Phase 2 Stage Controller software was loaded. That will start tomorrow (October 16) and that\u2019ll work through Sunday (October 18) and then in parallel with that we\u2019ll be removing engine section platforms which is really our critical path on getting to the Wet Dress [Rehearsal] date.\u201d<\/p>\n

\"\"<\/p>\n

Credit: NASA\/Joel Kowsky.<\/p>\n

(Photo Caption: Boeing Green Run Test Manager Mark Nappi (left) is one of the NASA and Boeing SLS officials briefing agency administrator Jim Bridenstine (middle) while standing under the Core Stage in the B-2 Test Stand at Stennis on February 10. Mr. Bridenstine is situated under the boattail\u2019s \u201cmanhole,\u201d which provides one of the access points into the engine section\/boattail compartment. The nozzles of the four RS-25 engines are covered with yellow bagging in part to keep the engine components dry.)<\/em><\/p>\n

Internal work platforms are deployed in the dry volumes of the Core Stage, the forward skirt, intertank, and engine section for pre-launch processing and then must be removed before flight or flight-like operations such as the final two Green Run tests. The liquid oxygen (LOX) and liquid hydrogen (LH2) propellant tanks are the biggest elements and have some machinery and sensory equipment, but the dry volumes contain almost all of the moving parts of the rocket and the platforms provide the reach and support for workers to get to them when necessary.<\/p>\n

The engine section is the most complicated and densely-packed area on the vehicle, with the aft dome of the LH2 tank filling the top and the RS-25 engine powerheads sticking up through the boattail into the bottom. In between and around those prominent parts are foam-covered propellant lines and valves, large, high-pressure bottles of helium gas, hydraulic power units and actuators, and dozens of computer devices all connected with miles of wiring runs.<\/p>\n

The engine section has a two-level set of ground platforms that provides access when the Core Stage is oriented vertically; due to the cramped quarters inside the aft compartment the platforms must be brought inside mostly one piece at a time and assembled in place. Similarly, for disassembly and removal the platforms cannot be taken apart in sections, but piece-by-piece in order to minimize the chances of damaging the rocket machinery.<\/p>\n

\u201cThe Engine Section platform set is two-hundred separate pieces small enough to fit thru the engine section access door and then can be assembled around all the engine section hardware to form a continuous area for employees to work off of,\u201d Nappi explained. \u201cIt is two separate levels, one at the lower boat tail area and a second story right below the LH2 tank. It has to be disassembled piece by piece and removed from the engine section thru the access door while inspections are performed of the area that was uncovered.\u201d<\/p>\n

See Also<\/h4>\n