NASA intends to have yet another countdown drill for the Space Flight System in beginning of June, delaying the vehicle’s first launch until at least August. NASA officials stated on 5th May they have made significant progress on two issues with the SLS and its transportable launch platform that were discovered during three unsuccessful WDR (wet dress rehearsal) operations at the Launch Complex 39B facility last month. NASA was compelled to return the spaceship to the Vehicle Assembly Building (VAB) on April 26 due to these concerns, as well as the need to improve the nitrogen gas supply at the pad.
A helium check valve found in the rocket’s upper stage was replaced as part of this maintenance. A little bit of rubber found in the valve prevented it from shutting, according to technicians. Cliff Lanham, who works as the senior vehicle operations manager for NASA’s Exploration Ground Systems program, said, “Right now they’re still researching what could be the source of that piece of rubber.”
He believes a hydrogen leak discovered at the pad was caused by loosened nuts on a gasket. The bolts have already been retorqued and show no evidence of leaks, but they won’t know for sure until the vehicle gets back at the pad as well as liquid hydrogen flows via that umbilical line, he added. “At this point, we believe we’ve done everything we can,” he stated.
While that work was going on at the VAB, Air Liquide, the business that distributes nitrogen gas to several KSC locations, was upgrading its system to match the SLS’s higher demands. “Air Liquide’s repairs are on schedule,” Jim Free, NASA’s associate administrator for the exploration systems development, said. He stated NASA would verify soon to see if the enhanced system could supply the nitrogen required for SLS activities at the pad.
When the VAB repairs are finished and the nitrogen modifications at the pad are completed, the SLS will be ready for another countdown rehearsal. If all goes according to plan, the car should be ready “around the late May period,” according to Free. Another WDR would be possible in early to mid-June.
He stated that NASA may need to conduct upwards of one WDR before deciding to proceed with final launch readiness. “Based on what we’ve done so far, we’re optimistic we only require one more,” he added. “However, we want to be honest with you and say that it may require more than one effort.”
He added the current timetable for Artemis 1 would allow for at least 2 countdown rehearsals at the pad in the month of June before returning to the VAB for final launch preparations, then returning to the pad for a launch “in the August time period.” One launch window runs from July 26 to August 9, but NASA is primarily interested in the early August portion of that window, according to Free. The deployment would have to be coordinated with the Falcon Heavy deployment of the Psyche asteroid program, that has a limited launch window that begins in early August.
Additional launch dates are August 23 to 29, and September 2 to 6. “We’ve got launch times planned for the rest of the year,” Free said, adding that dates beyond early September remain tentative.