SLS fully refueled for the first time despite the leak

The full moon is seen from Launch Complex 39B at NASA’s Kennedy Space Center in Florida on June 14, 2022. The Artemis I Space Launch System (SLS) and Orion spacecraft, atop the mobile launch pad, were in preparation to conduct exercises practicing schedules and launch procedures. The first in an increasingly complex series of missions, it will test Artemis I SLS and Orion as an integrated system prior to manned flights to the Moon. Through Artemis, NASA will land the first woman and first people of color on the Moon, paving the way for the Moon’s long-term existence and using the Moon as a springboard on the way to Mars. Credit: NASA/Ben Smegelsky

Artemis I’s dress rehearsal ended yesterday (June 20, 2022) at 7:37 PM ET (4:37 PM EDT) in T-29 seconds into the countdown. This test marks the first time the team has fully loaded all of the Space Launch System’s fuel tanks and then moved on to the countdown to launch the station, when many vital activities occur in quick succession.

NASA's Rocket and Orion Spacecraft Mobile Launcher with Umbilical Lines

Illustration of the mobile launcher with turret-mounted covert lines attached to the NASA Space Launch System rocket and Orion spacecraft. credit: NASA

During propellant loadings earlier in the day, the launch controllers encountered a hydrogen leak in the quick disconnect connecting the navel from the tail service mast on the mobile launcher to the rocket’s core stage. The team attempted to fix the leak by quickly heating the separation and then cooling it again to realign the seal, but their efforts did not solve the problem.

Next, the launch controllers developed a plan to mask the data associated with the leak that would cause a hold by the ground launch sequencer, or launch computer, in a real launch day scenario, to allow them to get as far as possible in the countdown. The time to develop the plan required extended comment time during the countdown activities, but they were able to resume with the last 10 minutes of the countdown, called the final count. During the final count, the teams performed several critical operations that needed to be accomplished for the launch, including switching control from a ground launch sequencer to an automated launch sequencer controlled by the missile’s flight program, an important step the team wanted to accomplish.

This second dress rehearsal for Artemis I began on June 18, 2022. After the launch team arrives at their stations inside the Launch Control Center at[{” attribute=””>NASA’s Kennedy Space Center in Florida at approximately 5 p.m. EDT to begin the wet dress rehearsal test for NASA’s Artemis I mission. The countdown began 30 minutes later at 5:30 p.m. or L-45 hours, 10 minutes before the initial target T-0 of 2:40 p.m. on Monday, June 20.

Overnight from June 18th to the 19th, engineers powered up the Orion spacecraft and the Space Launch System’s core stage. Teams also configured several systems on the ground, rocket, and spacecraft and performed activities to prepare umbilicals that connect the rocket and spacecraft to the mobile launcher and are used to provide power, communications, coolant, and propellant.

On the morning of June 20, the launch control team began chill down operations and resumed the countdown clock ahead of flowing super cold liquid oxygen (LOX) into the core stage tank. The T-0 time for today’s test is now 4:38 p.m. EDT for the first of the two terminal count runs for the wet dress rehearsal.

The process for filling the core stage tank begins with the chill down, or cooling, of the propellant lines to load the liquid oxygen and liquid hydrogen in preparation for tanking. The team will slowly fill liquid oxygen into the core stage tank with the fast fill beginning soon after. Teams will then proceed to slowly fill the core stage’s liquid hydrogen tank followed by fast fill.


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