A “Good Day” for the Artemis I Test, But Was It Enough?

A “Good Day” for the Artemis I Test, But Was It Enough?

Today’s fourth attempt at a critical test of the Artemis I rocket got much further than three tries in April, but still fell short. Launch Director Charlie Blackwell-Thompson called it a “good day” and an “exciting day” for the program and her team, but they need a chance to look at all the data before deciding whether a fifth test is needed.

The Wet Dress Rehearsal — so named because the rocket is loaded with propellant — actually started on Saturday, but today was the culmination where tanks on the core stage and upper stage were filled with liquid oxygen (LOX) and liquid hydrogen (LH2) and the team practiced the countdown sequence almost to launch.

The original plan was to count down to T-33 seconds, a critical point where ground launch computers hand off to automated launch computers on the rocket, then pretend a scrub happened and recycle to the T-10 minute mark, then count down again to another critical point, T-9.3 seconds, just before main engine start.

A variety of problems led to the three scrubs in April and some of them reappeared today.

Side view of the Space Launch System rocket and Orion spacecraft for the Artemis I mission at Launch Complex 39B for the fourth Wet Dress Rehearsal test, June 20, 2022. Photo credit: Screengrab from NASA TV. The SLS core stage is orange. One of the two Solid Rocket Boosters, with “NASA” on the side, is visible.  The Interim Cryogenic Propulsion Stage and Orion spacecraft, both white, are on top. The SLS/Orion “stack” is attached to the Mobile Launcher on the right.

The test was delayed early in day by a problem with the supply of gaseous nitrogen, or GN2, needed to purge propellant lines. The contractor that provides the GN2, Air Liquide, just upgraded its system because of issues that arose during the April tests. The system was deemed good to go, but this morning a faulty valve needed to be replaced, delaying the WDR for more than an hour.

Later in the day, a hydrogen leak was detected. The third April test was scrubbed because of a hydrogen leak. It could not be repaired on the pad and NASA decided to roll the Space Launch System rocket with its Orion spacecraft — the “stack” — back to the Vehicle Assembly Building for repairs while Air Liquide worked on its GN2 system.

That leak was fixed, along with other repairs, and the stack was rolled back to Launch Complex 39B on June 6.

Today’s leak was in a different place, a quick-disconnect fitting between the core stage and the Mobile Launcher. The launch team determined a seal was not properly seated and tried to remedy the situation remotely, but without success.

NASA decided to proceed with the test anyway, choosing to “mask” the leak from the ground launch sequencer, a computer that normally would stop the countdown after detecting the failure.

At one point, the launch team decided it would take the countdown to 9.3 seconds in one shot, instead of two as originally planned, but in the end they terminated the test at 29 seconds, just after the changeover from the ground launch sequencer to the automated launch sequencer on the rocket at T-33 seconds.

While the test did not achieve everything, they did fully fuel the rocket for the first time. The cryogenic LH2 must be kept at -423°Fahrenheit and LOX at -297°F. Both boil off while sitting on the pad so once the tanks are full they must be constantly replenished until launch.

Charlie Blackwell-Thompson, Artemis I Launch Director. Photo credit: NASA

Speaking with NASA’s Derrol Nail on NASA TV immediately after the test, Blackwell-Thompson called getting to that point, replenish, and into the last phase of the countdown, terminal count, a major milestone.

There’s a number of functions that we go through when we test as part of that final readiness for launch and we have done this many times in a sim[ulation] but we haven’t done it with cryogenics on the vehicle. And so today we got all stages to [the] replenish [point]. That was a big milestone for us getting both core stage and upper stage into replenish. And then our team really wanted to get into terminal count and work through those milestones and see how we performed, how the team performed and how the hardware performed, and they both performed very well.

She said she was comfortable proceeding with the countdown despite the hydrogen leak “because we were always protected in the flight software” and her team was monitoring for “anomalous conditions and I have ultimate faith in our team to be able to make those determinations and make those calls to cut off if we need to.”

What’s next? Blackwell-Thompson said they would evaluate the data they got today and “the couple of things that we didn’t get” and then decide if they need to do the WDR again.

NASA has scheduled a media telecon tomorrow morning where hopefully they will answer that question.

Artemis I is an uncrewed test launch of SLS and Orion around the Moon. Because of test constraints, such as ensuring that it returns to Earth in daylight, it can only launch during roughly two-week windows each month. NASA is currently shooting for the late August/early September time frame. The opportunities through the end of the year are as follows.

  • August 23- September 6, but not August 30, 31 or September 1
  • September 20-October 4, but not September 29
  • October 17-31, but not October 24, 25, 26 or 28
  • November 12-27, but not November 20, 21 or 26
  • December 9-23, but not December 10, 14, 18 or 23

User Comments

SpacePolicyOnline.com has the right (but not the obligation) to monitor the comments and to remove any materials it deems inappropriate.  We do not post comments that include links to other websites since we have no control over that content nor can we verify the security of such links.