NASA has concluded that Monday’s Wet Dress Rehearsal test of the Artemis I rocket met enough of its objectives that another test is unnecessary. That brings the agency one step closer to setting a launch date for this uncrewed test flight of the Space Launch System and Orion spacecraft around the Moon. More than three years behind schedule and billions over budget, it is a much-anticipated milestone that one day will lead to putting astronauts back on the lunar surface.

Monday’s test was supposed to rehearse the SLS/Orion launch all the way down to the T-9.3 second mark, just before the four Aerojet Rocketdyne RS-25 engines would ignite. It only got as far as T-29 seconds, just after the ground launch sequencer (computer) hands off to the automated launch sequencer on the rocket, but NASA decided that’s close enough.

Three prior attempts at the Wet Dress Rehearsal — “wet” because the tanks are loaded with propellant — were scrubbed in April for a variety of reasons. This fourth try encountered problems similar to some of those in the earlier tests, including another issue with the supply of gaseous nitrogen (GN2) that delayed the test for more than an hour and another hydrogen leak, this one in a different part of the system — a quick disconnect fitting between the rocket and the Mobile Launcher to which it is attached until the moment of liftoff.

But it achieved one key goal of filling the liquid hydrogen and liquid oxygen tanks on both the core stage and the upper stage (the Interim Cryogenic Propulsion Stage or ICPS) and another of getting into the last 10 minutes of the countdown, or terminal count, when many operations take place in rapid succession.

In a statement to SpacePolicyOnline.com, a NASA spokesperson said “the team is calling wet dress complete, and they are working on some additional checkouts before rolling back” to the Vehicle Assembly Building to fix the latest hydrogen leak and perform other tasks to get ready for launch.

NASA will brief the media tomorrow on what comes next.

Artemis I can launch only during roughly two-week windows every month to meet flight test criteria such as returning to Earth in daylight. Although there is a window in late July/early August, NASA managers already signaled they were not likely to be ready by then. The next window is August 23-September 6, but not August 30, 31 or September 1.

It is not clear what specific Wet Dress Rehearsal test criteria have or have not been met, although during a press briefing on Tuesday, Mike Sarafin, Artemis I Mission Manager, estimated they are “in the 90th percentile of where we need to be.”

At that briefing, Artemis I Launch Director Charlie Blackwell-Thompson said there were two primary and five secondary objectives and discussed them in broad terms, but a NASA spokesperson told SpacePolicyOnline.com they do not have a publicly available version of that list. One is being prepared, she said, but is not ready now.

Based on Blackwell-Thompson’s description, the two primary objectives were to demonstrate the cryogenic loading operation through all the phases of loading and draining propellant including the interaction between ground and flight systems, and to activate Launch Complex-39B assets and verify connectivity and communications across launch control centers and flight control teams at the relevant NASA Centers.

The five secondary objectives involved interfaces between systems shared across NASA Centers; thermal aspects of the vehicle; the timeline; electromagnetic interference/compatibility (EMI/EMC) data collection; and assembling and staging red crews and fire rescue crews.

Taking into account all four Wet Dress Rehearsals, Blackwell-Thompson said all the objectives were met in some way even if portions of an objective might not have been.

In primary objective one, for example, the plan was to count down to T-33 seconds where the ground launch sequencer  hands off to the automated launch sequencer (ALS), then pretend they had to scrub, recycle back to T-10 minutes, then resume the count to T-9.3 seconds.

By the time they got to that point in the test, about four hours later than planned, they decided to skip the first part and just count down to 9.3 seconds. To do that, they had to “mask” the hydrogen leak to prevent the computers from halting the countdown. That worked for the ground launch sequencer, but not the ALS, which scrubbed the test seconds after it took control at T-33 seconds. But they did complete many other portions of that objective — filling the tanks, counting down to T-29 seconds, draining the tanks and safing the vehicle.

The question was whether this fourth test was sufficient to convince NASA that Artemis I is ready to launch or if a fifth test would be needed.  Jim Free, head of NASA’s Exploration Systems Development Mission Directorate, was asked at a briefing last week if he would be willing to proceed with launch if all the objectives weren’t met. His instinct was no.

“This is the first time we’re flying this vehicle and I think we need to understand everything we can before we commit to launch. I think we’d have to look at the issue and say, hey, is it something that’s understandable, but my first caution is to say we’re gonna understand what every situation is and run it to ground before we would press to commit to a launch.” Jim Free, June 15, 2022

He is not participating in tomorrow’s briefing, but the question is sure to arise as how they reached the decision to move forward especially considering the hydrogen leak.

SLS has been under development since 2011 and Orion since 2006, although Orion was rebaselined because of design changes in the intervening years. The version flying on Artemis I does not have life support equipment. The next flight, Artemis II, scheduled for 2024, will be the first capable of accommodating people. They will fly around the Moon, but not go into orbit or land. Artemis III, currently anticipated in 2025, will be the flight to deliver astronauts to lunar orbit where they will transfer to another vehicle that will take them down to and back from the surface, putting astronauts on the Moon for the first time since 1972.

In 2014, NASA committed to the first SLS/Orion launch in November 2018. That slipped to December 2019-June 2020, then to mid-late 2021, and now into mid-2022.

The Government Accountability Office (GAO) reviews NASA’s major programs every year. Coincidentally the 2022 report came out today. It shows the development of SLS as 42 months behind schedule and $2.7 billion (42.5 percent) over cost. Using its most recent baseline (August 2021), Orion is 13 months behind schedule and $2.5 billion (37.4 percent) over cost.

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(NASA TV begins 5:00 am ET)

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