Plans to Resume Artemis I Test On Hold as Launch Date Slips

NASA is still deciding how and when to proceed with the Wet Dress Rehearsal test for the Artemis I mission. The test was scrubbed three times. Now the agency has decided to bring the Space Launch System rocket back to the Vehicle Assembly Building while a contractor upgrades equipment to supply gaseous nitrogen needed to purge propellant lines. NASA conceded today that launching Artemis I in early June is no longer in the cards and is looking at the June 29-July 12 window instead.

All three attempts to conduct the WDR test so far encoutered a variety of minor issues that could be resolved, but ultimately had to be scrubbed when bigger issues emerged. On April 3 it was malfunctioning fans on the Mobile Launcher needed to clear hazardous fumes. On April 4, it was a defective helium check valve on the Interim Cryogenic Propulsion Stage, ICPS, the Space Launch System’s second stage. On April 14, it was a hydrogen leak on the SLS first stage, or Core Stage.

On Friday, NASA was looking at resuming the test as early as this Thursday, but over the weekend decided to roll the SLS/Orion stack back to the Vehicle Assembly Building (VAB). Launch Director Charlie Blackwell-Thompson told reporters today that crews are now safing the system and preparing it for the 4-mile ride back to the VAB atop the Crawler-Transporter. Getting everything ready will take about a week. The earliest it will start moving is Tuesday, April 26, on its 11-12 hour journey home.

In a press release and at today’s media telecon, Blackwell-Thompson and Artemis Mission Manager Mike Sarafin explained that after reviewing all the data on Friday and assessing the various problems they’d experienced, one that stood out was the supply of gaseous nitrogen (GN2) needed to purge the propellant lines to the core stage and ICPS. Although GN2 supply problems were not responsible for any of the scrubs, they did delay the test on April 4 and April 14.

NASA and its GN2 supplier, Air Liquide, concluded that completing equipment upgrades that were long-planned and partially in place would make the system more robust, a process that would take weeks. NASA decided to “take advantage of the opportunity” and return SLS to the VAB to repair the other problems rather than trying to do it at the launch pad.

Air Liquide did not respond to a request for comment today.

Having made that decision, agency officials starting looking at alternatives for what to do next. Blackwell-Thompson listed three options under consideration:

• A quick turnaround in the VAB, basically fixing only those problems that cannot be addressed on the pad, like replacing the ICPS helium check valve, and completing other work once back at Launch Complex-39B.
• A longer stay in the VAB to fix everything, waiting to return to the launch pad until they are fully ready to resume the test.
• Instead of completing the test and returning again to the VAB in order to get ready for the actual launch, combining the test and launch so the SLS only has to make the trip one more time.

Blackwell-Thompson said it is too early to decide which to pursue. She could not offer timelines for any of them, but said the quick-turnaround option would mean resuming the test “in the weeks timeframe.”

NASA Deputy Associate Administrator for Common Exploration Systems Development Tom Whitmeyer reaffirmed that the WDR will take place one way or another. The goal is to test the entire system — the SLS with its Core Stage, ICPS, and Solid Rocket Boosters, and the Orion crew spacecraft — prior to launch. Many test objectives were met in the first three tries, but not filling the Core Stage and ICPS with propellant (Liquid Hydrogen and Liquid Oxygen) or conducting two practice countdowns.

Considering that the vehicle will not begin its trip back to the VAB until at least next Tuesday and the shortest time in the VAB is weeks, it clearly is a significant schedule hit.

The actual launch of Artemis I is constrained to certain windows of time each month to ensure, for example, that it splashes down in daylight when it returns to Earth. This is an uncrewed test flight that could spend 26-42 days in the Earth-Moon system depending on the day of launch. NASA wants visual imagery of it during descent and landing.

Most recently, the target was the June 6-16 window, but NASA conceded today that timeframe would be “a challenge,” meaning it is no longer possible. The next window is June 29-July 12 (but not July 2-4), all based on orbital dynamics and the relative positions of the Earth, Moon, and the spacecraft.

Artemis is NASA’s program to return astronauts to the Moon for the first time since the Apollo program. Assuming the uncrewed Artemis I flight is successful, the first test flight with a crew is currently planned for 2024. The first Artemis crew landing on the Moon is targeted for 2025, 53 years after the Apollo 17 crew departed.

SLS and Orion are years late and billions over budget. NASA’s Inspector General estimates Artemis — SLS, Orion, and associated Exploration Ground Systems — will cost $93 billion from FY2012 when SLS development began through FY2025, of which $53 billion is for FY2021-2025. He adds that each of the first four Artemis flights will cost $4.1 billion.