NASA Moves Forward with Artemis II Tanking Test that Could Set up Moonshot Mission

Why It Matters

A flawless tanking operation is the final gatekeeper before Artemis II can attempt its first crewed flight, directly influencing NASA’s schedule for returning humans to the Moon.

Key Takeaways

• NASA refuels SLS with 700,000 gallons propellant
• Second wet dress rehearsal addresses prior LH2 leak
• Valve and filter replacements aim to prevent leaks
• Successful tanking critical for March 6 launch window
• Artemis II will test Orion for future lunar missions

Pulse Analysis

The Artemis program’s momentum hinges on the Space Launch System’s ability to safely handle massive volumes of cryogenic propellant. Wet‑dress rehearsals simulate every step of a real launch, from chilling liquid hydrogen and oxygen lines to executing a fast‑fill sequence. After the February 2 test exposed an LH2 leak that threatened the countdown, NASA engineers replaced vulnerable valves and a problematic filter, reinforcing ground‑support infrastructure. These corrective actions are designed to eliminate the recurring leak pathways that have plagued both Artemis I and the initial Artemis II rehearsal.

Technical crews will commence the tanking on Thursday, first chilling the propellant lines before moving to a controlled slow‑fill that transitions to a rapid fill later in the day. The simulated countdown will run through terminal count, pause at T‑33 seconds, reset, and repeat, mirroring the exact timing constraints of an actual launch. By validating the fast‑fill process and confirming the integrity of the umbilical connections, NASA aims to demonstrate that the SLS can meet the tight launch window slated for early March. Any deviation could push the mission into a later window, affecting downstream schedules for Artemis III and the broader lunar gateway architecture.

Beyond the immediate launch timeline, a successful wet‑dress rehearsal reinforces confidence in Orion’s life‑support systems and the SLS’s heavy‑lift capability, both critical for sustained lunar exploration. The crew—Reid Wiseman, Victor Glover, Christina Koch, and Canada’s Jeremy Hansen—will rely on the data gathered from this test to ensure their safety during the ten‑day lunar flyby. Moreover, the rehearsal showcases NASA’s ability to iterate on complex hardware under pressure, a signal to commercial partners and international collaborators that the United States remains on track to re‑establish a permanent human presence on the Moon.

NASA moves forward with Artemis II tanking test that could set up moonshot mission

Phys.org · February 20 2026

Credit: CC0 Public Domain

NASA is set to begin fueling 700,000 gallons of cryogenic propellant on the Space Launch System rocket at Kennedy Space Center on Thursday as it moves ahead with a test countdown of the Artemis II mission.

A live stream of the rocket at KSC's Launch Pad 39‑B began before 10 a.m. as teams, after getting the green light from Artemis launch director Charlie Blackwell‑Thompson, began chilling down the liquid hydrogen (LH₂) and liquid oxygen (LOX) lines that will feed what has proved to be problematic fuels into the SLS rocket's core and upper stages. NASA was posting test updates to its Artemis II blog.

Once chilled, NASA will begin to load propellants using a slow‑fill process that will transition to a fast fill later in the day, leading up to a series of simulated countdown tests that will begin at 8:30 a.m. and could last through 12:30 a.m. Friday.

It’s part of NASA’s second go‑around at what’s called a wet dress rehearsal that simulates the processes that would be performed on an actual launch day.

The first wet dress rehearsal on Feb. 2, though, saw an LH₂ leak in the umbilical propellant line from the ground systems into the base of the core stage. While teams were able to mitigate the leak and get all 700,000 gallons of propellant into the rocket, the leak rate jumped above safe thresholds during NASA’s attempt to run through the final 10 minutes of the countdown.

Teams have since replaced valves on the ground equipment and swapped out a filter that caused issues last week during a check of those fixes, with NASA managers hoping the fueling operations don’t serve up a similar headache.

LH₂‑leak issues also plagued several test runs and launch attempts for the 2022 Artemis I flight, so it was somewhat of a surprise to see similar issues return after three years of hardware fixes and procedure adjustments.

If tanking is successful during the day, NASA will proceed with its attempt to complete what it could not during the first test run. That includes doing a run‑down through what is called terminal count, which happens at T‑10 minutes, holding the count at T‑33 seconds, resetting the clock back to T‑10 minutes and running through it again to just under T‑30 seconds.

The close‑out crew will also venture back to the launch pad during the countdown to run through the steps needed as if they were safely closing the hatch on a live crew.

The four astronauts set to fly on Artemis II won’t be at the pad for the test. NASA’s Reid Wiseman, Victor Glover and Christina Koch, as well as Canada’s Jeremy Hansen, remain in Houston and could go into quarantine once again on Friday, which would be two weeks out from the first potential launch date of March 6.

NASA won’t announce an official target launch date until it completes the wet dress rehearsal and reviews the test‑run data.

The mission aims to send the quartet in the Orion spacecraft launched atop the SLS rocket on a 10‑day mission that will take them out past the Moon and back. It is a test mission to prove Orion can support humans for future missions. Artemis III looks to return humans to the surface of the Moon for the first time since Apollo 17 in 1972.