NASA Delays Artemis II Launch to March After Hydrogen Leak

The launch of NASA’s Artemis II mission has been postponed until March following a fueling test that revealed hydrogen leaks. This mission marks the first time astronauts will travel to the Moon in over 53 years. The issues arose during a Wet Dress Rehearsal (WDR) at Kennedy Space Center in Florida, where engineers encountered difficulties while preparing the Space Launch System (SLS) rocket for its anticipated launch.

According to a statement from NASA, engineers successfully met several objectives during the two-day test. However, persistent hydrogen leaks were detected at the connection between the rocket and its launch platform. “To allow teams to review data and conduct a second Wet Dress Rehearsal, NASA now will target March as the earliest possible launch opportunity for the flight test,” the agency noted.

The Artemis II mission aims to send four astronauts aboard NASA’s Orion spacecraft on a trajectory around the far side of the Moon. This mission represents the first crewed lunar flight since 1972 and is part of a broader initiative to explore the Moon’s south pole and establish a sustainable presence there.

NASA had initially hoped to launch Artemis II as early as February 8, but the recurring hydrogen leaks—problems that previously delayed the uncrewed Artemis I mission in 2022—have complicated preparations. During the Artemis I campaign, engineers were able to resolve similar issues by modifying hydrogen loading procedures, but the same challenges have resurfaced with the current mission.

The first potential launch window for Artemis II is set for March 6, 2024, with a two-hour launch opportunity beginning at 20:29 EST (01:26 UTC on March 7). As a standard precaution, the crew, including commander Reid Wiseman, pilot Victor Glover, mission specialist Christina Koch, and Canadian astronaut Jeremy Hansen, has been in medical quarantine since January 21. They will now exit quarantine to resume training while awaiting a new launch date.

The countdown rehearsal began later than planned due to cold temperatures at the Florida launch site. Once fueling operations commenced, hydrogen leaks were detected shortly after loading the super-cooled fuel into the SLS core stage. The leaks originated from the same location identified during the Artemis I campaign. Liquid hydrogen and liquid oxygen are transferred from ground storage tanks into the SLS core stage through Tail Service Mast Umbilicals (TSMUs), which are crucial for propellant delivery.

Hydrogen is an efficient rocket fuel but poses significant handling challenges due to its extreme cold requirements—minus 423 degrees Fahrenheit (minus 253 degrees Celsius). This temperature can alter the shape of seals in the fueling line, creating leak paths that may not be detectable at ambient temperatures. NASA has established a safe limit of 4 percent hydrogen gas concentration around the fueling connector, which was exceeded during the rehearsal.

NASA’s statement indicated that attempts to resolve the issue included stopping the flow of liquid hydrogen and allowing the seals to reseat by warming the interface. By Monday evening, the team successfully loaded over 750,000 gallons of propellant into the 322-foot-tall (98-meter) rocket. However, complications arose when closing the hatch of the Orion spacecraft, leading to delays in the countdown.

Despite these challenges, the launch team aimed to stop the countdown clock at T-minus 33 seconds, simulating a real launch scenario. Instead, the countdown was halted at T-minus 5 minutes and 15 seconds due to a spike in the hydrogen leak rate. This interruption prevented the rocket from completing several critical pre-launch checks, including activating its auxiliary power units.

Following the premature end of the countdown, NASA managers decided to delay the Artemis II mission to allow for a thorough review of the data and to address the issues identified during the test. “As always, safety remains our top priority, for our astronauts, our workforce, our systems, and the public,” stated NASA Administrator Jared Isaacman in a social media post. “We will only launch when we believe we are as ready to undertake this historic mission.”

A press briefing is scheduled for Tuesday afternoon, where NASA officials will provide further insights into the outcomes of the test and discuss the path forward for the Artemis II mission.