A helium circulation subject within the SLS rocket’s higher stage has compelled NASA to roll Artemis 2 again to the VAB, nixing the mission’s March window and pushing launch to April.
NASA’s SLS rocket and Orion spacecraft at Launch Pad 39B on Feb. 1, 2026. The automobile will likely be rolled again to the Car Meeting Constructing after engineers detected a helium subject within the rocket’s higher stage. Credit score: NASA/Sam Lott
Within the newest delay for the Artemis 2 mission, NASA introduced on Saturday that it’ll roll the Area Launch System (SLS) rocket and Orion spacecraft again to the Car Meeting Constructing (VAB) as soon as Feb. 24, pushing the primary crewed lunar mission since Apollo 17 to April on the earliest.
Only a day earlier, NASA had introduced it was ready to launch Artemis 2 as early as March 6; that upbeat evaluation got here after the company accomplished a second moist costume rehearsal — a fueling check and simulated launch countdown — on Feb. 19. However on Feb. 21, engineers detected an interruption within the circulation of helium to the rocket’s higher stage. Helium is used to pressurize the stage’s liquid hydrogen and liquid oxygen tanks; with out it, propellant can’t be fed to the engine chargeable for sending Orion towards the Moon.
Notably, the helium system carried out usually in the course of the moist costume rehearsal itself. The interruption surfaced throughout routine monitoring afterward — which means the problem eluded the check that had been designed to be the ultimate validation earlier than flight. Engineers are working to find out whether or not the issue lies in helium supply traces, a valve within the higher stage, or a filter connecting the bottom traces to the rocket. Within the meantime, operators are utilizing a backup technique to keep up protected circumstances for the higher stage and rocket.
The difficulty echoes a problem encountered in the course of the Artemis 1 marketing campaign in 2022, when a malfunctioning helium examine valve in the identical sort of higher stage compelled a rollback to the VAB. In that case, nevertheless, the issue was caught in the course of the moist costume rehearsal.
Again to base
No matter the place the present drawback originates, the rocket should return to the VAB earlier than engineers can absolutely troubleshoot it. The 525-foot-tall constructing — one of many largest constructions on the planet by quantity and the one one ever used to assemble a rocket that carried people to a different world — offers engineers crane entry and the managed surroundings wanted to service the automobile’s higher stage.
To get there, the rocket will likely be transported down a 4.2-mile highway at roughly 1 mph by NASA’s shifting platform, referred to as the crawler. The crawler itself weighs roughly 6.65 million kilos unloaded and may haul as much as 18 million kilos — burning about 165 gallons of diesel per mile.
Pad entry platforms put in on Feb. 20 for launch preparations needed to be eliminated first — each to guard them from forecasted excessive winds and to clear the trail for a possible rollback. That work is completed, clearing the way in which for the journey again to the VAB as quickly as Feb. 24.
Because of trajectory necessities, Artemis 2’s launch home windows open for only some days, roughly each 4 weeks. The helium leak and related work means the mission will miss the March 6–11 window. The subsequent alternative runs April 1–6, which is what NASA is working towards — but when groups can’t resolve the problem and prepared the automobile in time, the mission would slip additional. The company plans to carry a media briefing within the coming days.
The Artemis 2 crew — Commander Reid Wiseman, Pilot Victor Glover, and Mission Specialist Christina Koch of NASA, together with Canadian Area Company Mission Specialist Jeremy Hansen — was launched from quarantine and returned to Houston for a second time. The crew first entered the usual 14-day pre-launch quarantine on Jan. 23 however was launched in early February when the launch slipped from its unique February window to March.
