NASA advances Artemis II with fuelling test ahead of launch

NASA teams in Florida are moving through a careful stretch of work as preparations continue for the Artemis II mission, the first crewed flight of the Space Launch System and Orion spacecraft.

Engineers at Kennedy Space Centre are finalising steps at the launch pad, coordinating ground systems, flight hardware, and support teams. A key milestone is now approaching with plans for a wet dress rehearsal, a full-scale fuelling and a countdown test. The exercise is designed to confirm that systems can operate together under launch conditions, without astronauts on board. While the launch itself remains ahead, the coming days focus on readiness, timing and problem-solving, as technicians check, adjust and rehearse each phase in a controlled but realistic setting.

NASA prepares Artemis II fuelling test as launch work continues

Engineers have remained on track or ahead of schedule as they work through planned activities at the launch pad and are getting ready to conduct a wet dress rehearsal, leading up to a simulated “launch” as early as Saturday, Jan. 31.The wet dress rehearsal will be the first time the SLS rocket is fully fuelled at the pad for Artemis II. During the test, teams will load more than 700,000 gallons of super cold liquid hydrogen and liquid oxygen into the rocket.

The countdown will proceed as if for launch, including pauses, restarts and checks during the final minutes. Engineers will also practise draining the propellants safely after the test, a step that is just as important as loading.Several runs are planned during the rehearsal. These runs are meant to test how the launch team responds to holds and recycled countdowns during the final ten minutes, known as terminal count.

The simulated launch point is set for the evening, though the test window allows flexibility if extra time is needed.

Countdown testing focuses on timing and control

The first run of the rehearsal begins nearly two days before the simulated launch. Teams will work through the countdown to just over a minute before liftoff, pause, then resume. Later, control will be handed to the rocket’s automatic launch sequencer, which manages the final seconds. A second run will follow, with another recycle of the countdown.

These steps help confirm that software, hardware and people can stay in sync under pressure.If issues appear during the rehearsal, NASA has the option to roll the rocket and spacecraft back to the Vehicle Assembly Building for further work before launch.

Hardware checks continue across the launch system

Alongside rehearsal planning, technicians have completed several important servicing tasks. The solid rocket boosters were recently loaded with hydrazine, a fuel used for control systems.

Inside Orion, teams are stowing equipment and carrying out planned pyrotechnic work on the launch abort system.Engineers have also tested the four RS 25 engines on the core stage and pressurised a key tank in Orion’s propulsion system. These checks are routine but critical, aimed at catching small issues before they grow into larger ones.

Cold weather and safety systems receive attention

Unusually cold weather expected in Florida has added another layer of preparation.

Teams are ensuring environmental control systems can keep the rocket and spacecraft within safe temperature limits.NASA is also addressing items identified during earlier evaluations. Adjustments have been made to the emergency egress baskets at the pad so they reach their full descent. Additional testing of Orion’s water system is under way after early samples showed higher organic levels than planned.

Crew readiness remains part of the picture

While hardware work continues in Florida, the Artemis II crew remain in quarantine in Houston. This period reduces health risks as launch preparations progress. For now, the focus stays on steady checks and rehearsals, with progress measured less by speed and more by how well each piece fits into the whole.