On March 17th, the Artemis I mission rolled out of the Vehicle Assembly Building and was transferred to Launch Complex 39B at the NASA Kennedy Space Center in Florida. This was the first time that a fully-stacked Space Launch System was brought to the launchpad in preparation for a dress rehearsal.
Technical issues forced ground controllers to scrub the dress rehearsal multiple times and return the Artemis I to the VLB on April 26th. There were reports that the issues were addressed and that the Artemis I rocket would return to LC 39B by June. The official launch of the mission is not likely to take place until August at the earliest, according to an official NASA statement.
A dress rehearsal is when the launch team runs through operations to load the core and upper stages of the rocket with liquid hydrogen and liquid oxygen. This is followed by the teams draining the tanks and conducting a full launch countdown. The two-day event is the last major hurdle before launch and allows teams to practice the timelines and procedures they will use during the real thing.
Three previous attempts were scrubbed for a variety of issues, most of which had to do with the mobile launcher the Artemis I rocket sits on. A small piece of rubber got caught in a check valve on the interim cryogenic propulsion stage, which was only repaired in the VLB. NASA's engineers replaced the valve and are trying to figure out where the piece of rubber came from.
There is a hydrogen leak on one of the two tail service mast umbilicals that connect the rocket to the mobile platform and provide propellant and electricity during the launch. The teams tightened bolts on the liquid hydrogen, LOX, and core stage intertank umbilical, which is believed to have caused the leak. The engineers reported that there were no leaks after the testing at ambient air temperature.
The fire suppression system of the launch pad is dependent on the flow of gaseous nitrogen. Air Liquide, the French multinational provider of industrial gases and services, is responsible for supplying this gas to the NASA Kennedy Space Center and is currently upgrading the flow lines to offer increased support and protection to the SLS rocket. NASA managers said that the Artemis I would be rolled back to the launch pad by June.
Jim Free confirmed that on May 8th, NASA Administrator Bill Nelson suggested that August would be the earliest for a launch attempt. In an interview with Richard Tribou, he stated that.
“As we’ve been saying, we’ll set that official launch date after we get through wet dress. But you know based on some of historical challenges from similar programs over the years and the schedule performance we’ve seen thus far, we are looking at a couple of launch periods through the August time frame.”
A few silver linings can be found inside the delay. The ability to detect and address issues during testing ensures that they don't arise during launches, where they could be fatal. Nelson said that the Artemis II and III missions will still be launched in May of 2024 and May of 2025.
NASA could conduct two wet dress rehearsals if the launch date of Artemis I is delayed.
“We are optimistic that we only need one more based on everything we’ve been able to do thus far to fine-tune our tanking procedures, but we also be realistic and up-front with you that it may take more than one attempt to get the procedures where we need them for a smoother launch count that gives us the best chance of making our launch windows when we get to launch day.”
When Artemis I launches, it will send an uncrewed spaceship on a six to eight week circumlunar flight around the Moon before returning to Earth. The Artemis II mission will send a crew of four on a similar flight in preparation for Artemis III and the long-awaited return to the Moon. The four-person crew will fly to the moon and two astronauts will land on the lunar surface.
Delays remind us that space is hard and that we must never launch anything hastily. Artemis I and the program's subsequent missions will be happening in the coming years, even though it has slipped from its original date. If everything goes according to plan, humanity's presence on the Moon will grow and become permanent.
Further reading is on NASA Blogs Artemis.