NASA Completes Successful Artemis II Launch Rehearsal, Paving Way for March Moon Mission

"...NASA is ready to go to the moon...."

"...The space agency conducted a successful rehearsal of launch events for the upcoming Artemis II moon mission that will include Canadian Space Agency Jeremy Hansen and NASA astronauts Reid Wiseman, Christina Koch and Victor Glover...."

"...The rehearsal reached its goal of counting down to just past T-minus 30 seconds twice, meaning the rocket would have launched in less than a minute on launch day...."

"...There have been issues in the past with the rocket rehearsal, particularly when it comes to fuel leaks...."

"...The first attempt at an Artemis II wet dress rehearsal — an almost three-day-long run-through of launch procedures that includes a countdown as well as loading the rocket with fuel — began on Jan. 31 and ended on Feb. 3, but ran into a familiar problem: a hydrogen leak during fuelling...."

"...A similar issue arose with the Artemis I mission...."

"...While Thursday's rehearsal had some hiccups, specifically an issue with ground communication, NASA appeared to clear the one hurdle that has held them back: loading the core stage of the rocket with hydrogen...."

"...Both the core stage of the rocket — the massive orange tank — and the second stage of the rocket are loaded with liquid oxygen and liquid hydrogen. The process is staggered, starting with a slow fill followed by a fast fill...."

"...In past attempts, a hydrogen leak above the acceptable threshold was detected, pausing the tanking process. Eventually, it had to be stopped altogether...."

"...Hydrogen is prone to leaking because it's the smallest molecule in the universe. But it's also an extremely efficient rocket propellant...."

"...During Thursday's wet dress rehearsal, it appeared that there was no leak that surpassed that threshold...."

"...This marks an important milestone in the test, as teams reached this step without exceeding the ground safety limit of the hydrogen leak concentration, as was observed during the first Artemis II wet dress rehearsal...."

"...The second stage also experienced no issues...."

"...The next Artemis II launch opportunity is in early March...."

"...A history of issues..."

"...NASA’s Space Launch System (SLS) rocket will launch the astronauts. But the program faced numerous development delays, pushing back the first launch of an uncrewed Orion capsule around the moon — Artemis I — by years...."

"...But then, once the rocket was ready, it faced additional challenges...."

"...Artemis I rolled out to the launch pad in March 2022 for an attempt at a wet dress, but the first attempts were delayed for several months due to numerous issues, including nitrogen tank concerns...."

"...When it came time for the actual Artemis I launch that August, the hydrogen leaks plagued the space agency, along with some lag with ground communications...."

"...The rocket was eventually rolled back to NASA’s iconic Vehicle Assembly Building to work on the problems. After NASA made several modifications, Artemis I lifted off in the early morning hours of Nov. 16, 2022...."

"...Even after the first Artemis II wet dress earlier this year, the space agency said it made some additional modifications. It appears that this time these changes may have worked...."

"...Artemis II will see the four astronauts fly around the moon testing their Orion spacecraft and conducting experiments. This is in preparation for the Artemis III mission that will return astronauts to the surface of the moon. That mission is currently scheduled for no earlier than 2028...."

"...There will be a NASA press conference tomorrow at 11 a.m. ET to discuss findings of the wet dress rehearsal...."