NASA gears up for one more key test before launching Artemis II to the Moon
If things don’t go so well, NASA’s chances of launching Artemis II this month will likely dwindle. NASA only has a handful of launch opportunities each month where everything lines up for Artemis II’s flight around the Moon. This month’s first two launch dates, February 6 and 7, are no longer an option after NASA ordered a two-day delay in this week’s drive countdown. Here are the three launch opportunities still available this month, each with a two-hour launch window:
- February 8 at 11:20 p.m. EST
- February 10 at 12:06 a.m. EST
- February 11 at 1:05 a.m. EST
If NASA misses this month’s launch opportunities, the next chance to send Artemis II to the Moon will be March 6. NASA released this table showing all available Artemis II launch dates through the end of April.
“The wet suit is the driving force for the launch. We have to go through the wet suit,” Blackwell-Thompson said. “We need to see what lessons we learn from this, and that will ultimately chart the path to launch.”
The fix is in
The Artemis II mission comes more than two years after NASA launched Artemis I, the first unmanned test flight of the Space Launch System rocket.
It took NASA four tests to fully load the boosters on the first SLS rocket during a wet rehearsal run (WDR) in 2022. None of the tests were problem-free. The list of technical problems included difficulties supplying nitrogen gas to the launch pad, problems keeping liquid oxygen at the right temperature, and a series of valve and seal failures that led to persistent hydrogen leaks.
Molecular hydrogen is notoriously difficult to master. It is highly flammable and its incredibly low mass and tiny dimensions make it difficult to contain. An additional complication is the cryogenic temperature of the liquefied form of hydrogen. Liquid hydrogen must be stored at temperatures of around minus 423° Fahrenheit (minus 253° Celsius), cold enough to solidly freeze any gas it comes into contact with, except helium.
When liquid hydrogen comes into contact with seals, the materials can change shape and size, creating leak paths that escape detection at room temperature. This happened repeatedly during several countdowns leading up to the launch of Artemis I, causing the joints to fall out of the hydrogen fueling line between the SLS core stage and its ground launch platform.
Two tail service masts, the gray structures erected near the base of the Space Launch System rocket, house the connections and joints where liquid hydrogen and liquid oxygen will flow into the core stage.
Credit: NASA/Joel Kowsky
Two tail service masts, the gray structures erected near the base of the Space Launch System rocket, house the connections and joints where liquid hydrogen and liquid oxygen will flow into the core stage.
Credit: NASA/Joel Kowsky
Finally, engineers designed what they called a “softer, gentler” approach to increasing hydrogen pressures and flow rates in the SLS rocket. The revised procedure wasn’t perfect and added time to the refueling schedule, but it worked well enough to allow NASA to successfully launch the Artemis I mission in November 2022.
NASA will use the same refueling procedure for Artemis II. “We believe this issue has been resolved,” Blackwell-Thompson said.
“Artemis I was a test flight, and we learned a lot during this campaign, before launch,” she said. “And the things that we learned about how to charge this vehicle, how to charge LOX (liquid oxygen), how to charge hydrogen, have all been incorporated into how we intend to charge the Artemis II vehicle.”
A one day test
There are other changes to the Artemis II launch countdown sequence, as astronauts will need to board the Orion spacecraft once the rocket is completely fueled. The crew will not be present Monday, but the rehearsal will include a built-in break when the astronauts board the spacecraft on launch day.
