NASA has a new problem to fix before the next Artemis II countdown test
John Honeycutt, chairman of NASA’s Artemis II mission management team, said the decision to relax the safety boundary between Artemis I and Artemis II was based on test data.
“The SLS program put together a test campaign that actually looked at this cavity, the characteristics of the cavity, the purging in the cavity…and they introduced the hydrogen to see when you could actually ignite it, and at 16 percent, you couldn’t,” said Honeycutt, who served as NASA’s SLS program manager before taking his new position.
Hydrogen is explosive in high concentrations when mixed with air. This is what makes hydrogen a great rocket fuel. But it is also notoriously difficult to contain. Molecular hydrogen is the smallest molecule, which means it can easily escape through escape routes and poses a materials problem for seals because liquefied hydrogen is cooled to minus 423 degrees Fahrenheit (minus 253 degrees Celsius).
So it turns out that NASA used the three-year gap between Artemis I and Artemis II to familiarize itself with a larger hydrogen leak, instead of fixing the leaks itself. Isaacman said that would change before Artemis III, which is also likely at least three years away.
“I will say almost conclusively for Artemis III, we will cryoprotect the vehicle before it reaches the platform, and the propellant loading interfaces that we are troubleshooting will be redesigned,” Isaacman wrote.
Isaacman took over as head of NASA in December and criticized the high cost of the SLS program.—estimated by NASA’s inspector general at more than $2 billion per rocket—with the launcher’s torrid flight rate.
NASA’s spending on the rocket’s ground systems at the Kennedy Space Center is equally enormous. NASA spent nearly $900 million on Artemis ground support infrastructure in 2024 alone. Much of the money went toward building a new launch platform for an upgraded version of the Space Launch System that may never fly.
All of this makes each SLS rocket a golden egg, a tailor-made specimen that must be treated with care because it is too expensive to replace. NASA and Boeing, the prime contractor for the SLS core stage, have never built a full-scale test model of the core stage. There is currently no way to fully test the cryogenic interaction between the core stage and ground equipment until the fully assembled rocket is on the launch pad.
Current law requires NASA to continue flying the SLS rocket on the Artemis V mission. Isaacman wrote that the Artemis architecture “will continue to evolve as we learn more and as the industry’s capabilities mature.” In other words, NASA will integrate newer, cheaper, reusable rockets into the Artemis program.
The next round of launch opportunities for the Artemis II mission begins March 3. If the mission doesn’t take off in March, NASA will have to return the rocket to the Vehicle Assembly Building to update its flight termination system. Other launch dates are available in April and May.
“Much work remains to be done to prepare for this historic mission,” Isaacman wrote. “We will not launch until we are ready and the safety of our astronauts will remain the top priority. We will keep everyone informed as NASA prepares to return to the Moon.”
