NASA has a new problem to fix before the next Artemis II countdown test
Source: Ars Technica
Background
John Honeycutt, chair of NASA’s Artemis II mission management team, said the decision to relax the safety limit between Artemis I and Artemis II was grounded in test data.
“The SLS program, they came up with a test campaign that actually looked at that cavity, the characteristics of the cavity, the purge in the cavity … and they introduced hydrogen to see when you could actually get it to ignite, and at 16 percent, you could not,” said Honeycutt, who served as NASA’s SLS program manager before moving to his new job.
Hydrogen is explosive in high concentrations when mixed with air, which makes it a powerful rocket fuel but also notoriously difficult to contain. Molecular hydrogen is the smallest molecule, so it can readily escape through leak paths and poses a materials challenge for seals because liquefied hydrogen is chilled to ‑423 °F (‑253 °C).
Hydrogen Leak Issue
During the three‑year interim between Artemis I and Artemis II, NASA chose to become comfortable with a more significant hydrogen leak rather than fixing the leaks themselves.
“I will say near‑conclusively for Artemis III, we will cryoproof the vehicle before it gets to the pad, and the propellant loading interfaces we are troubleshooting will be redesigned,” NASA Administrator Bill Isaacman wrote.
Isaacman, who took over as NASA’s administrator in December, has criticized the SLS program’s high cost—estimated by NASA’s inspector general at more than $2 billion per rocket—and the launch vehicle’s slow flight rate.
Budget and Infrastructure
NASA’s expenditures for the rocket’s ground systems at Kennedy Space Center are similarly enormous. In 2024 alone, NASA spent nearly $900 million on Artemis ground‑support infrastructure, much of it for constructing 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 bespoke 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, never built a full‑size test model of the core stage. Consequently, there is currently no way to completely test the cryogenic interplay between the core stage and ground equipment until the fully assembled rocket is on the launch pad.
Legal Requirements and Future Architecture
Existing law requires NASA to continue flying the SLS rocket through the Artemis V mission. Isaacman wrote that the Artemis architecture “will continue to evolve as we learn more and as industry capabilities mature.” In other words, NASA plans to incorporate newer, cheaper, reusable rockets into the Artemis program over time.
Launch Schedule for Artemis II
The next series of launch opportunities for the Artemis II mission begin March 3. If the mission does not lift off in March, NASA will need to roll the rocket back to the Vehicle Assembly Building to refresh its flight termination system. Additional launch windows are available in April and May.
“There is still a great deal of work ahead to prepare for this historic mission,” Isaacman wrote. “We will not launch unless we are ready and the safety of our astronauts will remain the highest priority. We will keep everyone informed as NASA prepares to return to the Moon.”