NASA is preparing to roll back its Space Launch System (SLS) rocket and Orion spacecraft from Kennedy Space Center’s Launch Pad 39B to the Vehicle Assembly Building (VAB) on Wednesday, , following the discovery of a helium flow issue. The rollback, a complex undertaking involving the massive Crawler-Transporter 2, is expected to take up to 12 hours to complete the four-mile journey.
The issue centers around the interruption of helium flow to the SLS rocket’s interim cryogenic propulsion stage. Helium is crucial for maintaining the proper temperature of the stage’s engine and for pressurizing the liquid hydrogen and liquid oxygen propellant tanks, which collectively hold approximately 730,000 gallons (2.76 million liters) of fuel. Without proper pressurization, the engine cannot reliably ignite, making a successful launch impossible.
This setback follows a series of tests and preparations for the Artemis 2 mission, which aims to send four astronauts – NASA’s Reid Wiseman, Victor Glover, and Christina Koch, and the Canadian Space Agency’s Jeremy Hansen – on a flight around the Moon and back. The mission represents the first crewed venture beyond low Earth orbit since the Apollo 17 mission in 1972.
The recent difficulties began after a wet dress rehearsal (WDR) conducted on . An initial WDR on was cut short due to a liquid hydrogen leak. Following repairs, the second WDR was successful, leading NASA to consider a launch attempt as early as . However, the helium flow issue, detected overnight from to , prompted the decision to roll back to the VAB for further investigation and repair.
The rollback to the VAB isn’t a simple procedure. It requires removing pad access platforms installed for the launch preparations, a task complicated by forecasted high winds. These platforms cannot be safely removed during strong wind conditions, necessitating careful timing of the operation. The entire process underscores the inherent complexities of working with such a large and sophisticated launch system.
The current situation impacts the launch schedule. The original launch window extended to , but is now closed. NASA is now targeting launch opportunities beginning on , with additional windows between and , and on .
The Artemis program, and specifically the Artemis 2 mission, represents a significant undertaking for NASA and its international partners. The mission is designed not only to return humans to the vicinity of the Moon but also to serve as a crucial stepping stone for future lunar surface missions and, crewed missions to Mars. The current delay, while frustrating, highlights the rigorous testing and safety protocols inherent in space exploration. Addressing the helium flow issue thoroughly is paramount to ensuring the success and safety of the Artemis 2 mission and the broader goals of the Artemis program.
The Artemis 2 crew, who had been in pre-launch quarantine, have been released to resume their normal schedules while the rocket undergoes repairs. They are scheduled to attend President Trump’s State of the Union address on , a symbolic gesture highlighting the national importance of the Artemis program.
