Nasa Moon rocket test flight delayed amid repairs and test complications

Space agency pulled rocket back indoors for repairs, pushing test flight back until August or later

Nasa’s big Moon rocket has returned indoors for repairs at Kennedy Space Center (Nasa)

Nasa’s Moon rocket has had its test flight delayed until later this year after crews were forced to move it back into the Vehicle Assembly Building at Florida’s Kennedy Space Center for repairs.

The roughly 10-hour journey on Nasa’s massive, treaded crawler-transporter vehicle began just before 8pm on Monday and saw the rocket slip back inside the building around 6am the following morning.

The big rocket had sat on the launch pad since 17 March and undergone three attempts and important pre-flight testing, but issues discovered during the testing forced the space agency to pull the rocket back indoors for repairs.

While Nasa officials have insisted the problems are minor, and the type of problems the testing was designed to sniff out in a new rocket, Nasa assistant administrator Bob Cabana admitted in a Tuesday press briefing that the space agency is now hoping to launch an SLS test flight in August. At the time the SLS rolled to the launch pad in March to begin testing, Nasa officials were still discussing launch windows in May.

“The team is evaluating options,” Mr Cabana said. “Once we have a better technical understanding of where we are, we'll make the final decision on what the plan forward is and when we'll launch.”

Nasa tried three times to conduct a “wet dress rehearsal” for launch with the SLS at the launch pad, a test which consists of a simulated countdown and filling the rocket with cryogenic liquid oxygen and hydrogen propellant, the “wet” portion of the test.

The first attempt on 3 April was foiled by malfunctioning fans designed to manage hazardous gasses on the rocket’s mobile launcher platform, while the 4 April test was scrubbed halfway through when a pressure valve on the mobile launcher was found to be malfunctioning. Following the aborted 4 April test, Nasa technicians also discovered a faulty helium pressure valve on the rocket’s upper stage

Nasa tried for a third wet dress attempt on 14 April, this time modifying the test to avoid fueling the rocket’s upper stage. But the test was cut short again due to a liquid hydrogen leak in the connection fueling the rocket.

Nasa officials have pointed out that the helium valve on the SLS upper stage is the only problem found on the rocket itself, but all of the issues need to be resolved, and a full wet dress likely conducted, before the SLS can fly.

It’s not clear how long the work on the SLS itself may take, but Cabana said that preparations for the launch range itself could take two weeks following the launch of Nasa’s Crew-4 mission to the International Space Station from Kennedy Space Center on Wednesday morning.

“The important thing now is, we’ve got to do this right,” Cabana said. “It's a big rocket, a lot of new equipment, new systems on the ground side and on the flight side.”

The SLS rocket and Orion spacecraft it launches are the backbones of Nasa’s Artemis Moon program, which aims to return humans to the moon during the program’s third mission in 2025. Artemis-II, a crewed lunar flyby is scheduled for 2024.

But before humans take a ride on the SLS, Nasa must launch an uncrewed flight that will propel the Orion spacecraft to beyond the Moon and back, the Artemis I mission. Based on Cabana’s comments Tuesday, that test flight may still happen this summer — if barely.

“August,” he said, “there are options that do still get us there.”