From leaks to liftoff: Axiom-4 mission back on track for June 19 Launch

Axiom Space’s next astronaut mission is back on track—for now.

The mission, called Ax-4, is Axiom’s fourth trip with astronauts to the International Space Station (ISS). It was originally planned to launch on June 11 using a SpaceX Falcon 9 rocket. However, the launch was delayed by a day after engineers found a liquid oxygen leak in the rocket booster.

Later, another issue came up—this time, a leak was detected on the space station itself, where the Ax-4 crew was supposed to stay. This added further uncertainty to the mission’s timing.

In short, while Ax-4 is still expected to fly, technical problems both with the rocket and the ISS have caused delays.

Cosmonauts on the International Space Station recently noticed a new pressure change in Zvezda, the Russian service module located at the back end of the station. Zvezda has had small air leaks in the past, but this new pressure reading raised concerns.

Because of this, the launch of the Ax-4 mission was put on hold again as a safety precaution. NASA and Axiom announced on June 12 that the mission was delayed indefinitely, meaning they haven’t set a new launch date yet. The teams are being extra careful to make sure everything is safe before sending the astronauts.

“The Zvezda module first started leaking back in 2019. Since then, astronauts have regularly checked its air pressure and patched it up using special space-grade sealing methods—similar to a heavy-duty version of tape,” explained space analyst Girish Linganna. 

Now, it looks like the necessary repairs have been completed successfully. NASA is no longer as concerned about the safety risk to the new crew. As a result, both NASA and Axiom have decided to move forward and have announced a new tentative launch date for the Ax-4 mission: Thursday, June 19.

After the latest repair, the air pressure in the transfer tunnel of the Zvezda module has remained steady, NASA said in a June 14 update. Earlier, the pressure in this area used to drop, which pointed to leaks. The fact that it’s now stable suggests that the small leaks may have been successfully fixed.

However, NASA is not fully relying on these early signs just yet. The space agency wants to be sure and is continuing to monitor the situation carefully before making any final decisions.

NASA officials explained that the stable pressure in the transfer tunnel might not be due to a full fix. It could simply be because a small amount of air is slowly leaking in from the main part of the space station through the hatch seal.

To better understand what’s really happening, the teams are adjusting the pressure in the tunnel and observing it over time. This will help them check the actual condition of the tunnel and the seal between the main station and the back end of the Zvezda module, reports Space.com

“The leak in the Falcon 9 rocket’s first stage has been properly fixed, and this issue seems to be clearly resolved. This rocket booster, named B1094, is one of the newer ones in SpaceX’s fleet and has only flown once before. It was used in the Starlink 12-10 mission at the end of April. During that earlier flight, engineers had already noticed some signs of a leak, which likely carried over to this mission as well”, remarked Linganna. 

During a press conference on June 9, Bill Gerstenmaier, SpaceX’s Vice President of Build and Flight Reliability, explained that the team had missed the leak during the booster’s earlier repair work. He said, “We didn’t fully fix the booster during its refurbishment—in fact, we didn’t even detect the leak at the time, so it wasn’t corrected.”

The good news is that the repairs are now finished. On June 12, SpaceX announced that it had successfully carried out a “wet dress rehearsal”—they tested the rocket by filling it with fuel to make sure everything worked properly. With this test completed, the rocket is fully ready for the Ax-4 launch.

Now, the mission team and astronauts are getting ready for an early morning launch on June 19. The liftoff is planned for 4.53 am EDT (8.53 am GMT / 2.23 pm. IST). The rocket will take off from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.

A brand-new SpaceX Crew Dragon spacecraft, sitting atop a Falcon 9 rocket, will carry the Ax-4 crew to the International Space Station. Leading the mission as commander is Peggy Whitson, Axiom’s Director of Human Spaceflight and a former NASA astronaut. Joining her are three other astronauts: Shubhanshu Shukla from India, who will serve as the mission pilot; Sławosz Uznański-Wiśniewski from Poland; and Tibor Kapu from Hungary—both serving as mission specialists.

This mission marks the first time astronauts from India, Poland, and Hungary will travel to the International Space Station (ISS). It will also carry the highest number of research experiments ever sent on an Axiom mission—more than 60 scientific studies and educational outreach activities related to science, technology, engineering, and mathematics (STEM). 

Sci/Tech