NASA was forced to delay a spacewalk that was scheduled for Thursday after officials discovered a leak on the International Space Station (ISS) earlier this week.

The space agency said that the decision was made to call off the planned ISS spacewalk as a precautionary measure following the leak of ammonia coolant discovered on Monday. The incident involved a backup radiator on the Russian Nauka science module and marks the third time such a leak has happened on the spacecraft.

ISS Leak Delays Scheduled Spacewalks

Officials also postponed another spacewalk that was scheduled for Oct. 20 and noted that new dates will be announced in the near future. In an update on Wednesday, they said that NASA engineering and flight control teams continue to review data and video from the leak. They added that they would wait until the completion of the review before authorizing the planned spacewalks.

Roscosmos flight controllers later said the leak had ceased, evidenced by NASA external station camera views showing only residual coolant droplets. Spacewalks with floating ammonia flakes present often need extra steps to avoid potential contamination of equipment or astronauts, as per Space.

Roscosmos also announced on Tuesday via Telegram that it was planning to task two cosmonauts with checking out the radiator during a previously planned spacewalk on Oct.25. Officials from both agencies repeatedly said that the leak, which is the third in Russian ISS equipment in the past year, had no material impact on the operations of the ISS.

However, the delay of the spacewalk will result in the pushing off of some minor maintenance on the station, along with a test scheduled to support future moon exploration. The Extravehicular Activity (EVA) originally scheduled for Thursday was supposed to have NASA astronaut Loral O'Hara and European Space Agency astronaut Andres Mogensen exit the ISS's Quest airlock to collect samples.

These would then be used for analysis to see whether or not microorganisms could exist on the exterior of the orbital complex. A second activity was to preview what could be possible with a planned lunar orbiting station called Gateway by replacing a high-definition camera on the port truss of the ISS.

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Reviewing the Incident

Fortunately, the primary radiator on Nauka continues to work normally as it provides full cooling to the module without impacting the crew or ISS operations. According to NASA, the backup radiator that was found with a leak was delivered to the station on the Rassvet module during the space shuttle mission STS-132 in 2010.

The recent incident is not as dramatic as the one that involved a Russian Soyuz capsule in late 2022. At the time, the incident rendered the MS-22 spacecraft unable to carry the crew back to Earth as scheduled.

The occurrence forced multiple astronauts and cosmonauts to extend their stay on the ISS while Roscosmos prepared another Soyuz vehicle to bring the space workers back home to Earth, said Extreme Tech.

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