A few days ago, ISS operators determined that the air leak recorded on board the station was in one of the Russian modules . It has just been precisely located using tea leaves, before finally being sealed.
The International Space Station, which will soon celebrate its 20th anniversary in space, is not completely waterproof. The structure indeed regularly loses tiny quantities of gas in space. This is why it is regularly re-pressurized by means of oxygen and nitrogen transported by cargo ships. A year ago, however, ISS operators noticed a slight increase in this loss rate, considering the presence of a small leak on board the station.
However, this was not important enough to worry the astronauts and cosmonauts on board, the two agencies "let it go" for a few months, before finally dealing with of the problem in early September, when the loss rate had just quintupled.
From then on, astronaut Chris Cassidy and cosmonauts Anatoly Ivanishin and Ivan Vagner were tasked with gradually closing the hatches of each module to pass them through the leak detector at ultrasound. Within days, the astronauts then discovered that the leak was in the service module Zvezda, the station's main Russian module.
Last Thursday, the Roscosmos agency finally announced that the crew members had identified the location of the leak after developing an unusual test.
Specifically, cosmonaut Anatoly Ivanishin took out a few leaves from a tea bag in the transfer chamber of the Zvezda service module. The crew then sealed the chamber by closing its hatches and monitored the behavior of the tea leaves on video cameras as they evolved in microgravity.
The leaves then seemed to move slowly near the module's communication equipment. The presence of a small crack on the shell of the module was then confirmed. The cosmonauts then used Kapton adhesive tape to butcher it. This device, assures the Russian agency, can remain stable and sticky over a wide range of temperatures. However, they plan to replace it soon with a more reliable patch .
As a reminder, the station's Russian segment is home to some of the station's oldest modules. Over the past few months, cosmonauts have had problems with toilets, and more recently, the oxygen supply system failed. Crew members fixed it this Saturday, according to Roscosmos.
This latest leak was also not the first on the Russian side. In August 2018, crew members isolated a two millimeter diameter borehole in a Soyuz capsule docked at the station. This hole had apparently been "hidden" with paint by a ground operator hoping no one would notice. The paint then crumbled, eventually revealing the crack. The cosmonauts then repaired it with an epoxy sealant.
