A hole was drilled on board the Russian segment of the International Space Station (ISS) earlier by someone, now sealed with epoxy. Moreover, the cosmonauts managed to close up the hole qualitatively: the spacecraft on December 20 will be used to launch the astronauts to Earth. On the evening of December 11, Russian cosmonauts Oleg Kononenko and Sergei Prokopyev will enter outer space. The main task of the six-hour extravehicular activity will be to remove the anti-meteor protection of the Soyuz MS-09 to inspect the hole in the ship's side from the outside.
When the hole was discovered
On August 30, a pressure drop of several millimeters of mercury per hour was recorded onboard the ISS onboard means. The crew of the station immediately began to search for a "leak" - that is, holes in the station's body through which air escapes into outer space.
Astronauts and astronauts have sequentially pressurized the station's compartments to isolate the one with damage. Gradually they got to the utility compartment of the Soyuz MS-09 spacecraft.
The first small, 3-4 mm, hole in the Soyuz hull was discovered by the astronaut of the European Space Agency Alexander Gerst. Then the astronauts tried to seal the hole with a special tape, the air leak decreased, but not completely - the ultrasonic device showed the presence of a leak. The fact is that the hole is located in the ship's frame shelf - a structural element that is welded to the sealed hull skin at certain points. Due to spot welding, a thin gap is formed between the body and the shelf of the frame, through which air also passed. The Mission Control Center (MCC) suggested that the cosmonauts take a piece of medical gauze, impregnate it with epoxy resin and put the resulting "swab" inside the hole to block both it and the gap between the frame and the compartment lining.
After the performed procedure, the station manometers showed constant pressure during the day. It was recorded that the leak had been eliminated, but to be faithful, the astronauts on the next day, August 31, strengthened the resulting plug with additional layers of sealant.
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Hole pattern
Immediately after the discovery of the hole, both Russian cosmonauts and the station commander, NASA astronaut Andrew Feustel, noticed drill marks around it. On the photographs of the hole available on the Web, eight traces of drill work are noticeable: three small points at the vertical wall of the frame (the drill head was stuck here), four “snake” marks due to the trail sliding along the surface of the frame shelf, including at the hole itself, and the trace from the drill chuck on the edge of the vertical wall of the frame. As the Rocket and Space Corporation (RSC) Energia told reporters earlier, traces were also found on the yellow upholstery, which covers the entire inner surface of the utility compartment.
The hole itself is located near the toilet tanks, located in a small "locker" behind a plastic door. Above the place where they drilled, a white quilted mat is normally attached. It is firmly glued to the casing - even with a strong hand it will not work to tear it off. That is, the one who drilled the Soyuz first cut off the mat and bent it aside.
On the day the hole was discovered, the cosmonauts filmed it from different angles and sent photos and videos to the MCC. Also, shooting was carried out with the help of an endoscope, which made it possible to photograph an anti-meteor shield standing outside (an unsealed "cocoon" of metal sheets, installed 15 mm from the sealed hull outside the ship). It also showed traces of the drill head - the one who drilled the casing from the inside of the compartment rested against this outer screen. The screen itself could not be drilled: either the person who was wielding the drill in the ship deliberately stopped at this stage, or simply could not drill it - the meteor shield is made of strong but flexible sheets of metal that bend even with a slight touch, drill such a "walking" the surface is hard.
An important conclusion follows from this: when the Soyuz MS-09 was drilled, the meteoric screens were already installed. This protection consists of separate rectangular sheets of metal of different shapes, which are overlapped on special legs on the outer case of the BO. They cover almost the entire surface of the compartment, with the exception of a few narrow areas. The sheets are screwed to the legs with screws on a special putty. It is physically impossible to unscrew them, according to the assurances of representatives of Energia, after the putty has dried. Unless you warm it up in a special way.
Where were they drilled?
So far, neither RSC Energia nor the "big" Roscosmos commission has a priority version of what happened - how and where the Soyuz was drilled. From the question "why?" experts abstain altogether.
At the same time, from conversations with representatives of the corporation and Roscosmos, we can conclude: they exclude the versions of accidental damage during assembly that previously appeared in the media and on the forums (supposedly the employee could have made a hole in the wrong place, where the drawing is intended). Also excluded is vandalism by an employee, for example, who performed an erroneous operation under the influence of alcohol. According to the head of RKK Sergei Romanov, there are too many stages of verification in the course of assembling the Soyuz, including photographic recording with documentary control, to make mistakes of this kind. In any case, as Nikolai Sevastyanov, First Deputy Head of Roscosmos, told reporters, following an internal audit, RKK could not find those potential problems in the production processwhich could result in accidental injury or burnout for a drunk worker.
The ship was drilled with installed meteor screens, which means that damage to the Soyuz is excluded during work with individual parts. As Romanov told reporters, in addition to footprints on the screen, this is also evidenced by the fact that the ship is checked so thoroughly before being transported to the final assembly workshop that even "clues on the fabric" are not accepted. Consequently, the ship could have been damaged at the stage of work in the final assembly shop (the utility compartment as a whole is practically ready) or during the testing of the finished ship at the control and test station. There are also versions of damage to the ship during transportation to Baikonur, when it travels by rail for almost a month, or at the cosmodrome itself in the Energia assembly and testing complex, or …
The question also remains - how the drilled hole was repaired so that the ship would leak only almost two months after launch. Soyuz MS-09 launched into space on June 6 this year, docked at the station on June 8. The leak was found, respectively, only after 53 days. In one of the scenarios, which was previously announced to TASS by a source in the rocket and space industry, a hole was made on Earth, and then closed with some special sealant outside the compartment (that is, the plug should have been on the hole from the side of the meteor shield). According to the interlocutor of TASS, in the conditions of a space vacuum, all the liquid gradually evaporated from this glue plug, it lost its elasticity,decreased in size and at some point was squeezed out by the difference in pressure at the station (1 atm) and space vacuum (0 atm) into the space between the BO body (utility compartment) and the meteor shield.
The version that the hull was sealed from the outside appeared due to the absence of traces of sealant inside the ship. Astronauts who carefully examined the hole on August 30, as well as specialists on Earth who studied high quality photographs of the hole, did not find even the smallest traces of sealant or glue that should have covered the hole since the damage on Earth. Moreover, according to Energia's specialists, when applying the sealant from the inside of the compartment, its small fractions should have remained in the very cut of the hole, but it is clean.
The situation will clear up the exit
Initially, it was planned to carry out a spacewalk to survey Soyuz MS-09 on November 15, but it was postponed due to the Soyuz-FG rocket accident on October 11, which was supposed to deliver cosmonaut Alexei Ovchinin to the station. Soyuz MS-10 with Ovchinin and Nick Haig made an emergency landing, the cosmonauts were intact, but Prokopiev lost his partner to go overboard. He had to wait for Kononenko, who flew to the ISS on December 3 in Soyuz MS-11.
Kononenko and Prokopyev's exit should last about six hours (as a rule, a typical exit takes about six to seven hours). During this time, the cosmonauts have been performing a number of different works outside the station - these are experiments, installation / dismantling of equipment, and other service work. So far, two hours are planned for the operation with the Soyuz.
In order to get close to the drilled utility compartment of the Soyuz MS-09 spacecraft, there are certain difficulties: the compartment itself does not have handrails for the work of astronauts. They will have to move to the compartment on the telescopic boom on the side of the station, however, it does not provide a rigid fixation and will "walk", which will create difficulties during work.
Another question is how to open the fabric thermal insulation screen covering the entire household compartment from the outside, and then the meteor protection screen. It is planned that the astronauts will first cut the thermal insulation opposite the hole in the ship's hull, and then cut out a small section of meteor protection using metal scissors. Upon completion of the work, the meteoric protection will remain open in this place, and the thermal insulation will be closed with a "patch" on special clamps.
The cosmonauts will return the cut panel of meteor protection to Earth on the Soyuz MS-09 itself, which is to land on December 20. Sergei Prokopyev, NASA astronaut Sirena Auneon and Alexander Gerst will return from the station.
Having opened both external leaky screens, the Russians should see the exit "rosette" of the hole - the jagged jagged edges that form when drilling almost any metal. Tests on Earth have shown that in the aluminum alloy from the lining of the household compartment, such a "rosette" will necessarily appear. If the sealant was glued on the Earth, then it should definitely remain on these teeth, its presence will unambiguously determine that the hole was made before the flight.
RSC Energia carried out experiments with various sealants and adhesives, including those brands that are not used at the enterprise. Certain species have shown properties that theoretically prove the ability to hold out on a hole in space for two months, as well as pass all vacuum tests on Earth.
The last vacuum tests are carried out at the Baikonur cosmodrome shortly before the launch, there are eight in total. In such tests, the ship or its compartments are placed in a pressure chamber, where a vacuum is created, in the ship itself or in the compartment, all technological openings are closed, and it is inflated to 1.3 atm. Tests are also carried out using a helium-air mixture, which, in theory, can pass through the sealant.