A spacewalk to inspect the hole of the Soyuz MS-09

A spacewalk to inspect the hole of the Soyuz MS-09 https://danielmarin.naukas.com/files/2018/12/sas-1.jpg

The cosmonauts of the Expedition 57 of the ISS, Oleg Kononenko and Sergei Prokopyev made an unplanned spacewalk on 11 December 2018 to inspect the hole found in the orbital module of the Soyuz MS-09. The extravehicular activity, called EVA-45A -or VKD-45A (VKD-45A) by its initials in Russian- had a duration of 7 hours and 45 minutes (according to the Russian criterion of calculation of the time of space walks, different from the American) , almost one hour more than planned (it was 6 hours and 33 minutes). The walk, the 213th in the history of the ISS, began at 15:59 UTC and ended at 23:44 UTC. The two cosmonauts had to move from the lock of the Pirs module (SO-1) to the Soyuz MS-09, coupled to the Rassvet module, to carry out the inspection operations, so they were forced to use the Strelá cranes to move around. one point to another.

Inspecting the Soyuz MS-09 during the EVA-45A (NASA TV).

During the EVA the Orlan MKS-4 (Prokopyev) and MKS-5 (Kononenko) wetsuits were used. On August 29, the International Space Station suffered a slight depressurization due to a small hole of two millimeters in the orbital module (BO) of the Soyuz. The crew plugged the leak from the inside with medical gauze and epoxy resin. The characteristics of the hole, apparently made with a drill, made it suspect that it was a manufacturing defect - intentional or not - in the assembly line of the company RKK Energy in Moscow. To complete the analysis of the incident, Roscosmos considered that an inspection of the hole from the outside was necessary in order to collect more data and rule out that there was more damage than was visible from within. Do not forget that the BO will be destroyed during the atmospheric reentry of the MS-09, so there will be no other opportunity to inspect the happy hole.

The hole in the BO of the Soyuz MS-09 (it is the smallest hole near the finger of the astronaut) (NASA).

Another view of the hole from the inside once repaired (Roscosmos).

The Soyuz MS-09 coupled to the ISS (NASA).

The decision to carry out the EVA was not easy because it was an unplanned spacewalk, although it is not true as it has been said in some media that the two men had not trained for it: Kononenko, who recently arrived in The ISS on board the Soyuz MS-11, received specific training for this spacewalk. Of course, it is not easy to move around a Soyuz coupled to the ISS because these vehicles lack grapples to ensure the movement of the cosmonauts. In any case, both Roscosmos and the leadership of RKK Energía considered the risk worthwhile. The cosmonauts went to the BO of the Soyuz and, next to it, they used several tools to cut the various layers of insulating material that cover the Soyuz, called EVTI (ЭВТИ, Экранно-Вакуумая Теплоизоляция, «Thermal Insulation of Shielding» ) and then the shield against micrometeors. The EVTI is made up of insulating fabrics that are easily cut, but the shield material - an innovation of the new Soyuz MS - is more resistant and the cosmonauts had to use special scissors to cut metals. The two men took longer than expected to find the hole, and then collected samples of the area and the resin that oozed through the hole.

Training the cosmonauts on the ground to cut the insulation material of the Soyuz (RKK Energy).

Cutting the EVTI during the trainings (RKK Energy).

«Stabbing» the Soyuz (RKK Energy).

Tools used in the spacewalk (Roscosmos).

The use of various sharp tools by cosmonauts clad in pressure suits is a delicate issue, but the procedure itself was not very complex. The "destruction" of the exterior of the Soyuz caused consternation among the public not familiar with the details of the Soyuz, but, although cumbersome, the operation did not present any risk to the vehicle. The EVTI is not an essential element of the Soyuz, since its main function is to regulate the temperature of the ship, a task that is not vital once the Soyuz is coupled to the ISS and, therefore, is receiving a constant supply of air at the temperature of the rest of the season. On the other hand, the Soyuz MS-09 is about to return to Earth, so the EVTI has already fulfilled its function of protecting the vehicle during its stay in space. The return maneuver of the Soyuz lasts a few hours and the cosmonauts will be inside the capsule (SA), so even with the EVTI damaged, the Soyuz can work properly. However, once the hole was identified, the cosmonauts found that the surrounding area was not damaged and the TsUP indicated that it was not necessary to add an additional thermal protection panel over the area.

The Orlan MKS suitcases used in this VKD (Roscosmos).

The cosmonauts next to the Soyuz using the crane Strelá (NASA TV).

Next to the Soyuz (NASA TV).

Next to the BO (NASA TV).

Starting to cut the EVTI (NASA TV).

It is also important to note that this is not the first time that an EVA is performed to inspect a Soyuz in orbit. In 1990 the cosmonauts Soloviov and Balandin made a spacewalk to fix the petals of the EVTI that had partially detached around the capsule of the Soyuz TM-9 (the capsule is a much more delicate element than the BO). On July 10, 2008, almost ten years ago, two cosmonauts performed an EVA to inspect the Soyuz TMA-12. On that occasion the crew also had to cut the EVTI to inspect the segment that joins the capsule with the propulsion module (PAO) in order to remove one of the explosive bolts that serve to separate both modules before the reentry (the two Previous Soyuz, the TMA-10 and the TMA-11, had suffered high deceleration ballistic reentries because the SA and the PAO had not separated properly and the engineers suspected the bolts). The cosmonauts of that EVA were Sergei Volkov and ... Oleg Kononenko. Indeed, the good Oleg has become the second cosmonaut to "destroy" the external isolation of a Soyuz in orbit.

The hole at last (NASA TV).

Prokopyev and Kononenko next to the Soyuz (NASA TV).

Expedition 57 of the ISS after the EVA (Roscosmos).

For Kononenko this has been his fourth spacewalk and he has already accumulated 26 hours and 12 minutes of experience in EVAs, while for Prokopyev he was the second and accumulated a total of 15 hours and 31 minutes. It was also the eighth spacewalk in 2018 and the second from the Russian segment of the ISS. The Soyuz MS-09 will return next week and, with it, the samples collected by the cosmonauts from the hole area. Hopefully they serve to clarify once and for all the cause of this potentially very dangerous incident (if the hole had been uncovered during the trip of the Soyuz to the ISS could have caused a depressurization more serious than the one caused once coupled with the ISS , which would have forced the return of the crew to Earth or something worse). When the MS-09 returns, the orbital module, along with its hole, will burn in the atmosphere disappearing forever.

# ВКД45а: космонавты Сергей Прокопьев и Олег Кононенко открыли выходной люк стыковочного отсека «Пирс» и приступили к работе на внешней поверхности МКС.

Расчётная продолжительность выхода в открытый космос составляет более 6 часов.

Трансляция → https://t.co/tL30gTow3Y pic.twitter.com/lSHoYYEat4

- РОСКОСМОС (@roscosmos) December 11, 2018

And another spectacular shot of spacewalker Oleg Kononenko working outside the Soyuz orbital module preparing to begin inspection work as the Earth passes below. #AskNASA | https://t.co/yuOTrYN8CV pic.twitter.com/N2RnfETpIV

- Intl. Space Station (@Space_Station) December 11, 2018

Spacewalker Oleg Kononenko begins cutting into the insulation on the Soyuz crew vehicle where a pressure leak was detected and fixed in August. #AskNASA | https://t.co/yuOTrYN8CV pic.twitter.com/I4JMjewB5h

- Intl. Space Station (@Space_Station) December 11, 2018

# ВКД45а: Космонавты Роскосмоса Сергей Прокопьев и Олег Кононенко завершили выход в открытый космос, проработав за пределами Международной космической станции 7 часов и 45 минут. pic.twitter.com/K3u9t19Kgm

- РОСКОСМОС (@roscosmos) December 11, 2018