Progress MS-21 Leak Due to External Impact

Russia’s space agency Roscosmos said today that whatever caused the leak on the Progress MS-21 cargo spacecraft was an external impact.  A little over a week ago Progress MS-21 sprang a leak and lost its coolant to space, an event reminiscent of a coolant leak on the Soyuz MS-22 spacecraft two months earlier.  Investigations continue as to what happened, but Roscosmos is convinced the next spacecraft, Soyuz MS-23, will not suffer the same fate. Its launch is on track for Thursday EST.

Cameras on the International Space Station took images as Progress MS-21, or Progress 82 in NASA parlance, undocked on Friday to get a better look at the damaged part of the spacecraft. Based on initial analysis, Roscosmos said in a post on Telegram today that the preliminary conclusion is the leak was caused by an external impact.

Damage to the ship “Progress MC-21” caused by an external impact – preliminary conclusions

The analysis of unusual situations with the Soyuz MC-22 and Progress MC-21 spacecraft continues on the ISS. After the departure of the “Progress” from the ISS, detailed photo- and video shooting of the ship was carried out.

According to preliminary data of РКК “Energia”, “Progress MC-21”, as well as earlier “Soyuz MC-22”, were subjected to external impact. These conclusions are based on pictures that show changes on the outer surface of the ship, including the radiator of the instrument-aggregate compartment and solar battery panels.

In addition, in order to exclude the version of the defect during production, РКК “Energia” analyzed the history of comments to the system of thermoregulation for the last 15 years.

The analysis of the received information is ongoing, and a number of ground experiments are planned for the simulation of damage. [Per Google Translate. The letter “C” in cyrillic is “S” in English and Google does not always make that transliteration. Progress MC-21 is Progress MS-21 for example.]

The post included photos of the damaged area and video of the coolant leaking out of Progress MS-21, looking like snowflakes.

And here is the video of the leak. pic.twitter.com/zyW9sQAWbu

— Katya Pavlushchenko (@katlinegrey) February 21, 2023

It looked very much like the coolant leak from the Soyuz MS-22 crew spacecraft in December.

Roscosmos and NASA concluded the most likely cause that time also was an external impact, in that case from a micrometeoroid hitting the spacecraft’s radiator and penetrating through to the coolant loop.

The ISS and low Earth orbit in general is full of Micrometeoroid and Orbital Debris — MMOD.

Micrometeroids are tiny pieces of meteors that remain in orbit after the meteor enters the atmosphere. Orbital debris, as the term implies, is essentially trash from sending satellites into space over the past six and a half decades.

Concerns are growing about the increasing amount of MMOD in low Earth orbit. The possibility that two spacecraft attached to the ISS were seriously damaged in just two months is worrisome. Progress and Soyuz have very similar designs. Progress is for cargo, Soyuz is for crews.

NASA’s Dana Weigle, however, said this evening it’s not clear the Russians are implying Progress MS-21 necessarily was hit by MMOD. Weigle is Deputy Manager of the ISS program.

During a media teleconference about the upcoming launch of Crew-6, she said NASA and Roscosmos are still studying the imagery and she doesn’t think any conclusion has been drawn about what caused the external impact.

“I actually don’t interpret that as micrometeoroid damage. I think what they’re trying to understand is are there any signs or signatures that somewhere along the spacecraft’s journey, whether it’s launch or launch vehicle separation, there’s some other external influence or damage that could have occurred. … I don’t actually think they meant that statement to mean that there was a micrometeroid, we certainly did not see that type of indication, but that’s still part of the forward work that we’ve got to do in helping review the imagery.”

The ISS and the crew and cargo vehicles that come and go from it are all in the path of MMOD. That includes SpaceX’s Crew Dragon spacecraft.

Crew Dragon Endurance is docked there now. It delivered Crew-5 and will bring them home after Crew-6 arrives. That launch has been delayed from February 26 to February 27 for unrelated reasons.

SpaceX Vice President of Build and Flight Reliability Bill Gerstenmaier said they’ve inspected Endurance and “it all checked out fine.” He also pointed out that unlike Soyuz and Progress, Crew Dragon has two coolant loops and redundant pumps. Also, Crew Dragon spacecraft are reused and detailed inspections are performed after they return to Earth giving more insight to any MMOD they might have encountered.

Progress MS-21 is a cargo spacecraft and not designed to survive reentry through the atmosphere. It reentered and burned up over the Pacific on Saturday.

Soyuz MS-22 is still docked to the ISS, but is not considered safe to bring its three crew members back to Earth because the thermal system is compromised. Roscosmos is getting ready to launch Soyuz MS-23 as a replacement. After re-checking its radiator to make sure there is no design or manfacturing defect common to all the spacecraft, on Saturday Roscosmos gave the go-ahead for launch on Thursday, February 23 EST (Friday, February 24, Moscow Time).

NASA confirmed the launch this evening. NASA TV coverage of the 7:24 pm EST launch begins at 7:00 pm. Docking is scheduled for Saturday at 8:01 pm EST.