Old Russian Proton rocket engine explodes in orbit, creating more space junk	
According to tracking data from the Space Force, an old Russian Proton upper stage engine, originally launched in 2007, broke up on April 15, 2022, creating a small cloud of  new space junk in a highly elliptical orbit.
These Proton upper-stage ullage motors are known as SOZ motors, and there are currently 64 of them in Earth orbit, McDowell tweeted. The acronym is short for “Sistema Obespecheniya Zapuska,” which translates roughly as “Launch Assurance System,” he said.
“The SOZ motors don’t use up all their propellant when they fire. And they have an unfortunate tendency to go bang years or decades later, leaving a bunch of debris in highly elliptical orbit. At least 54 SOZ motors have now exploded,” McDowell tweeted. 
The SOZ motor that just blew up had been racing around Earth in a highly elliptical path, getting as close as 241 miles (388 kilometers) and as far away as 11,852 miles (19,074 km), McDowell said in another tweet, noting that “the debris will take quite a while to reenter.”
“So — this debris event was predictable and is well understood; still very unfortunate,” he wrote. [emphasis mine]
The highlighted words suggest a certain irresponsibility on the Russian’s part. If these upper stage engines are abandoned with fuel still on board, why doesn’t Russia use that fuel to fire the engines to de-orbit them safely, especially as the engines have a tendency to eventually blow up and cause space junk? There might be complex technical reasons, but I suspect the real reason is pure laziness on Roscosmos’ part. No one ever bothered to think about it.
 
According to tracking data from the Space Force, an old Russian Proton upper stage engine, originally launched in 2007, broke up on April 15, 2022, creating a small cloud of new space junk in a highly elliptical orbit.
These Proton upper-stage ullage motors are known as SOZ motors, and there are currently 64 of them in Earth orbit, McDowell tweeted. The acronym is short for “Sistema Obespecheniya Zapuska,” which translates roughly as “Launch Assurance System,” he said.
“The SOZ motors don’t use up all their propellant when they fire. And they have an unfortunate tendency to go bang years or decades later, leaving a bunch of debris in highly elliptical orbit. At least 54 SOZ motors have now exploded,” McDowell tweeted.
The SOZ motor that just blew up had been racing around Earth in a highly elliptical path, getting as close as 241 miles (388 kilometers) and as far away as 11,852 miles (19,074 km), McDowell said in another tweet, noting that “the debris will take quite a while to reenter.”
“So — this debris event was predictable and is well understood; still very unfortunate,” he wrote. [emphasis mine]
The highlighted words suggest a certain irresponsibility on the Russian’s part. If these upper stage engines are abandoned with fuel still on board, why doesn’t Russia use that fuel to fire the engines to de-orbit them safely, especially as the engines have a tendency to eventually blow up and cause space junk? There might be complex technical reasons, but I suspect the real reason is pure laziness on Roscosmos’ part. No one ever bothered to think about it.










