Nothing lasts forever.
And early Monday morning, a Russian module of the International Space Station detached from the ISS and later burned up in the atmosphere, with "non-combustible structural elements" falling into the Pacific Ocean, according to a NASA blog post and a tweet from the Russian space agency, Roscosmos.
And a new Nauka module will soon replace it.
Russian ISS docking station was 20 years old
It was 6:55 AM when an uncrewed Progress MS-16 transport cargo vehicle undocked, in addition to the Pirs docking station, from the ISS. Both compartments were almost totally pulverized upon controlled re-entry into the atmosphere. The Progress 77 mission reached the station in February, transporting cargo and supplies to the Expedition 65 crew of the orbital station. But the Pirs section had been in continual operation for 20 years, after its initial launch on Sept. 14, 2001. Translated to "pier" in Russian, the Pirs module was decommissioned to clear space for the incoming Nauka module, also called the Multipurpose Laboratory Module (MLM), which was lifted into orbit last Wednesday.
Officials had planned to undock the Pirs on Friday, July 23, but this was pushed back three days once several problems arose with the Nauka mission, after it launched from the Baikonur Cosmodrome in Kazakhstan on July 21. Some of the issues involved a failure to complete its first orbit-raising burn, which was corrected via backup thrusters, in addition to a problem with the Nauka module's antenna. Scarily, there's something wrong with the docking target, which could seriously disrupt attempts to dock with the ISS on Thursday, July 29.
Last Saturday, it was finally confirmed that Nauka could make it to the ISS, and Roscosmos cosmonauts Oleg Novitskiy and Pyotr Dubrov started prepping for the big undocking. They closed the transfer hatches between the Russian segment of the ISS and Pirs, and confirmed pressure integrity of the station before detaching. Pirs measured 16 ft (4.9 m) long and 8.4 ft (2.6 m) wide, weighing 8,461 lbs (3,838 kg), read another NASA blog post. In the last 20 years, the Pirs docking station was also a functional science lab, in addition to a final airlock for spacewalk ventures.
Russia could still withdraw from ISS
Once the module and spacecraft were detached, they were moved to a safe distance, where controllers slowed both down via Progress' thrusters at roughly 10:00 AM EDT. After most of the craft burned up in the atmosphere, the remaining structure plunged into "a non-navigable area of the Pacific Ocean," Roscosmos said. Without Progress and Pirs, the Earth-facing port on the Russian segment stands ready to hook up with the incoming Nauka (which translates to "science"). Once it's connected, astronauts will have extra space for cargo, equipment, and science experiments. Notably, the incoming module will also deliver a new robotic arm capable of servicing the Russian region of the ISS.
This comes on the heels of a concerning development, when Roscosmos Director Dmitry Rogozin threatened to withdraw from the ISS during a Russian Parliament hearing, with a tentative pull-out date of 2025, if U.S. sanctions against Russia are not dropped. "If the sanctions against Progress and TsNIIMash remain and are not lifted in the near future, the issue of Russia's withdrawal from the ISS will be the responsibility of the American partners," warned Rogozin during the hearing, according to an NBC translation. "Either we work together, in which case the sanctions are lifted immediately, or we will not work together and we will deploy our own station." With Progress gone, and a new module on its way, it seems there's still time for relations to mend.