After nearly 20 years of service as a docking port and airlock, the Russian Pirs module left the International Space Station on Monday under tow of a Progress supply ship, heading for a destructive re-entry into Earth’s atmosphere to open the way for the arrival of a larger science lab later this week.
The Russian Progress freighter MS-16 detached from the space station at 6:55 a.m. EDT (10:55 GMT) Monday as the outpost soared 260 miles (418 kilometers) above northern China.
Instead of leaving the station alone, the Progress spacecraft moved away from the complex with Russia’s Pirs docking compartment, freeing up a port on the Zvezda service module which has been occupied since 2001.
The Pirs module was launched to the space station on September 14, 2001, aboard a Soyuz rocket from the Baikonur Cosmodrome in Kazakhstan. A modified Progress cargo vessel delivered the Pirs module to the station, resulting in docking with the port facing Earth on the Zvezda service module two days after launch.
Since then, the Pirs module has supported dozens of Russian spacewalks and served as a docking port for Russian Soyuz and Progress ferries carrying crew and cargo to the space station. The Russian Poisk module, launched in 2009 and similar in design to Pirs, remains in the space station on the opposite side of the Zvezda module to serve as an airlock for future Russian spacewalks.
The Russian Pirs module detached from the International Space Station at 6:55 a.m. EDT (10:55 GMT) over China, freeing a docking port on the Zvezda service module for the first time since 2001.
The new Russian science laboratory Nauka is expected to dock there on Thursday.https: //t.co/lYliaJtblF pic.twitter.com/w0Ka92aw9H
– Vol spatial maintenant (@SpaceflightNow) July 26, 2021
The Progress MS-16 freighter became the last inspection vehicle to dock with Pirs in February. On June 2, cosmonauts Oleg Novitskiy and Pyotr Dubrovnik ventured outside the space station to prepare the Pirs module for disposal. Their tasks included repositioning an expandable cable attached to the Pirs and disconnecting the rendezvous antenna cables from the module.
The Pirs is approximately 4.9 meters long and 2.55 meters in diameter at its widest point, according to NASA.
Once these preparations were completed, Russian officials awaited the launch of the module that will replace the Pirs at the docking port facing Zvezda Land.
The Nauka Science Lab, a long-delayed extension of the Russian segment of the space station, was launched last Wednesday from Baikonur aboard a Proton rocket. After working on post-launch issues with the new spacecraft’s propulsion system and the Kurs automated rendezvous radar, Russian mission controllers finally completed the first orbital maneuvers with Nauka’s main engines over the week. -end and verified that the Kurs system was functional for docking the science lab with space. station.
As ground crews worked on these issues, Russian officials delayed the departure of the Pirs module from Friday to Monday to get a clearer picture of the state of the new Nauka spacecraft.
Satisfied that the Nauka module is on track to arrive at the space station on Thursday, mission control in Moscow has given the green light to depressurize the docking system connecting Pirs to Zvezda in preparation for departure on Monday.
After undocking, the Progress MS-16 spacecraft fired thrusters to transport the Pirs module to a safe distance from the space station. This paved the way for an almost 18-minute deorbitation at 10:01 a.m. EDT (1401 GMT) on Monday to guide the Progress spacecraft, laden with space station trash, and the Pirs module into Earth’s atmosphere for a reentry. less than an hour later.
Russian space agency Roscosmos said any debris that survives the scorching re-entry is expected to fall in a remote part of the South Pacific Ocean around 10:51 a.m. EDT (1451 GMT).
With Pirs out of the way, ground crews planned to inspect the Earth-facing docking port on the Zvezda module later Monday using cameras on the space station’s Canadian-built robotic arm. The seven hour video inspection will ensure that there is no debris or obstructions on the mooring mechanism, which was last used for mooring when Pirs connected to the station in 2001.
If the teams run into any issues, cosmonauts Oleg Novitskiy and Pyotr Dubrovnik could exit the space station for a spacewalk later this week to clean up the docking system.
The Nauka module is scheduled to dock with the space station on Thursday at 9:24 a.m. EDT (1324 GMT).
After docking the Nauka module, Russian cosmonauts are planning a series of up to 11 spacewalks later this year and early next year to equip the new outdoor lab item.
The Progress freighter carrying the Pirs module away from the International Space Station has completed a fire to leave the vicinity of the complex.
This sets the stage for a desorbit burn at 10:01 a.m. EDT (1401 GMT), soon followed by a destructive re-entry. pic.twitter.com/FUNwjggMRT
– Vol spatial maintenant (@SpaceflightNow) July 26, 2021
Once fully operational, Nauka will be able to accommodate moorings for Progress Supply Ships, Soyuz Crew Capsules and Russia’s new Prichal node module later this year.
Inside Nauka, Russian cosmonauts will set up and activate science experiments, prepare a new oxygen generation system for operation, install new toilets, and prepare a new sleeping compartment for an additional Russian crew member on the space station.
The Nauka Module, also known as the Multipurpose Laboratory Module, carries the European robotic arm, which was completed 15 years ago to wait for the opportunity to fly to the space station.
Weighing 20.2 metric tons (44,500 pounds), the Nauka module is more than five times the mass of the Pirs docking compartment. Nauka stretches approximately 43 feet (13 meters) long, which will make it one of the largest modules on the International Space Station.
The bus-sized Nauka research module has been in development for over 20 years, originally as a backup of the Russian Zarya module, the first space station component to be launched in 1998. Russia has stated in 2004 that Zarya’s save would be converted into a lab module for launch in 2007.
But the delays kept the Russian lab on the ground for years. Engineers from Energia, the prime contractor for Russia’s manned space flight program, discovered flaws in the module’s propulsion system in 2013. The module was returned to Khrunichev, its manufacturer, for lengthy repairs. which delayed the launch of Nauka by several years.
Nauka is the first pressurized module to be added to the space station since the arrival of the small expandable Bigelow activity module in 2016. The last Russian pressurized element of any size launched to the space station was the Rassvet docking module, which was delivered by a NASA Space Shuttle in 2010.
Send an email to the author.
Follow Stephen Clark on Twitter: @StephenClark1.