Progress M-SO1 was a modified Progress spacecraft used to deliver the Pirs module to the International Space Station. It was based on the Progress-M 11F615A55 spacecraft, with the pressurised cargo module removed to accommodate Pirs, and had the serial number 301.

Progress M-SO1 was launched by a Soyuz-U carrier rocket from Site 1/5 at the Baikonur Cosmodrome. Launch occurred at 23:34:55 GMT on 14 September 2001. The spacecraft docked with the Nadir port of the Zvezda module at 01:05 GMT on 17 September. It remained docked for nine and a half days before it was jettisonned from Pirs at 15:36 GMT on 26 September. It was deorbited at 23:30 GMT on the same day, and burned up in the atmosphere over the Pacific Ocean, with any remaining debris landing in the ocean at around 00:01 GMT on 27 September.

See also

• List of Progress flights
• List of unmanned spaceflights to the ISS
• Progress M-MIM2

References