Today under supervision of Mission Control Center in Korolev near Moscow, robotic cargo spacecraft Progress-MS performed successful undocking from International Space Station.

Undocking was performed at 03:48 GMT from Pirs module nadir berthing port. It was end of mission of Progress MS-01, which docked to International Space Station on December 23, 2015, after two days of space journey. It begun after launch from Baikonur Cosmodrome. With weight of 7284 kg, Progress delivered to ISS 718 kg of fuel, 22 kg of compressed air, 420 kg of water, 1252 kg of pressurized cargo including tools, spare parts for Poisk module, food and hygiene articles. During previous days before undocking Progress was loaded with trash and unused equipment. Progress started its autonomous flight just after undocking. After few hours Progress performed engine burn to reduce speed and start reentry maneuver at 07:00 GMT. After burning in dense layers of atmosphere it will fall into South Pacific.

Progress was created by TsKBEM design office which is commonly known as RCC Energia as robotic spacecraft for cargo missions to Salyut and Mir space station. Maiden flight with cargo for Salyut-6 took place on 20 January 1978 with Soyuz-U as launch vehicle. Progress is designed as fully automatic spacecraft – docking is performed autonomously (there is backup option for remote docking performed by operators in control center). It is slightly heavier than Soyuz spacecraft; mass for MS version of Progress is around 7250 kg. Progress is built with three modules: cargo module, refueling module, and instrument-service module. Cargo module is pressurized to allow transferring supplies (or loading trash to empty module) by crew members of space station from spacecraft to space station. Number of fuel tanks in Progress depends on version. In M version module contains two tanks for propellant, two for oxidizer and two for water, M1 version is equipped in eight tanks for propellant with no water tanks installed. After docking, fuel is pumped from Progress with special connecting lines mounted in docking system; in case of transporting air it is released directly into ISS atmosphere. Fuel and oxidizer from Progress tanks are also utilized to perform maneuvers of ISS with Progress thrusters. Service module is pressurized and its capacity is twice as big as in Soyuz. It is place where avionics and onboard computers are installed. After launch and reaching correct orbit, Progress is automatically performing lasting two days rendezvous with ISS. During flight, spacecraft is powered by two deployable solar arrays mounted to service module (Progress is able to operate for 30 days and remain in space for up to 6 months), active flight is possible thanks to KTDU-80 (S5.80) engine (fueled with UDMH and N2O4  and generating 2.95 kN of thrust) and 28 control (130N) thrusters.

Progress-MS is modernized M version. Additional deployment device was added to allow deploying small satellites during flight. Each container can hold up to four small satellites and release them in space. Docking became safer due the installing backup electrical system responsible for docking and sealing. Cargo module has improved resistance for damages caused by asteroids due the additional protective panels installed. For control and telemetry Progress can utilize Luch satellites when ground stations are out of reach. RCC Energia decided also to add receiver of global navigation satellite system (GNSS) for real-time determination of spacecraft’s speed and orbit parameters with no necessity of contact with ground stations. New onboard radio (Unified Command Telemetry System – UCTS) improves quality of video transmitted   during docking. Navigation system for docking was replaced with modern Kurs-NA using less power and utilizes one antenna instead five. It could be seen on picture above – small antennas surrounding docking port are belonging to previous navigation system.