Busy Monday morning in Baikonur Cosmodrome - Progress with supplies for ISS launched on atop Soyuz-2.1a.
ISS does not exist without supplies provided by spacecrafts. This time, just before Christmas, Progress spacecraft was launched at 08:44 GMT from launch site 31/6. This mission would not be special, if not the fact of utilizing for the first time modernized Progress-MS. This version was supposed to be launched on 21 November 2015, but mission was postponed to 21 December 2015.
Progress unmanned spacecraft has its origins in Soyuz manned spacecraft. It was created by TsKBEM (now known as RKK Energia) to meet demands of cargo missions with supplies for 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 was designed as fully automatic spacecraft - docking is performed by spacecraft autonomously (there is backup option for remote docking performed by operators in control center). It is slightly heavier than Soyuz, mass for MS version 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 up to 2600 kg of supplies (or loading trash to empty module) by crew members from spacecraft to space station. Refueling module replaced descent module which was necessary in Soyuz. Number of fuel tanks in Progress is depending 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. After docking, ISS is pumping fuel from Progress with special connecting lines mounted in docking system; in case of transporting air it is released into ISS atmosphere. Fuel and oxidizer from Progress tanks are also utilized for reboosting ISS by Progress or for performing maneuvers of ISS with Progress thrusters. Service module is pressurized and its size was doubled, comparing to Soyuz. It is place where avionics and onboard computers are installed. Progress is usually launched with utilization of rocket utizlized during Soyuz missions - usually it is Soyuz-U or Soyuz-2.1a (like this time). After 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), moving 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.
New version of Progress marked as MS contains previous upgrades from M version. Spacecraft was equipped in additional device for deploying small satellites. Each compartment 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 micro meteoroids after installing additional protective panels. For control and telemetry Progress can utilize Luch satellites when ground stations are out of reach. RKK Energia decide 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 from camera utilized during docking. Navigation system for docking was replaced with modern Kurs-NA using less power and utilizing one antenna instead five. It could be seen on picture above - small antennas surrounding docking port are belonging to previous navigation system.
RKK Energia is planning to replace in future Progress with alternative spacecraft called Parom. It will be automatic spacecraft remaining in space, not launched with rocket. Payload will be launched in special container and left in space. Parom will reach and grab up to two containers and move with them to ISS, perform rendezvous and dock container into docking port of ISS. Parom will be able to perform autonomous flight for 180 days - operational life is predicted for 15 years. At the moment it is not known when Progress will be retired.