TKS

The TKS (Tкс, Транспортный корабль снабжения, transl. transport logistics ship) is a large spacecraft, which was designed for supplying russian military space stations of the Almaz program. It weighs around 20 metric tons and is 17.5 m long. It only flew 3 times in its original configuration. It was designed for launching with a crew of 3 cosmonauts and 4500 kg of cargo in its pressurized section.

Later its hull formed the skeleton of the russian space station modules Cosmos 1686 for Salyut 7, Kvant, Kvant 2, Kristall, Piroda for Mir and the FGB of the ISS. It was also used as the service module for the titanic Polyus satellite.

Dimensions

Launch weight	about 19,000 kg
Length	17.51 m
Diameter	4.15 m
Span across solar arrays	16 m
Number of main engines	2
Main engine thrust (each)	400 kg
Habitable volume	about 60 m³
Number of crew	3
Capsule diameter	305 cm
Capsule height	206 cm

Configuration

The TKS consists of two parts, the FGB and the Merkur capsule. The Merkur capsule is an apollo like reentry vessel with a base diameter of 3m and a long slender nose containing deorbit engines, RCS and parachutes. The Merkur is attached at the aft end of the FGB. Its was entered from the FGB by a hatch through the heatshield. The heatshield was not ablative, which made the spacecraft reuseable.

The FGB consists of a large diameter section on the front, which contains the control systems and a docking port. Directly above the docking ports are two windows which allowed the crew to control the docking or manually dock to a station. behind the large diameter section is the small diameter with only 2.9 m diameter, which contained most of the cargo.

It has two solar panels, and two main engines on the small diameter section. The TKS could remain docked to a station for months, providing it with attitude control, orbit reboosts, additional volume and power from its solar arrays. The small diameter section can be surrounded by up to 16 propellant tanks.

It got launched by a three stage Proton launcher

Flight history

December 15, 1976	Kosmos 881 and Kosmos 882	Test flight for two Merkur capsules, launched with a single Proton.
July 17, 1977	Kosmos 929	First test of the complete TKS spacecraft.
August 4, 1977	Launch failure	Launch failure during a Merkur test. Top Capsule got rescued by the SAS.
March 30, 1978	Kosmos 997 and Kosmos 998	Merkur dual launch test
May 22, 1979	Kosmos 1100 and Kosmos 1101	Merkur dual launch test
April 25, 1981	Kosmos 1267	Docked with Salyut 6 and deorbited it later.
March 2,1983	Kosmos 1443	Docked with Salyut 7. Merkur capsule solid at Sotheby's for %552,500.