Space station

                         A space station is a crewed satellite designed to remain in low Earth orbit for a long period of time. In general, space stations have the ability for other spacecraft to dock to them. As of 2019, the International Space Station is the only operational crewed space station currently in orbit. Other experimental and prototype labs are also in orbit. Previous stations include the Salyut and Almaz series, Skylab, Mir and the Tiangong series.

Space stations are used to study the effects of long-term space flight on the human body. They also serve as a platform for extended scientific studies.All space stations have been designed with the intention of rotating multiple crews, with each crew member staying aboard the station for weeks or months, but rarely more than a year. As of today, Vladimir Titov, Musa Manarov, Sergei Avdeyev and Valeriy Polyakov have completed single missions of over a year, all aboard Mir.

Space stations have been used for both military and civilian purposes. The first military-use space station was Salyut 2, which was launched by the Soviet Almaz program in 1973.The Soviet Union also claimed the first civilian space station with the launch of Salyut 1. As of 2019, Russia, China, India , and private companies are building space stations.

List of space station :-

Name	Entity	Program	Crew size	Launched	Reentered	Days in orbit	Days occu- pied	Total crew and visitors	Number of crewed visits	Number of robotic visits	Mass (* = at launch)	Pressurized volume
Salyut 1	USSR	DOS	3	19 April 1971	11 October 1971	175	24	6	2	0	18,425 kg (40,620 lb)	100 m3 (3,500 cu ft)
DOS-2	USSR	DOS	—	29 July 1972	29 July 1972	failed to reach orbit	—	—	—	—	18,000 kg (40,000 lb)	—
Salyut 2	USSR	Almaz	—	3 April 1973	16 April 1973	13	—	—	—	—	18,500 kg (40,800 lb)	—
Kosmos 557	USSR	DOS	—	11 May 1973	22 May 1973	11	—	—	—	—	19,400 kg (42,800 lb)	—
Skylab	NASA	Skylab	3	14 May 1973	11 July 1979	2249	171	9	3	0	77,088 kg (169,950 lb)	360 m3 (12,700 cu ft)
Salyut 3	USSR	Almaz	2	25 May 1974	24 January 1975	213	15	2	1	0	18,900 kg (41,700 lb)	90 m3 (3,200 cu ft)
Salyut 4	USSR	DOS	2	26 December 1974	3 February 1977	770	92	4	2	1	18,900 kg (41,700 lb)	90 m3 (3,200 cu ft)
Salyut 5	USSR	Almaz	2	22 June 1976	8 August 1977	412	67	4	3	0	19,000 kg (42,000 lb)	100 m3 (3,500 cu ft)
Salyut 6	USSR	DOS	2	29 September 1977	29 July 1982	1764	683	33	16	14	19,000 kg (42,000 lb)	90 m3 (3,200 cu ft)
Salyut 7	USSR		3	19 April 1982	7 February 1991	3216	861	22	10	15	19,000 kg (42,000 lb)	90 m3 (3,200 cu ft)
Mir	USSR  RFSA		3	19 February 1986	23 March 2001	5511	4594	125	39	68	129,700 kg (285,900 lb)	350 m3 (12,400 cu ft)
Tiangong-1	CNSA	Tiangong program	3	29 September 2011	2 April 2018	2377	25	6	2	1	8,506 kg (18,753 lb)	15 m3 (530 cu ft)
Tiangong-2	CNSA		2	15 September 2016	19 July 2019	1037	26	2	1	1	8,506 kg (18,753 lb)	15 m3 (530 cu ft)

Soyuz
The Soyuz spacecraft was initially designed to carry two cosmonauts at a
time, but was later expanded to accommodate three passengers. It consists
of an Orbital Module, a Descent Module and an Instrumentation/Propulsion
Module.




 The apollo-Soyuz Mission
By the mid-70s, things had changed. The US had won the race to the Moon,
with six Apollo landings between 1969 and 1972. Both nations had launched
space stations, the Russian Salyut and American Skylab. With the Space
Shuttle still a few years off and the diplomatic chill thawing, the time was
right for a joint mission.
The Apollo-Soyuz Test Project would send NASA astronauts Tom Stafford,
Deke Slayton and Vance Brand in an Apollo Command and Service
Module to meet Russian cosmonauts Aleksey Leonov and Valeriy Kubasov
in a Soyuz capsule. A jointly designed, US-built docking module fulfilled the
main technical goal of the mission, demonstrating that two dissimilar craft
could dock in orbit. But the human side of the mission went far beyond that.
On July 17, 1975, the five explorers and the two craft – launched two days
before – approached each other for docking. As Stafford guided the Apollo
forward, Soyuz commander Leonov quipped, “Tom, please don’t forget about
your engine.” With a live TV audience watching, the two craft finally met:
“Soyuz and Apollo are shaking hands now.”

 The Apollo Soyuz Test Project Crew Deke Slayton, Thomas Stafford, Vance Brand, Alexei
Leonov, Waleri Kubassov.

 A few hours later it was the crew members who were literally shaking
hands, exchanging hugs and ceremonial gifts, including US, Soviet and United
Nations flags, commemorative plaques, medallions, certificates and tree seeds.
The crews received a congratulatory message from Soviet premier Leonid
Brezhnev and a phone call from US President Gerald Ford.
Apollo Commander Stafford had another unique cultural exchange for
the cosmonauts. He’d gotten country music star Conway Twitty to record
‘Privet Radost’, a Russian version of his hit ‘Hello, Darlin’. About an hour
before the two craft undocked, the song was played from orbit and heard
all over the world.
The Apollo crew returned to Earth on July 19, and their Russian counterparts
two days later. It would be two decades until the countries teamed up
again with the Shuttle-Mir program, but the seed was planted. As Brand said,
“I really believe that we were sort of an example … to the countries. We were
a little of a spark or a foot in the door that started better communications.”
  
Salyut

Chelomei and his staff developed a military station for two to three cosmonauts,
with a design life of 1 to 2 years. They designed an integrated system:
a single-launch space station dubbed Almaz (“diamond”) and a Transport
Logistics Spacecraft for reaching it. Chelomei’s three-stage Proton booster
would launch them both.
Almaz was to be equipped with a crew capsule, radar remote-sensing
apparatus for imaging the Earth’s surface, cameras, two re-entry capsules
for returning data to Earth, and an anti-aircraft cannon to defend against
American attack. It would be the world’s first military space station.

 

 model of the Salyut space station

 Skylab
While the Soviets were the first to launch the space station with the Salyut programme,
reclaiming their pride in the field of space, the Americans weren’t far
behind. On May 14, 1973, NASA launched a Saturn V rocket carrying its first
space station, Skylab. This too would be a monolithic station, constructed in its
entirety on the ground before being launched into space. Crew would use the
Apollo spacecraft to board it.

 Skylab