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Assembly of the International Space Station

An artist's impression of the International Space Station's configuration as of November 2010.
International Space Station on 16 October 2002
Rear of the station
Technical blueprint of components

The process of assembling the International Space Station (ISS) has been under way since the 1990s. Zarya, the first ISS module, was launched by a Proton rocket on November 20, 1998. The STS-88 shuttle mission followed two weeks after Zarya was launched, bringing Unity, the first of three node modules, and connecting it to Zarya. This bare 2-module core of the ISS remained unmanned for the next one and a half years, until in July 2000 the Russian module Zvezda was launched by a Proton rocket, allowing a maximum crew of two astronauts or cosmonauts to be on the ISS permanently.

The ISS has a pressurized volume of approximately 1,000 cubic meters, a mass of approximately 420,000 kilograms, approximately 100 kilowatts of power output, a truss 108.4 meters long, modules 74 meters long, and a crew of six. Building the complete station required more than 40 assembly flights. As of March 2011, 26 Space Shuttle flights have docked with ISS to add elements, and 9 other Shuttle flights have flown logistics-servicing missions to ISS without adding major external elements. These 35 Shuttle missions include 9 SpaceHab and 10 MPLM logistics-servicing missions in various combinations. The last two Shuttle flights added one of the two final elements of ISS, followed by a Proton launch to deliver the European Robotic Arm in 2019. Other assembly flights consisted of modules lifted by the Russian Proton rocket or in the case of Pirs and Poisk by a Soyuz-U rocket.[needs update]

Some of the larger modules include:



International Space Station mockup at Johnson Space Center in Houston, Texas.

The space station is located in orbit around the Earth at an altitude of approximately 410 km (250 mi), a type of orbit usually termed low Earth orbit (the actual height varies over time by several kilometers due to atmospheric drag and reboosts). It orbits Earth in a period of about 90 minutes; by August 2007 it had completed more than 50,000 orbits since launch of Zarya on 20 November 1998.

A total of 14 main pressurized modules were scheduled to be part of the ISS by its completion date in 2010.[1] A number of smaller pressurized sections will be adjunct to them (Soyuz spacecraft (permanently 2 as lifeboats - 6 months rotations), Progress transporters (2 or more), the Quest and Pirs airlocks, as well as periodically the H-II Transfer Vehicle).

The ISS, when completed, will consist of a set of communicating pressurized modules connected to a truss, on which four large pairs of photovoltaic modules (solar panels) are attached. The pressurized modules and the truss are perpendicular: the truss spanning from starboard to port and the habitable zone extending on the aft-forward axis. Although during the construction the station attitude may vary, when all four photovoltaic modules are in their definitive position the aft-forward axis will be parallel to the velocity vector.[2]

In addition to the assembly and utilization flights, approximately 30 Progress spacecraft flights are required to provide logistics until 2010. Experimental equipment, fuel and consumables are and will be delivered by all vehicles visiting the ISS: the SpaceX Dragon, the Russian Progress, the European ATV and the Japanese HTV, and space station downmass will be carried back to Earth facilities on the Dragon.[3]

Columbia disaster and changes in construction plansEdit

Columbia lifting off on its final mission.

Disaster and consequencesEdit

10 March 2001 - The Leonardo Multi-Purpose Logistics Module rests in Discovery's payload bay during STS-102.

At one point, there was some uncertainty over the future of the ISS. The Space Shuttle Columbia disaster on 1 February 2003, the subsequent two and a half-year suspension of the U.S. Space Shuttle program, followed by problems with resuming flight operations in 2005, were major obstacles.

The Space Shuttle program resumed flight on 26 July 2005, with the STS-114 mission of Discovery. This mission to the ISS was intended both to test new safety measures implemented since the Columbia disaster, and to deliver supplies to the station. Although the mission succeeded safely, it was not without risk; foam was shed by the external tank, leading NASA to announce future missions would be grounded until this issue was resolved.

Between the Columbia disaster and the resumption of Shuttle launches, crew exchanges were carried out solely using the Russian Soyuz spacecraft. Starting with Expedition 7, two-astronaut caretaker crews were launched in contrast to the previously launched crews of three. Because the ISS had not been visited by a shuttle for an extended period, a larger than planned amount of waste accumulated, temporarily hindering station operations in 2004. However Progress transports and the STS-114 shuttle flight took care of this problem.

Changes in construction plansEdit

Construction of the International Space Station over New Zealand.

ISS construction experienced delays due to the halting of all NASA Shuttle flights following the Columbia disaster in early 2003, although there had been prior delays due to Shuttle problems, and the Russian space agency's budget constraints. During the shuttle stand-down, construction of the ISS was halted and the science conducted aboard was limited due to the crew size of two. Many changes were made to the originally planned ISS, even before the Columbia disaster. Modules and other structures were cancelled or replaced and the number of Shuttle flights to the ISS was reduced from previously planned numbers. However more than 80% of the hardware intended to be part of the ISS in the late 1990s was orbited and is now part of the ISS's configuration.

In March 2006, a meeting of the heads of the five participating space agencies accepted the new ISS construction schedule that planned to complete the ISS by 2010.[4] A crew of six has been established as of May 2009, following 12 Shuttle construction flights after the second "Return to Flight" mission STS-121. Requirements for stepping up the crew size included enhanced environmental support on the ISS, a second Soyuz permanently docked on the station to function as a second 'lifeboat', more frequent Progress flights to provide double the amount of consumables, more fuel for orbit raising maneuvers, and a sufficient supply line of experimental equipment.

Later additions included the Bigelow Expandable Activity Module (BEAM) in 2016, and numerous Russian components are planned as part of the in-orbit construction of OPSEK.

Assembly sequenceEdit

ISS elements
A 3d CAD model of the Space Station

The ISS is made up of 16 pressurized modules: four Russian modules (Pirs, Zvezda, Poisk and Rassvet), nine US modules (Zarya,[5], BEAM,[6] Leonardo, Harmony, Quest, Tranquility, Unity, Cupola, and Destiny), two Japanese modules (the JEM-ELM-PS and JEM-PM) and one European module (Columbus). One more Russian pressurized module (Nauka) is scheduled to be added to the station.

Although not permanently docked with the ISS, Multi-Purpose Logistics Modules (MPLMs) formed part of the ISS during some Shuttle missions. An MPLM was attached to Harmony (initially to Unity) and was used for resupply and logistics flights.

Spacecraft attached to the ISS also extend the pressurized volume. At least one Soyuz spacecraft is always docked as a 'lifeboat' and is replaced every six months by a new Soyuz as part of crew rotation.

The table below shows the sequence in which these components were or will be added to the ISS. The numbers provided are indications and represent launch weight and dimensions.

Element Assembly
Pressurized Volume
Isolated View Station View
Zarya (FGB)[7] 1A/R 1998-11-20 Proton-K 12.6 4.1 19,323    
Unity (Node 1),[8] PMA-1 & PMA-2 2A 1998-12-04 Space Shuttle Endeavour (STS-88) 5.49 4.57 11,612    
Zvezda (Service Module)[9] 1R 2000-07-12 Proton-K 13.1 4.15 19,051 75    
Z1 Truss & PMA-3 3A 2000-10-11 Space Shuttle Discovery (STS-92) 4.9 (Z1) 4.2 (Z1) 8,755 (Z1)    
P6 Truss & Solar Arrays 4A 2000-11-30 Space Shuttle Endeavour (STS-97) 73.2 4.9 15,824    
Destiny (US Laboratory)[10] 5A 2001-02-07 Space Shuttle Atlantis (STS-98) 8.53 4.27 14,515 106    
External Stowage Platform-1 5A.1 2001-03-08 Space Shuttle Discovery (STS-102)    
Canadarm2 (SSRMS) 6A 2001-04-19 Space Shuttle Endeavour (STS-100) 17.6 0.35 4,899    
Quest (Joint Airlock)[11] 7A 2001-07-12 Space Shuttle Atlantis (STS-104) 5.5 4 6,064 34    
Pirs (Docking Compartment & Airlock) 4R 2001-09-14 Soyuz-U
(Progress M-SO1)
4.91 2.55 3,580 13    
S0 Truss[12] 8A 2002-04-08 Space Shuttle Atlantis (STS-110) 13.4 4.6 13,970    
Mobile Base System UF2 2002-06-05 Space Shuttle Endeavour (STS-111) 5.7 2.9 1,450    
S1 Truss 9A 2002-10-07 Space Shuttle Atlantis (STS-112) 13.7 4.6 14,120    
P1 Truss 11A 2002-11-23 Space Shuttle Endeavour (STS-113) 13.7 4.6 14,000    
ESP-2 LF1 2005-07-26 Space Shuttle Discovery (STS-114) 3.65 4.9 2,676    
P3/P4 Truss & Solar Arrays[13] 12A 2006-09-09 Space Shuttle Atlantis (STS-115) 13.8 4.9 15,900    
P5 Truss[14] 12A.1 2006-12-09 Space Shuttle Discovery (STS-116) 3.4 4.6 1,818    
S3/S4 Truss & Solar Arrays 13A 2007-06-08 Space Shuttle Atlantis (STS-117) 13.8 4.9 15,900    
S5 Truss and ESP-3 13A.1 2007-08-08 Space Shuttle Endeavour (STS-118) 13.7 3.9 12,598    
Harmony (Node 2)
Relocation of P6 Truss
10A 2007-10-23 Space Shuttle Discovery (STS-120) 7.2 4.48 14,288 75.5    
Columbus (European Laboratory)[15] 1E 2008-02-07 Space Shuttle Atlantis (STS-122) 7 4.5 12,800    
Dextre (SPDM)
Japanese Logistics Module (ELM-PS)
1J/A 2008-03-11 Space Shuttle Endeavour (STS-123) 3.9 (ELM-PS) 4.4 (ELM-PS) 4,200 (ELM-PS)    
Japanese Pressurized Module (JEM-PM)
JEM Robotic Arm (JEM-RMS)[16][17]
1J 2008-05-31 Space Shuttle Discovery (STS-124) 11.2 (JEM-PM) 4.4 (JEM-PM) 15,900 (JEM-PM)    
S6 Truss & Solar Arrays 15A 2009-03-15 Space Shuttle Discovery (STS-119) 73.2 10.7 15,900    
Japanese Exposed Facility (JEM-EF) 2J/A 2009-07-15 Space Shuttle Endeavour (STS-127) 4,100    
Poisk (MRM-2)[18][19] 5R 2009-11-10 Soyuz-U
(Progress M-MIM2)
ExPRESS Logistics Carriers 1 & 2 ULF3 2009-11-16 Space Shuttle Atlantis (STS-129)    
Cupola &
Tranquility (Node 3)
20A 2010-02-08 Space Shuttle Endeavour (STS-130) 6.5 (Node 3)
1.5 (Cupola)
4.25 (Node 3)
2.95 (Cupola)
12,247 (Node 3)
1,800 (Cupola)
Rassvet (MRM-1)[20] ULF4 2010-05-14 Space Shuttle Atlantis (STS-132) 5,075    
Leonardo (PMM) and EXPRESS Logistics Carrier 4 ULF5 2011-02-24 Space Shuttle Discovery (STS-133) 6.6 4.57 9,896 (Leonardo) 31  


Alpha Magnetic Spectrometer, OBSS and EXPRESS Logistics Carrier 3 ULF6 2011-05-16 Space Shuttle Endeavour (STS-134) 6,731 (AMS-02)  


Bigelow Expandable Activity Module[21] 2016-04-08 Falcon 9

(SpaceX CRS-8)

4 3.2 1,360 16  
NanoRacks Airlock Module 2019-10-15[22][23] Falcon 9

(SpaceX CRS-19)[24]

Nauka (MLM)
European Robotic Arm[25]
3R 2020[26] Proton-M 20,300 (Nauka) 70  
Prichal 2022 (TBD)[27] Soyuz 2.1b

(Progress M-UM)

NEM-1 (SPM-1) 2022 (TBD)[27] Proton-M
Element Assembly
Pressurized Volume
Isolated View Station View

Cancelled modulesEdit

Diagram of planned ISS design circa 1999

Proposed modulesEdit

The following modules are proposed, but not yet confirmed in the ISS launch manifests.

  • American Node 4 - Also known as the Docking Hub System (DHS),[28] would allow the station to have more docking ports for visiting vehicles and would allow inflatable habitats and technology demonstrations to be tested as part of the station.[29]
  • Nautilus-X Centrifuge Demonstration - If produced, this centrifuge will be the first in-space demonstration of sufficient scale centrifuge for artificial partial-g effects. It will be designed to become a sleep module for the ISS crew.[30]


The ISS is credited as the most expensive item ever built, costing around $150 billion (USD),[31] making it more expensive than Skylab (costing 2.2 billion USD) [32] and Mir (4.2 billion USD).[33]

See alsoEdit


  1. ^ "Consolidated Launch Manifest". NASA. Archived from the original on 7 July 2006. Retrieved 15 July 2006.
  2. ^ "What are the ISS attitudes?" (Flash). NASA. Archived from the original on 2 September 2006. Retrieved 11 September 2006.
  3. ^ Black, Charles (24 December 2012). "When Dragon made commercial spaceflight a reality". SEN. Retrieved 26 December 2012. [Dragon's] ability to return goods is currently unique because all the other regular supply ships - Europe's Automated Transfer Vehicle (ATV), Japan's HTV (or "Kounotori") and Russia's Progress - all burn up during controlled re-entry.
  4. ^ Coppinger, Rob (3 March 2006). "NASA commits to Shuttle missions to International Space Station". FlightGlobal. Retrieved 16 September 2006.
  5. ^ . Retrieved 3 March 2019.
  6. ^ . Retrieved 27 November 2017.
  7. ^ Wade, Mark (15 July 2008). "ISS Zarya". Encyclopaedia Astronautica. Archived from the original on 27 February 2009. Retrieved 11 March 2009.
  8. ^ "Unity Connecting Module: Cornerstone for a Home in Orbit" (PDF). NASA. January 1999. Archived (PDF) from the original on 17 March 2009. Retrieved 11 March 2009.
  9. ^ "Zvezda Service Module". NASA. 11 March 2009. Archived from the original on 23 March 2009. Retrieved 11 March 2009.
  10. ^ "US Destiny Laboratory". NASA. 26 March 2007. Archived from the original on 9 July 2007. Retrieved 26 June 2007.
  11. ^ "Space Station Extravehicular Activity". NASA. 4 April 2004. Archived from the original on 3 April 2009. Retrieved 11 March 2009.
  12. ^ "Space Station Assembly: Integrated Truss Structure". NASA. Archived from the original on 7 December 2007. Retrieved 2 December 2007.
  13. ^ "P3 and P4 to expand station capabilities, providing a third and fourth solar array" (pdf). Boeing. July 2006. Retrieved 2 December 2007.
  14. ^ "STS-118 MISSION OVERVIEW: BUILD THE STATION…BUILD THE FUTURE" (PDF). NASA PAO. July 2007. Archived (PDF) from the original on 1 December 2007. Retrieved 2 December 2007.
  15. ^ "Columbus laboratory". ESA. 10 January 2009. Archived from the original on 30 March 2009. Retrieved 6 March 2009.
  16. ^ "About Kibo". JAXA. 25 September 2008. Archived from the original on 10 March 2009. Retrieved 6 March 2009.
  17. ^ "Kibo Japanese Experiment Module". NASA. 23 November 2007. Archived from the original on 23 October 2008. Retrieved 22 November 2008.
  18. ^ Zak, Anatoly. "Docking Compartment-1 and 2". Archived from the original on 10 February 2009. Retrieved 26 March 2009.
  19. ^ Bergin, Chris (9 November 2009). "Russian module launches via Soyuz for Thursday ISS docking". Archived from the original on 13 November 2009. Retrieved 10 November 2009.
  20. ^ "NASA Extends Contract With Russia's Federal Space Agency" (Press release). NASA. 9 April 2007. Archived from the original on 23 June 2007. Retrieved 15 June 2007.
  21. ^ "NASA to Test Bigelow Expandable Module on Space Station". NASA. 16 January 2013. Retrieved 16 January 2013.
  22. ^ Frommert, Hartmut (8 December 2018). "International Space Station Flight Schedule". Retrieved 10 December 2018.
  23. ^ Pietrobon, Steven (19 January 2019). "United States Commercial ELV Launch Manifest". Retrieved 19 January 2019.
  24. ^
  25. ^ "FGB-based Multipurpose Lab Module (MLM)". Khrunichev State Research and Production Space Centre. Archived from the original on 27 September 2007. Retrieved 31 October 2008.
  26. ^ Pietrobon, Steven (8 February 2019). "Russian Launch Manifest". Retrieved 8 February 2019.
  27. ^ a b "Рогозин — РБК: "Формула "космос вне политики" не работает"" [Rogozin to RBC: The "cosmos out of politics" formula does not work]. (in Russian). 10 January 2019. Retrieved 12 January 2019.
  28. ^ ISS Managers review long-term configuration of International Space Station |
  29. ^ Test article could facilitate space station applications - 31 August 2010
  30. ^ Nautilus-X-Holderman_1-26-11
  31. ^ "Is The International Space Station The Most Expensive Single Item Ever Built?". Science 2.0. 27 August 2014. Retrieved 3 May 2018.
  32. ^ "The Space Review: Costs of US piloted programs". Retrieved 3 May 2018.
  33. ^ Tyler, Patrick E. (24 March 2001). "Russians Find Pride, and Regret, in Mir's Splashdown". The New York Times. ISSN 0362-4331. Retrieved 3 May 2018.

External linksEdit

Media articles