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Space engineering at its best: The modules of the International Space Station

Boban Docevski


Today is an important day for space exploration. Humanity put another milestone on the road to sustainable life in space, or to be more exact, in zero-gravity conditions. Astronaut Scot Kelly, and Russian cosmonauts Mikhail Kornienko and Sergey Volkov returned to Earth from one of the longest missions in space . Kelly and Kornienko launched to the space station on March 27, 2015 and this is the end of their one-year mission in space (340 days to be exact). This was the longest continuous human mission in space so far. The goal of this mission was to understand how the human body reacts and adapts to the harsh environment of space. Data from the expedition will be used to reduce risks to the health of crew-members as NASA prepares to advance space travel beyond low Earth orbit.

Another important human effort is the (ongoing) construction of the home for the brave people that venture into space for the past 18 years. Humanity’s space temple.

Since 1998, the joint effort of many countries from all around the world is slowly making the futuristic idea of space dwelling into reality. The effort of all those nations is materialized into a marvelous and complex piece of engineering called the International Space Station.

The International Space Station (ISS) is a space station, or a habitable artificial satellite, in low Earth orbit. Its first component launched into orbit in 1998, and the ISS is now the largest artificial body in orbit and can often be seen with the naked eye from Earth.

According to the original Memorandum of Understanding between NASA and Rosaviakosmos, the International Space Station was intended to be a laboratory, observatory and factory in low Earth orbit. It was also planned to provide transportation, maintenance, and act as a staging base for possible future missions to the Moon, Mars and asteroids. In the 2010 United States National Space Policy, the ISS was given additional roles of serving commercial, diplomatic and educational purposes.


The ISS in 2010

The assembly of the International Space Station, represents a major endeavor in space architecture. It began in November 1998. Russian modules launched and docked robotically, with the exception of Rassvet. All other modules were delivered by the Space Shuttle, which required installation by ISS and shuttle crew-members using the Canadarm 2 and EVAs; as of 5 June 2011, they had added 159 components during more than 1,000 hours of EVA. 127 of these spacewalks originated from the station, and the remaining 32 were launched from the airlocks of docked Space Shuttles.

The beta angle of the station had to be considered at all times during construction, as the station’s beta angle is directly related to the percentage of its orbit that the station (as well as any docked or docking spacecraft) is exposed to the sun. the Space Shuttle would not perform optimally above a limit called the “beta cutoff”. Many of the modules that launched on the Space Shuttle were integrated and tested on the ground at the Space Station Processing Facility to find and correct issues prior to launch.

As a tribute to all the engineers and brave astronauts that worked (and for those who still work) on this marvelous project, here is a chronological list of assembly for all the bigger modules that were installed on the ISS. These highly complex pieces of engineering are the life-giving organs of the International Space Station. The experiments that the astronauts perform inside (and outside) them are constantly spreading our understanding of space, but also give us more perspective into the nature of our own Planet.


Zarya (20 November 1998)



Zarya (also known as the Functional Cargo Block) was the first module of the International Space Station to be launched. The FGB provided electrical power, storage, propulsion, and guidance to the ISS during the initial stage of assembly. With the launch and assembly in orbit of other modules with more specialized functionality, Zarya is now primarily used for storage, both inside the pressurized section and in the externally mounted fuel tanks. The name Zarya, means sunrise on Russian. It was given to the FGB because it signified the dawn of a new era of international cooperation in space. Although it was built by a Russian company, it is owned by the United States.

Unity (6 December 1998)



The Unity connecting module was the first U.S. component of the International Space Station. It is cylindrical in shape, with six docking locations (forward, aft, port, starboard, zenith, and nadir) facilitating connections to other modules. Essential space station resources such as fluids, environmental control and life support systems, electrical and data systems are routed through Unity to supply work and living areas of the station. Sometimes referred to as Node 1, Unity was the first of the three connecting modules.

Zvezda (26 July 2000)



was the third module launched to the station, and provides all of the station’s life support systems, as well as living quarters for two crew members. It is the structural and functional center of the Russian portion of the station – the Russian Orbital Segment.

Destiny (10 February 2001)



The Destiny module is the primary operating facility for U.S. research payloads aboard the International Space Station (ISS). Astronauts work inside the pressurized facility to conduct research in numerous scientific fields. Scientists throughout the world are using the results to enhance their studies in medicine, engineering, biotechnology, physics, materials science, and Earth science. Destiny has a 20-inch (510 mm) optically pure, telescope-quality glass window located in an open rack bay used primarily for Earth science observations. Station crewmembers use very high quality video and still cameras at the window to record Earth’s changing landscapes.

Quest (14 July 2001)



The Quest Joint Airlock, previously known as the Joint Airlock Module, is the primary airlock for the International Space Station. The Quest Airlock consists of two segments, the “Equipment lock” that stores spacesuits and equipment, and the “Crew Lock” from which astronauts can exit into space. Quest was necessary because American suits will not fit through a Russian airlock hatch and have different components, fittings, and connections. The airlock is designed to contain equipment that can work with both types of spacesuits.

Pirs (16 September 2001)



Pirs provides the ISS with one docking port for Soyuz and Progress spacecraft, and allows egress and ingress for spacewalks by cosmonauts using Russian Orlan space suits.

Harmony (23 October 2007)



Harmony (Node 2) is the “utility hub” of the International Space Station. The hub contains four racks that provide electrical power, plus electronic data, and act as a central connecting point for several other components via its six docking mechanisms. Harmony added 2,666 cubic feet (75.5 m3) to the station’s living volume, an increase of almost 20 percent.

Columbus (7 February 2008)



Columbus is a science laboratory that is part of the International Space Station (ISS) and is the largest single contribution to the ISS made by the European Space Agency (ESA). The laboratory can accommodate ten active International Standard Payload Racks (ISPRs) for science payloads. Agreements with NASA allocate to ESA 51% usage of the Columbus Laboratory. ESA is given five active rack locations, with the other five being allocated to NASA.

Kibo (2008)



The Japanese Experiment Module (JEM), also known with the nickname Kibo (Hope), is a Japanese science module for the International Space Station (ISS). It is the largest single ISS module. It is constructed out of three pieces. The Pressurized Module (PM) is the core component connected to the port hatch of the Node 2 Module. It is cylindrical in shape and contains twenty-three International Standard Payload Racks (ISPRs), ten of which are dedicated to science experiments while the remaining 13 are dedicated to Kibo’s systems and storage.  Kibo is also the location for many of the press conferences that take place on board the station.

Poisk (12 November 2009)



Also known as the Mini-Research Module 2 (MRM 2), is a docking module of the ISS. Poisk serves as a docking port for Soyuz and Progress spacecraft and as another airlock for spacewalks. Poisk also provides extra space for scientific experiments.

Cupola (8 February 2010)



A magnificent module that offers astronauts an unprecedented view of the Earth. The Cupola is an ESA-built observatory module of the International Space Station (ISS). Its seven windows are used to conduct experiments, docking and observations of Earth. The Cupola provides an observation and work area for the ISS crew giving visibility to support the control of the space station remote manipulator system and general external viewing of Earth, celestial objects and visiting vehicles. Its name derives from Italian word cupola, which means “dome”. Because of its shape and multi window configuration the Cupola has been compared to the cockpit window of the Millennium Falcon.

Tranquility (8 February 2010)



Tranquility, (also known as Node 3) provides six docking hatches with power, data and commanding, thermal and environmental control, and crew access for more attached habitable volumes or for crew transportation vehicles or stowage, or an appropriate combination of all of these. One of the berthing locations is used by Cupola, which houses a Robotic Work Station inside it to assist in the assembly/maintenance of the ISS, and offers a window for Earth observations.

Rassvet (14 May 2010)



Rassvet is primarily used for cargo storage and as a docking port for visiting spacecraft.

Leonardo (24 February 2011)



Leonardo is primarily used for storage of spares, supplies and waste on the ISS, which is currently stored in many different places within the space station. The Leonardo  was a Multi-Purpose Logistics Module (MPLM) before 2011, but was modified into its current configuration. It was formerly one of three modules used for bringing cargo to and from the ISS with the Space Shuttle.