In the previous article, we covered how the various components of ISS were made and transported. Today we will see how it was assembled.

The process of assembling the International Space Station (ISS) has been underway since the 1990s. Zarya, the first ISS module, was launched by a Proton rocket on 20 November 1998. The STS-88 Space 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 uncrewed 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 2020, 36 Space Shuttle flights delivered ISS elements. Other assembly flights consisted of modules lifted by the Falcon 9, Russian Proton rocket, or, in the case of Pirs and Poisk, the Soyuz-U rocket.

Some of the larger modules include:
- Zarya (launched 20 November 1998)
- Unity Module (launched 4 December 1998, also known as Node 1)
- Zvezda (launched 12 July 2000)
- Destiny Laboratory Module (launched 7 February 2001)
- Harmony Module (launched 23 October 2007, also known as Node 2)
- Columbus orbital facility (launched 7 February 2008)
- Japanese Experiment Module, also known as Kibo (launched in multiple flights between 2008–2009)
- The truss and solar panels are also a large part of the station. (launched in multiple flights between 2000–2009)
After the Space Shuttle Columbia disaster on 1 February 2003, there was some uncertainty over the future of the ISS. 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.
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.
So with that, we complete the series on ISS. We are currently having an in-depth series on ISS going on Instagram with more than 30 posts covered with lots of information. Do check it out.
Good explanation