SpaceX's Crew Dragon Demo-2 mission marked the first time a commercial company launched astronauts to the ISS. NASA astronauts Doug Hurley and Bob Behnken were launched from American soil for the first time since the end of the Space Shuttle program. This mission was a significant milestone in the commercialization of space travel.

NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko embarked on a one-year mission aboard the ISS. This mission aimed to study the effects of long-duration spaceflight on the human body, providing critical data for future missions to Mars and beyond. The mission concluded successfully on March 2, 2016.

The first 3D printer was installed on the ISS as part of the 3D Printing in Zero-G Experiment. This milestone allowed astronauts to produce tools and parts on-demand, reducing the need for resupply missions. The experiment demonstrated the potential for additive manufacturing in space, paving the way for future deep-space missions.

STS-135 was the final mission of NASA's Space Shuttle program, marking the end of an era in space exploration. The shuttle Atlantis delivered supplies and parts to the ISS. This mission underscored the transition to a new phase of space exploration, with increased reliance on international partnerships and commercial spaceflight providers.

The Rassvet module, also known as Mini-Research Module 1, was launched aboard Space Shuttle Atlantis on mission STS-132. It provided additional storage space and a docking port for Russian spacecraft. Rassvet's integration into the ISS was part of ongoing efforts to expand the station's capabilities and support a larger crew.

The European Space Agency's Columbus Laboratory was launched aboard Space Shuttle Atlantis on mission STS-122. As Europe's primary contribution to the ISS, Columbus provided a state-of-the-art laboratory for conducting a wide range of scientific experiments in microgravity. Its addition marked a significant milestone in international collaboration on the ISS.

The Destiny Laboratory Module, launched aboard Space Shuttle Atlantis on mission STS-98, was the first science laboratory added to the ISS. It significantly expanded the station's research capabilities, allowing scientists to conduct experiments in microgravity across various disciplines, including biology, physics, and materials science.

Expedition 1 marked the beginning of a continuous human presence on the ISS. The crew, consisting of American astronaut Bill Shepherd and Russian cosmonauts Sergei Krikalev and Yuri Gidzenko, arrived aboard a Soyuz spacecraft. Their mission lasted 136 days, during which they activated critical systems and conducted scientific research, setting the stage for future expeditions.

The Unity module, also known as Node 1, was the first U.S.-built component of the ISS. It was launched aboard the Space Shuttle Endeavour on mission STS-88. Unity served as a connecting node for future modules and was critical for the expansion of the ISS. Its successful docking with Zarya marked a significant milestone in international cooperation in space.

The Zarya module, also known as the Functional Cargo Block, was the first module of the International Space Station (ISS) to be launched. It was launched by a Russian Proton rocket from the Baikonur Cosmodrome. Zarya provided initial power and propulsion for the ISS and marked the beginning of the station's assembly in orbit.