What is the largest artificial structure in space?

The largest artificial structure in space is currently the International Space Station (ISS). The ISS is a joint project of NASA, Roscosmos, the European Space Agency (ESA), the Canadian Space Agency (CSA), and the Japanese Aerospace Exploration Agency (JAXA). It is a modular space station that has been continuously inhabited since November 2000 and orbits the Earth at an altitude of approximately 408 kilometers (253 miles).

The ISS has a mass of approximately 420,000 kilograms (925,000 pounds) and measures 73 meters (239 feet) in length and 109 meters (357 feet) in width, including its solar arrays. It is also the most expensive object ever built, with an estimated cost of over $150 billion.

The ISS is used for a wide range of scientific research, including studies on the effects of microgravity on the human body, investigations into the behavior of fluids in space, and experiments in materials science, biology, and physics.