Salyut 1 was the world’s first space station—a predecessor to the likes of today’s International Space Station (ISS). It was built by the USSR, which launched it into low Earth orbit on 19 April 1971. As part of the Salyut program (it means “salute” in Russian), the Soviets built steadily improved versions of the space station, culminating in Salyut 7 in 1982.

Space stations enable us to experience and take advantage of spaceflight over long periods of time. Their unique environment allows us to conduct experiments that aren’t possible on Earth—directly observing the universe and our planet with multiple sensor types, and using the unending, near-perfect vacuum and microgravity environment for research and manufacture. They are also a testbed for spaceship hardware, to gain proven experience and confidence close to home before we head further into the solar system.

Salyut 1 grew out of the Soviet Union’s top-secret military Almaz space station program. Its structure was heavily based on the Almaz, as were later Russian civilian space stations.

The space race between the USSR and the United States in the 1960s and 1970s accelerated the development of the Salyut space station. After NASA achieved the first moon landing with Apollo 11, the Soviet Union was determined to outdo the American agency’s equivalent space station program, Skylab. That space station ultimately launched a few years later, in 1973, using the heavy-lift capabilities of the Saturn V rocket.

Cylindrically shaped and weighing 40,620 pounds, Salyut 1 was made up of four compartments.

1. The docking module (pressurized). This compartment contained the docking port that allowed Soyuz spacecraft to supply the space station.

2. The main module (pressurized). About 13 feet in diameter, this was the primary living quarters for Russian cosmonauts aboard the Salyut 1.

3. The auxiliary module (pressurized). It carried the life support system, the power supply, control panel, communications for speaking to ground control, and other equipment. The outside held solar panels.

4. The engine and control system (unpressurized).

Salyut 1’s stay in space was brief but impactful. Below are four significant milestones in its six-month lifetime.

1. 19 April 1971. The Salyut station lifts off from the Baikonur Cosmodrome launch site in southern Kazakhstan, using the Proton-K rocket as a carrier.

2. 22 April 1971. What is meant to be space station’s first crew launches aboard the Soyuz 10. However, they are unable to dock and join the space station, and so they return to Earth.

3. 6 June 1971. A replacement crew launches on Soyuz 11. They manage to dock with Salyut and stay on board for more than 23 days. However, the entire Soyuz 11 crew die during an accident on re-entry, necessitating a redesign of the Soyuz spacecraft and a halt to further missions.

4. 11 October 1971. Salyut re-enters the Earth’s atmosphere and crashes into the Pacific Ocean, having been intentionally de-orbited. Without missions to enable refueling, it had run out of fuel.

Salyut 1 marked significant progress in the history of human spaceflight. It paved the way for future Salyut iterations—Salyut 2 and Salyut 3 weren’t successful, but Salyut 4 spent more than four years in Earth orbit—and eventually the Russian Mir space station.

These were some of the legacies of the Salyut program:

• The early Salyut design was adapted, with the addition of a second docking port, into the Salyut 6 and 7—space stations meant for long-term continuous occupation.
• Its later DOS-7 station evolved into the core module for the Mir station, which orbited the earth for 15 years in the 1980s and 1990s.
• The DOS-8 evolved into the Zvezda service module, which, combined with another Russian module, Zarya, formed the core part of the ISS.