The 20th century was largely a space age first and foremost, despite the great breakthroughs it brought in science, medicine, and engineering. The creation of super-powerful liquid fuel rockets made it possible to overcome gravity and launch the first spacecraft into orbit and land people on the Moon. And by the end of the century, 16 countries had jointly built a real engineering miracle in orbit: the International Space Station (ISS). Today, we are recalling the most important events over the past 100 years that contributed to the development of space.

Get off the ground: “Sputnik-1”

Plans to launch a satellite into Earth’s orbit appeared immediately after the first concepts for liquid fuel rockets were invented. However, despite the fact that the first rocket designed to launch a payload into orbit (designed by Goddard) was created back in 1926, engineers first had to solve a number of technically complex problems:

  • Build a high-velocity launch vehicle. To overcome the force of gravity, a rocket launched from the Earth had to reach a speed of ≈7.91 km / s (first space velocity). This required both a powerful rocket engine and a huge supply of fuel.
  • Break the altitude threshold. In order for a satellite to orbit, it must be brought to an altitude where the resistance of the earth’s atmosphere has a minimal effect on it. Despite the fact that outer space begins at the Karman line (100 km above the Earth), calculations showed that the planet’s atmosphere would provide resistance against a satellite even in low Earth orbit (400 km).
  • Design composite materials. This applied both to the rocket on which the device would be launched into space, and the payload itself, which had to be strong enough to withstand the massive stresses that occur during launch.
  • Transmit back to Earth. The artificial satellite had to be equipped with a radio transmitter strong enough to be picked up from the Earth as the satellite was orbiting. This would allow anyone with even the most basic radio equipment to verify that the object had indeed reached orbit.

In the USSR, a talented Ukrainian rocket engineer, Serhii Korolyov, took on the task of solving these technical problems. Together with a team of space engineers, he began work on the first man-made spacecraft destined to go into orbit – Sputnik-1 (developed under the code name PS-1).

Sputnik-1 spacecraft
Sputnik-1 was a very simple spacecraft whose main purpose was to prove the very fact that long-term orbital travel is possible

The spherical shell, only 2 mm thick, was made of an aluminum-magnesium alloy, with a diameter of 58 cm. On the outside of Sputnik-1, there were four antennas with pressure-tight fittings, which provided a uniform coverage area around it with a radio signal. Inside the probe, there was a PS-1 radio transmitter, an on-board automatic switching device, and a set of electrochemical power sources.

To launch Sputnik-1, the Soviets chose a modified version of the intercontinental ballistic R-7, one of the USSR’s first combat missiles. Redesigned for space launch, the rocket was also designated “Sputnik”. It consisted of two stages: the first was equipped with four boosters with RD-107 sustainer engines, and the second was , powered by a single RD-108 engine operating on oxygen-kerosene liquid fuel.

Sputnik launch rocket
The Sputnik launch vehicle

The launch, a landmark in human history, took place on October 4, 1957. 314.5 seconds after launch, Sputnik 1 separated from the second stage of the launch vehicle and transmitted the first radio waves, signaling the success of its orbital mission. The farthest point of its orbit from the Earth (apogee) was 939 km, and the closest (perigee) was 230 km above the Earth. The device could complete a complete orbit around our planet in just 96 minutes. Sputnik 1 ran until January 1958, after which its orbit predictably worsened, as a result of which it burned up in the upper layers of the earth’s atmosphere.

This mission marked the beginning of the era of physical exploration of space, which until that moment was limited only to astronomical observations from the Earth. The strong radio signal broadcast by Sputnik 1 flying over the planet could be picked up even with ordinary home radios.

The success of the first Soviet satellite came as a real shock to American society. New York Herald Tribune columnist Walter Lippman erupted in an angry column a month and a half after the launch of Sputnik-1. He assessed what the triumph of Soviet space would mean for America and its inhabitants, and also tried to focus on the problem of bringing American society together to achieve new feats in space. Lippmann was awarded a special Pulitzer Prize in 1958 for his firm position.

And although American President Dwight Eisenhower tried to downplay the importance of the Soviet satellite’s launch, it was this event, accompanied by the subsequent debacle it caused in the American press, that prompted the head of the White House to increase funding for American space development. The positive experience achieved by the Soviet space program prompted the Americans to develop their own, which, after only 10 years, jumped ahead of the USSR in the lunar race.

Saturn V, Apollo, and the lunar triumph

The space race between the US and the USSR was gaining momentum. And after the Soviets’ successful launch of the first man into space with Yuri Gagarin’s flight on April 12, 1961, the American government went for broke, declaring its intention to send the first humans to the Moon. In many ways, this was facilitated by the 1960 election of President John F. Kennedy. In 1961, during a speech to Congress, Kennedy issued the American people a bold challenge – to send a  manned mission to the Moon and then return the astronauts to Earth by the end of the decade. The United States took on the ambitious goal, which would develop into a real national initiative: to overtake the communists and become the most advanced space power in the world.

To achieve these goals, NASA approved the Apollo lunar program, named after the ancient Greek god of light. The agency also gave the same name to a manned three-seat spacecraft that was supposed to deliver American astronauts into lunar orbit. In total, the Apollo space program lasted 11 years (from 1961 to 1972), during which the United States conducted 11 successful space launches. The most important was the Apollo 11 mission, in which two American astronauts, Neil Armstrong and Edwin Buzz Aldrin, set foot on the surface of the Moon for the first time in human history. Another crew member, astronaut Michael Collins, remained aboard the Apollo spacecraft as it orbited the Moon.

Core modules of Apollo spacecraft
Core modules of the Apollo spacecraft. The crew of three astronauts was located in the command module, just behind the emergency evacuation system

The mission used the American-made super-heavy three-stage launch vehicle, the Saturn V. It was developed by a team led by the German rocket scientist Wernher von Braun, who was responsible for the creation of the first V-2 ballistic missile. Having survived the Second World War, von Braun was taken to the United States, where he agreed to participate in the American space program, which was pursuing peaceful purposes.

F-1 oxygen-kerosene propulsion engines of the Saturn V’s first stage
Five F-1 oxygen-kerosene propulsion engines of the Saturn V’s first stage
The Saturn V remains the largest heavy-lift rocket in the world

The Saturn V launched on schedule at 9:32 am (EST) on July 16 from Launch Pad 39A at the Kennedy Space Center in Florida. The live broadcast was watched by about 25 million people from all over the world. After the phased separation of all of the Saturn V’s three main stages, the Apollo spacecraft carrying the Lunar Lander Module (LM) on board set course for the Moon’s orbit. The journey took four days, after which Armstrong and Aldrin moved into the lunar module, and on Apollo’s 13th orbit around the Moon, separated from the spacecraft and sped towards the Moon’s surface. Immediately after undocking, the lunar module was assigned the call sign “Eagle”, and the remaining Apollo in orbit was assigned the call sign “Columbia”.

Having deviated slightly to the west from the intended landing site, on July 20, 1969, the Eagle made a soft landing, immediately after which the astronauts began a planned two-hour preparation for disembarking upon the lunar surface. Neil Armstrong was the first to set foot on the fine-grained lunar soil. Its descent was monitored by Edwin Aldrin from the lunar module’s cockpit.

Neil Armstrong and  the American flag on the Moon
Neil Armstrong near the American flag on the Moon. He accompanied his first step upon the lunar surface with the famous words, “That’s one small step for man, one giant leap for mankind”

Armstrong and Aldrin spent a total of 21 hours and 36 minutes on the Moon, and their walk on the lunar surface lasted just over two and a half hours. During this time, the LM crew took an impressive amount of photo and video material, collected about 22 kg of lunar rocks for delivery to Earth, and even planted the American stars and stripes on the Moon’s surface (which, unfortunately, was knocked down by a jet stream from the Eagle’s engine at the moment its takeoff). After landing on the lunar surface and successfully returning to the LM, his crew had a scheduled seven-hour sleep window. However, as both astronauts later admitted, because of the excitement, they barely managed to sleep a wink.

The engine of the lunar module lift stage started up as planned at the 124th hour and 22nd minute of the Apollo 11 mission, and began the Eagle’s smooth ascent for its subsequent docking with Columbia and return to Earth. An hour after takeoff, Armstrong activated the thrusters of the attitude control system, which set both spacecraft on approach to each other at a distance of 30 m. The manual docking procedure was carried out by Collins, who remained aboard Columbia the whole  time. He managed to stabilize the strong circular rotation of the vehicles relative to each other, which arose after the Eagle activated its maneuvering thrusters responsible for stabilizing its spatial orientation. After docking, all three Apollo crew members were reunited in the command module, and their four-day journey to Earth began. On the way back, the astronauts learned that on the day of their departure from the Moon, the Soviet lunar platform Luna-15 crashed there, marking the USSR’s last illusory chance to prove its superiority in the lunar race.

Apollo 11 command module in the Pacific Ocean
Apollo 11 command module splashed down in the Pacific Ocean off the coast of  Hawaii on July 24, 1969 at 11:49 am (CST)
Source: NASA

The American lunar triumph of 1969 was the culmination of eight years of hard work that had begun in 1961 after Kennedy’s speech to Congress. In total, about 300,000 US residents were involved in the lunar project, taking part in various stages of the preparation and implementation of the mission.

There has perhaps never been an event in the history of the 20th century that united the American nation more than the success of the legendary Apollo 11 lunar mission. However, by the end of the century, there was a project in store which the whole world was rallying behind.

The eighth wonder of the world: The ISS

Immediately after the launch of the first satellite into orbit, mankind began to imagine plans for the construction of a future orbital station which could serve as a permanent research hub for all countries that have reached orbit. As the first reusable space shuttles were developed in the United States toward the end of the 1970s, plans to regularly launch astronauts into orbit became more realistic. It only remained to decide where exactly in orbit they would be based.

In 1984, the United States, Canada, European countries, and Japan announced their first intentions to create an international orbital station that could accommodate space mission crews for decades, with periodic rotations. The plans were ambitious, but by the end of the 1980s, it became obvious that the cost of the space station project (which was to be called Freedom) significantly exceeded declared budgets.

In order not to curtail the grandiose construction, they decided to bring in democratic Russia, which had recently reappeared on the political map of Europe, to the creation of the orbital station. The Russians had experience in developing such structures, since the USSR had already launched the Salyut space station into orbit in 1971 (it ended operation in 1991), and in 1986 deployed the Mir orbital station (which operated until 2001). Russia was officially brought into the project in March 1993, after which construction work began on the production of the ISS’s main modules. It was at this point that the name of the station was proposed.

An important innovation during construction was the integration of the Mir-Shuttle docking system, which allowed American transport shuttles to dock with the Russian Mir orbital module. The United States, for its part, agreed to the participation of Russian cosmonauts in the crews of American shuttle missions.

Space Shuttle Endeavor docked at the ISS
Space Shuttle Endeavor docked at the ISS. Photo by ESA astronaut Paolo Nespoli taken from the SoyuzTMA-20 spacecraft in 2011

The frame of the station consisted of the Russian Zarya module, launched on October 20, 1998, and the American Unity, which docked to the first module in December. The ISS was able to take crews of astronauts on board after the installation of its third module, Zvezda, which was docked in the summer of 2000. This module made it possible for a crew of up to three people to stay at the station for long durations. The next 11 years were the most fruitful in the construction of the station, with its area expanding to almost 1 sq. km. 

The ISS is a technically living and constantly evolving mechanism, whose construction is still ongoing. To date, the station consists of 16 modules (the last Nauka module docked to it in 2021) and can accommodate up to seven crew members on board at the same time. The energy capacity of the ISS is 1000 kW, generated by a system of solar panels attached to its main body. The station even has its own technical truss with an area of ​​just over 100 m, which contains all the main power and control facilities, as well as communication and radio telemetry systems.

main modules of the ISS
The main modules of the ISS and an illustration of the process of step-by-step assembly of the station over a 23-year period
how the ISS was built

The ISS’s main priority remains contributing to the development of astronomy and understanding of space. Over the station’s more than 20 years of operation, more than 3000 experiments have been carried out in matters like microgravity, astrobiology, the study of the human body during weightlessness, meteorology, and astrophysics. This number is expected to rise even further, as the orbital station’s lifespan was recently extended to 2030.

While it started with a fierce race whose participants put it all on the line to end up ahead, by the end of the 20th century, the space age finally culminated in what cosmologists and futurologists of the 19th century had dreamed about: a space for ​planetary development and cooperation. The ISS is the greatest embodiment of this worldwide unity.