“New Planet” by Konstantin Yuon, 1921

The starter's pistol for the space race was fired on October 4, 1957. For three months a small highly-polished sphere with antennae orbited Earth every 98 minutes, emitting beep-beep-beeps. This was the Soviet Union's Sputnik, Earth's first artificial satellite. It shook up the United States, and there was more to come.

Two halves of the story
The Science Museum in London displays the Apollo 10 command module and a mock-up of the Apollo 11 lunar lander. However, apart from a replica of Sputnik 1, half the story of the space race is missing. Although the US landing on the Moon was a hard act to follow, the main factor that created this gap was the decades of secrecy surrounding the Soviet space program.

The Soviet Union was officially broken up at the end of 1991, and Russia took over the space program. Telling the other part of the space story took over three years of discussion and diplomacy with Russian agencies and individuals. But the final result was a superb collection of archives, artworks and artifacts to produce the 2015-16 special exhibition "Cosmonauts: Birth of the Space Age".

Most of the 150 objects on display had never been seen outside Russia, or even by the public inside Russia. There were actual spacecraft, engineering models, uniforms, equipment, manuscripts and mementos. Here are some of the highlights.

Konstantin Tsiolkovsky (1857-1935) was fascinated by space travel long before the Wright brothers' first plane flew 120 feet. When it was still science fiction to most people, he was developing the theory and doing the math for multistage rockets. It was inspiring to see some of Tsiolkovsky's original manuscripts and drawings.

But I was intrigued by a model spaceship which was made following Tsiolkovky's ideas. What were the bathtubs for? An explainer said that the strong gravitational forces on the crew at liftoff were supposed to be eased by immersion in the water. (No one seemed to know how they'd deal with the water in freefall.)

Sergei Korolev (1907-1966) was the mastermind of the Soviet space program, and a state secret, referred to only as the Chief Designer. His engineering expertise, hard work and organizational abilities – even on a shoestring budget and bedeviled by bureaucracy – kept the Soviets ahead of the Americans in the race.

The first cosmonauts were not human, but canine. Laika didn't survive her trip in Sputnik 2, but others were more fortunate. Strelka returned safely and had a litter of pups, one of which was presented to the family of President Kennedy.

A new challenge was the Moon. The same side of it always faces us, but in 1959 Luna 3 flew around the Moon to provide humanity with its very first view of the far side. Unlike the near side, it doesn't have many craters, but they named one of them Tsiolkovsky.

Korolev's greatest coup was getting the first man into space. On April 4, 1961 Vostok 1 took Yuri Gagarin (1934-1968) into orbit. Gagarin was a smart, personable military pilot who made a great ambassador. He was also even braver than you might think. They didn't know how to get Vostok safely back to Earth, so Gagarin had to eject at 7 km up (4.4 miles) and parachute to Earth.

Having sent the first man into space, in 1963 they sent the first woman, Valentina Tereshkova (born 1937). She spent three days in orbit, her flight time exceeding the combined times of all the American astronauts who had flown before her. (She was also an experienced parachutist.) Dr. Tereshkova attended the opening of the Cosmonauts exhibition.

Alexei Leonov (born 1934) made the first space walk in March 1965. It was nearly his last when his suit swelled and became rigid in the vacuum of space, and wouldn't go back through the hatch into the spacecraft. With luck and ingenuity he survived that, as well as the re-entry malfunction. But the cosmonauts spent two nights in a freezing forest before being recovered. Leonov is also an artist, and some of his drawings were on show.

Artists and designers were quite taken with space themes. My favorite item was the "into the cosmos" tea set made by the State Dmitrovskii Porcelain Factory.

When the Americans landed men on the Moon, the Soviets abandoned their manned lunar program, denying there had been one. However we saw test models and the awesome LK-3 lunar lander. At five meters tall, the only way of getting into the museum was to take it apart in Moscow and reassemble it in London.

Sergei Krikalev (born 1958) also came to the exhibition. For a long time he held the record for the most hours in space. This included five unexpected extra months on the space station Mir while the Soviet Union collapsed beneath him. Fortunately, the new Russian republic did finally bring him home.

The final room was like an installation at the Tate Modern gallery. An eerie blue light lit a room whose only occupant was the Phantom Mannequin that was flown around the Moon in 1969. It was studded with radiation sensors in order to estimate the effects of cosmic radiation on living tissue. Its face could have been blank, but it was modeled on Yuri Gagarin who had died the year before.

On the wall was written Tsiolkovky's famous words:

Earth is the cradle of the mind, but one cannot live in the cradle forever.