By Paul Rincon
Science reporter, BBC News
Sergei Khrushchev is used to having a seat on the front row of history.
Sergei Khrushchev travelled the world with his father
Not only because his father, Nikita, was a premier of the Soviet Union, but also because he worked as an engineer at the forefront of Russia's space programme.
As a young man, he was at his father's side on many of his official visits around the Soviet Union and abroad, including the historic visit to the US in 1959.
On 4 October 1957, Sergei was in Kiev, Ukraine, where his father was visiting on military business. What started out as a routine engagement for the First Secretary of the Communist Party was to take on an historic dimension.
In the evening, Nikita and Sergei sat down to dinner with Ukrainian leaders in Kiev's Mariyinsky Palace.
Back then, we lived in the same situation as Iran is in now
"It was after dinner - late in the evening, or early in the morning. Then, the secretary came in and said: 'Telephone call for you Mr Khrushchev'," Sergei recalls.
Nikita Khrushchev had been expecting a call from Sergei Korolev, the Soviet space programme's "chief designer".
Message from Kazakhstan
Korolev was phoning from the Tyuratam missile range in Kazakhstan to report the outcome of an attempt to launch the world's first satellite - Sputnik.
"My father returned smiling. And he told all the people that we had launched Sputnik. He started to talk about how important it was, for science, for everybody. We were first and ahead of the United States," Sergei tells me.
Nikita Khrushchev's dinner companions agreed politely, but remained largely uninterested.
"The local officials did not really understand. They thought that what they had discussed before was more important: their funding, their local projects. They lived very far from space and other 'fantasies'."
The principal focus of technological development in the USSR was on intercontinental ballistic missiles. Security - specifically the prevention of attack by the US - was the main priority, not space.
"Back then, we lived in the same situation as Iran is in now," says Sergei Khrushchev.
Outside the USSR, where many people had expected America to launch first, Sputnik was a shocking demonstration of technological might.
For the American public, in particular, the Soviets' ability to launch a satellite was equated with a capability to launch ballistic missiles at the US.
"It was a signal to the United States that now you have to be very cautious if you decide to attack us," Khrushchev explains.
"You have to remember that even in the 1950s, [US Air Force General Curtis] LeMay sent one memo after another that the Soviet Union must be destroyed before it is too late.
"We feared that one day, a US president would say: 'go ahead', instead of throwing them away. So this was not an escalation, it was more like a cold shower to the opposite side."
After graduating as an engineer from Moscow's Electric Power Institute, Sergei went to work for one of three design bureaux developing spacecraft and missiles for the Soviet Union.
Sergei Korolev ran one design team. Khrushchev went to work for a rival bureau run by Vladimir Chelomei. Here, he was to work on ballistic missiles, military satellites, Moon vehicles, on the first space station and on the Proton space rocket still in use today.
The competition between design outfits was fierce. But, ultimately, internal competition would contribute to the Soviet Union losing the race to land humans on the Moon.
Korolev fell out with Valentin Glushko, his chief engine designer. Glushko's expertise was sorely missed; without him, Korolev's Moon rocket - known as the N-1 - was destined to fail.
"Korolev's N-1 could only deliver 90 tonnes into orbit, while the American rocket could deliver 129 tonnes," Khrushchev tells me. "Since Soviet electronics were heavier, it was clear Korolev's rocket would not reach the Moon."
Meanwhile, Vladimir Chelomei had been drawing up his own proposal for a Moon rocket, called the UR-700, which could launch 145 metric tonnes - sixteen more than the US rocket.
But after Nikita Khrushchev was ousted from power by Communist Party bosses in 1964, Chelomei's design bureau fell from political favour. After the N-1 failed dismally in tests, both the N-1 and UR-700 programmes were cancelled.
Sergei would later help his father write down his memoirs, during Nikita's forced retirement in Moscow. This provoked the ire of party members, who forced Sergei out of the Chelomei design bureau. He later found work at the Control Computer Institute in Moscow.
In 1991, Sergei began lecturing at Brown University in the US and, in 1999, took American citizenship with his wife Valentina. They now live in Rhode Island, where Sergei teaches at Brown's Watson Institute for International Studies.
Sergei and Valentina became US citizens in 1999
He also speaks to audiences across the US, sharing his memories of the Cold War, and has been working on a series of books about his father - a figure who is still a subject of fascination for many in the West who lived through the Cold War.
After all, this is the man who sent Soviet tanks to crush a revolution in Hungary and terrified the West for 13 long days when he deployed missiles to Cuba. But he is also admired as a political reformer.
"My father was interested in communicating with the rocket and space designers, with the house builders and with the agronomists. And they were able to call him to discuss things.
"If you are a leader of a centralised economy, you are not just a political figure, you are more like the CEO of a company, who has to know exactly what is going on. He was a driving force in many aspects of the country."