These star-crossed superpowers

After decades of rivalry, brilliance and a little lunacy, Arthur C. Clarke thinks it is time to explore space internationally.

A reviewer should declare if he has any special interest in the work he is writing about. I must therefore admit that I can hardly take an impartial view of a book that describes an incident in which the Central Committee of the Communist Party of the late unlamented USSR was told: "You aren't worth the nail on Arthur C. Clarke's little finger." I am thinking of having it gilded in honour of the occasion.

The speaker was my good friend cosmonaut Alexei Leonov, the first man to walk in space - perhaps the only man in the USSR who could have got away with that kind of remark. The incident took place in the early 1980s, soon after the Russian youth magazine Tekhnika Molodezhy began serialising my 2010: Odyssey Two . Halfway through the story, the serialisation was abruptly stopped and the Central Committee summoned Leonov to ask why in the novel the crew of the spaceship Alexei Leonov consisted of Soviet dissidents.

Of course, Leonov knew nothing of this, even though only a few months earlier, he had shown me around "Star City" - I must have been one of the first westerners allowed in. I had just sent the manuscript of 2010 to my editors when I visited Russia for a most memorable and enjoyable visit. In between toasts at Leonov's apartment, I revealed that most of the action in my novel was taking place on board the Cosmonaut Alexei Leonov . A delighted Leonov quipped: "Then it must be a good ship."

I added that it was my hope and belief that 2010 - in which seven Russians and three Americans start off as acquaintances and end up as friends - would help improve understanding between the US and the USSR. But genuine understanding must be based on honesty, and I cautioned Leonov that some aspects of the book might not be well received in his country.

I had dedicated 2010 to Leonov and Andrei Sakharov, physicist, Nobel laureate and humanist, whose outspoken views led to his internal exile in Gorky until 1986. But what irked the Central Committee even more was my naming of Russian cosmonauts after several dissidents. "The small-mindedness of such people has always amazed me," writes Leonov in Two Sides of the Moon . "Pettiness and lack of appreciation of true talent and creativity by certain party members was one of the factors that crippled our system."

Another interesting example is how the Central Committee pooh-poohed the idea of a reusable orbiter spacecraft, for which Leonov and a group of students in astronautics had prepared a 12-volume dissertation in 1968. The project was returned by the Soviet Ministry of Defence with the words "fantasy" and "mind your own business" scrawled across it. More than a decade later, when the Americans were preparing to launch the space shuttle, Leonov said gleefully to the Central Committee "I told you so".

Coming from one of the USSR's most highly decorated heroes, these remarks constitute a severe indictment of the system. Leonov was in the first group of cosmonauts selected in 1960 and flew two space missions - as pilot of Voshkod 2 in 1965 and, a decade later, as commander of Soyuz 19 during the Apollo-Soyuz Test Project. The ASTP was the first human spaceflight mission managed jointly by the cold-war rivals and demonstrated how much could be achieved through international cooperation in space exploration.

That is the central theme of this unique memoir by an American and a Russian who were at the cutting edge of their respective countries' space efforts during the first two decades of the space age. They recount their own roles and insights in what Neil Armstrong, in his foreword, calls "the most fascinating and most expensive race in human history".

Co-author David Scott flew three space missions, and became one of 12 humans to walk on the Moon. His career culminated as commander of Apollo 15 , when he spent three days on the surface of the Moon. More recently, he has been associated with two major visual reconstructions of those heady days: the movie Apollo 13 and the superb TV series From the Earth to the Moon .

And here's something for future historians of the space age: I have only recently discovered - from a highly authoritative source - that the late Wernher von Braun used my Exploration of Space (1951) to persuade President Kennedy to commit the US to going to the Moon. Although I knew von Braun very well, and taught him scuba diving, he never mentioned this to me in person - perhaps out of consideration for my well-known modesty.

I first met Leonov in 1968 during the height of the cold-war rivalry in space, when the two superpowers were trying to outdo each other in landing humans on the Moon. When he came to the United Nations Conference on Peaceful Uses of Outer Space (Unispace) in Vienna that year, Leonov was already a celebrity for his pioneering space walk. The conference coincided with the European premiere of 2001: A Space Odyssey , and, after seeing the film, Leonov paid it one of the finest tributes: "Now I feel I have been in space twice."

When he did return to space, the Apollo-Soyuz joint mission set the tone for international collaboration in space for decades to come. Before and since, it has taken massive efforts by scientists and space travellers of both nations to get the two leading space-faring nations to work together.

The late Carl Sagan and Roald Sagdeev, the former Russian space chief, shared a dream of a joint US-Russian Mars mission, which I hope will come true in the foreseeable future. 2010 , with its mixed American-Russian crew, was a deliberate attempt at a self-fulfilling prophecy, and I am delighted to see that 20 years after it was first published, there seems to be a greater chance of that happening. (Joint space missions in Earth orbit have become commonplace, yet were unimaginable even two decades ago.) I have had the privilege of shaking the hand of the first man to orbit the Earth, the first man to walk in space and the first to land on the Moon. So I cannot help wondering what chances I have of greeting the first man - or woman - to set foot on Mars.

Sir Arthur C. Clarke was a founder, and later chairman, of the British Interplanetary Society. He covered the Apollo programme for CBS with Walter Cronkite and wrote the epilogue to the official story of the first moon landing.