Scientists and fellow writers paid tribute to Sir Arthur C. Clarke, who died on Tuesday at the age of 90,but even in death the sage of science fiction could not shake off the accusations of paedophilia levelled against him.

His reputation never fully recovered from allegations, made a week before he was due to be knighted by the Prince of Wales, that he had had sex with young boys in his adopted home of Sri Lanka.

He eventually received his honour in a low-key ceremony two years later than planned.

Although he met the Prince during the state visit in 1998, the investiture was delayed until 2000 and conducted by Linda Duffield, Britain’s Ambassador to Sri Lanka. Clarke told bystanders that he was delighted by the honour but was uncomfortable in his choice of dress. “I feel like a lobster,” he said, flapping his arms in an impression of a crustacean.

Clarke had allegedly told a newspaper reporter that he did not know how old his sexual partners had been, but that “most of them had reached puberty”. Asked whether it was morally wrong, it is claimed that he replied: “No. I mean, it depends on the country. You can’t have absolute morality.”

He declined to sue the newspaper, saying that it would be a waste of time and money. He said that the allegations were “not aimed specifically at me but designed to embarrass Prince Charles”, and that he had not been sexually active for more than 20 years.

He issued a more robust denial later: “Having always had a particular dislike of paedophiles, few charges can be more revolting to me than to be classed as one. The allegations are wholly denied. My conscience is perfectly clear.”

Clarke made his biggest impact with The Sentinel, a short story that he and Stanley Kubrick used as the basis for 2001: A Space Odyssey.

Terry Pratchett, a fellow science fiction author, said that he was the first writer to break out of the genre. “Everyone had heard of Arthur C. Clarke — the Goodies made jokes about him, Terry Wogan made jokes about him,” he said. “He became a national treasure like Patrick Moore.

“Before 2001, you could see the string, you could see what was holding the rocket ships up. The first time you saw it you thought, ‘Here’s something totally new’,” Pratchett said. “The amount of work and effort and research that went into that movie was just astonishing.”

Pratchett said that Clarke’s authority came from his engineering background. “You got the impression you were dealing with a man who put some science into science fiction.”

Clarke is credited with inventing the concept of geostationary telecommunications satellites, which would remain above a fixed point on the Earth’s surface by orbiting at the same speed as the planet’s rotation. He wrote about the idea in 1945, 17 years before the first telecommunications satellite was sent into space.

He also predicted, in 1940, that human beings would walk on the Moon before the end of the century. He was derided at the time but vindicated in 1969.

Sir Patrick Moore, the British astronomer and veteran broadcaster of The Sky at Night, said: “He was a great visionary, a brilliant science fiction writer and a great forecaster.”

President Rajapaksa of Sri Lanka described Clarke as a great visionary.

Alan Stern, associate administrator for the Nasa Science Mission Directorate, said: “Arthur Clarke was a gifted writer of science and science fiction, and an unparalleled visionary of the future, inspiring countless young people with his hopeful vision of how space flight would transform societies, economies and humankind itself. Although his personal odyssey here on Earth is now over, his vision lives on through his writing; he will be sorely missed.”

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