Photo: Saswato R. Das

Sir Arthur C. Clarke and Saswato R. Das in the Apollo Hospital in Colombo, Sri Lanka in January

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“He was a good diver, very calm. He could hold his breath for a long time, sometimes for 3 minutes,” said Hector Ekanayake, Sir Arthur C. Clarke's friend and diving partner from the 1950s. Clarke, unfortunately, could no longer breathe easily, much less dive when I met him. He was confined to a wheelchair. His last dive was a number of years ago—Ekanayake thinks it was when Clarke was in his early eighties but isn't quite sure. “We took him down to 100 feet,” his friend noted. “He loved it.” See sidebar, “Sir Arthur C. Clarke's Treasure-Diving Days”

I sat with Ekanayake in a hospital waiting room in Colombo, Sri Lanka, waiting for Clarke to recover his breath. When I arrived in Colombo a couple of days earlier, Clarke's assistant, Nalaka Gunawardene, told me that Clarke, who had turned 90 last December, had taken ill and been hospitalized at Colombo's Apollo Hospital, Sri Lanka's most advanced multispecialty facility, the previous night. He was in severe pain and couldn't sit up, and his doctors were performing various tests on him. He would be there for a while but was still interested in talking with me when he was able over the course of two days.

Clarke's private suite overlooked the city. There was a large waiting room, complete with a sofa and coffee tables, and beyond that, the actual hospital room. There were many people milling about—friends, hospital staff, personal staff, other visitors. I noticed a curious thing. When people went in to meet Clarke, they took off their shoes outside the room. When they came out after meeting him, they put them on again. In Sri Lanka, almost everyone knew who Clarke was. I took the shoe removal to be a mark of veneration—Sri Lanka has a long Buddhist tradition, and you take off your shoes before you enter a Buddhist shrine.

When I entered the hospital room, Clarke was lying flat in bed. He looked pale and in some pain but he seemed to be in fine humor—except every so often he had to pause for breath. We chatted about “the design faults of the human body” briefly and discussed a few apparent exceptions to the rule—an octogenarian who completed the New York City marathon in about 6 hours a few years ago.

I started our interview sessions with geostationary satellites—those in orbit above Earth's equator that have the remarkable property of matching the period at which Earth rotates. As a result, these satellites look stationary to someone on Earth. They are extremely useful for communications, because transmitting and receiving antennas on Earth don't have to track them. In a 1945 article, “Extra-terrestrial Relays,” published in Wireless World, Clarke proposed that geostationary satellites would be ideal telecommunications relays. I asked Clarke whether he'd ever suspected that these satellites would one day prove to be so valuable to telecommunications.

He laughed. “I'm often asked why I didn't try to patent the idea of communications satellites. My answer is always, ‘A patent is really a license to be sued.' ”

Clarke couldn't pinpoint the exact reference that got him thinking about geostationary satellites. “One of the moons of Mars, Phobos, is always in a stationary orbit,” he mused. “That probably got me thinking.”

He had discussed his ideas with his friends in the nascent British Interplanetary Society but didn't get many comments, he reminisced. “I never received any additional input, so it was all my own work in the end,” he said.

While Clarke came up with the idea of the communications satellite, it was John Pierce of Bell Telephone Laboratories who was instrumental in developing the first communications satellites, Echo I and Telstar, which launched in the early 1960s. Clarke had interacted with Pierce during their development in the 1950s.

“We were good friends; we wrote a number of papers together,” he said about his relationship with Pierce.

Clarke won the 1982 Marconi Prize and Lifetime Achievement Award for his idea of geostationary satellites as telecommunications relays. It's an irony that in his final days—while he was confined to Sri Lanka because of poor health—his connection to the wider world (via the phone and television) often relied on these very satellites.

“It's definitely my most important contribution,” he said of his seminal paper. In the next breath, he added, “And maybe in a generation or so the space elevator will be considered equally important.”

The space elevator is another technology that Clarke championed. The concept of a space elevator basically involves a huge cable connecting the Earth to orbital altitude, along which payloads can be launched using electromagnetic vehicles. The cable's center of mass would remain in a geostationary orbit while the cable is tethered to an object beyond that orbit. Current plans call for a cable about 50,000 to 100,000 kilometers long. Clarke first wrote about a space elevator in his 1979 book, The Fountains of Paradise.

Clark smiled. “I'm often asked when I think the space elevator will be built,” he said. “My answer is about 10 years after everyone stops laughing. Maybe 20 years. But I am pretty sure that the space elevator is an important element in future space travel.” He elaborated, saying that the space elevator allows one to get to orbit “purely by electrical energy, and you recover it on the way down.” He called it a “very efficient, economical system and the key to the planets.”