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Arthur C. Clarke
Arthur C. Clarke offered a round of predictions for space exploration in an 1963 TV interview, recently rediscovered. (credit: BBC)

The perils of spaceflight prediction

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“Prediction is difficult, especially about the future,” goes a famous saying attributed, curiously, in roughly equal measure to Nobel laureate physicist Neils Bohr and baseball Hall of Fame player and manager Yogi Berra. Regardless of the source, its message about the difficulty of prediction is clear, which means that when someone makes a prediction that is far from obvious to the broader community, yet does come true, that person is heralded as a seer and is sought out for other predictions.

“I think that in a few generations, all serious astronomy will be conducted either on the Moon or in space,” Clarke predicted.

A case in point in the space field is the late Arthur C. Clarke. In the mid-1940s he not only predicted the development, but also invented the concept, of geosynchronous communications satellites. Within two decades such satellites had become reality; today they’re an essential part of global communications and the most lucrative element of the overall commercial space industry. It’s little surprise this concept was the centerpiece of an episode of the Science Channel’s “Prophets of Science Fiction” show about him last week, even if some of the other concepts from his works featured in the show, like the space elevator from The Fountains of Paradise, have yet to become reality.

Back in the early 1960s, when Clarke’s concept of the geosynchronous communications satellite was becoming reality and his visions for spaceflight in general were being realized in the nascent space race between the United States and the Soviet Union, Clarke had indeed become something of a prophet about space exploration. That is evident in a 1963 episode of the BBC’s long-running “The Sky at Night” program featuring a rare in-studio interview with Clarke. That episode had long ago been lost, but a copy was recently discovered in an African TV station and, last week, posted online by the BBC.

The episode, about lunar exploration, starts off with an illustration of a lunar base concept, dominated by a large silvery dome. “I expect that this scene looks rather strange to you,” the show’s host, Patrick Moore, says in a voiceover. “Even though it may look like something out of science fiction, it is something that will probably be set up before the end of this century.”

After discussing some of the issues associated with lunar exploration, including the debate about whether spacecraft attempting to land on the Moon would sink into deep banks of lunar dust, Moore then introduces Clarke, who first reviews his concept of geosynchronous communications satellite. (He notes that the first such satellite, Syncom, had been launched by NASA “just a few weeks ago”; the date of the program isn’t given, but Syncom 2—Syncom 1 failed before reaching geosynchronous orbit—was launched on July 26, 1963.) Such satellites, he said, “are probably the key to the future of world communications,” an assessment that may today be overstating its impact, if only moderately, given the major role played by terrestrial alternatives like fiber optic links and wireless systems.

Clarke then launches into a discussion of human lunar exploration, noting the similarities to design studies of lunar landers and bases done by the British Interplanetary Society (BIS) in the 1940s and 1950s with contemporary efforts by NASA (although the BIS’s lander appears considerably larger than what NASA’s Lunar Module turned out to be). Later, he showed illustrations of a Mars base that, like the lunar base, were dominated by giant domes. “It’s a good deal further away in time,” Clarke said of the Mars base, “but it undoubtedly will come.”

The concept of domed bases has not weathered the succeeding decades very well: more recent concepts have replaced large domes with alternatives like cylindrical modules, in many cases covered by a layer of regolith, while others have explored the use of lava tubes as lunar habitats. Such subterranean concepts would not have pleased Clarke in 1963. “I rather hope the necessity of a lunar underground movement does not arise,” he quipped. “I hope we can stay on the surface and look at the stars.” He was referring to concerns of that era about the need to protect from meteor bombardment; radiation exposure was not a concern expressed in the interview.

One reason for a lunar base, Clarke argued in the show, is for science, particularly astronomy. He described the benefits of basing observatories on the airless Moon, including locating radio observatories on the far side, shielded from the “electronic racket” of radio communications. “I think that in a few generations, all serious astronomy will be conducted either on the Moon or in space,” he predicted.

Clarke said he predicted a human flight around the Moon, without landing, “possibly in five years, certainly in ten.” Apollo 8 orbited the Moon in December 1968.

That prediction has turned out, so far, to be only partially correct. Although astronomical observatories on the Moon remain only concepts, observatories in Earth orbit and beyond have been a boon to astronomy. In addition to the Hubble Space Telescope, arguably one of the most famous telescopes on space or on Earth, other spacecraft have also played a major role in advancing various fields of astronomy, particularly in regions of the electromagnetic spectrum, like x-rays and gamma rays, not observable from the ground. Yet, much “serious” astronomy is still performed by groundbased telescopes, both radio and optical, a trend unlikely to change given plans for larger, more ambitious observatories like the Square Kilometer Array radio telescope and the European Extremely Large Telescope.

Those lunar observatories and other scientific facilities on the Moon would almost certainly be manned, Clarke believed. “Automatic space probes, sooner or later, and usually sooner, go wrong. You have many times the example of a satellite, which has cost millions of pounds to build and launch, going out of action because there wasn’t a man with a screwdriver to make some trivial adjustment,” he said. “Ultimately you have to have a man on the job to maintain the equipment and to discover new things and to consider new types of observations.” And while Hubble did benefit from servicing missions where astronauts repaired and upgraded the telescope, that has been an exception to the rule. Scientists have made great use of “automatic space probes” in their studies of the solar system and the universe, despite the lack of humans able to make repairs on the scene, as robotic spacecraft have proven to be far less expensive than crewed missions.

Clarke also emphasized the role of the Moon as a “stepping stone” for future human exploration elsewhere in the solar system, a place to build up experience in spaceflight in relative safety—only a few days’ travel back to the Earth if something goes wrong—and perhaps a source of resources for future missions. “I get rather annoyed with people who seem to regard the Moon as the be-all and end-all of space travel,” he said. “The Moon is just the first stepping stone on the way to the planets, which may be much more important.” That justification for lunar exploration remains in place today.

But when would all of this happen? Moore flattered Clarke with praise for his previous predictions, particularly with the communications satellite, near the end of the twenty-minute program. “Everything is going more or less as you expected, although I agree that it’s gone more quickly,” he said, prompting Clarke to provide “a few more forecasts” for the immediate future.

Clarke said he predicted a human flight around the Moon, without landing, “possibly in five years, certainly in ten.” That prediction was on the money: Apollo 8 orbited the Moon in December 1968, a little over five years after the show’s original broadcast. A landing on the Moon, he said, would probably come “around 1970”. However, he thought that it might well be the Soviet Union that landed humans on the Moon first, timed to the fiftieth anniversary of the October Revolution (which he mistakenly said was in November 1968, rather than 1967). While ultimately incorrect, that was not an unreasonable prediction at the time, given the pace of Soviet space activities and all the firsts they had racked up since Sputnik.

Clarke was skeptical that NASA could meet the goal set by President John F. Kennedy of human lunar landing by 1970. “I think that it’s very unlikely that the American Moon project, which is really a colossal thing, costing $10 million a day, will succeed in getting a man to the Moon and back—which is equally important—before 1970, but it will not be much after that,” he said. In fact, NASA did beat the 1970 goal with the landing of Apollo 11 on the Moon in July 1969.

And what about Mars? Clarke admitted that was more speculative, but predicted that there would be a human mission to orbit, but not land, on Mars in 20 years, with a landing in 25 years, or 1988. “So a Martian base may just come in this century,” he concluded.

“[T]he space research program has gone forward much more quickly than Arthur Clarke and the other pioneers believed it could possibly do,” Moore said. “Whether this progress is going to be maintained, well, of course, it’s just too early to say.”

Unlike some of his previous predictions, though, that one turned out to be overly optimistic. We are, perhaps, farther from having humans on Mars now, in 2011, then what Clarke foresaw in 1963. NASA’s long-term goals for Mars exploration, as laid out by President Barack Obama in a speech at the Kennedy Space Center in April 2010, call for a human mission to orbit Mars in the mid-2030s—about 25 years from now—with a landing to follow in an unspecified time (but short enough for Obama, who turned 50 earlier this year, to say in that speech that he expected to be around to see it.)

It’s easy to see, though, why Clarke fell short in his prediction. Advancements in space exploration were proceeding at a rapid pace in the 1960s, exceeding even the predictions of advocates like Clarke. Extrapolating that progress made conclusions like human missions to Mars in the 1980s appear quite reasonable, almost to the point of being conservative.

That is, though, one of the primary perils of prediction in any field, not just spaceflight: the assumption that a trend will continue unabated for an extended time. Progress instead ebbs and flows over time, subject to factors both internal and external. Could Clarke have foreseen that the US-Soviet space race would decelerate from its early breakneck pace, putting into doubt those long-range predictions of Martian and even lunar bases by century’s end? He made those predictions years before competing priorities, like the Great Society programs and the Vietnam War, emerged in America to sap funding from NASA. Then again, one has to consider if an effort like landing humans on the Moon that even Clarke admitted at the time was “colossal” could be sustained over the long haul, regardless of what external pressures might have developed.

“I think one thing stands out very clearly indeed,” Moore said at the show’s conclusion. “That is that the space research program has gone forward much more quickly than Arthur Clarke and the other pioneers believed it could possibly do. Whether this progress is going to be maintained, well, of course, it’s just too early to say.” That pace, though, could not be maintained, making the visions of domed bases on the Moon and Mars seem just as futuristic now as they did when the program aired nearly a half-century ago. It’s a lesson worth remembering today as we make predictions for the future of commercial and government spaceflight in the coming years and beyond.