Astronauts lift our spirits. But can we afford to send humans into space?

http://www.theguardian.com/science/2014/dec/07/can-we-afford-to-send-humans-into-space

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America’s first step in its attempt to reconquer worlds beyond our planet ended in spectacular success on Friday. An unmanned version of its Orion spacecraft soared more than 3,000 miles into space before splashing down on target in the Pacific ocean. The flight was hailed by Nasa, which says that the spaceship is destined to be the first of a fleet that will carry humans to the Moon, Mars and beyond.

In many laboratories and research centres, this delight was shared by scientists. A return to sending men and women to other parts of the solar system – years after the US scrapped its last manned space vehicle, the shuttle – cannot come soon enough for them.

But for others, the test flight was viewed as a distinctly unhappy event. Putting humans into space is futile, expensive and ultimately harmful to real science, argue researchers who believe that robot craft represent the future of space exploration and are dismayed by the US’s commitment to return to expensive manned missions.

“For a while I thought president Obama was going to see sense and would wean America off its fascination with putting men and women into space by scrapping manned missions,” the Nobel laureate Steven Weinberg told the Observer. “Unfortunately, with the flight of Orion, that hope has now been dashed.”

Scientists like Weinberg point to missions such as Europe’s Rosetta and Philae probes which have successfully begun an exploration of Comet 67P. They argue that these missions represent the real future of the solar system’s exploration. Men and women will remain expensive nuisances when it comes to discovering other worlds, they say. Relatively cheap robot probes are the future.

The existence of these two camps – manned versus unmanned – reveal a deep division in attitude to space exploration. On one hand, enthusiasts such as astronomer Professor Ian Crawford of Birkbeck College, London, believe that, although modern robots are capable of highly sophisticated tasks, only humans can carry out some forms of exploration.

“We learned a great deal from the Apollo missions, but their landings were all confined to sites near the lunar equator on one side of the Moon,” he said. “The samples they returned to Earth were made up of rocks found lying around the surface. But on the far side of the Moon, there is a region where meteorite impacts have excavated material from deep below the lunar surface. If we could explore these regions and bring samples back to Earth, we will transform our understanding of how the Earth and its satellite, the Moon, formed in the distant past.”

Crawford envisages setting up a handful of lunar colonies that would mirror the establishment of research bases in the Antarctic. From these, small numbers of astronauts would survey the lunar landscape, make observations and collect samples.

“These missions would use robot vehicles as assistants but would depend on human intuition and leadership,” he said. “Humans and robots would work together.” And after the Moon, targets such as Mars and possibly the asteroids would be explored in a similar manner, he added.

This vision is not shared by all scientists. Martin Rees, the Astronomer Royal, believes the cost of putting humans in space is harder to justify because of the rising sophistication of robots. “If you look at the great discoveries that have already been made in the solar system’s exploration, the vast majority have been carried out by robot probes: the discovery of the great hydrocarbon lakes on Saturn’s moon, Titan, and the discovery of the underground ocean on another of its moons, Enceladus, are good examples,” he said.

Rees stresses that human spaceflight could still be pursued, without damage to science, if it was left to entrepreneurs such as Elon Musk, whose SpaceX rockets are now used to carry cargo to the space station: “However, I think the future of planetary exploration will continue to be dominated by robot probes which will be spread throughout the solar system. You can imagine robot fabricators mining the asteroids and building large structures in space or on the Moon.”

From this perspective, relying on humans to carry out scientific exploration in space is unjustified, a point emphasised by Weinberg, who describes the International Space Station – claimed by Nasa to be an orbiting multidisciplinary laboratory – as “an orbital turkey”.

No important science has ever emerged from it with the exception of one cosmic ray experiment which could easily have been done on an unmanned satellite, he believes. Indeed, he adds, the whole manned spaceflight programme, which is so enormously expensive, has produced very little of scientific value.

Manned space flight crowds out real science, Weinberg argues. As an example, he points out that in 2004, president George W Bush announced a new vision of manned space missions for Nasa in which the agency would return to the Moon then head on to Mars. A few days later, Nasa revealed it was making major cutbacks in its programmes of unmanned research in astronomy because they “do not clearly support the goals of the president’s vision for space exploration”. In other words, to support manned missions science projects were cut back.

Even worse, says Weinberg, was the example of the US Superconducting Super-Collider, which was designed to study the structure of matter by crashing sub-atomic particles into each other at colossal energies. Its $12bn construction, in Texas, was cancelled in 1993 because Congress decided the US could not build the SSC and the International Space Station, of which the US was the main supporter of funds, at the same time. So it chose to build the space station, mainly for political reasons.

This left Europe free to build its own Large Hadron Collider, at Cern, Geneva, a decade later, where scientists discovered the Higgs Boson in 2013 and are set to begin the search for dark matter and other exotic particles when the LHC reopens next year after a refit.

By contrast, the US ended up with that “orbital turkey”, a decision described by Weinberg as a tragic mistake. “The only real technology that the space station has produced concerns the technology of keeping humans alive in space – which is a senseless and circular process if you realise there is no point in having humans in space,” he said.

So are science and manned spaceflight virtually incompatible? No, says Crawford. For a start, the idea of robot efficiency is a myth, he says, as there is no substitute for putting a person into space to get things done. “Just consider Philae,” he said. “It did bounce when it landed on comet 67P and in the end only carried out a couple of days’ work – albeit very, very important work – before it stopped working. By contrast, if we had had a bigger mission, with humans on board, the pilot would have been able to land it expertly on that tricky terrain.

“There would have been no bouncing. Instrument packages would then have been left on the surface while samples of rock, soil and ice from the comet would have been brought back to Earth so they could be studied in detail and at leisure in laboratories. That’s what you get with a manned mission.”

The difference in scientific return rates from manned and unmanned missions is vividly illustrated by the Apollo 17 mission, flown by astronauts Gene Cernan and Harrison Schmitt in 1972, and the robot rover Opportunity which, in 2004, was dropped on to the surface of Mars and has been exploring ever since, said Crawford. “Apollo 17 spent three days on the Moon while its astronauts made journeys across the lunar surface that totalled 31 kilometres,” he said. “They also drilled a three-metre hole into the surface, the deepest made in an object outside Earth, left a range of instrument packages behind them, and then brought back a 76kg of rock back to Earth.

“Opportunity took 10 years before it managed to run up a travel total of 31km. More to the point, it returned no samples of any kind, did no drilling and returned only limited data.”

The contrast between the scientific returns of the two approaches is revealed by examining the number of scientific papers based on the Apollo missions, says Crawford. These vastly outnumber the papers produced from all the robot missions that have been carried out on the Moon and Mars. And the number of publications based on Apollo sample is still rising. “Its scientific legacy has been far greater than any other mission we have made to another world,” said Crawford.

It was a legacy that was bought at a considerable price, however. The Apollo missions in the 1960s and 1970s cost $25bn –more than $100bn today. From this perspective, manned missions are more than 100 times more expensive than robot missions, it is calculated. In the early days of spaceflight, there was little alternative to putting humans in spacecraft. But now robotics has achieved an advanced status and is constantly becoming more sophisticated. Martian rovers can navigate rocky terrains, drill holes and analyse soil samples – using 20th-century technology.

“Just consider the Rosetta mission,” argues Rees. “It was designed using 1990s technology – when mobile phones were the size of bricks. Now they are compact and contain a wide array of different functions. Imagine what Rosetta would have been able to do if it had been built from that technology. Imagine what future robot spacecraft will be able to do.”

Supporters of manned spaceflight, such as Professor Martin Barstow, of Leicester University, accept human flights are much more expensive but say they are justifiable because they are much, much more effective than robot missions: “Consider Mars. You could get robots to scrape its surface and send back material to Earth, but if you want to hunt down the few places that might still support primitive life you will need to send humans. Only they possess the necessary intuition for that kind of task.”

Others point to the inspirational effects of putting men in space. In the 1960s astronauts such as Yuri Gagarin and Neil Armstrong stimulated youngsters into careers in science because manned flights create heroes who spark an interest in technology. But again this claim is disputed. If a classroom today displays space photographs, these are more likely to be glorious images of stars and galaxies taken by the Hubble space telescope than pictures of astronauts. “It’s the robot probe that captures interest today,” said Rees. “The only time an astronaut makes news is when a space station toilet gets blocked.”

In short, the jury is still out over the future of humans in space. However, one thing is clear: we may one day return to other worlds, like the Moon and maybe Mars, but current global economic problems suggest these trips will happen later rather than sooner.

OUT OF THIS WORLD: A SHORT HISTORY

Yuri Gagarin became the first human to fly in space when he orbited the Earth in his Vostok spacecraft on 12 April 1961. His mission was followed by a series of flights - by the US and the Soviet Union - of larger and larger capsules. These culminated in the lunar landings of the US Apollo programme in the late 60s and early 70s.

The 12 men who landed on the Moon on Apollo spacecraft are the only humans to have walked on another world.

After the Apollo programme was brought to a premature close, largely due to lack of public interest in the US, America concentrated its efforts on constructing a fleet of reusable space shuttles. These were intended to become the nation’s primary means of launching payloads into orbit and were to be launched once a week when fully operational according to Nasa’s ambitious timetable. The first shuttle, Columbia, was launched on 12 April 1981.

Thirty years later the fleet was retired after a total of only 135 flights - including two catastrophic accidents which destroyed the shuttles Challenger and Columbia and killed each of their seven-person crews.

Since then, the only craft capable of carrying astronauts to the International Space Station has been Russia’s Soyuz space capsule.

At the same time the Chinese have pursued their own manned spaceflight programme, which began in 2003, when Yang Liwei became the first person sent into space by the Chinese space programme after orbiting the Earth 14 times in his Shenzhou 5 capsule, making China the third country to independently send humans into space.