The conventional wisdom of space exploration suggests that robotic probes are both more scientifically efficient and cost effective. Not so, argues a professor of planetary science.
Astronaut Edwin E. Aldrin Jr., lunar module pilot, poses beside the deployed flag of the United States during the Apollo XI moon landing July 20, 1969. [Reuters]
When the Space Shuttle Atlantis rolled to a stop in July 2011, NASA bid farewell to the nation's symbol of manned spaceflight. The Obama administration has scrapped NASA's plan to return humans to the Moon by 2020, which was behind schedule because of technical and budgetary problems. As financial constraints threaten the possibility of future ventures into outer space, many in the astronomical community are advocating for the increased use of unmanned robotic
space, arguing that they will serve as more efficient explorers of planetary surfaces
than astronauts. The next giant leap, then, will be taken with robotic feet.
At the core of Crawford's argument is that human beings are much better at performing the type of geological fieldwork that makes planetary exploration scientifically valuable: they're faster and significantly more versatile than even the most advanced autonomous probes. "People who argue for robotic exploration argue for more artificial intelligence, the capacity for robots to make more complex decisions that somehow leads to increased efficiency," explains Crawford. "But one of the things that make them cheap is miniaturization.You can make robots more intelligent and efficient to a certain point, but they wont get smaller and therefore cheaper." With miniaturization, he explains, comes a depletion in the number of scientific instruments a probe can carry, the number of samples it can collect, and its ability to cover more ground. " [Mars rovers] Spirit and Opportunity are fantastic things on Mars, but the fact that they've traveled as far in eight years as the Apollo astronauts traveled in three days speaks volumes." At a certain point, the costs of developing 'smarter' (but not better equipped) autonomous rovers will exceed the meager gains in scientific collection and outstrip existing scientific budgets.
The advantages of human over robot explorers are recognized in the planetary sciences community: a 2005 report by the Commission on the Scientific Case for Human Space Exploration noted that "the expert evidence we have heard strongly suggests that the use of autonomous robots alone will very significantly limit what can be learned about our nearest potentially habitable planet." Steve Squyres, the Principal Investigator for the Mars Exploration Rovers Spirit and Opportunity, conceded in his book Roving Mars that "[t]he unfortunate truth is that most things our rovers can do in a perfect sol [a martian day] a human explorer could do in less than a minute." But Crawford also expresses concerns over the capacity of robots for "making serendipitous discoveries."
"We may be able to make robots smarter, but they'll never get tot he point where they can make on the spot decisions in the field, where they can recognize things for being important even if you don't expect them or anticipate them," argues Crawford. "You can't necessarily program a robot to recognize things out of the blue."
The other downside of a shift towards robotic exploration is the decline of samples, the real meat of the planetary sciences. Robotic expeditions have always been one-way trips: the probes go, land, take readings, and don't come back. But the collection and prolonged study of planetary samples are real drivers of scientific knowledge, which Crawford measures in terms of published scientific literature:
Several things are immediately apparent from Figure 2. Most obvious is the sheer
volume of Apollo's scientific legacy compared to the other missions illustrated. This
alone goes a long way to vindicate the points made above about human versus robotic
efficiency. The second point to note is that the next most productive set of missions
are the lunar sample return missions Lunas 16, 20 and 24, which highlights the
importance of sample return. Indeed, a large part of the reason why Apollo has
resulted in many more publications than the Luna missions is due to the much larger
quantity and diversity of the returned samples which, as we have seen, will always be
greater in the context of human missions. The third point to note is that, despite being
based on data obtained and samples collected over 40 years ago, and unlike the Luna,
Lunokhod, or Surveyor publications, which have clearly levelled off, the Apollo
publication rate is still rising. Indeed, it is actually rising as fast as, or faster than, the
publications rate derived from the Mars Exploration Rovers, despite the fact that data
derived from the latter are much more recent. No matter how far one extrapolates into
the future, it is clear that the volume of scientific activity generated by the MERs, or
other robotic exploration missions, will never approach that due to Apollo.
"We're still benefiting from the scientific legacy of those few soil samples brought by the Apollo mission, but we can only do this because we went to the Moon, got these samples, and came back," says Crawford. "If we sent a rover to Mars along with a return vehicle, that would enormously increase its scientific impact, but that's hasn't been implemented yet because its still incredibly expensive. If a mission goes to Mars, lands in one place, bring back half a kilogram of Mars rocks, it will be immensely valuable, but compared to Apollo, which not only visited six sites (and many hundred of sites with the help of the lunar rover) but came back with 382 kilograms of lunar material, it sort of pales in comparison."
While robotic probes find a permanent home on a planetary surface, sending manned expeditions inherently means planning for a return trip. Would a manned trip to Mars, replete with a sample-laden return vehicle, yield a similar explosion in scientific literature? Crawford thinks so. "A Martian expedition would be 5 or 10 times more expensive than Apollo in real terms, but not so much more expensive that it would negate the added benefit of being able to collect samples. They'll bring back a much larger quantity and diversity of samples than a robotic mission, and this is especially important with regards to Mars: there are reasons for wanting more lunar samples, but Mars is a much bigger and much more geologically diverse planet, with a much more complicated geology so much more inconceivably complicated history than the Moon, we won't get a full sense of its history or evolution just by scraping around on the surface with these smalls robot probes."
The scientific impact of these moon rocks is compelling: our whole
chronology of the solar system is built on the radiometric dating of the
Apollo samples. "The top scientific benefit is that it's been possible
to date areas of the lunar surface. We have this curve that plots crater density versus age, which we can use to get an estimated age of
virtually anywhere else in the Solar System," explains Crawford.
"The last major eruption of Olympus Mons [on Mars] was 400 million years
ago, and the only way we have this measurement is because of Apollo
So why, then, are scientists resigned to sending probes and rovers to the corners of the galaxy? Scientists, argues Crawford, tend to look at the enormous costs for Apollo, which nobody will ever be able to afford again, as an artificial baseline for gradual streamlining of space exploration. This is the wrong approach to take "There's lots of collective amnesia as to how efficient Apollo really was, which is really the only example of exploring the surface of another planet," explains Crawford. "An enormous amount was achieved in a very short total contact time with the lunar surface."
Planners feel the microscopic formations in Mars meteorite ALH84001, found in Antarctica, and the highly diverse samples of rocks believed to have been strewn about by ancient rivers seen at the Mars Pathfinder landing site, provide a strong motive for sending human exobiologists and geologists to the Red Planet. [Pat Rawlings/NASA]
But Crawford recognizes that, despite its benefits for scientific research, manned missions are subject to domestic forces and rarely undertaken for the sake of science alone. The United States was willing to shoulder the enormous costs of the Apollo mission because of the geopolitical and economic interests (namely, besting the Soviet Union), an argument advanced most recently by science communicator Neil DeGrasse Tyson.
"Science was the beneficiary of a human spaceflight mission that was undertaken for geopolitical purposes," explains Crawford. "The total costs is large, but the best way for scientists to look at it is not 'this is a science function.' They need to look at Apollo as the confluence of geopolitical, industrial, and social factors. You need all of these things to spend the money necessary."
Crawford's theory, then, is not necessarily targeted towards the general public: he recognizes the difficulty of justifying an expensive manned mission with no immediate economic benefit (although he notes notes that the 1987 NASA procurement of $8.6 billion generated a turnover of $17.8 billion and created 209,000 private sector jobs, according to an article in Nature), especially in the throes of an global economic downturn. His main argument, then is those scientists consigning themselves to a future of interstellar probes are shooting themselves in the foot. Ventures like the James Webb Space Telescope may hit the ceiling for government expenditures on purely scientific ventures, but researchers and scientists can -- and should -- try to make the case for manned spaceflight in other contexts, if only for the sake of maximizing the scientific gains made from planetary exploration.
"Humans bring a net benefit to space exploration that, in my opinion, outweighs the costs," says Crawford. "But people need to realize that the overall case for manned spaceflight is multifaceted, a totality woven out of these different strands, of which science is one. Industry, innovation, inspirational value -- all of these factors must be addressed before manned spaceflight can return."
He lives near San Francisco, makes more than $50,000 per year, and is voting for the billionaire to fight against political correctness.
For several days, I’ve been corresponding with a 22-year-old Donald Trump supporter. He is white, has a bachelor’s degree, and earns $50,000 to $60,000 per year.
He lives near San Francisco.
“I recently became engaged to my Asian fiancée who is making roughly 3 times what I make, and I am completely supportive of her and proud she is doing so well,” he wrote. “We’ve both benefitted a lot from globalization. We are young, urban, and have a happy future planned. We seem molded to be perfect young Hillary supporters,” he observed, “but we're not. In 2016, we're both going for Trump.”
At first, we discussed Bill Clinton.
Last week, I wrote an article asking why Trump supporters aren’t bothered that their candidate called Clinton a shameful abuser of women who may well be a rapist. After all, Trump used to insist that Clinton was a victim of unfair treatment during his sex scandals. Either Trump spent years defending a man that he believed to be a sexual predator, even welcoming him as a guest at his wedding, or Trump is now cynically exploiting a rape allegation that he believes to be false.
Finally, an explanation for Bitchy Resting Face Nation
Here’s something that has always puzzled me, growing up in the U.S. as a child of Russian parents. Whenever I or my friends were having our photos taken, we were told to say “cheese” and smile. But if my parents also happened to be in the photo, they were stone-faced. So were my Russian relatives, in their vacation photos. My parents’ high-school graduation pictures show them frolicking about in bellbottoms with their young classmates, looking absolutely crestfallen.
It’s not just photos: Russian women do not have to worry about being instructed by random men to “smile.” It is Bitchy Resting Face Nation, seemingly forever responding “um, I guess?” to any question the universe might pose.
This does not mean we are all unhappy! Quite the opposite: The virile ruler, the vodka, the endless mounds of sour cream—they are pleasing to some. It’s just that grinning without cause is not a skill Russians possess or feel compelled to cultivate. There’s even a Russian proverb that translates, roughly, to “laughing for no reason is a sign of stupidity.”
Demonizing processed food may be dooming many to obesity and disease. Could embracing the drive-thru make us all healthier?
Late last year, in a small health-food eatery called Cafe Sprouts in Oberlin, Ohio, I had what may well have been the most wholesome beverage of my life. The friendly server patiently guided me to an apple-blueberry-kale-carrot smoothie-juice combination, which she spent the next several minutes preparing, mostly by shepherding farm-fresh produce into machinery. The result was tasty, but at 300 calories (by my rough calculation) in a 16-ounce cup, it was more than my diet could regularly absorb without consequences, nor was I about to make a habit of $9 shakes, healthy or not.
Inspired by the experience nonetheless, I tried again two months later at L.A.’s Real Food Daily, a popular vegan restaurant near Hollywood. I was initially wary of a low-calorie juice made almost entirely from green vegetables, but the server assured me it was a popular treat. I like to brag that I can eat anything, and I scarf down all sorts of raw vegetables like candy, but I could stomach only about a third of this oddly foamy, bitter concoction. It smelled like lawn clippings and tasted like liquid celery. It goes for $7.95, and I waited 10 minutes for it.
The Democratic insurgent’s campaign is losing steam—but his supporters are not ready to give up.
SANTA MONICA, Calif.—This is how a revolution ends: its idealism tested, its optimism drained, its hope turned to bitterness.
But if Bernie Sanders’s revolution has run aground in California, which will be one of the last states to vote in the Democratic primary on June 7, he was not about to admit it here, where thousands gathered on a sun-drenched high-school football field of bright green turf.
“We are going to win here in California!” Sanders said, to defiant cheers. In the audience, a man waved a sign that said, “Oh HILL no!”
This is Sanders’s last stand, according to the official narrative of the corrupt corporate media, and if there is anything we have learned in the past year, it is the awesome power of the official narrative—the self-reinforcing drumbeat that dictates everything.
Narcissism, disagreeableness, grandiosity—a psychologist investigates how Trump’s extraordinary personality might shape his possible presidency.
In 2006, Donald Trump made plans to purchase the Menie Estate, near Aberdeen, Scotland, aiming to convert the dunes and grassland into a luxury golf resort. He and the estate’s owner, Tom Griffin, sat down to discuss the transaction at the Cock & Bull restaurant. Griffin recalls that Trump was a hard-nosed negotiator, reluctant to give in on even the tiniest details. But, as Michael D’Antonio writes in his recent biography of Trump, Never Enough, Griffin’s most vivid recollection of the evening pertains to the theatrics. It was as if the golden-haired guest sitting across the table were an actor playing a part on the London stage.
“It was Donald Trump playing Donald Trump,” Griffin observed. There was something unreal about it.
Three Atlantic staffers discuss “Blood of My Blood,” the sixth episode of the sixth season.
Every week for the sixth season of Game of Thrones, Christopher Orr, Spencer Kornhaber, and Lenika Cruz will be discussing new episodes of the HBO drama. Because no screeners are being made available to critics in advance this year, we'll be posting our thoughts in installments.
A rock structure, built deep underground, is one of the earliest hominin constructions ever found.
In February 1990, thanks to a 15-year-old boy named Bruno Kowalsczewski, footsteps echoed through the chambers of Bruniquel Cave for the first time in tens of thousands of years.
The cave sits in France’s scenic Aveyron Valley, but its entrance had long been sealed by an ancient rockslide. Kowalsczewski’s father had detected faint wisps of air emerging from the scree, and the boy spent three years clearing away the rubble. He eventually dug out a tight, thirty-meter-long passage that the thinnest members of the local caving club could squeeze through. They found themselves in a large, roomy corridor. There were animal bones and signs of bear activity, but nothing recent. The floor was pockmarked with pools of water. The walls were punctuated by stalactites (the ones that hang down) and stalagmites (the ones that stick up).
For centuries, philosophers and theologians have almost unanimously held that civilization as we know it depends on a widespread belief in free will—and that losing this belief could be calamitous. Our codes of ethics, for example, assume that we can freely choose between right and wrong. In the Christian tradition, this is known as “moral liberty”—the capacity to discern and pursue the good, instead of merely being compelled by appetites and desires. The great Enlightenment philosopher Immanuel Kant reaffirmed this link between freedom and goodness. If we are not free to choose, he argued, then it would make no sense to say we ought to choose the path of righteousness.
Today, the assumption of free will runs through every aspect of American politics, from welfare provision to criminal law. It permeates the popular culture and underpins the American dream—the belief that anyone can make something of themselves no matter what their start in life. As Barack Obama wrote in The Audacity of Hope, American “values are rooted in a basic optimism about life and a faith in free will.”
The U.S. president talks through his hardest decisions about America’s role in the world.
Friday, August 30, 2013, the day the feckless Barack Obama brought to a premature end America’s reign as the world’s sole indispensable superpower—or, alternatively, the day the sagacious Barack Obama peered into the Middle Eastern abyss and stepped back from the consuming void—began with a thundering speech given on Obama’s behalf by his secretary of state, John Kerry, in Washington, D.C. The subject of Kerry’s uncharacteristically Churchillian remarks, delivered in the Treaty Room at the State Department, was the gassing of civilians by the president of Syria, Bashar al-Assad.