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."
Rioting broke out on Monday in Baltimore—an angry response to the death of Freddie Gray, a death my native city seems powerless to explain. Gray did not die mysteriously in some back alley but in the custody of the city's publicly appointed guardians of order. And yet the mayor of that city and the commissioner of that city's police still have no idea what happened. I suspect this is not because the mayor and police commissioner are bad people, but because the state of Maryland prioritizes the protection of police officers charged with abuse over the citizens who fall under its purview.
The citizens who live in West Baltimore, where the rioting began, intuitively understand this. I grew up across the street from Mondawmin Mall, where today's riots began. My mother was raised in the same housing project, Gilmor Homes, where Freddie Gray was killed. Everyone I knew who lived in that world regarded the police not with admiration and respect but with fear and caution. People write these feelings off as wholly irrational at their own peril, or their own leisure. The case against the Baltimore police, and the society that superintends them, is easily made:
Freddie Gray's death on April 19 leaves many unanswered questions. But it is clear that when Gray was arrested in West Baltimore on the morning of April 12, he was struggling to walk. By the time he arrived at the police station a half hour later, he was unable to breathe or talk, suffering from wounds that would kill him.*
Gray died Sunday from spinal injuries. Baltimore authorities say they're investigating how the 25-year-old was hurt—a somewhat perverse notion, given that it was while he was in police custody, and hidden from public view, that he apparently suffered injury. How it happened remains unknown. It's even difficult to understand why officers arrested Gray in the first place. But with protestors taking to the streets of Baltimore since Gray's death on Sunday, the incident falls into a line of highly publicized, fatal encounters between black men and the police. Meanwhile, on Tuesday, a reserve sheriff's deputy in Tulsa, Oklahoma, pleaded not guilty to a second-degree manslaughter charge in the death of a man he shot. The deputy says the shooting happened while he was trying to tase the man. Black men dying at the hands of the police is of course nothing new, but the nation is now paying attention and getting outraged.
In Baltimore, where 25-year-old Freddie Gray died shortly after being taken into police custody, an investigation may uncover homicidal misconduct by law enforcement, as happened in the North Charleston, South Carolina, killing of Walter Scott. Or the facts may confound the darkest suspicions of protestors, as when the Department of Justice released its report on the killing of Michael Brown.
What's crucial to understand, as Baltimore residents take to the streets in long-simmering frustration, is that their general grievances are valid regardless of how this case plays out. For as in Ferguson, where residents suffered through years of misconduct so egregious that most Americans could scarcely conceive of what was going on, the people of Baltimore are policed by an entity that perpetrates stunning abuses. The difference is that this time we needn't wait for a DOJ report to tell us so. Harrowing evidence has been presented. Yet America hasn't looked.
Cinderella marries Prince Charming. Aladdin weds Princess Jasmine. In 50 Shades of Grey, Ana falls for Christian. From bedtime stories to films, we are exposed to a repeated idea: that love, or at least lust, crosses class lines. In fiction, cross-class relationships either end in marriage and happily-ever-after, or else in dissolution and even death. But what happens in real life?
Last year, I set out to answer this question by interviewing college-educated men and women who had married partners from different class backgrounds, for my book The Power of the Past: Understanding Cross-Class Marriages. Not surprisingly, their relationships had little in common with the romances we see in the movies.Class had shaped each spouse so much that the people I interviewed had more in common with strangers.
On Monday, Americans watched televised images of riots and looting in Baltimore, Maryland, where days of peaceful protests sparked by the killing of Freddie Gray gave way to mayhem in at least several locations. As CNN broadcast scenes of young people looting a CVS pharmacy and police cars burning in the streets, its commentators, including anchor Wolf Blitzer, criticized Baltimore officials for allowing such flagrant lawlessness to transpire. "I keep asking where are the police," he said. "They seem to be invisible." In fact, law enforcement had come under attack by high school students throwing cinder blocks, dispersed that crowd, and had officers massed at several spots, just not the particular corner where the news helicopter trained its cameras. The anchor treated truths not captured on CNN's video feeds as if they didn't exist. Americans should avoid that sort of myopia.
“As a basic principle, we can’t tell you to stop recording,” says Delroy Burton, chairman of D.C.’s metropolitan police union and a 21-year veteran on the force. “If you’re standing across the street videotaping, and I’m in a public place, carrying out my public functions, [then] I’m subject to recording, and there’s nothing legally the police officer can do to stop you from recording.”
“What you don’t have a right to do is interfere,” he says. “Record from a distance, stay out of the scene, and the officer doesn’t have the right to come over and take your camera, confiscate it.”
Officers do have a right to tell you to stop interfering with their work, Burton told me, but they still aren’t allowed to destroy film.
Does Adam Sandler have an expiration date? Does his particular brand of slapstick—humor that's infused with a wan self-deprecation, that manages to be simultaneously silly and sociopathic, that once found Sandler punching Bob Barker in the face while informing him that "the price is wrong, bitch"—hold up? Is Sandler's own price now, finally, wrong?
Recent events would suggest yes. Late last week, in the course of filming Sandler's newest project, the made-for-Netflix Western spoof The Ridiculous 6, a Native-American cultural advisor and several performers and extras walked off the set in protest. (Sample characters: Beaver Breath, No Bra, Sits-on-Face. Sample line: "Say honey: how about after this, we go someplace and I put my peepee in your teepee?") As Allison Young, a Navajo actress who quit after being asked to do a scene "requiring her to fall down drunk, surrounded by jeering white men who rouse her by dousing her with more alcohol" told the Indian Country Media Network, “We talked to the producers about our concerns. They just told us, ‘If you guys are so sensitive, you should leave.’”
Police say that intentionally banging a suspect around in the back of a van isn't common practice. But the range of slang terms to describe the practice suggests it's more common that anyone would hope—and a roster of cases show that Freddie Gray is hardly the first person whose serious injuries allegedly occurred while in police transit. Citizens have accused police of using aggressive driving to rough suspects up for decades in jurisdictions across the country. Though experts don't think it's a widespread practice, rough rides have injured many people, frayed relationships, and cost taxpayers, including Baltimore's, millions of dollars in damages.
Atheism is intellectually fashionable. In the past month, The New York Times has run severalstories about lack of faith in its series on religion. The New Yorker ran an article on the history of non-belief in reaction to twonew books on the subject that were released within a week of each other in February. The veteran writer, Adam Gopnik, concludes this:
What the noes, whatever their numbers, really have now … is a monopoly on legitimate forms of knowledge about the natural world. They have this monopoly for the same reason that computer manufacturers have an edge over crystal-ball makers: The advantages of having an actual explanation of things and processes are self-evident.
This is a perfect summary of the intellectual claim of those who set out to prove that God is dead and religion is false: Atheists have legitimate knowledge, and those who believe do not. This is the epistemological assumption looming in the so-called “culture war” between the caricatures of godless liberals and Bible-thumping conservatives in America: One group wields rational argumentation and intellectual history as an indictment of God, while the other looks to tradition and text as defenses against modernity’s encroachment on religious life.
In a recent dispatch from Ferguson, Missouri, Jelani Cobb noted that President Obama's responses to "unpunished racial injustices" constitute "a genre unto themselves." Monday night, when Barack Obama stood before the nation to interpret the non-indictment of Darren Wilson for the killing of Michael Brown, he offered a particularly tame specimen. The elements of "the genre" were all on display—an unmitigated optimism, an urge for calm, a fantastic faith in American institutions, aneven-handedness exercised to a fault. But if all the limbs of the construct were accounted for, the soul of the thing was not.
There was none of the spontaneous annoyance at the arrest of Henry Louis Gates, and little of the sheer pain exhibited in the line, "If I had a son, he'd look like Trayvon." The deft hand Obama employed in explaining to Americans why the acquittal of George Zimmerman so rankled had gone arthritic. This was a perfunctory execution of "the genre," offered with all the energy of a man ticking items off a to-do list.