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."
The Islamic State is no mere collection of psychopaths. It is a religious group with carefully considered beliefs, among them that it is a key agent of the coming apocalypse. Here’s what that means for its strategy—and for how to stop it.
What is the Islamic State?
Where did it come from, and what are its intentions? The simplicity of these questions can be deceiving, and few Western leaders seem to know the answers. In December, The New York Times published confidential comments by Major General Michael K. Nagata, the Special Operations commander for the United States in the Middle East, admitting that he had hardly begun figuring out the Islamic State’s appeal. “We have not defeated the idea,” he said. “We do not even understand the idea.” In the past year, President Obama has referred to the Islamic State, variously, as “not Islamic” and as al-Qaeda’s “jayvee team,” statements that reflected confusion about the group, and may have contributed to significant strategic errors.
Maya Arulpragasam is a famous rapper, singer, designer, producer, and refugee. When she was 9, her mother and siblings fled violence in Sri Lanka and came to London, and the experience was formative for her art. As she explained to The Guardian in 2005 after the release of her debut Arular, “I was a refugee because of war and now I have a voice in a time when war is the most invested thing on the planet. What I thought I should do with this record is make every refugee kid that came over after me have something to feel good about. Take everybody’s bad bits and say, ‘Actually, they’re good bits. Now whatcha gonna do?’”
That goal—to glorify people and practices that the developed world marginalizes—has been a constant in her career. Her new music video tackles it in a particularly literal and urgent way, not only by showing solidarity with refugees at a moment when they’re extremely controversial in the West, but also by posing a simple question to listeners: Whose lives do you value?
Without the financial support that many white families can provide, minority young people have to continually make sacrifices that set them back.
The year after my father died, I graduated from grad school, got a new job, and looked forward to saving for a down payment on my first home, a dream I had always had, but found lofty. I pulled up a blank spreadsheet and made a line item called “House Fund.”
That same week I got a call from my mom—she was struggling to pay off my dad’s funeral expenses. I looked at my “House Fund” and sighed. Then I deleted it and typed the words “Funeral Fund” instead.
My father’s passing was unexpected. And so was the financial burden that came with it.
For many Millennials of color, these sorts of trade-offs aren’t an anomaly. During key times in their lives when they should be building assets, they’re spending money on basic necessities and often helping out family. Their financial future is a rocky one, and much of it comes down to how much—or how little—assistance they receive.
In the name of emotional well-being, college students are increasingly demanding protection from words and ideas they don’t like. Here’s why that’s disastrous for education—and mental health.
Something strange is happening at America’s colleges and universities. A movement is arising, undirected and driven largely by students, to scrub campuses clean of words, ideas, and subjects that might cause discomfort or give offense. Last December, Jeannie Suk wrote in an online article for The New Yorker about law students asking her fellow professors at Harvard not to teach rape law—or, in one case, even use the word violate (as in “that violates the law”) lest it cause students distress. In February, Laura Kipnis, a professor at Northwestern University, wrote an essay in The Chronicle of Higher Education describing a new campus politics of sexual paranoia—and was then subjected to a long investigation after students who were offended by the article and by a tweet she’d sent filed Title IX complaints against her. In June, a professor protecting himself with a pseudonym wrote an essay for Vox describing how gingerly he now has to teach. “I’m a Liberal Professor, and My Liberal Students Terrify Me,” the headline said. A number of popular comedians, including Chris Rock, have stopped performing on college campuses (see Caitlin Flanagan’s article in this month’s issue). Jerry Seinfeld and Bill Maher have publicly condemned the oversensitivity of college students, saying too many of them can’t take a joke.
The generation has been called lazy, entitled, and narcissistic. Their bosses beg to differ.
Yes, many Millennials are still crashing on their parent’s couches. And there’s data to support the claim that they generally want more perks but less face time, and that they hope to rise quickly but don’t stick around for very long. Millennials have also been pretty vocal about their desire to have more flexible jobs and more leave time.
But does all of this mean that all Millennials are actually worse workers?
Laura Olin, a digital campaigner who ran social-media strategy for President Obama’s 2012 campaign, says that’s not been her experience. “You always hear about Millennials supposedly being entitled and needing coddling, but the ones I’ve encountered have been incredibly hard-working and recognize that they need to pay their dues.”
To solve climate change, we need to reimagine our entire relationship to the nonhuman world.
Humans were once a fairly average species of large mammals, living off the land with little effect on it. But in recent millennia, our relationship with the natural world has changed as dramatically as our perception of it.
There are now more than 7 billion people on this planet, drinking its water, eating its plants and animals, and mining its raw materials to build and power our tools. These everyday activities might seem trivial from the perspective of any one individual, but aggregated together they promise to leave lasting imprints on the Earth. Human power is now geological in scope—and if we are to avoid making a mess of this, our only home, our politics must catch up.
Making this shift will require a radical change in how we think about our relationship to the natural world. That may sound like cause for despair. After all, many people refuse to admit that environmental crises like climate change exist at all. But as Jedediah Purdy reminds us in his dazzling new book, After Nature, our relationship with the nonhuman world has proved flexible over time. People have imagined nature in a great many ways across history.
Jeb Bush, John Kasich, and other presidential contenders appease Donald Trump at their own peril.
Give Donald Trump this: He has taught Americans something about the candidates he’s running against. He has exposed many of them as political cowards.
In August, after Trump called undocumented Mexican immigrants “rapists” and vowed to build a wall along America’s southern border, Jeb Bush traveled to South Texas to respond. Bush’s wife is Mexican American; he has said he’s “immersed in the immigrant experience”; he has even claimed to be Hispanic himself. Yet he didn’t call Trump’s proposals immoral or bigoted, since that might offend Trump’s nativist base. Instead, Bush declared: “Mr. Trump’s plans are not grounded in conservative principles. His proposal is unrealistic. It would cost hundreds of billions of dollars.” In other words, demonizing and rounding up undocumented Mexican immigrants is fine, so long as it’s done cheap.
While Saint Nicholas may bring gifts to good boys and girls, ancient folklore in Europe's Alpine region also tells of Krampus, a frightening beast-like creature who emerges during the Yule season, looking for naughty children to punish in horrible ways—or possibly to drag back to his lair in a sack.
While Saint Nicholas may bring gifts to good boys and girls, ancient folklore in Europe's Alpine region also tells of Krampus, a frightening beast-like creature who emerges during the Yule season, looking for naughty children to punish in horrible ways—or possibly to drag back to his lair in a sack. In keeping with pre-Germanic Pagan traditions, men dressed as these demons have been frightening children on Krampusnacht for centuries, chasing them and hitting them with sticks, on an (often alcohol-fueled) run through the dark streets.
Why are so many kids with bright prospects killing themselves in Palo Alto?
The air shrieks, and life stops. First, from far away, comes a high whine like angry insects swarming, and then a trampling, like a herd moving through. The kids on their bikes who pass by the Caltrain crossing are eager to get home from school, but they know the drill. Brake. Wait for the train to pass. Five cars, double-decker, tearing past at 50 miles an hour. Too fast to see the faces of the Silicon Valley commuters on board, only a long silver thing with black teeth. A Caltrain coming into a station slows, invites you in. But a Caltrain at a crossing registers more like an ambulance, warning you fiercely out of its way.
The kids wait until the passing train forces a gust you can feel on your skin. The alarms ring and the red lights flash for a few seconds more, just in case. Then the gate lifts up, signaling that it’s safe to cross. All at once life revives: a rush of bikes, skateboards, helmets, backpacks, basketball shorts, boisterous conversation. “Ew, how old is that gum?” “The quiz is next week, dipshit.” On the road, a minivan makes a left a little too fast—nothing ominous, just a mom late for pickup. The air is again still, like it usually is in spring in Palo Alto. A woodpecker does its work nearby. A bee goes in search of jasmine, stinging no one.
What I learned from attending a town-hall meeting and listening to students’ concerns
Sometimes it takes a group of young people to set you straight.
For months now, I’ve been reading about college students who’ve been seeking “safe spaces.” They’ve often been met by derision—even the highest ranked Urban Dictionary definition is mired in sarcasm, describing them as having “pillows” and “soothing music” that “allows them to recover from the trauma... of exposure to ideas that conflict with their leftist professors.”
I also had some mid-life skepticism about teenage hyperbole, that is, until I attended a town hall meeting at Duke University (my alma mater) earlier this month. The “community conversation,” as it was called, had been hastily convened to discuss the rash of racist and homophobic incidents on campus. Listening to those students—and watching their expressions—I realized that what’s been happening at Duke is serious, and no amount of sarcasm can disguise the pain and anger on campus, or cover up the real dangers lurking there.