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."
It isn’t the only democratic institution that finds itself in danger.
Four years ago, as a speechwriter for President Obama, I commissioned a binder full of women.
A little context. It was the morning of the Al Smith Dinner, the election-year tradition in which both parties’ nominees don white-tie attire and deliver comedy monologues to New York City’s elite. Our opponent, Governor Mitt Romney had recently used the words “binders full of women” while discussing gender parity in government. Eager to mock the clumsy phrase, I asked a staffer on the advance team to put together a prop.
But our binder never saw the light of day. Obama nixed the idea. I remember being disappointed by the president’s decision, and wondering if POTUS was phoning it in. Of the jokes that did make it into the final draft, one in particular stood out for its authenticity.
The easiest way to take down the web is to attack people’s access to it.
For more than two hours on Friday morning, much of the web seemed to grind to a halt—or at least slow to dial-up speed—for many users in the United States.
More than a dozen major websites experienced outages and other technical problems, according to user reports and the web-tracking site downdetector.com. They included The New York Times, Twitter, Pinterest, Reddit, GitHub, Etsy, Tumblr, Spotify, PayPal, Verizon, Comcast, EA, the Playstation network, and others.
How was it possible to take down all those sites at once?
Someone attacked the architecture that held them together—the domain-name system, or DNS, the technical network that redirects users from easy-to-remember addresses like theatlantic.com to a company’s actual web servers. The assault took the form of a distributed denial-of-service attack (DDoS) on one of the major companies that provides other companies access to DNS. A DDoS attack is one in which an attacker floods sites “with so much junk traffic that it can no longer serve legitimate visitors,” as the security researcher Brian Krebs put it in a blog post Friday morning.
The candidates are back on the campaign trail, following the third, and final, debate on Wednesday night.
It’s Friday, October 21—the election is now less than three weeks away. Donald Trump and Hillary Clinton are back on the campaign trail to deliver their final pitch to voters, ahead of Election Day. We’ll bring you the latest updates from the trail, as events unfold. Also see our continuing coverage:
AT&T is reportedly in advanced talks to buy Time Warner, South Africa says it will leave the ICC, ISIS attacks Kirkuk, and more from across the United States and around the world.
—The Wall Street Journal is reporting that a deal for AT&T to buy Time Warner could come as early as this weekend. More here
—South Africa has notified the UN that it is withdrawing from The Hague-based International Criminal Court. A government minister said South Africa didn’t want to carry out ICC arrest warrants against other African leaders—warrants, he said, that would lead to “regime change.” More here
—ISIS, under sustained attack in its last major Iraqi stronghold, Mosul, attacked the city of Kirkuk. At least 19 people are dead in the attacks. More here
Science says lasting relationships come down to—you guessed it—kindness and generosity.
Every day in June, the most popular wedding month of the year, about 13,000 American couples will say “I do,” committing to a lifelong relationship that will be full of friendship, joy, and love that will carry them forward to their final days on this earth.
Except, of course, it doesn’t work out that way for most people. The majority of marriages fail, either ending in divorce and separation or devolving into bitterness and dysfunction. Of all the people who get married, only three in ten remain in healthy, happy marriages, as psychologist Ty Tashiro points out in his book The Science of Happily Ever After, which was published earlier this year.
Social scientists first started studying marriages by observing them in action in the 1970s in response to a crisis: Married couples were divorcing at unprecedented rates. Worried about the impact these divorces would have on the children of the broken marriages, psychologists decided to cast their scientific net on couples, bringing them into the lab to observe them and determine what the ingredients of a healthy, lasting relationship were. Was each unhappy family unhappy in its own way, as Tolstoy claimed, or did the miserable marriages all share something toxic in common?
Theories on what’s behind one of the biggest puzzles facing America today
U.S. economic growth is anemic, and the country needs to do something about it, quickly. This was one of the central themes of the third presidential debate. “China is growing at 7 percent. And that for them is a catastrophically low number. We are growing—our last report came out, and it is right around the 1 percent level,” Trump said Wednesday night. “Look, our country is stagnant.”
Trump is right that U.S. growth has not been very impressive of late, especially when compared to rates of the past. Though the United States gross domestic product (GDP) grew at a rate of more than 3 percent for much of the 1980s and 1990s, the rate has slowed significantly since the recession, according to the Bureau of Economic Analysis. In the second quarter of this year, for instance, GDP increased at a rate of just 1.4 percent. After a recession, an economy should come roaring back, but this time around, it hasn’t, and that’s left many concerned about the state of the economy. GDP growth, economists say, helps raise wages and living standards, and increases the size of the entire economic pie—making it possible for more people to have a bigger share.
How the national mythos and U.S. labor laws influence geographic mobility.
Kevin Bacon moves from a big city to a small town in Middle America where dancing is outlawed. Ralph Macchio moves from New Jersey to California, where he learns the art of life and combat. Dianne Wiest moves with her two sons to a California town stocked with vampires.
The trope of American families settling in faraway places isn’t just a plotline for terrible 1980s movies, but a national phenomenon. Decades of data, including a more recent Gallup study, characterizes the United States as one of the most geographically mobile countries in the world. “About one in four U.S. adults (24 percent) reported moving within the country in the past five years,” the report noted. With the comparable exceptions of Finland (23 percent) and Norway (22 percent), Americans also move considerably more than their European peers.
Among the major sites that had trouble staying online or functioning properly: The New York Times, Twitter, Pinterest, Reddit, GitHub, Etsy, Tumblr, Spotify, PayPal, Verizon, Comcast, EA, and the Playstation network. Aside from the inconvenience to those attempting to visit those sites, there’s the question of how an attack like this affects the companies who run those sites. System outages—even seemingly brief ones—can have huge repercussions on the bottom line.
Why her vow not to “add a penny to the debt” is an impossible pledge to keep
Hillary Clinton said nothing on Wednesday night that should derail her considerable chances of winning the presidency on November 8. But if she wins, one simple promise she repeated over and over again could come back to haunt her reelection bid in 2020.
“I also will not add a penny to the debt,” Clinton said toward the beginning of her final presidential-debate performance. She made a similar pledge two more times that night, and it’s a line she has used before on the campaign trail. It’s a short-hand reference to the fact that although she has proposed hundreds of billions in new federal spending for infrastructure, paid family leave, education, and other items, she would pay for those investments by raising an equal or greater amount in revenue through higher taxes on the wealthy and corporations.
An interview with Bill O’Reilly Monday night distilled many of the struggles the Late Show host has had in his first year on the job.
Almost 10 years ago, Stephen Colbert appeared on Fox News’ The O’Reilly Factor in character as the Colbert Report host—a pugnacious, egotistical super-pundit who tolerates no criticism. Colbert has frequently acknowledged that O’Reilly was the chief inspiration for his on-screen persona, and it was hilarious to see the imitation go up against the real thing. “What I do, Bill, is I catch the world in the headlights of my justice,” Colbert bragged to a smirking O’Reilly. “I’m not afraid of anything. Well, I might be afraid of you.” The same day, O’Reilly went on Colbert’s show; the combative tension between the two remains genuinely thrilling to watch.
On Monday night O’Reilly went on The Late Show With Stephen Colbert to talk about the state of the Republican Party and Fox News. The conversation was civil, at times energetic, but mostly bland. O’Reilly, clearly far more at ease, pontificated on the state of the Trump campaign while dodging any discussion of some of its biggest controversies. Ultimately, it was a notable reminder of just how much things have changed for Colbert since he cast off his late-night character and joined CBS. To stand out in a crowded landscape, Colbert has pursued even-handedness and empathy, a drastic swerve away from his former public persona. It’s an approach both noble and misguided, but a year into his Late Show run, it’s kept him firmly out of the zeitgeist.