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."
Senator John McCain and White House Chief of Staff John Kelly offered starkly different visions of service—and of America.
It was a week of powerful speeches. The least memorable, oddly, was delivered by the most naturally gifted speaker, former President Barack Obama at a campaign rally in Virginia. “Our democracy is at stake,” he said, before harking back to the trope of his 2008 campaign: “Yes, we can.” Compelling in the setting, but not special.
Far more powerful was former President George W. Bush’s indictment of Donald Trump that didn’t mention the 45th president by name. It was a cry for freedom as a theme in American policy, a denunciation of “casual cruelty” in American discourse, of “nationalism distorted into nativism,” of isolationism, of attempts to turn American identity away from American ideals and into something darker, driven by “geography or ethnicity, by soil or blood.” In itself it would have been noteworthy.
Emma Perrier was deceived by an older man on the internet—a hoax that turned into an unbelievable love story.
Emma Perrier spent the summer of 2015 mending a broken heart, after a recent breakup. By September, the restaurant manager had grown tired of watching The Notebook alone in her apartment in Twickenham, a leafy suburb southwest of London, and decided it was time to get back out there. Despite the horror stories she’d heard about online dating, Emma, 33, downloaded a matchmaking app called Zoosk. The second “o” in the Zoosk logo looks like a diamond engagement ring, which suggested that its 38 million members were seeking more than the one-night stands offered by apps like Tinder.
She snapped the three selfies the app required to “verify her identity.” Emma, who is from a volcanic city near the French Alps, not far from the source of Perrier mineral water, is petite, and brunette. She found it difficult to meet men, especially as she avoided pubs and nightclubs, and worked such long hours at a coffee shop in the city’s financial district that she met only stockbrokers, who were mostly looking for cappuccinos, not love.
A stunning new speculative-fiction book by Naomi Alderman couldn’t be more timely.
One of the most succinct definitions of sexual harassment I’ve read over the past few weeks goes like this: For men, it’s anything they might say to a woman that would make them uncomfortable if it were said to them, but in prison. It’s glib, sure. But it gets at the fundamental imbalance of power that characterizes relationships between men and women. To understand what it’s like for a woman to be catcalled, or harassed, or propositioned, it isn’t enough for men to simply put themselves in that woman’s place. They also have to imagine what it’s like to sense the imminent danger in those interactions—to be weaker than their aggressor in every way, and to have that weakness woven into the fabric of society itself. As the adage often attributed to Margaret Atwood goes, “Men are afraid that women will laugh at them. Women are afraid that men will kill them.”
More comfortable online than out partying, post-Millennials are safer, physically, than adolescents have ever been. But they’re on the brink of a mental-health crisis.
One day last summer, around noon, I called Athena, a 13-year-old who lives in Houston, Texas. She answered her phone—she’s had an iPhone since she was 11—sounding as if she’d just woken up. We chatted about her favorite songs and TV shows, and I asked her what she likes to do with her friends. “We go to the mall,” she said. “Do your parents drop you off?,” I asked, recalling my own middle-school days, in the 1980s, when I’d enjoy a few parent-free hours shopping with my friends. “No—I go with my family,” she replied. “We’ll go with my mom and brothers and walk a little behind them. I just have to tell my mom where we’re going. I have to check in every hour or every 30 minutes.”
Those mall trips are infrequent—about once a month. More often, Athena and her friends spend time together on their phones, unchaperoned. Unlike the teens of my generation, who might have spent an evening tying up the family landline with gossip, they talk on Snapchat, the smartphone app that allows users to send pictures and videos that quickly disappear. They make sure to keep up their Snapstreaks, which show how many days in a row they have Snapchatted with each other. Sometimes they save screenshots of particularly ridiculous pictures of friends. “It’s good blackmail,” Athena said. (Because she’s a minor, I’m not using her real name.) She told me she’d spent most of the summer hanging out alone in her room with her phone. That’s just the way her generation is, she said. “We didn’t have a choice to know any life without iPads or iPhones. I think we like our phones more than we like actual people.”
Four families of fallen servicemembers received next-day UPS letters from President Trump after a turbulent week in which Trump falsely claimed he had called “virtually all” of the families.
Updated on October 22, 2017.
The Trump administration is scrambling to defend the president’s characterization of his communications with grieving military families, including rush-delivering letters from the president to the families of servicemembers killed months ago. Donald Trump falsely claimed this week that he had called “virtually” all fallen servicemembers’ families since his time in office.
Timothy Eckels Sr. hadn’t heard anything from President Trump since his son Timothy Eckels Jr. was killed after a collision involving the USS John S. McCain on August 21. But then, on October 20, two days into the controversy over the president’s handling of a condolence call with an American soldier’s widow, Eckels Sr. received a United Parcel Service package dated October 18 with a letter from the White House.
A neuroscientist on how we came to be aware of ourselves.
Ever since Charles Darwin published On the Origin of Species in 1859, evolution has been the grand unifying theory of biology. Yet one of our most important biological traits, consciousness, is rarely studied in the context of evolution. Theories of consciousness come from religion, from philosophy, from cognitive science, but not so much from evolutionary biology. Maybe that’s why so few theories have been able to tackle basic questions such as: What is the adaptive value of consciousness? When did it evolve and what animals have it?
The Attention Schema Theory (AST), developed over the past five years, may be able to answer those questions. The theory suggests that consciousness arises as a solution to one of the most fundamental problems facing any nervous system: Too much information constantly flows in to be fully processed. The brain evolved increasingly sophisticated mechanisms for deeply processing a few select signals at the expense of others, and in the AST, consciousness is the ultimate result of that evolutionary sequence. If the theory is right—and that has yet to be determined—then consciousness evolved gradually over the past half billion years and is present in a range of vertebrate species.
Monday afternoon, President Trump delivered a press conference from an alternative reality, or perhaps a slightly-less-dark timeline. His relationship with Mitch McConnell is great! They have the votes for Obamacare repeal! The hurricane relief effort in Puerto Rico is a smashing success! Democrats are to blame for GOP divisions on Capitol Hill! These claims range from the highly dubious to the patently false.
A new bookfollows Joseph Lister as he ushers surgery into the modern age.
Joseph Lister came of age as surgery was being transformed. With the invention of anesthesia, operations could move beyond two-minute leg amputations that occasionally lopped off a testicle in haste. (True story.) But as surgeons poked and prodded deeper into the body, surgery only became more deadly.
It was the infections that killed people.
And it was Lister who first realized that germ theory has profound implications for medicine. In a new biography of Lister, Lindsey Fitzharris argues that the invention of antisepsis marks the true beginning of modern surgery. The Butchering Art: Joseph Lister’s Quest to Transform the Grisly World of Victorian Medicine takes its title from Lister’s own notes, where he writes of his love for “this bloody and butcherly department of the healing art.”
The foundation of Donald Trump’s presidency is the negation of Barack Obama’s legacy.
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Honoring the sacrifice of servicemembers requires understanding why they were put at risk, and demanding that those who did so hold themselves to account.
On Thursday morning, I planned to write a pointed screed decrying President Trump’s propensity to view the military community as a problem he can buy off with a check. Then, on Thursday afternoon, White House Chief of Staff John Kelly, himself a Gold Star father, decried the noxious politicization of the deaths of servicemembers and how we treat their families in the aftermath. His remarks gave me pause, as they were meant to.
“Let’s not let this maybe last thing that’s held sacred in our society, a young man, young woman, going out and giving his or her life for our country, let’s … keep that sacred” he implored, lamenting the ugly and voyeuristic events of the past week.
Who better to set the protocol and define the limits of this sacred space than a father who lost his son in Afghanistan? Unless you’ve walked in his shoes, don’t ask questions.