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."
Ted Cruz suspends his campaign after losing Indiana, all but assuring the front-runner of the Republican nomination.
“Republican nominee Donald Trump.”
That phrase, once the stuff of fantasy, is now all but set in stone. The entertainer scored a huge victory on Tuesday in Indiana, as Senator Ted Cruz of Texas announced that he was ending his bid for president after being routed in the Hoosier State.
Trump will be the first major-party nominee without prior experience in elected office since General Dwight Eisenhower in 1952. With most of the vote in, Trump was on course to win around a large majority of the state’s 57 delegates. Those numbers, the subject of obsessive calculation and analysis over the last month, have now become somewhat academic. With Cruz out of the race, Trump is effectively assured of winning a majority of the delegates ahead of the July Republican National Convention in Cleveland.
Rampant drug use in Austin, Indiana—coupled with unemployment and poor living conditions—brought on a public-health crisis that some are calling a “syndemic.”
Jessica and Darren McIntosh were too busy to see me when I arrived at their house one Sunday morning. When I returned later, I learned what they’d been busy with: arguing with a family member, also an addict, about a single pill of prescription painkiller she’d lost, and injecting meth to get by in its absence. Jessica, 30, and Darren, 24, were children when they started using drugs. Darren smoked his first joint when he was 12 and quickly moved on to snorting pills. “By the time I was 13, I was a full-blown pill addict, and I have been ever since,” he said. By age 14, he’d quit school. When I asked where his caregivers were when he started using drugs, he laughed. “They’re the ones that was giving them to me,” he alleged. “They’re pill addicts, too.”
When Apple announced in 2013 that its next iPhone would include a fingerprint reader, it touted the feature as a leap forward in security. Many people don’t set up a passcode on their phones, Apple SVP Phil Schiller said at the keynote event where the Touch ID sensor was unveiled, but making security easier and faster might convince more users to protect their phones. (Of course, Apple wasn’t the first to stuff a fingerprint reader into a flagship smartphone, but the iPhone’s Touch ID took the feature mainstream.)
The system itself proved quite secure—scanned fingerprints are stored, encrypted, and processed locally rather than being sent to Apple for verification—but the widespread use of fingerprint data to unlock iPhones worried some experts. One of the biggest questions that hung over the transition was legal rather than technical: How might a fingerprint-secured iPhone be treated in a court of law?
A claymation video with a grim plot line accompanies a blessedly straightforward if nerve-wracking tune.
Radiohead’s music often works like a puzzle, and it’s not clear whether many people ever solved the one posed by their 2011 album, The King of Limbs, whose funereal swirl only fleetingly provided the beauty and pop payoff that defined the band’s previous work.
Today’s new Radiohead song, “Burn the Witch,” blessedly does not hide its power. Sonically novel yet viscerally moving, gorgeous yet terrifying, it is the sound of Radiohead returning to do what it exists to do. The video is a claymation retelling of The Wicker Man, in which a police officer arrives at a town that is—spoiler alert!—secretly preparing to burn him in a ritual sacrifice. Thom Yorke’s lyrics speak of the kind of mass action and complacency that allows such a crime and, the logic probably goes, many other cruelties committed by societies.
The billionaire’s bid for the nomination was opposed by many insiders—but his success reveals the ascendance of other elements of the party coalition.
In The Party Decides, an influential book about how presidential nominees are selected, political scientists John Zaller, Hans Noel, David Karol, and Marty Cohen argue that despite reforms designed to wrest control of the process from insiders at smoke-filled nominating conventions, political parties still exert tremendous influence on who makes it to general elections. They do so partly through “invisible primaries,” the authors posited—think of how the Republican establishment coalesced around George W. Bush in 2000, long before any ballots were cast, presenting him as a fait accompli to voters who’d scarcely started to think about the election; or how insider Democrats elevated Hillary Clinton this election cycle.
Nearly half of Americans would have trouble finding $400 to pay for an emergency. I’m one of them.
Since 2013,the Federal Reserve Board has conducted a survey to “monitor the financial and economic status of American consumers.” Most of the data in the latest survey, frankly, are less than earth-shattering: 49 percent of part-time workers would prefer to work more hours at their current wage; 29 percent of Americans expect to earn a higher income in the coming year; 43 percent of homeowners who have owned their home for at least a year believe its value has increased. But the answer to one question was astonishing. The Fed asked respondents how they would pay for a $400 emergency. The answer: 47 percent of respondents said that either they would cover the expense by borrowing or selling something, or they would not be able to come up with the $400 at all. Four hundred dollars! Who knew?
The Texas senator stepped out of this year’s race after a stinging defeat by Donald Trump in Indiana. But he’s not going anywhere.
In the end, Republicans didn’t much like Ted Cruz.
The party establishment hated him from the start. He had nearly single-handedly destroyed their effort to govern in Congress in the age of Obama, and he insulted GOP leaders in a way that left party elders aghast. When former Speaker John Boehner called Cruz “Lucifer in the flesh,” what was most noteworthy wasn’t the barb itself but how little protest it generated in Washington. The establishment would have preferred almost anyone else as their standard-bearer in 2016. Really: Almost anyone else—including, for many of them, Donald Trump, a man who these same top Republicans viewed as a usurper, a phony who talked tough and learned just enough of the conservative language to hoodwink the party’s faithful in state after state.
The Republican front-runner’s repetition of a blatantly ridiculous story about Ted Cruz’s father shows his symbiotic relationship with the press.
Brace yourselves for shock, but Donald Trump said something ridiculous and baseless Tuesday morning. The subject was Rafael Cruz, Cuban-born father of his primary remaining rival, Senator Ted Cruz.
“His father was with Lee Harvey Oswald prior to Oswald's being—you know, shot. I mean, the whole thing is ridiculous,” Trump said during a phone interview with Fox News. “What is this, right prior to his being shot, and nobody even brings it up. I mean, they don't even talk about that. That was reported, and nobody talks about it.”
Let’s clear a few things up: It has been reported, which is why Trump knows about it, but it was reported in the National Enquirer. Also there is no evidence for it; it’s bogus. Yes, the National Enquirer has been right about some things in the past, most notably John Edwards’s affair; no, that does not prove that it is right about this.
It’s a paradox: Shouldn’t the most accomplished be well equipped to make choices that maximize life satisfaction?
There are three things, once one’s basic needs are satisfied, that academic literature points to as the ingredients for happiness: having meaningful social relationships, being good at whatever it is one spends one’s days doing, and having the freedom to make life decisions independently.
But research into happiness has also yielded something a little less obvious: Being better educated, richer, or more accomplished doesn’t do much to predict whether someone will be happy. In fact, it might mean someone is less likely to be satisfied with life.
That second finding is the puzzle that Raj Raghunathan, a professor of marketing at The University of Texas at Austin’s McCombs School of Business, tries to make sense of in his recent book, If You’re So Smart, Why Aren’t You Happy?Raghunathan’s writing does fall under the category of self-help (with all of the pep talks and progress worksheets that that entails), but his commitment to scientific research serves as ballast for the genre’s more glib tendencies.
A professor of cognitive science argues that the world is nothing like the one we experience through our senses.
As we go about our daily lives, we tend to assume that our perceptions—sights, sounds, textures, tastes—are an accurate portrayal of the real world. Sure, when we stop and think about it—or when we find ourselves fooled by a perceptual illusion—we realize with a jolt that what we perceive is never the world directly, but rather our brain’s best guess at what that world is like, a kind of internal simulation of an external reality. Still, we bank on the fact that our simulation is a reasonably decent one. If it wasn’t, wouldn’t evolution have weeded us out by now? The true reality might be forever beyond our reach, but surely our senses give us at least an inkling of what it’s really like.