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."
No one will ever find a closer exoplanet—now the race is on to see if there is life on its surface.
One hundred and one years ago this October, a Scottish astronomer named Robert Innes pointed a camera at a grouping of stars near the Southern Cross, the defining feature of the night skies above his adopted Johannesburg. He was looking for a small companion to Alpha Centauri, our closest neighboring star system.
Hunched over glass photographic plates, Innes teased out a signal. Across five years of images, a small, faint star moved, wiggling on the sky. It shifted just as much as Alpha Centauri, suggesting its fate was intertwined with that binary system. But this small star was closer to the sun than Alpha. Innes suggested calling it Proxima Centauri, using the Latin word for “nearest.”
The dim red star soon entered the collective imagination, inspiring dreams of interstellar travel. Gravity has linked the star to the Alpha Centauri system, but our culture of science and storytelling has linked it to the solar system. Today, that link will grow stronger, when an international team of astronomers announces that this nearest of stars also hosts the closest exoplanet, one that might look a whole lot like Earth.
A new anatomical understanding of how movement controls the body’s stress response system
Elite tennis players have an uncanny ability to clear their heads after making errors. They constantly move on and start fresh for the next point. They can’t afford to dwell on mistakes.
Peter Strick is not a professional tennis player. He’s a distinguished professor and chair of the department of neurobiology at the University of Pittsburgh Brain Institute. He’s the sort of person to dwell on mistakes, however small.
“My kids would tell me, dad, you ought to take up pilates. Do some yoga,” he said. “But I’d say, as far as I’m concerned, there's no scientific evidence that this is going to help me.”
Still, the meticulous skeptic espoused more of a tennis approach to dealing with stressful situations: Just teach yourself to move on. Of course there is evidence that ties practicing yoga to good health, but not the sort that convinced Strick. Studies show correlations between the two, but he needed a physiological mechanism to explain the relationship. Vague conjecture that yoga “decreases stress” wasn’t sufficient. How? Simply by distracting the mind?
Do mission-driven organizations with tight budgets have any choice but to demand long, unpaid hours of their staffs?
Earlier this year, at the encouragement of President Obama, the Department of Labor finalized the most significant update to the federal rules on overtime in decades. The new rules will more than double the salary threshold for guaranteed overtime pay, from about $23,000 to $47,476. Once the rules go into effect this December, millions of employees who make less than that will be guaranteed overtime pay under the law when they work more than 40 hours a week.
Unsurprisingly, some business lobbies and conservatives disparaged the rule as unduly burdensome. But pushback also came from what might have been an unexpected source: a progressive nonprofit called the U.S. Public Interest Research Group (PIRG). “Doubling the minimum salary to $47,476 is especially unrealistic for non-profit, cause-oriented organizations,” U.S. PIRG said in a statement. “[T]o cover higher staffing costs forced upon us under the rule, we will be forced to hire fewer staff and limit the hours those staff can work—all while the well-funded special interests that we're up against will simply spend more.”
City dwellers spend nearly every moment of every day awash in wi-fi signals. Homes, streets, businesses, and office buildings are constantly blasting wireless signals every which way for the benefit of nearby phones, tablets, laptops, wearables, and other connected paraphernalia.
When those devices connect to a router, they send requests for information—a weather forecast, the latest sports scores, a news article—and, in turn, receive that data, all over the air. As it communicates with the devices, the router is also gathering information about how its signals are traveling through the air, and whether they’re being disrupted by obstacles or interference. With that data, the router can make small adjustments to communicate more reliably with the devices it’s connected to.
If his administration gets its way, it would be even easier for future commanders in chief to take military action without approval from Congress.
President Obama has been emphatically warning Americans about the dangers of a Trump presidency. But these warnings divert attention from a much darker reality. His Justice Department is in fact pushing the law in a direction that will enable the next president to declare war against any “terrorist” group or nation without the consent of Congress.
This reality is clear from the Department’s response to a lawsuit challenging the legality of Obama’s war against the Islamic State.
In 1973, Congress passed the War Powers Resolution over President Richard Nixon’s veto. It represented the culmination of a national effort to prevent future presidents from repeating Nixon’s unilateral escalations in Vietnam. The Resolution provides that, when a president commits American forces to a new military engagement, he has 60 days to gain the explicit authorization of Congress for the war. If Congress refuses its consent, the Resolution requires the commander in chief to withdraw his forces from the battlefield within the next 30 days.
A new survey suggests the logistics of going to services can be the biggest barrier to participation—and Americans’ faith in religious institutions is declining.
The standard narrative of American religious decline goes something like this: A few hundred years ago, European and American intellectuals began doubting the validity of God as an explanatory mechanism for natural life. As science became a more widely accepted method for investigating and understanding the physical world, religion became a less viable way of thinking—not just about medicine and mechanics, but also culture and politics and economics and every other sphere of public life. As the United States became more secular, people slowly began drifting away from faith.
Of course, this tale is not just reductive—it’s arguably inaccurate, in that it seems to capture neither the reasons nor the reality behind contemporary American belief. For one thing, the U.S. is still overwhelmingly religious, despite years of predictions about religion’s demise. A significant number of people who don’t identify with any particular faith group still say they believe in God, and roughly 40 percent pray daily or weekly. While there have been changes in this kind of private belief and practice, the most significant shift has been in the way people publicly practice their faith: Americans, and particularly young Americans, are less likely to attend services or identify with a religious group than they have at any time in recent memory.
This much is obvious: Young people don’t buy homes like they used to.
In the aftermath of the recession and weak recovery, the share of 18- to- 34 year olds—a.k.a.: Millennials—who own a home has fallen to a 30-year low. For the first time on record going back more than a century, young people are now more likely to live with their parents than with a spouse.
It’s become en vogue to argue that young people’s turn against homeownership might be a good thing. After all, houses are not always dependable investment vehicles, a lesson the country learned all too painfully after the Great Recession. Without being anchored to any one city from their mid-20s and into their 30s, young people who don’t own are free to roam about the country in search of the best jobs. What’s more, given the copious advantages of a college degree in this economy, perhaps many young people could be commended for investing in their intelligence, professional networks, and abilities rather than devote that same income to a roof, floor, and furniture.
The many obstacles trans men and other transmasculine people run into when feeding infants
When Trevor MacDonald started chestfeeding about five years ago, he didn't know anyone who had attempted it, nor had any of his doctors ever encountered someone who had. In fact, he was shocked that his body could even produce milk. As a trans man—someone who was assigned female at birth but has transitioned to identifying as male—he was born with the mammary glands and milk ducts required for lactation, but he'd had his breasts removed. Once he had his baby, his care providers supported his desire to nurse, but it was up to him figure out how.
MacDonald began blogging about chestfeeding from his home in Winnipeg, Manitoba, and soon discovered a whole community of transmasculine people around the world in the same boat, looking for guidance. For trans men and transmasculine folks, putting a baby to their chest to suckle can lead to complicated feelings about their gender. Many lactation support services are available for “nursing mothers,” which sounds unwelcoming to men and non-binary individuals. And many trans people say doctors don’t understand their bodies or experiences.