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."
In his first extended press conference at the White House, the president railed against his critics and unspooled a series of bitter complaints.
Have you ever had a job you loved, but one where you felt like you’d achieved everything you could? So you looked for a new job, went through a fairly grueling application process, if you do say so yourself, got the offer. Then you started the job, and you hated it. Worse, all the tricks you’d learned in your old job seemed to be pretty much useless in the new one. Did you ever have that experience?
The president of the United States can sympathize.
Donald Trump held the first extended press conference of his presidency on Thursday, and it was a stunning, disorienting experience. He mused about nuclear war, escalated his feud with the press, continued to dwell on the vote count in November, asked whether a black reporter was friends with the Congressional Black Caucus, and, almost as an afterthought, announced his selection for secretary of labor.
Plagues, revolutions, massive wars, collapsed states—these are what reliably reduce economic disparities.
Calls to make America great again hark back to a time when income inequality receded even as the economy boomed and the middle class expanded. Yet it is all too easy to forget just how deeply this newfound equality was rooted in the cataclysm of the world wars.
The pressures of total war became a uniquely powerful catalyst of equalizing reform, spurring unionization, extensions of voting rights, and the creation of the welfare state. During and after wartime, aggressive government intervention in the private sector and disruptions to capital holdings wiped out upper-class wealth and funneled resources to workers; even in countries that escaped physical devastation and crippling inflation, marginal tax rates surged upward. Concentrated for the most part between 1914 and 1945, this “Great Compression” (as economists call it) of inequality took several more decades to fully run its course across the developed world until the 1970s and 1980s, when it stalled and began to go into reverse.
Neither truck drivers nor bankers would put up with a system like the one that influences medical residents’ schedules.
The path to becoming a doctor is notoriously difficult. Following pre-med studies and four years of medical school, freshly minted M.D.s must spend anywhere from three to seven years (depending on their chosen specialty) training as “residents” at an established teaching hospital. Medical residencies are institutional apprenticeships—and are therefore structured to serve the dual, often dueling, aims of training the profession’s next generation and minding the hospital’s labor needs.
How to manage this tension between “education and service” is a perennial question of residency training, according to Janis Orlowski, the chief health-care officer of the Association of American Medical Colleges (AAMC). Orlowski says that the amount of menial labor residents are required to perform, known in the profession as “scut work,” has decreased "tremendously" since she was a resident in the 1980s. But she acknowledges that even "institutions that are committed to education … constantly struggle with this,” trying to stay on the right side of the boundary between training and taking advantage of residents.
It’s a great physics thought experiment—and an awful accident in 1978.
What would happen if you stuck your body inside a particle accelerator? The scenario seems like the start of a bad Marvel comic, but it happens to shed light on our intuitions about radiation, the vulnerability of the human body, and the very nature of matter. Particle accelerators allow physicists to study subatomic particles by speeding them up in powerful magnetic fields and then tracing the interactions that result from collisions. By delving into the mysteries of the universe, colliders have entered the zeitgeist and tapped the wonders and fears of our age.
By excusing Donald Trump’s behavior, some evangelical leaders enabled the internet provocateur’s ascent.
The Conservative Political Action Conference (CPAC) takes place this week near Washington, D.C., the first such gathering since Donald Trump took office. The conference purports to be a gathering for like-minded folks who believe, generally, in the well-established principles of the conservative movement, as enunciated by the American Conservative Union.
This year, aside from President Trump himself, activist Milo Yiannopoulos was briefly granted a featured speaking slot, and it caused a lot of disruption, garment-rending, gnashing of teeth, and in-fighting on the right.
Yiannopoulos, who prefers to go by MILO (yes, capitalized), is a controversial figure with dubious conservative credentials, most famous for being outrageous during speeches on his college campus tour, soberly called the “Dangerous Faggot” tour. Throughout the 2016 election, Yiannopoulos seemed to enjoy nothing quite so much as the crass, antagonistic side of candidate Trump. He didn’t just celebrate it; he rode it like a wave to greater stardom.
The preconditions are present in the U.S. today. Here’s the playbook Donald Trump could use to set the country down a path toward illiberalism.
It’s 2021, and President Donald Trump will shortly be sworn in for his second term. The 45th president has visibly aged over the past four years. He rests heavily on his daughter Ivanka’s arm during his infrequent public appearances.
Fortunately for him, he did not need to campaign hard for reelection. His has been a popular presidency: Big tax cuts, big spending, and big deficits have worked their familiar expansive magic. Wages have grown strongly in the Trump years, especially for men without a college degree, even if rising inflation is beginning to bite into the gains. The president’s supporters credit his restrictive immigration policies and his TrumpWorks infrastructure program.
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The Italian philosopher Julius Evola is an unlikely hero for defenders of the “Judeo-Christian West.”
In the summer of 2014, years before he became the White House chief strategist, Steve Bannon gave a lecture via Skype at a conference held inside the Vatican. He spoke about the need to defend the values of the “Judeo-Christian West”—a term he used 11 times—against crony capitalism and libertarian capitalism, secularization, and Islam. He also mentioned the late Julius Evola, a far-right Italian philosopher popular with the American alt-right movement. What he did not mention is that Evola hated not only Jews, but Christianity, too.
References to Evola abounded on websites such as Breitbart News, The Daily Stormer, and AltRight.com well before The New York Timesnoted the Bannon-Evola connection earlier this month. But few have discussed the fundamental oddity of Evola serving as an intellectual inspiration for the alt-right. Yes, the thinker was a virulent anti-Semite and Nazi sympathizer who influenced far-right movements in Italy from the 1950s until his death in 1974, but shouldn’t his contempt for Christianity make him an unlikely hero for those purporting to defend “Judeo-Christian” values?
Trump’s attacks on the free press don’t just threaten the media—they undermine the public’s capacity to think, act, and defend democracy.
Are Donald Trump’s latest attacks on the press really that bad? Are they that out-of-the-ordinary, given the famous record of complaints nearly all his predecessors have lodged? (Even George Washington had a hostile-press problem.)
Are the bellows of protest from reporters, editors, and others of my press colleagues justified? Or just another sign that the press is nearly as thin-skinned as Trump himself, along with being even less popular?
I could prolong the buildup, but here is the case I’m going to make: Yes, they’re that bad, and worse.
I think Trump’s first month in office, capped by his “enemy of the people” announcement about the press, has been even more ominous and destructive than the Trump of the campaign trail would have prepared us for, which is of course saying something. And his “lying media” campaign matters not only in itself, which it does, but also because it is part of what is effectively an assault by Trump on the fundamentals of democratic governance.
The provocateur at the center of the controversy that engulfed the right this weekend offers a qualified mea culpa.
NEW YORK — Milo Yiannopoulos has a new mode, and it’s contrition.
Yiannopoulos appeared before reporters on Tuesday in a rented Soho loft to announce his resignation from Breitbart News and apologize to abuse victims for over-a-year-old remarks on pedophilia that incited a political firestorm over the weekend. Wearing a conservative navy blue suit and sunglasses, which he switched to regular glasses shortly into the conference, Yiannopoulous read a prepared statement in which he said he had been the victim of sexual abuse between the ages of 13 and 16. Yiannopoulos said he was “partly to blame” for the remarks on the tape and that he was “certainly guilty of imprecise language.”
“I haven’t ever apologized before,” Yiannopoulos said. “I don’t anticipate ever doing it again. Name-calling doesn’t bother me, misreporting doesn’t bother me. But to be a victim of child abuse and for the media to call me an apologist for child abuse is absurd. I regret the things I said. I don't think I've been as sorry about anything in my whole life.”