This article is from the In-Depth Report The 40th Anniversary of Apollo 8's Journey to the Moon
Science Talk

Space For Both?--Human Vs. Robotic Space Missions

In this episode Cornell University astronomer Jim Bell talks about future space missions and why people need to be part of them. Bell is the leader of the team operating the color cameras on the Mars rovers, and the author of the book Postcards From Mars and of an opinion piece in the August issue of Scientific American on humans in space. Plus we'll test your knowledge of some recent science in the news. Websites mentioned in this episode include;

Science Talk July 18, 2007 -- Space for Both?—Human vs. Robotic Space Missions

Steve: Welcome to Science Talk, the weekly podcast of Scientific American for the seven days starting July 18th. I am Steve Mirsky. This week on the podcast:

Bell: People with training, who can use judgment and context can make decisions on the spot on Mars or on asteroids, or back on the moon.

Steve: That's Jim Bell, an astronomer and planetary scientist at Cornell University. We'll talk to him this week, plus we'll test your knowledge about some recent science in the news. Jim Bell is intermittently involved in the Mars Rovers mission and he has an opinion piece in the Forum section of the August issue of Scientific American about "Robotic Versus Human Spaceflight". To find out more about both subjects, I called Bell at his office at Cornell.

Steve: Hi Professor Bell. How are you doing today?

Bell: I am fine Steve. It's great to be here.

Steve: Good to talk to you. So first of all, you are the leader of the Pancam Team on the planet Mars right now. Tell us about that and how long has that taken out of your life and what have been some of the real challenges and rewards of working on that?

Bell: Well, the Pancams are the color cameras on the Mars Rovers, Spirit and Opportunity; and we have a team of about 20 or so people here at Cornell and dozens and dozens of other people at JPL and around the country who have been working with the rovers everyday for more than three and a half years now, collecting the camera pictures and other data from the surface of Mars. We use the camera data, of course, to learn about the geology; to help to drive the rovers from place to place—the robot driver's at JPL; to figure out where to put the arm down; and make detailed chemical measurements of the surface; and of course to take the spectacular and often times very beautiful photos of Mars. The cameras were designed and built to try to simulate what we would see if we were there. It's sort of 20/20 human vision—they can see in color, they can also see in the ultraviolet and the infrared, so they are a little better than human vision in many ways—but they provide our best view so far of what Mars would look like if we were there ourselves.

Steve: Talk a little bit about the book you have with some of those amazing images.

Bell: Yeah! The book is a sort of a typical kind of coffee table book called Postcards From Mars,and it is an attempt to showcase sort of the best 150 or so photos—including some large foldout panoramas—from what are now, more than, almost 200,000 photos from the mission. So, it's really an attempt to kind of capture the greatest hits, both from the standpoint of science, but also just beauty. Some of the shots these rovers have taken on Mars are just absolutely beautiful, provocative, poetic, desolate—I mean, so many adjectives. I would run out of adjectives to describe these photos.

Steve: Well, you know, a picture is worth at least a thousand words, probably more when you have pictures of an alien landscape there.

Bell: At least a thousand kilobytes. I am not sure about that.

Steve: (laughs) Okay, tell me about what's going on, on Mars right now. I've heard about this gigantic dust storm—and where does that put the rovers?

Bell: Right! Well Mars has dust storms all the time. Most of them are relatively small but occasionally—like right now—they grow to be larger and they spread over large parts of the planet. So there's a large region of the southern hemisphere and the equatorial region of Mars that's being covered by this dust storm, and the dust storms don't really provide any physical danger to the rovers, they don't shake the rovers around or [damage](unclear 4:00) them, things like that. What the danger [is,] is that they block the sunlight. They produce these dusty clouds in the atmosphere. The scenery gets very dark, the terrain gets very dark because the sun gets blotted out and these rovers are—they live by sunlight. They need solar power on their solar panels to recharge the batteries to run the instruments every day and so as the dust is blocking out the sun, they are sort of chocking off our lifeline to power, and that's the risk. Now so far, they've been able to sort of survive quite well, even though the dust is very high. We basically put them into a sort of a survival mode. We don't do any driving, we don't do a lot of activities; we just monitor the sunlight and just keep track of the variations from day to day as the storm is going on. However, if the storm continues or gets even more intense, and blocks out even more sunlight and maybe even some of that dust might settle onto the solar panels blocking out even more sunlight—then we could be in a very, very risky situation, and that we might not have enough power generated each day to recharge the batteries to run the heaters at night. And so we would have to dip into the batteries more and more and more everyday, and we would eventually discharge them entirely. But we don't anticipate that happening. We of course don't know how long that would really take to go into that sort of so-called death spiral with the rover, but you know that's a potential thing. This could happen, so we are obviously watching the storm very closely.

Steve: So the rovers are like professional athletes such as you hear about who are about slightly injured, they are day to day.

Bell: They are day to day. (laughs) That's terrific. They are day to day, and they do have some, you know, little bumps and small or minor ailments here and there. The right front wheel has stopped working on Spirit rover, the arm on the Opportunity rover is flaky—works on some days, doesn't work on other days. So they are showing their signs of age, but they still are definitely in the major leagues and still are pitching again.

Steve: And let's remind everybody that these things were designed for a useful life of, what is it again, 90 days?

Bell: They were designed for, right, 90 days on Mars, and right now we are at 1,256 on Spirit.

Steve: So you've done pretty well so far. Is there any kind of a system in place to get dust off of the collection panels, off of the solar panels?

Bell: No, not intentionally at least. We thought about designing you know some kind of a wiper or something like that, but you know it's a shell game. If you put something on like that, you have to take something out of, because you can only get so much mass volume into the rocket and we decided to not put a system like that on and just take the chance that we will able to survive at least 90 days. And we obviously, you know, won that bet, had no problems surviving 90 days and much longer.

Steve: Right, right.

Bell: It turns out that Mars itself has helped us a lot. When we get up to a windy ridge, the wind has blown the dust off the solar panels. It happened during our first Martian summer, several years ago. It's happened right now. We are in Martian summer again. It happened a month and half ago on Spirit, it happened just in the last few days on Opportunity. Wind comes along, blows the dust off, our power goes up.

Steve: It reminds me, there is a punch line to an old joke, you know: "If I’d known I was to going to live this long, I would've taken better care of myself."

Bell: (laughs)

Steve: If you had known it was going to last 1,200 days, maybe would have put a wiper on it.

Bell: I don't know, maybe.

Steve: So lets talk about your Forum piece in the current issue of Scientific American—it's called "Have Brain, Must Travel", and it's an interesting take from somebody who is so intermittently involved in unmanned missions into space. But why don't you tell us what your opinion is on this whole issue?

Bell: Steve, I think the common assumption is that there are sort of two camps: There is the robot people who do robotic exploration, and then there is the human astronaut, people who work on that side of NASA; and that you have to have—If you support robots, you are against human exploration and vice versa. And one of the points of my piece is that just isn't so. There are plenty of people who do robotic exploration work like myself, who are very strong supporters of human exploration. I mean that's what got me and many of my colleagues into the business in the first place. You know, watching guys bounce around on the moon, watching people in Skylab and in space shuttle. And you know those are the adventures, those are the human interest stories, those are the dramas that capture the attention of the public and the kids who eventually are going to go on to get into these kinds of science and engineering fields. And so the first premise is that just because you are for robotic exploration, doesn't mean you are against human exploration. But even more importantly than that, I try to make the case that, I think—if you are a supporter of robotic exploration—I think you ought to be a supporter of human exploration, because they are very intimately linked. One of the reasons why we have this very successful robotic exploration program—and it is phenomenally successful; I mean just if you think about the places that we've sent these robotic emissaries in the past few decades, it's absolutely incredible. Some of the greatest achievements of NASA in the last few decades have been made through robotic program. But the reasons that we have this successful robotic program is—in my opinion—has a lot to do with the public support and enthusiasm for the human exploration program. And that of course was at its apex during the Apollo when the entire point was to beat the Soviet Union to the moon, show the power of freedom and democracy—it was really a political statement that had some wonderful scientific exploration side effects to it. And the success of the robotic program really started during the Apollo mission since in—the robotic program is very, very successful in support of and even in some sense dragging the coat tails of the Apollo program. One of the things that I worry about, more recently, is that there is less and less support in the public for the human exploration program. Certainly the shuttle and the space station haven't turned out to be a kind of program that really captures public interest, They[that] capture[s] the imagination of kids, and that really inspire the public. That hasn't happened, and so I worry if that doesn't happen, if there is an invigorated program or a long-term effort to say, send astronauts to the moon and near-Earth asteroids, or Mars, or make some exciting compelling destination-driven human exploration program; if that doesn't happen, then I worry that the robotic program is going to whither as well because robotic programming, I believe, is just as dependent upon that public support to for the space program overall.

Steve: I was going to ask what you thought the primary places that we should send people were, and I guess you covered it—the moon, Mars and near-Earth asteroids.

Bell: Well those are the, I mean, more than the primary places, those are the only places right now, I mean. Nobody is really thinking hard about sending humans to the outer solar system. For example, it's a fundamentally different scale of problem. If you get farther from the sun, you need different power sources, the travel times are enormous, so that dictates a very different kind of vehicle as opposed to a few day trips to the moon or maybe a six-month or nine-month trip to Mars. Those seem to be manageable within sort of current technologies and current thinking about long-duration space flight. But now sending people [way] out way into the outer solar system, we're not there yet. It's coming, that day is coming, but we are not there yet, so the near-term destinations are, you know, close to home—the moon, near-earth asteroids; and then the closest place that we can get to easily that's not within near-earth environment is Mars. I mean Venus is close too, but that's a hellish environment on the surface, and we just don't have the technology to get people down there and survive in that environment yet.

Steve: What do we mean by near term?

Bell: What I mean by near term is in the next several decades. And a lot of my thinking on this was framed by a very interesting authored piece that NASA administrator, Mike Griffin, wrote recently for, I think, it was for Space News, where he tried to think about the next 50 years of NASA. I mean this is the time to do it because this is the 50th anniversary year of NASA, so [we've] had a half century of space exploration—what could the next half century look like? And, you know, he tries to lay out, you know, how this proposed program for [the] moon and Mars could evolve over the next few decades. If it has—and I think this is the key—it just has constant public support and, you know, if you look back throughout NASA's first 50 years, there is sort of a historical level, budget level of support; and public support often expresses itself as the budget level granted to a program by Congress. The Congress is representing the public after all. And he makes the case—which I think is a very compelling one, and I wanted to learn more about this myself—he makes the case that if NASA is just funded at the same level that it has been, in the next 50 years, [the] same level of what it has been for the past 50 years then we should be able to do things like sending people to the moon, perhaps even sending them onto Mars within the next several decades. If we can just maintain our focus, we can take this gift of the taxpayers to spend on this enterprise and just apply it towards a focussed, well-directed sort of destination-driven modular kind of program to get people reliably back into space and out of lower orbit. Now there is, you know, [a] lot of assumptions that go into that, and there is a lot of hopeful thinking about, you know, what the national budget is going to be like and whether, you know, the country will head down some different task that we'll see less and less support for human space exploration, but I want to remain optimistic. So in my optimistic view point, I think we are talking about the next several decades.

Steve: What do you get by sending people to a near-Earth asteroid or to Mars that you don't get with a robotic mission in addition to the actual experience of having human beings there and the inspiration that, that carries—I mean what do you actually get, from a scientific view point? What do you get to do that you can't do robotically?

Bell: Well there is no specific, one specific answer to that question; but I can give you an example that I sort of talk about in the opinion piece in Scientific American and that has to do with the ability of scientists, say geologists for example, to use judgment to react to a situation—and this is something that we actually saw in some of the Apollo missions, like the Apollo 17 for example. Harrison Schmidt is a geologist, and he was on the ground and turned and saw something that in his judgment was important. It was not clear that it would have been picked out by a robotic algorithm or even seen by a robotic mission, even sort of joysticked by people from the Earth. This was different kinds of gasses with different chemical compositions that he could spot from his training, his experience, his context. Well I think the same kinds of things are going to happen on Mars or on asteroids or back on the moon; in that people with training who can use judgment and context can make decisions on the spot for what kinds of samples to acquire or how to dig, or where to acquire samples, that just can't be put into a computer program, that can't be processed autonomously by a robotic mind. Robotic brains are good, they are getting better all the time, but I don't know if it will ever pass that threshold where they will have the same kind of judgment and learn from experience, learn from context, capabilities that human scientists do. I mean this is why we do our fieldwork on the Earth, we go to these places, we study them in person wherever we possibly can, and so that kind of experienced, context judgment, it's impossible to quantify, right? I can't tell you, well we are going to get 18 percent more science because of this. It's impossible to put it in that kind of framework. But will people be able to discover things, notice things, take a hunch and head down a path that leads to something entirely new and unexpected? Absolutely and I think that's one of the reason why it is critical to send people.

Steve: It's interesting you mentioned Harrison Schmidt. I was going to tell you a story about Harrison Schmidt. I was on an eclipse trip in 1991 and Harrison Schmidt was also on the trip to see a total solar eclipse; and Schmidt gave a talk in which he actually expressed the kind of existential view point of the reason to do things—just in terms of the most, I think it was, he said something like, the most important aspect of all of this—and he was talking about both going to the moon and seeing the solar eclipse, is the human experience that you get from it. So Schmidt who, as you just pointed out, brought his scientific training to bear on the moon, still thought that the most important aspect of his trip was as a representative of humanity experiencing this for us and for himself.

Bell: Well look, I would agree with you. You framed the question. You told me not to include inspirational kind of stuff, but I would completely agree with you. I think that probably number one is that inspirational, motivational, educational, non-quantifiable aspect of people pushing the edge that you know that we can experience—what's it like being there by having some of our colleagues from this planet being there for us or seeing that place through their eyes, or experiencing it through their emotions—and that is a huge driver, and [a] much, much more important driver in my opinion than most of the scientific goals that you can come up with; and maybe finding life on Mars would be a pretty big drive—okay, so that might be that one exception—but for most sort of the average everyday people who support the space program, it is that feeling of projecting ourselves through our colleagues, through our friends, through these very brave people who are themselves on the top of the rocket and experiencing space for us. I think that's a huge, huge factor; and that kind of enthusiasm we've seen to trickle down in the robotic program too. The way that these rovers are anthropomorphized to where the people relate to them, partly because they give us a humanlike experience of seeing through human-like eyes, of driving around, moving from place to place, of touching the ground with an arm and making some detailed measurements and sensing it. I think that kind of emotional connection trickle-down comes through the human exploration program.

Steve: The piece is in the August Scientific American is called "Have Brain, Must Travel", by Jim Bell. Professor Bell, thanks very much.

Bell: Thanks so much Steve. It's been a great time.

Steve: Jim Bell's article is also available free on our Web site; just go to and scroll all the way down to the Forum section for the piece, titled again, "Have Brain, Must Travel". Speaking of traveling, we'll be right back.

Male voice: Send your science videos to Scientific American and see if yours becomes a featured video. Follow the simple instructions at

Steve: Now it's time to play TOTALL.......Y BOGUS. Here are four science stories; only three are true, see if you know which story is TOTALL.......Y BOGUS.

Story number 1: Teenage girls' willingness to discuss their personal problems with friends helps them compared with more sullen and solitary teenage boys.

Story number 2: Reformed wildlife poachers in Zambia are selling jewelry made from the wire snares once used to catch the animals.

Story number 3: Brightly colored birds around Chernobyl are more affected by the toxic environment than our drab birds.

And Story number 4: Earthquakes along the ocean floor are smaller than you'd expect because sea floor faults are different than theory would have them.

Time is up.

Story number 4 is true. Many earthquakes in the deep ocean are much smaller than expected and researchers from the Woods Hole Oceanographic Institution, writing in the July 12th issue of the journal Nature think they know why. Plate tectonic theory says that transformed faults should be long fault lines on the sea floor, but the faults are in fact much more segmented and show signs of recent or current volcanism and with the falls busted up, the earthquakes are damped down.

Story number 3 is true. Drab birds are doing better in Chernobyl possibly because brightly colored birds expend their antioxidant molecules on flashy pigments while drab birds can use antioxidants to detox. For more, check out the July 18th episode of the daily SciAm podcast, 60-Seond Science.

And Story number 2 is true. Former poachers in Zambia are selling necklaces and bracelets made from the wire snares formerly used to trap wildlife. It's part of a program by the Wildlife Conservation Society in which poachers can turn in snares and guns in exchange for training in farming, carpentry and jewelry making. Over 40,000 snares and 800 firearms have been turned in with thousands of animals estimated to have been saved. For more, check out

All of which means that story number 1 about teen girls being better off because they talk to their girlfriends about personal problems is TOTALL.......Y BOGUS. Because teenage girls ruminating together about problems may actually help contribute to emotional difficulties. That's according to a study in the July issue of the journal Developmental Psychology. Researchers found that girls are more likely than boys of the same age group to develop anxiety and depression as a result of extensive conversations with their friends about their problems. Researchers call such conversations co-rumination, and for girls co-rumination did indeed help the friendship but the study also found an increase in depressive and anxiety symptoms, which in turn contributed to greater co-rumination. Interestingly for boys, co-rumination seemed to help the friendship but did not increase depression and anxiety. For college kids, co-rumination usually begins as soon as they move off campus.

Well that's it for this edition of the weekly Scientific American podcast. You can write to us at; check out news articles at our Web site,’ the daily SciAm podcast, 60-Second Science, is at the Web site and at iTunes. For Science Talk, the weekly podcast of Scientific American, I am Steve Mirsky. Thanks for clicking on us.

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