[applause] >> thank you. my presentation today is about the mars exploration rovers with robotic laboratories that began operating eight years ago on mars. one of which took several years to explore mars today and is as most of you know i am sure, curiosity i know they're rover

landed just a few weeks ago and i will have a few words to say about that at the end of my presentation. my story is about how people relate to these robotic systems. the mars exploration rover mission also known as mer challenge is how we usually think about the role of robots in space exploration. it provides a new way of understanding how computer tools and a proper social operation can be orchestrated to extend human capabilities. whether flying by beautiful blue neptune like voyager in the 1970s, orbiting saturn like you see today, or roving mars, like mer. the spacecraft must be computer controlled the cut is the communication time delay at the.

>> light and their great distance makes it impractical to control them directly from earth. weekend joystick a rover on the earth's moon. it takes about 1.5 seconds for the signal to be received, but that the speed a flight to mars at least five minutes away and sometimes 20 minutes. radio time to jupiter is on average about 45 minutes and saturn is twice that. when the new horizons spacecraft reaches pluto and its moon in 2015, after a nine year flight, it will take about four hours before we know whether the mission was a success and it will be long gone, passed pluto by that time. given the great distances we can go to these places in person anytime soon, so to carry out a scientific study, we must repeatedly reprogram and redirect the spacecraft

,-com,-com ma specifying where to go and how the various instrument are going to be used. science teams working together for five or 10 years or more interpreted the data that is returned and discuss with engineers what's interesting and what's possible to do next. so at its heart, the story of planetary exploration today is about the relation of people and robotic spacecraft. machines that are actually complex laboratories capable of operating in extreme cold with little power, package to handle the vibrations of launch and work for years without repair. sending the scientific instrumeninstrumen ts throughout the solar system is one of the great successes of the computer age and it it will surely market our place in history of science and exploration. that these missions also show that we understand how to design

machines and organize people so everything fits, and that is my story today about the mars exploration rovers, how the design of the spacecraft as you see and me are here organization of people, the software tools and their work schedule makes it possible for scientists to work on mars. on the scale of of the universe mars is right next door. it's about my -- nine months traveled using conventional chemical rockets. mars is about half the diameter of the earth but it lacks oceans and so it has roughly the same surface area as the earth and that is a lot of landscape for us to explore. the climate is often colder than the antarctic whose great extremes during the day but on a summer afternoon on the mars

equator, you could survive wearing something like a lightweight scuba and pressurized helmet. actually a scuba suit might have been propria to three or 4 billion years ago. we believe then that mars was more like the earth, wet in with a thicker atmosphere. one striking elevation map created from orbit shows the lure areas colored blue and suggest that large parts of the northern hemisphere might have been as covered in c. and is evidence for -- so what happened? did life form on mars? why was its atmosphere lost? are microorganisms living today below the surface? and if life form fair, did it form separately from earth, or are we related? these are the big questions that make many of us very excited about mars.

as i have said it's not practical to directly control a spacecraft on mars excess of the speed of the radio wave, which is the same as the speed of light. and it causes a time delay in seeing and affecting what is happening. but i acting indirectly, through computer programs that monitor and control the rovers, and their instruments throughout the work day, people have been working on mars for over eight years. two teams of scientists and engineers operating the twin rovers called spirit and opportunity has driven together over 25 miles of -- in and out of a dozen creators and climbed hills hundreds of feet high to analyze the layers of deposits and they have also stopped to admire the views and take photographs. the scientists have scraped the

rock surfaces, microphotographed their texture and analyzed them electric composition. in february 2004, month after the landing, i had the privilege to observe mission operations a jet propulsion lab in pasadena for almost two weeks. the two rover teams had twin facilities on different floors of a given building at jpl and they lived and worked according to the timezone of their rover. because the martian day is longer than earth's that means that they reported for work about 40 minutes later each day. if you were at the gate at jpl you would see people coming in 40 minutes later then they came in the day before. the main science meeting room was darkened so they could orient to what they called mars time. each team had about 75 scientists and student

researchers, organized into what are called science theme groups, mineralogy and geochemistry, soils and rocks, geology, atmosphere. they were arranged at their own tables and they gave presentations interpreting what they were learning and what they would like to do tomorrow on mars. the long-term planet group setting off to one side review the overall mission engineering objectives, measures of how far they had traveled, the number of images they had taken, how the instruments had been used and how these affected the plan for tomorrow. in the words of steve squires, the principle investigator of the mer mission this has been the first over lag expedition on another planet. applying rovers tools have chosen spots along the martian landscape we have learned how water is affected the chemistry

of soil and rocks and we found places in the past that were similar to where life thrives on earth. home plate for example, an area behind the columbia hills, is about 100 meters across. it might be a remnant of hot springs like those we find that yellowstone national park. so this is how planetary field science proceeds, by recognizing minerals, formations and processes that are familiar to what we understand on our home planet. the success of what is called comparative climatology on mars is partly why it's such an exciting place to study. we are on another planet, but it looks and feels a bit like home. now just as the mer scientists make analogies with earth, my study of field science on mars started by comparing it to how

field science is done on earth. since the late 1990s, i have been joining mars scientists on an expedition in the canadian art, a nearly lifeless landscape called tarpon crater. the scientist chose this place because it is mars like, allowing them to understand how life exists in extreme environments. an expedition itself reveals how people might live and work on mars if they were studying the landscape there, and that is of interest to the mission. so i followed the scientists in the field to understand how they explored. it was a big topic at nassau, exploration but we had never even in cognitive science, my home discipline, had never studied exploration in the field as people really explore a new landscape. how did they decide where to go? what tools did they use?

i documented how they collected and organize samples that they would analyze with instruments in their laboratories back on earth. i studied how they diagrammed and described their work in their notebooks and how this related to their published work. i observed especially how i intended to work alone or in small groups, but observing the scientists in pasadena i was taken by the incredible contrast. the scientists are indoors, in a dark room, part of a large team doing everything by consensus, people from different disciplines are required to work together. geologist who in the arctic would race to the nearest hill to survey the landscape where working with mineralogy is, who wanted the rover to stop and take a new sample every few meters along the way. and among them were laboratory

scientists who have never done fieldwork before. so working remotely through a rover creates a new way of field science and this new practice changes the scientists and leads them to relate to their tools, the rovers,, and not in expected ways. so how could the scientists work together under these conditions? how could they accept the anonymity of the mission team where their names would never be associated in the public press with any of the decisions of rock to analyze, how long to stay in what the data means. how could people used to seeing, touching and roving at will, study the landscape through programmed laboratory? how was it possible at all to do field science on another planet while remaining here on earth, let alone keep these people engaged for 80 years?

the key is that although the scientists can't directly see and control what is happening, the design of the rover instruments and computer software makes it possible for them to be virtually present on mars through the combination of stereo and spectro images and being able to move around and scrape the rocks. they experienced being there. for example steve squires describes their landing. quote, we realized we had landed in a crater, and that is where we were. and then we noticed 800 meters away, there is endurance crater. would it wouldn't it be great to actually get there? squires descriptions are all first-person. we had landed. we noticed. maybe we can make it. in this imaginative projection, the scientists become the rover,

and this experience on mars is essential to the success of the mission. it enables them to hatch new field science. to know what rocks and soils are nearby, and what they can reach or how long it might take to get somewhere, they use a combination of 3-d images, computer graphics and simulations often overlaying them. these visualizations allowed them to point to places, give them names and control precisely where new photographs are taken and where the instruments are placed. so for example, they would draw a yellow bounding box to specify where a camera should zoom in for a more detailed image. each photograph can be used like a map of an area on mars because its location relative to the rover is precisely registered in

the planning program. as we move in from panoramas used for navigating to images of outcrops to the microphone of graphs, we can see and mark off the details. even small rocks and patches of soil might be named and become targets for spectral analysis or microphotograph. combining these tools in their imagination, the scientists can work as if they were on mars. jim rice, a geologist on the mission said, i put myself out there in the sand with the rover, with two boots on the ground, trying to figure out where to go and what to do. how to make that what we are observing with the instruments. day in and day out there was always the perspective of being on the surface and trying to draw on your own field experience in places that might

be similar. david demaret, a biologist at nasa ames described it this way. the first few months of the mission they have these huge charts on the wall's engineering rover with all these dimensions. we would have some geometric question. well, can we see this? can we reach that? is this rock going to be in the shade or will it be in the sun? we would go and stand and we would stare at those charts. over overtime, we stopped doing it so much because we began to gain a sense of -- that is projecting yourself into the rover. it's just an amazing capability of the human mind that you can sort of retool yourself. so acting through the robots, the control, the scientist look around, they manipulate materials and the move over the

landscape. they may pretend to be a rover, crouching down and gesturing with an arm to better imagine what is reachable. and through the eyeglasses and special cameras, they can directly see iron minerals in the rocks. they are transformed in a way to -- on mars. now that is all pretty different from doing field science on earth and this is an odd kind of expedition for another reason. usually scientists go off in different directions, different times, using their own tools. for mer, the entire team was altogether, 150 scientists and engineers balancing together as it were like on a huge skate toward creeping over the sand, up and down the hills and craters meters at a time. so it's something like being on

a ship on an early voyage of discovery. the scientists in the sailing crew were all having to travel together. they had to negotiate how long are we going to stay here? where are we going to go next and what should we do at each site? and this requires a well coordinated understanding of their roles, schedules, resources, long-term plans and a clear chain of command. if you visit the science and engineering coordination meeting during the prime mission, which was the first 90 days of landing on mars in 2004, the same thing we are going through now with curiosity during these 90 days you can see that scientists upfront on the bridge as it were, with huge displays of the martian surface that lay before them. behind the scientists below the decks on the ship were the engineers, arrayed behind them square monitors showing the ship's power, memory and an

evolving timeline for tomorrow's work. now this coordination meeting would have occurred about 6:00 p.m., just before dinner, local mars time every day. the scientists arrived at work about three hours before, midafternoon rover time. they were ready to receive photographs and other analyses coming back from the rover's work during the day. so you see the mer's are solar-powered so they work roughly on a 9 to 5 schedule. every morning each rover would receive a new program for its day's work, so between dinnertime on mars and sunrise, the scientists and engineers must finalize the plan for the next day, and this requires a second shift of engineers, who refine and test that program before it's sent to mars, what's called the uplink.

now that weren't enough, keep in mind we are simultaneously operating two rovers on mars for over five years. spirit and opportunity were in fact two missions operating in parallel. they had their own rooms as i said for science operations or jpl. they have their own engineering programming teams. 6:00 p.m. coordination meetings and they're on cash of course a free ice cream. but the team shared a single mission control center where the engineers attend to monitors a lot like you would see at houston's mission control. their computers are connected to satellites and earth stations that allow them to communicate with the rover's. so this common engineering activity, sharing this room that i showed a moment ago, required two missions to be coordinated in a special way. if you look at the map of mars with the landing sites of the

two rovers, opportunity or mer b or spirit, mer a you will notice we landed the rover's 180 degrees apart near the equator. most people will realize that the sun's angle is going to be important because rovers are solar-powered so that is why we put them near the equator. few people realize how the geography of the mission relates to the problem of commanding the rovers every day. placing spirit and opportunity on opposite sides of mars allowed a single command center in a management organization operating around-the-clock to focus on one rover at a time, controlling them separated by a half a day on mars. this illustrates very clearly why understanding and designing the mission has to be comprehensive, what we call a total system, the choice of landing sites it self affects

the scheduling of facilities and operations in pasadena. so, i described the logistics, the tools and the mental projections involved in working on mars. but there's another angle to how people talk and think about the rover that i found fascinating and very strange. it is how the rover becomes the hero of the story in official reports on the web, in the press and even in in the scientists on publications. what i have learned is that anthropomorphizing the rover is both practical and poetic. it facilitates the scientists work, helping them to work together as a team and it provides a way for them to express their feelings. nassau's 2001 press release on this mer project epitomizes the personification of the robots.

quote, in 2003 nasa plans to launch a relative of the now famous 1997 mars rover. this cousin is expected to reach the red planet in january 2004. this new robotic explorer will be able to track up to 100 meters across the surface each margin day. the mars program director at nasa headquarters said quote this mission will give us the first ever road ' field geologist on mars. now the metaphors in this poetic narrative such as referring to the earlier mission as mer's cousin simplify understanding but they also serve as a kind of cultural cheerleading in praise of america's new robotic explorer. but years later, the tone was distinct when the "associated

press" reported spirits demise. quote, spirit, the scrappy robotic geologist that captivated the world for his antics on mars before getting stuck in a sand trap, trap, is about to meet tomatoes and after six productive years. so the chum of the rover -- rover is told in the genre of the last person. spirit is said to be incommunicado and it's personified by characters. as far as sibling rivalry went, opportunity was the overachiever while spirit was the drama queen underdog. [laughter] surprisingly lead scientists on the mission are quoted as speaking in the same matter-of-fact way. the mission's deputy investigator ray arvidson of washington university said he will remember spirit as a fighter. quote, it wouldn't quit just

like the little engine that chugged up the hill. sometimes this poetry appears a bit overdone but they may find quite serious descriptions of the rovers character and its accomplishments, like a children's bedtime story. the plucky rover will be remembered for demystifying mars to the masses. this is a story of perseverance. talking about the rovers in this way in the third person makes it possible for the scientists to tell us about themselves, how they feel about the rovers and the challenges they encounter. this is a personal emotional presentation that you will not find in the journal of science and nature. now, this metaphor of the robotic explorer actually appeared on the planetary spacecraft in the 1970s and it

has become a journalistic cliché. a few years ago andrew jenkins subtitle this book intrepid explorers of the red planet. now the book is about the scientists passion for mars, but in his poetic graphic the intrepid explorers are the spacecraft. over the past decade, the clicée became a conceptually, somewhat confused debate in the space exploration community between the advocates of science, meaning robotic spacecraft and the advocates of exploration, meaning human spaceflight. this was a debate about the control for money. but a genuine question remains about the relative roles of people and robots as the distances beyond mars make daily reprogramming more and more typical in the robots become more able to identify what is

worth studying. some have summarized an economy as human explorers versus robot explorers. at a stanford university symposium i attended in 2008 called humans and robots in exploration, one topic was quoted to us as, when does the human become the tool of choice for solar system exploration? by this phrasing, people and robots are those tools and then they asked, very puzzled now, what is the right mix? of course viewing people and robots as interchangeable tools from the sun is absurd. i believe some of the difficulties that arise here are occurring because it's hard for us to understand this new working relationship between people and robots. spacecraft that fly by a planet and carry out a canned program

and send the data back is a one time package, are very different from mobile laboratories with sensors and manipulators that are programmed by us for every day for years. and he gives a totally different experience to the scientists in carrying out the mission. this new way of working which mer epitomizes can be difficult to think about because it's a relationship among people, technology and work processes. it's not a property or a capability that can be ascribed to people or robots independently and that is why the term robotic geologists is so misleading. the relation of people and robots in practical work is difficult even for the scientists to describe. mer scientists have said they could do in a day what took rover many months, but they are thinking mostly about those long

drives. astronauts would leave rovers in the dust, but there is no shortcut for the hours required to do a spectral analysis or a pixel by pixel scan of an infrared panorama. nobody has has used since germans like these in the field before. so how the rovers automation and human actions are dependent on each other can be difficult to explain because we don't think about in practice. in terms of what is called phenomenology, the rover is seen through, as we say like using a cane. in terms of the rovers embodiment in our activity it becomes transparent like a hammer, a bicycle or even an automobile. we ride, we go places. we don't have to think about the machinery. it becomes part of us. the rovers arm reaching out is the mer's scientists aren't

touching a rock on mars. jim val's book shows the difficulty of talking about this embodiment. the titleist postcards from mars, the first photographer on the red planet. as the panoramic camera believes he's referring to himself. he writes that the rovers have allowed us to be in a sense the first photographers on the red planet. now he puts quotes around photographers. but i would have put the quotes around on the red planet, because bell and his colleagues really took the pictures but they are not actually of mars. they are photographers. how should we describe this? who sent the postcards? i believe some of this poetry is revealing that this joint action between machinery, robotic systems and people, is difficult

to think about or describe. these phone cameras that many of you are carrying around in your pockets provide a good example of how viewing robots as being free agents, robotic geologists, and giving them credit for doing the work can easily arise. cameras like this today are all computerized, so when you press the buttons computations determined to the exposure and other settings. they might even decide that you are taking a portrait and to focus accordingly and they will compensate for backlighting but still you are going to say, i took this photograph. now separate that button press and the creation of the photograph by something between 30 and 240 million miles and add an overnight delay. now you want to say, spirit took this photograph today. all the people in the technology

in between just drop out. it's a narrative shorthand. philosophically it raises the question that we call agency and is at the heart of this humans versus robots dichotomy. ascribing agency to the rover appears throughout the scientists writings. for example in the planetary report in 2007, matt golan back of lead mer scientists provided a superbly readable technical summary of the science. the title spirit and opportunity, martian geologists. in a clear presentation about ancient processes formed that alter the rockets and materials during the mer site he alternates away to catch up editions about the robots actions. mer scientists observations and conclusions. listen to this. after exploring endurance crater

opportunity drove south to investigate the heat shield that it used during landing. next to the heat shield we notice the only rocks on the planet. opportunities investigation of this rock revealed it as nickel iron meteorite, a very exciting finding, on a as it was our first discovery of the meteorite on another planet. since then spirit has discovered two others. it appears that spirit caught on pretty quickly to how to recognize meteorites, doesn't it? so when i first heard this term robotic geologist, i felt the phrase was just hype, unfair to the people who are actually doing the work and it turns the mission story into kind of a public show or something like the "wizard of oz." pay no attention to the scientists behind the curtain.

i wondered and i worried that this was going to confuse the public and was obscure in the real story of how people were able to work on mars. people might begin to wonder, why should we send scientist to mars if we already have robotic geologist working there? ally of artie mentioned how viewing the rover in this third person on mars provides a way for the scientist to talk about themselves. but over time has come to realize that this perspective has many practical benefits. as an example superimposing the rovers route on orbital images, that is why this image is so funny -- provides a birdseye view of the regions that we have been exploring. we hover over that landscape and we see mer from orbit. the third person view of the rover is also expressed vividly in computer composites like this that show the rover working along -- alone.

does this express a wish for us to be present at the scene of rover? or does it make tangible the images for scientists and engineers are imagining in their minds? is it another practical projection, another way of understanding the rovers orientation and its context, which actually makes the field science possible. here we see the interplay of imagination, science and technology, all motivated and enabling each other. other less dramatic computer graphics composed with mars images are used routinely to orient the planning and programming of routes and targets. such third person views provide an important way of locating the rover and then by projection locating yourself in the work on mars. yet there is another way of relating to the rover, the

second person perspective. window lead mer rover planners said he viewed the rover as a partner, i was shocked. he told me the rover and i were working as a team. he did not mean though it's the same as working with the jpl colleagues. instead he was using the best words he could find relating to the rover as a peer to express how he delegated work to the rover. so we would plan portions of the route that he didn't have sufficient time or data to analyze and program himself. he relates to the rover in terms of what i do and what you do. for him, this second person i/you relation is practical. the rover is an agent you can rely on. now talking about spirit and opportunity is investigating, driving and so one has also taken hold because it fits so

well in the convention of scientific writing in which we depersonalize our contributions. reports focus on the goals, the methods and the date of. the emphasis is on mars, not on the scientists or how they do their work. individual scientists are also properly wary of taking the limelight. everyone knows they work as a team. in this respect, to find out this phrase robotic geologist was pivotal in deciding the rover itself and promoting teamwork. a central concept in the original mer mission is that the robotic geologists is a physical surrogate for the science team. unlike the boxy spacecraft that we send to orbit or flyby other planets, mer was deliberately

designed to personify a scientists, about human height, little short with stereo vision, mobile with an arm holding a hammer and other sensors. combining the disciplinary teams in one persona, mer realizes the mission that they called one instrument, one team. the team's ability to identify with the rover is fundamental to mer's design esquires explains. he said the whole idea behind mer is that these tools work together. look at the discovery of the silicon. the mobility system by which he means the rovers wheels, we notice with the pan cam wide-angle camera. we hit it with the many test to check for iron. it looks interesting and we go over it and we figure out its molecular composition with the

ap's ex, everything works together. having instruments that work together encourages the teams to work together. this was choir's vision which he called science systems engineering. he said you have got those sensors in each and each of them provides complementary bits of knowledge. you are going to use the payload to the fullest advantage if people look at it as being entirely at their disposal. if you are out there the field he says doing geology with your field partner, you might be arguing about what this rock means or what that rock means that you're not going to be arguing about should we use the rock hammer or should we use the compass? we don't have pan cam guys arguing with other guys but rather geologist arguing with chemists about exploration. now to appreciate that, you need to know that this design and

organization starkly contrast with almost every other planetary mission and the contrasts in a way with our current mission curiosity. for example, the spacecraft now orbiting saturn has 12 instrument teams, each with its own principle investigator. remember that mer had one principle investigator. curiosity has 10 or 11. these teams are matrixed and they have different terps that they are interested in, studying the planet center. its rings, the moon or the i see mountains. it is at best a consortium sharing a single platform jockeying for control or resources. who gets to use their instrument now and for how long? the scale and the reality of two boots on the ground enables and

requires a completely different technical design and social organization. rather than features on a planetary scale cnas from orbit are fine by rovers instrument targets are palpable and they are directly manipulatable. feeling rover is a geologist physical surrogate makes sense. typically a robot is a machine that acts without human intervention but the vision of the robot geologist is broader and multidimensional. instead of replacing the scientists ,-com,-com ma the robotic geologist was conceived as a collaboration tool, a way of getting the disciplinary teams to work together. it didn't replace them. it provided a way for them to work together, very very different. combined with the virtual-reality planet tools and the commanding every day that enable frequent individual

contributions, the mer expiration system help the scientist to ward a new kind of field science collaboration. it made them -- working through a programmable world laboratory. although many people speak about humans and robots in space as if there is a choice, human explorers or robot explorers, our relationship to these computer-controlled devices is more complicated. envisioning the field science, the science is become the rover, a first-person view. programming the rovers drive an engineer may view the work is a joint accomplishment, a second person view. and then working as an ensemble, acting together for the rovers hardware and software systems. everything turns inside out in this third person perspective. the rover becomes the team and they can write about x. exploits

proudly. i would paraphrase that "associated press" story about spirit's demise by saying, this intrepid team of scientific explorers will be remembered for demystifying mars to the masses. this is a story of perseverance. the mer scientists and engineers have invented a new practice of planetary field science. these are their footprints on mars. the robotic geologists metaphor in this metaphor, the team tolerates it in some ways they refill in their anonymity. the more fantastic the historic exploits of spirit and opportunity the more proud you can field to play even a small part in this mission. this projecting up personal ambition onto the groups efforts and its accomplishments is no

small part of our power and joy is human beings. so the accomplishments of mer are intricately based on relating technology to both the psychology and sociology of people. it is a textbook example of how to design a complex system of people and missions. so, reaching the conclusion now, the mer mission objective was to travel a third of a mile in the 90-day mission taking perhaps dozens of photographs and learning something about the history of mars. in this extended mission over in unimaginable eight and a half years, we have traveled over 25 miles, taken 300,000 images and spectral scans. the science itself could fail a textbook or two. now with the somewhat elderly craft, we have arrives with

opportunity and a deep crater 14 miles wide called endeavor with clay soils and new layers to investigate. we waited out the last martian winter at greeley haven with this commanding view of endeavor crater. tilted toward the north to better catch the sun on our gusty solar panels. this image from an amazing panorama was completed in may. as of july we have been working on mars for over 3000 martian days and the voyage of scientific discovery continues. using high-resolution images and scans from orbit, we have identified interesting mineralogy a long endeavor crater's rim. since arriving we have been exploring cape york and eventually we might set a course for salanter points. opportunity will almost certainly span its last days or years here at endeavor.

meanwhile, as you all know, another mars rover, a relative of mer, has landed in gale crater. she will climb and explore the central mount of mount sharp over several years. it towers three miles high over the floor of the crater and it has been built up over perhaps 2 billion years. we will be especially looking for carbon-based materials that are essential for life. he calls his rover the mars science laboratory or msl. is loaded with new instruments and ways about a metric ton, five times a mer. perhaps with the name science laboratory instead of robotic geologists, the mer experience has clarified the true nature of the spacecraft's tools for the scientist and perhaps this time

may place themselves more public in the drivers seat. you will be sure there will be more poetry. spirit and -- has been personified by a nickname. they call her curiosity and perhaps you can artie see how this will play out. thank you for your attention. [applause] >> have a seat. the. >> thanks. >> thank you for that. we do have some of your questions already ready here and we will continue to take them. we are going to talk for another 20 to 25 minutes and i do ask if you have time constraints and need to leave the peep could do so by the back because it's much quieter there but i hope you can say for all the missions.

>> are you going to mention the book signing? >> of the books are available in the gift shop which is right outside the door here and you will be staying for signing. >> i will and as a civil servant at the government i don't receive any royalties so the prices been said very low and i hope you all enjoy it. >> let's talk a little bit about an idea that these machines have preceded us to mars. is a still ultimately the target to put a human being they're? >> for sure, and it's sometimes very surprising and all of the scientists i have spoken to really want to be there. they sense that they need to be there in order to do ask for nate -- exploration the way it should be done and part of it has to do with all those limitations i talked about. they want to go in different places and we accomplish a lot more with six people than with six people standing on a skateboard together. i think your point though about anticipating and comparing has

become more and more real. i don't think we understood that so well before mer, that we could for reasonable cost put these rovers in different places around mars and figure out where we want to go. where should we lab? where should the human land? >> so it's -- what's the timeline? >> i am not allowed to lobby. it's all about priorities. >> one of the things a human can accomplish that you mentioned, the limitation of the robers, the rovers are dependent on the sun and they need to stay near the equator so it strikes me that some of the science we are missing out on soap or has to do with guys polls, the polar caps in the and the water systems in that sort of thing. are there other sciences that will have to wait until a human can get up there without those limitations? >> we actually have had a lander, phoenix in 2008, went to the mars art.

so there we were looking specifically at landing on as we did in understanding how ice causes different formations there in understanding the chemistry. so there are limitations. i think with curiosity though, we have learned now with this combined director of fire and soft landing of the sky crane, that is quite general.