MR. KOJO NNAMDINASA shut down its shuttle program last year, leaving many Americans with impression that meant the end of space exploration for the time being. So last month you may have been surprised to hear that a very earth-like planet was spotted outside our solar system. In our search for life on a planet other than our own has made great strides in the last few decades. Exactly where that life might be found and what it might look like, are questions that have captured the imagination of earthlings for centuries. And discoveries over the last two decades in our own oceans and distant universes alike, have caused researchers to reconsider how they define life and what may be revealed on the final frontier.

MR. KOJO NNAMDIJoining us in studio to talk about this is Roger Launius. He is a senior curator at the Smithsonian National Air and Space Museum, where he oversees the human space-flight collection. He's written and edited numerous books and is co-author of "Robots in Space: Technology, Evolution and Interplanetary Travel." Roger Launius, thank you for joining us.

MR. ROGER D. LAUNIUSThank you and Happy New Year.

NNAMDIHappy New Year to you. Joining us by phone from Seattle, Wa., is Roger's co-author, Howard McCurdy. He is a professor of Public Affairs at American University, where one of his specialties is space policy. Howard McCurdy, thank you for joining us. Happy New Year to you, good to hear from you.

MR. HOWARD MCCURDYSame back to you.

NNAMDIHoward, I'll start with you. Space has captured countless imaginations. What is it? what is it about the universe beyond earth that fascinates us so?

MCCURDYI think what we're driven to do is migrate. We weren't happy on one continent. We spread across the face of the earth and now we're trying to repeat that experience in space. So I think there's just a fundamental, underlying drive that causes humans to want to look over the horizon to see what's on the other side of the hill. I think the other part of this is the greatest scientific mystery that exists around us, is the question of whether or not we're alone in the universe. Whether or not complex life forms have developed on other spheres and we'd like to know the answer to that and now we've got some of the technology necessary to find out the answer to the question.

NNAMDIWell, I migrated so I can relate to that. Roger, what is this human instinct?

LAUNIUSWell, we clearly want to learn what is out there. This quest for knowledge is a key part of what has driven space exploration from the very beginning and ultimately for humans to go through and perhaps colonize and move elsewhere and become a multi-planetary species is a real driver. We're a long way from that happening but we've already started taking the steps, now more than 50 years since we started flying humans into space.

NNAMDIIt's a conversation about space that you can join by calling 800-433-8850. Do you think it's just a matter of time before we find life on another planet? Or are you convinced that earth is home to all that there is? 800-433-8850, you can also send us email to kojo@wamu.org, a tweet at kojoshow or simply go to our website, kojoshow.org, join the conversation there. Roger, in early December NASA confirmed the detection of a new planet, Kepler 22B, that looks an awful lot like earth and just a few weeks later, two more planets even closer in size to earth were discovered. What's significant about these discoveries and what does Goldilocks have to do with all of this?

LAUNIUSWell, we are the Goldilocks, quite frankly. We live on a planet that is in the perfect place. It's neither too hot nor too cold, just the right distance from the sun in which all of the habitable capabilities that have made life on this planet possible, exist, and so looking for that Goldilocks planet that's out there around another star in some other place, has driven a lot of activities. We have found, literally, since 1992, was the first extra-solar planet discovered. We have found since that time more than 700 of them. Most of them are big and look like Jupiter but these more recent ones are only a couple of times the size of earth and the possibilities for potential for life to exist there, are very real.

NNAMDISo, Howard, what Roger's saying here is that all of this stuff that we've been imaging might be real?

MCCURDYIt could be real and that's the great scientific question. You'd like to find a planet, which is in an area which is not too hold and not too cold, hopefully with liquid water. That would be the real key because life -- we know that life develops on a planet like our own in the presence of liquid water but that's not exclusively where we may find life. So there are efforts to find it within our own solar system and on planets that aren't like the earth. But right now we're focusing on planets that would in that perfect zone that would permit the existence of liquid water. Once we find that then it's a step to the next mission to try and determine whether or not there actually is water on those planets.

NNAMDIRoger, while earth-like in a lot of ways, Kepler 22B is closer in size to Neptune, leading most researchers to conclude that discovering life there is unlikely. Can size alone tell us whether a planet can support life?

LAUNIUSSize alone can't tell us. We don't know what kind of life might actually exist in some of the gas giants. People have speculated and it's only speculation, that there might be other forms of life, carbon based or not, that might be able to live in some of those places. But they're strikingly different from us. if they are out there and clearly if there's a life form that exists on Kepler 22B, it'll be pretty different from any kind of life that we're familiar with of a 1G earth type environment.

NNAMDIOnto the telephones. Here is Jeff, in Washington D.C. Jeff, you're on the air. Go ahead please.

JEFFYes, one of the questions that I'd like to ask is, why scientists, cosmologists, space scientists, astronomers, aren't looking more carefully into the documentation that certainly suggests that the earth has been and is already been visited by extraterrestrials. I'm somebody who really respects scientists and the scientific method and I find it quite puzzling that the abundance of evidence, radar, visual, photograph, is not being considered as proof that the earth has been visited by extraterrestrials.

NNAMDIHoward McCurdy, how do you take evidence and make it proof?

MCCURDYI'd like Carl Sagan's old saying that extraordinary claims require extraordinary proof. The evidence is not extraordinary and it's also confronting the difficulty of interstellar transport, which we haven't been able to figure out how to do. If civilizations existed on other planets they presumably would be communicating with each other and we would've picked up those communications. And furthermore, if they decided to come to earth for some reason they would have to conquer the problem of interstellar transportation and that's just a huge barrier. So it's interesting to imagine, but so far, it's been in the realm of science fiction.

NNAMDIJeff, thank you for your call. Howard, we still have a lot to learn about Mars and the moon, which we'll get to in a minute. But these new planets are even farther away, about 600 light years to Kepler 22B. Just how far is that and how are we able to spot them at such a great distance?

MCCURDYSome of the proposals for interstellar spacecraft, carrying various kinds of payloads, both robotic and organic, suggest that we may be able someday to obtain velocities of one-tenth of the speed of light. So just multiple any distance to an extra-solar planet by ten, you'd have a sense of how long it would take to get even a small robotic payload to that planet. the energy requirements are also extraordinary. By one calculation it would take all the energy that exist on the earth to propel a space craft to a nearby star. So physical movement the stars is extraordinarily difficult.

MCCURDYThe easy thing to do is to rely on light waves to capture information from the planets. The next two telescopes in NASA's search for extra-solar planets would rely on light waves, basically trying to capture images and spectrographic studies of extra-solar planets to find out what their composition is. Life has a signature, it's in the atmosphere. If you can take a spectrographic study of an extra-solar planet, you can detect whether or not there are life forms on that planet.

NNAMDIHow would you say, we can observe it, but we are not going there anytime soon?

MCCURDYThe Kepler mission does not observe the planets. What it observes is variation in the light intensity of the star as the planet passes in front of it. It's like the transit of Venus across the face of the sun. The sun doesn't shine quite as bright to a sensitive instrument when Venus does that so the next round of exploration would make use of telescopes that are actually able to eliminate the glare from the central planet and then image the planets that are around it. You want to know where they are first, which is what Kepler is doing and then capture spectrographic studies of those images.

MCCURDYFor example, if a planet had 20 percent free oxygen in its atmosphere, that would be very earth-like. We have free oxygen, it's a consequence of life forms on the earth, particularly trees and plants, giving out oxygen. It's a characteristic signature of life. So that's what you'd look for once you could capture images. And then there's telescopic technologies, interferometry that has the capability of actually capturing pictures of these planets. And I remember Dan Golden stating he wanted to build a telescope that would provide a picture of an extra-solar planet that was as clear as a picture of the earth from the moon. That would be an ultimate goal and that's certainly within the reach of technology.

NNAMDIRoger, you say forms of life, that seemed very sci-fi just a few decades ago, seem more and more plausible. Why is that?

LAUNIUSWell, one of the things that we're finding is that the kind of life that we have found, literally, since the mid-1990s that exist in very unlikely locations, or at least so we thought until that point on earth. Like at the bottom of the Pacific Ocean, in these deep trenches, that are -- there's a whole biosphere there that lives around sea vents and it has no connection with anything on the surface whatsoever. That kind of life might well exist at the bottom of some liquid ocean some other place, maybe in an ice-encased planet or moon. Maybe even in this solar system. But those are possibilities and that's carbon-based life. There might also be life based on some other element like silica. People have talked about that as well. the question we have is, since we have no experience with that would we even recognize it as life if we encountered it.

NNAMDIHoward, you point out that basing all of our assumptions about life on other planets on what we know about earth probably is not very smart.

MCCURDYIt's like doing a statistical study by asking one person for their opinion about something like who's going to win the Iowa primary. The margin of error is quite large. Everything we know about life has been accumulated by studying a sample of one. So we don't really know what the range of conditions might be. There's a great space race on right now, in the U.S. Civil Space Program to try and locate something within the solar system that could have the conditions that would harbor strange life forms. It's basically a contest right now between Mars, Europa and Titan and there's been a proposal, which will be decided in the next year as to whether or not to attempt to land the boat on one of the methane lakes on Titan. It's actually a low-cost project, quite affordable and would provide a basis for discovering whether or not life forms could exist under those conditions.

NNAMDIIn case you're just joining, we're talking about space exploration with Roger Launius and Howard McCurdy. They are co-authors of the book, "Robots in Space: Technology, Evolution and Interplanetary Travel." Roger Launius is a senior curator at the Smithsonian National Air and Space Museum, where he oversees the human space-flight collection. And Howard McCurdy is a professor of Public Affairs at American University, where one of his specialties is space policy. We're taking your calls at 800-433-8850. Have questions about what NASA has been up to since stopping the shuttle program, give us a call, 800-433-8850. Here is Emmanuel in Martinsburg, W.Va. Emmanuel, your turn.

EMMANUELThank you, Kojo. Great show. My question is this. The mass of the newly discovered planet is two times that of the Earth. What's going to be the effect on the human body if anybody ever steps on that planet?

NNAMDIRoger Launius?

LAUNIUSYou bet. Well, obviously humans will not survive all that well there. It's not that you can't take two Gs and operate with it, but your muscles, your bones, all of your structure is built around a one G environment. So clearly, that would be a difficult thing to do. That does not mean, however, that we cannot send robots there, although it's a long way off and the chances of ever getting there, and we certainly wouldn't see it in our lifetime, is a very small one.

LAUNIUSBut that's probably not a place we're going to visit, at least any time that one can project, but it is certainly one that looks inviting in terms of the possibilities of life that might be adapted to a two Gravity environment.

NNAMDIGot to take a short break. When we come back, we will continue this conversation. If you have already called, stay on the line. If you haven't yet, the number is 800-433-8850. Should the U.S. be spending more or less on space exploration? What's your view? You can also send email to kojo@wamu.org, go to our website kojoshow.org, or send us a tweet @kojoshow. I'm Kojo Nnamdi.

NNAMDIWe're talking space exploration with Howard McCurdy. He's a professor of public affairs at American University where one of his specialties is space policy. He is co-author of the book "Robots in Space: Technology, Evolution, and Interplanetary Travel." His co-author is Roger Launius. He's a senior curator at the Smithsonian National Air and Space Museum where he oversees the Human Space Flight Collection.

NNAMDIRoger, last year, NASA flew its last shuttle flight. You say this has led to a lot of misunderstanding about what the U.S. is doing when it comes to space exploration, and that we often fail to realize how important space flight is to our everyday lives. What do you mean?

LAUNIUSOh, absolutely. The first misnomer that comes out of this is that when NASA retired the Space Shuttle after the last flight last summer, many people had the misperception that NASA's out of business, that we're not gonna do anything anymore in space, and that's simply not true. NASA is very much alive and doing all kinds of things. Its human space flight program is making a transition, a very important transition, one that is going to change the way in which is does things for the next numbers of years.

LAUNIUSHaving spent 30 years flying the shuttle, it was time to give it an honorable retirement, and now it's moving forward with efforts to build a new launcher for humans and servicing of the International Space Station, and pursing deep space technologies that will enable them to go maybe back to the Moon, maybe to Mars, maybe to some other location.

NNAMDICare to comment on that, Howard?

MCCURDYI would just say that we should have retired the shuttle in 1994, which was the original plan. The difficulty was that it cost so much to fly the thing that NASA didn't have enough money left over to invest in its replacement, and now it's turned to the private sector for an essential replacement to low earth orbit. So it's important that you trade in your old vehicle and buy a more modern one every once in a while, so I don't see this as some great tragedy or turning point.

MCCURDYI think it's a great opportunity. What's interesting in what's coming down the road is whether or not the replacement vehicle is going to look like a gumdrop or a little mini Space Shuttle. There's a huge technological and entrepreneurial contest underway between the advocates of flying things that have wings and flying things that look more like the Mercury Apollo capsule. So we'll see how that unfolds in the next year or two.

NNAMDIWell, two aspects of that, first you, Roger, it's my understanding that the Air and Space Museum maybe set to benefit in a way from the shattering of the shuttle program.

LAUNIUSNo question. Air and Space is definitely excited about the prospect. We are going to receive from NASA, where it will be put on display at our Dulles facility, the Udvar-Hazy Center, the Discovery Space Shuttle, and that is a very exciting experience. We had out there for a number of years now the enterprise which is a flight vehicle that was used for atmospheric testing. That vehicle is going to depart, it's going to go to New York where it will be a part of the Intrepid Museum, and we're getting Discovery, a flown orbiter. We're really excited.

NNAMDIAnd Howard, you mentioned NASA working with the private sector, but it's working with private sector partners to create the next generation of shuttlecraft. One entrepreneur recently pledged to have people on Mars within a decade, two at the most, and at the relatively low cost of $5 billion max. So what's on the horizon for commercial space flight, Howard?

MCCURDYWell, one wonders whether or not that includes the trip back. For that price it seems like a one-way voyage. Buzz Aldrin proposed a one-way voyage. I remember that because he said people went across the Oregon Trail with no expectation of coming back to Missouri, so why couldn't we do that on Mars, just leave them with enough food to last out the remainder of their lives as colonists on the planet. So yes, there's a contest between NASA and private entrepreneurs to go as far as Mars, and in fact, we have an existing X Prize right now for a Rover on the moon for which we've got close to 20 contestants who are competing to build that vehicle.

MCCURDYSo one of the big space races in the future that replaces the Russian-American space race is going to be a race between people in the private sector who have made billions of dollars in a variety of entrepreneurial industries and NASA, which is great for NASA because it makes the kind of competition that spurred them to do technological innovations during the Apollo years. But we could see private entrepreneurs not only going to low earth orbit, which is the plan, but going beyond to the Moon and potentially to Mars which is still at this stage imagination.

NNAMDIHere is John in Arlington, Va. John, you're on the air. Go ahead, please.

JOHNHey, Kojo. Just to add a little to this conversation, they're playing with what they call low gravity wells, which means go out to asteroids and things like that which you can send a spaceship back and forth to those without a lot of worry about taking off and landing from something that has a lot of gravity like the Moon or Mars, and you can get further out in space like that, but unfortunately, it's sort of like going to a department store and looking into the windows.

JOHNYou could get to Phobos, but you couldn't get down on Mars. So that's the direction they're kind of going. We'll have to see where it goes. My concern was that if they're serious about looking for life in the solar system, they have to get back to the Saturnian system, look on Titan and look on Enceladus. Enceladus is where they have these geysers coming off of. The reason is a lot of fascination with Io is a little misplaced. Io is the moon of Jupiter where they think there's a big ocean.

JOHNUnfortunately, A, it's 10 to 20 or 30 miles under a big chunk of ice, and it's at a very nasty radiation environment. So to me, it would be -- money would better be spent going out back to Saturnian system with stuff that can survive and has access to areas which are a little more likely to show signs of any kind of biological activity, if any.

NNAMDIRoger?

LAUNIUSYeah. There's two proposals that are on the table right now for flagship missions to the outer planets, and both of them are aimed, the first one at the possibilities of Titan, and as Howard said a moment ago, landing something there, sailing a boat on one of the methane lakes that exist there and see what they might be able to fine. The other one that they're really talking about is Europa, which is where the ice is.

LAUNIUSIt's very, very deep. It's a difficult process, but if you could land on that ice, melt through it, and put down underneath it what is referred to as a hydrobot, you might be able to find some remarkable things. That's a tougher mission in some ways and NASA's not made the decision yet as to what direction they're going to go, but they will do so in the next few months.

NNAMDIHoward...

MCCURDYAnd let's not forget Mars.

NNAMDIOh, yes, indeed.

MCCURDYYes. Because, you know, following the current Mars Science Laboratory which is set to land in 2012, NASA would like to undertake a Mars methane orbiter and a large Mars rover that would land at one of the methane sites and drill to the subterranean surfaces to see if Mars has got some subterranean life.

LAUNIUSYou bet.

NNAMDISince you mentioned Mars, NASA is also exploring our nearest neighbor with new technology, Howard. What's going on on the moon even as we speak?

MCCURDYWhat's going on on Mars is the Mars Science Laboratory is set to land in August 2012. This is about the size of a Volkswagen Beetle, and it is capable of roving across Mars and doing a great deal of science sample analysis which was not capable on Sprit and Opportunity and that's an amazing thing about Spirit and Opportunity is that Spirit got stuck in the sand, but Opportunity is still working. These were 90-day mission, 90-days, not 90 months, and they've been operating since 2004.

MCCURDYSo our capabilities to do exploration on Mars have expanded greatly with robotic technology, and there will be decisions in the future after I think the Mars Science Laboratory successfully lands on what the next steps would be on that planet. So there's this contest that's underway and you heard about it from John who was saying well, it could be here or it could be there, and I would bet that it's in this place, and that's where we should concentrate our resources.

NNAMDIRoger, to the moon.

LAUNIUSYes. There's lots of activities on the moon as well, and some of those are very exciting. NASA's missions to go there to map the moon in a very thorough manner, more thoroughly than anything has been attempted even since the 1960s moon landing program, and to determine whether or not there actually is ice that might be at the poles there. We've been talking about that now for more than a decade. We've found lots of evidence to suggest that it is there. If it is there, what can we do with it? Can we get to it? Can we mine it? Can we use it to make fuel, to make oxygen? Can we do a variety of other things with it?

LAUNIUSThat's a very cool and interesting approach that might change the dynamic in terms of moon exploration. There is also this commercial activity, the Google Lunar X PRIZE, which is just fascinating. There are several teams that are building landers and rovers that will go to the moon, image sites, some of those sites might be Tranquility Base where Apollo 11 is located today, and send back data about -- after 40 years what has happened at those particular places. A very exciting prospect.

LAUNIUSBy the way, and I think that we're going to see some form of tourism at some point to the moon. I've already volunteered to become the first curator there. I'll be glad to up the ropes and stanchions for all of the visitors who are going to come as tourists to see Tranquility Base. NASA has not taken me up on that, but it's a fascinating possibility that I think we will see in the next hundred years.

NNAMDINote to self, volunteer to broadcast that. Here is -- well, before I get to our caller, Howard, space exploration doesn't come cheap, and the stakes are high, making cost another area where Goldilocks and Congress come into play.

MCCURDYYes. NASA has basically got a budget that's set at $18 billion a year. That's a lot of money except that the demands on that funding well exceed the actual amounts that are available. So anytime something like the Hubble Space Telescope doubles its budget -- excuse me, the Web Space Telescope doubles its budget, that means that you can't do some other science mission that someone is dying to do. So a very constrained environment that's really going to favor enterprises that are able to reduce the cost of conducting missions and reduce the cost of access to space.

MCCURDYYou know, we're paying as much to fly on the Russian Soyuz as we paid to deliver people into space on the shuttle in the 1990s. So it's not a great bargain. We're still looking for bargains in space and the breakthroughs that will make this technology affordable so that basically we can do more missions within the $18 billion ceiling.

NNAMDIHere is John in Reston, Va. John, you're on the air. Go ahead, please.

JOHNHi, thanks very much. I'm a scientist by the way, so my comment comes from that background. I hear NASA continually fantasize and frantically speculate about life on other planets, and that's all very well and interesting, and I would not be surprised if some form of biological life did exist. But frankly, I don't feel it's worth the roughly $20 billion price tag that it's costing every year, and it's sort of like pouring money down a black hole and not one that's in outer space, but one that's here on the surface of the Earth. I wonder if any of your pro-NASA folks there, or on the other end of the line, could comment on that kind of...

NNAMDIWhat is the value, Roger Launius, of this kind of exploration?

LAUNIUSYeah. It's certainly not pouring it down a hole in my estimation. You know, one can question whether or not the search for life beyond Earth and asking the question and finding an answer to it, are we alone in the universe, might not be the most important thing to be pursued. I contend that it is. But nonetheless, we can differ on that particular part of it. But, in terms of the science program that NASA's engaged in, a very small part of it is really built around those kinds of questions.

LAUNIUSMost of it is about astronomy, about various other types of sciences including Earth science, which I think most people would agree is a very important thing to pursue, and then there's obviously the human space flight piece of it, and an aeronautics research program which is a part of NASA as well. So of the $18 billion and change that NASA spends on an annual basis, only a smaller percentage of that is actually dedicated to science, and of that smaller percentage, an even lesser amount is dedicated to the question of are we alone in the universe.

NNAMDICare to also answer that, Howard?

MCCURDYI would just say we go into space for a number of reasons. We go in for commerce, we go in for national security, we go in for national prestige, and we go in for science. It's an essential part of the civilization that we are, and I know everybody doesn't support it, but everybody doesn't support farm subsidies and we do that, too. There's probably more people who support space exploration than support farm subsidies. And the -- Roger knows the figures, he's done a number of articles on public opinion.

MCCURDYThere's about 100 million people who are the space cadets in America, and they're a very driving force behind the expenditure of the $18 billion a year for civil space.

NNAMDINot to mention the people who are DirecTV subscribers, but that's a whole 'nother question.

LAUNIUSYeah. The reality is there's -- it's a miniscule amount of the federal budget that is expended on NASA in any way shape or form. Less than one half of one percent of the federal budget. I think you could easily double that and you still would be able to justify the fact that NASA is not a large amount of what we spend very much money on at all.

NNAMDIWe're running out of time very quickly, but Titan and Europa, moons of Saturn and Jupiter respectively will also be explored in more depth by NASA soon. What other destinations are on the agenda in 2012?

LAUNIUSWell, there's people who are talking about -- and we don't have missions for this yet, but the possibility of going to an asteroid, of going to L2, which is a very quiet place that's out there where you can sit with a satellite without any expenditure of energy whatsoever, and those may actually take place. Probably not in 2012, but down the road.

NNAMDIRoger Launius a senior curator at the Smithsonian National Air and Space Museum. He oversees the Human Space Flight Collection there. He's written and edited numerous books and is co-author of "Robots in Space: Technology, Evolution, and Interplanetary Travel." Roger, thank you for joining us.

LAUNIUSThank you.

NNAMDIHoward McCurdy is a professor of public affairs at American University where one of his specialties is space policy. He has written numerous books, and is also co-author of "Robots in Space: Technology, Evolution, and Interplanetary Travel." Howard, thank you so much for joining us.

MCCURDYThank you.

NNAMDIAnd thank you all for listening. I'm Kojo Nnamdi.