Profiles

Shadi: I would like to start by asking you, if you would tell us about your main research interest areas.

Dr. McKay: I am primarily interested in the question: Is there life beyond the Earth? More importantly in a more focused sense, is there separate life beyond the Earth? Is there life on another planet that represents a separate origin of life from the life we have here on Earth? In our solar system, the planets and natural satellites that look like this could be a possibility are Mars and Europa. So, in practice, my research interests are focusing on preparing to go to places like Mars and Europa, to find life there and to characterize that life, and to understand if, that life is the same or different from the life here on Earth.

Shadi: So what makes Mars and Europa different from the other bodies in our Solar System? Why specifically focus on those two?

Dr. McKay: Mars and Europa are interesting because we have evidence that those worlds have water or had water in the past. When we look at life on Earth, we see that the one thing that all life on Earth requires is liquid water.

Shadi: Tell me more about Mars. Obviously, many people watched when the Mars Rovers were sent to Mars. How much do we know at this point about Mars?

Dr. McKay: What we know for sure is that it had liquid water in the past. I think we have really good evidence of that. That evidence comes from features which look like river channels, lakes and seas even. We don't know when that water was there. We don't know how long it was there or why it went away. We have ideas on these, but we don't know for sure. Also, we don't know if there was life in that water when the water was there. But those are the questions we would like to address. So right now the missions to Mars are focused on understanding of the history of water. NASA calls it the Follow the Water strategy. But eventually we would like to look at the possible life which might have been in that water.

Shadi: So do the long term plans or visions include sending humans to Mars? What are those plans?

Dr. McKay: I think it does. NASA's current long term vision is to send humans back to the moon and set up a base on the moon. Then use that base as a way to develop the technologies required to send humans to Mars. I think we all agree that the real goal is to send humans to Mars. But there is a perception and a decision to first send them to the moon as a way of developing the techniques. It's like before you go on a very long, six months camping trip in the desert; you might go on a shorter trip first to make sure all your equipments are working. I think that is the role the moon is playing. So that means it will be quite sometime before humans go to Mars or even go back to the moon.

Shadi: What do you imagine it will be like? Obviously, it will take a long time to get to Mars. So do you imagine we will have a base or even a community of humans there?

Dr. McKay: I imagine that it would be like the bases in Antarctica ? United States has had scientific research bases in Antarctica for 50 years continuously now. Those bases are small. The one at the South Pole may have 20 or 30 people. McMurdo [base] on the coast is bigger and during summer it could have 1000 people. But everybody is there as part of a scientific expedition. No body lives there. There are no families, children or schools there. It is not a town. It is a research base. People will go there and work for a little time, for six months, a year and will come back home. There are research assignments. I think that is the way a moon base and a Mars base will be. It will be a small group, a small station. Scientists, students, and technicians come there for six months in case of the moon, and perhaps, in case of Mars for two years. Graduate students will probably be a large part of the population. Most of the scientists in McMurdo are graduate students doing their PhD research on some part of Antarctica . If you walk down in a lab in Antarctica , more than half of the people you meet are graduate students doing PhD research. Graduate students will do projects that will take them to the moon and Mars, will work for a couple of years and then come back to write their theses. That will be the way I imagine it to be.

Shadi: I imagine that you can recruit a lot of graduate students to go to Mars.

Dr. McKay: There will be lines as long as there are for research in Antarctica . They will love the opportunity. They will do great research; and there will be a lot of interesting work to come out of it.

Shadi: How much can you tell us about Europa?

Dr. McKay: Europa is a much harder world to explore than Mars. Mars is closer, easier to get to. It will only take six months for a spacecraft to get to Mars. It takes several years to get to Europa, because it's around Jupiter. It has no atmosphere. And it is inside Jupiter's Magdalen belt, the radiation around Europa is very deadly. We cannot imagine people going to Europa. “2001” and “2010”, the movies in which they sent people to Jupiter and they went to Europa, is just not possible right now. Because the radiation is so intense people would be killed in a matter of a few minutes. It is difficult to imagine any human expeditions. It is also difficult to imagine robotic expeditions, because the radiation is so intense that it will even burn out computers. But, some how, we will be able to solve that problem with computers so that they will be able to take the radiation.

Then, there is the challenge of getting through the ice down to the ocean below. We think that the ice is probably about 10 kilometers thick. So Europa is an interesting challenge, but it is a big challenge as compared to Mars. I think we will do a lot more and make more progress on a Mars exploration before we do it on Europa. But Europa is still out there as a distant goal.

Shadi: I know that you have been involved with studying Titan which is a moon around Saturn. How much can you tell us about Titan?

Dr. McKay: Titan is interesting in a different way. Mars and Europa are interesting because they have evidence of water. And that opens up the possibility of life as in living organisms. Titan does not have water. It is so cold on surface about 95 Kelvin. It is unlikely that there is liquid water there. People have speculated that there might have been temporary water due to meteor effect, or subsurface water due to geothermal heat. All of this is very speculative. On the face of it, there is no water on Titan. The reason that Titan is interesting is that it has organic production going on. In the atmosphere of Titan, methane and hydrogen is being produced by sunlight and that is producing organic material. There is this ‘brown stuff' in the atmosphere. Think of it like chocolate, it probably does not taste like chocolate. This ‘brown stuff' in the atmosphere is being made non-biologically.

One of our theories for the origin of life is that this is how life started—non-biologically in a soup of organic material that was also made non-biologically. So, Titan could be a good example of how life started. It is not going to go all the way through to life, because Titan does not have water and water is necessary for life. It is not a perfect model for the origin of life but it is the first step. That's why Titan is also interesting in terms of understanding of life on other worlds.

Shadi: How about Saturn itself? How did you and other scientists come to be interested in Titan and not Saturn?

Dr. McKay: Saturn is interesting but not in terms of the origins of life. Titan is much more like the Earth. It has a surface. It has an atmosphere mostly made of nitrogen. The gravity is lower than the Earth. It is a world like Earth, Venus, or Mars—a terrestrial type planet. Saturn is a gas giant. It does not have a surface and it's completely dominated by helium and hydrogen. It is more like a failed star than an Earth-like planet. Saturn and Jupiter are not interesting from the point of view of Earth-like life. And, there is not a good theory as to how life could exist on those planets. There are, of course, other planetary scientists who are interested in studying Saturn; but, for me, from the astrobiology point of view Titan is much more interesting. We learned that in early 80s when the Voyager spacecraft flew through the Saturn system and gave us our first close-up look at Titan. We saw that it had atmosphere and the atmosphere was rich in organic materials. It is much richer than Saturn's and Jupiter's atmospheres. Their lack of richness is because there is so much hydrogen on Saturn and Jupiter that any organic material gets forced back to methane—any organic material gets completely saturated with hydrogen bonds. Where as on Titan, hydrogen is leaving from the top of the atmosphere, and you can make unsaturated hydrocarbons which can persist. A world where there is so much hydrogen that organics are not stable is not interesting from the origins of life point of view.

Shadi: So for you, after looking at Mars, Europa and Titan, what other planets do you think will be interesting to study?

Dr. McKay: Unfortunately, there aren't very many good choices in our solar system. We have to look at other solar systems. The good news is that they are starting to discover worlds around other solar systems. What I am hoping is that pretty soon we will discover earth-size planets around other stars. Then we can extend our studies. The good thing about our Solar System is that we can go there. We can send a probe to Titan even though it takes seven years to get there. We can send probes to Mars and Europa, but we can not send probes to the other stars at least not for unforeseeable future. So, we have to content ourselves with studying those worlds remotely through telescopes. But, we might still learn a lot about those worlds with telescopes. Telescopes are becoming very sophisticated. Imagine large telescopes in space. We might learn a lot about a world, just by just looking at its atmosphere and gases in it and what it is made of. We are not completely without hope that we will develop some information about the nature life on other planets around other stars.

Shadi: What does studying other planets tell us about life on Earth? Why study Mars for example?

Dr. McKay: What I am interested in is: Is life on Earth unique? On Earth, we only have one example of life. As you know all organisms on Earth have the same fundamental genetic code, the same fundamental biochemical structure and processes, all based on DNA, RNA, and L-amino acids. In fact, all life on Earth is believed to be traced back to one single ancestor. So, we have exactly one example of life. As far as we can know scientifically, that is the only life in the universe. And that to me is the question we want to ask: Is it really true that this is the only life in the universe? There are a couple of ways to think about this. Maybe this is really the only life in the universe. So we go to Mars, Europa, a couple of other places in the solar system, and we find life which is exactly the same as life on Earth. The other possibility is that we go to Mars and Europa and we find completely different life forms—maybe still based on organic materials but not based on the same amino acids and genetic code; maybe based on a completely different solution to the problem of being alive.

That will be interesting to know. It's interesting in two ways. First, it is interesting philosophically: Are we alone? Some people really want to know the answer to that. They imagine that aliens have come and told them the answer to that. I want to know the answer to that too. But, I want to know the answers to that within the confines of scientific method. We have got to go there and look. That is the philosophical motivation.

Second, there is also a potentially very practical motivation. If you think of the basis of our knowledge for medicine, biology, agriculture, antibiotics, etc. is all based on knowledge we gained from one book of life—one example of how life works. If you imagine that now we have another example of how life works, slightly different, then suddenly we might be able to understand life at a deeper level as we have more than one example to study. It might have very practical applications—you never know how the knowledge will be helpful.

Shadi: Times now are difficult when it comes to funding. How does that affect the possible missions to Mars, Europa and so on. How much money do we need to go to Mars?

Dr. McKay: My view on that is that NASA's budget which is a small percentage of the federal budget is what it is. There has been long standing bi-partisan agreement that this is all we are going to spend on NASA. It is a low level of spending compared to many other things, but it has been relatively constant over the last 15 years. So I think we should say that's the money we get. Period. We ask then the questions: how can we do what we want to do within that budget?; how long will it take and what kind of new technologies do we need to develop to allow us to do that? So, the real question is not how much money, but how long—given the NASA budget, how long will it take us to get back to the moon and then to Mars. Given that we know the level of support the nation is willing to give. The level of support has stayed almost the same since the Carter administration, it has gone up a little and down a little but it has remained consistent. So to expect the level of funding to change, for example by a factor of five, is unrealistic.

So, instead I ask how we get to where we want to go within that budget and how long will it take us. Some people say, it only took us 8 years to go to the moon the first time and how come it takes us 12 to go back? I say because we are not doing a crash blank-check program like we did the first time. Also, we were not going to stay. We are not going there to plant the flag, play golf and come home. This time is different. I think we are going to be back on the moon in 2018, that's still 12 years from now. From there, it will take us five or six years to get to the Mars. So at least, it will be 2024, may be 2025, for the first human to step on Mars. The first astronaut, man or woman, who will step on Mars is probably about 10 years old right now. It is a long time away. I think that is the way it is going to be to stay within NASA's budget.

However, you can imagine that some how if this becomes a national priority and we decide to spend $80 billion on this, then that will be different. We could do it faster but I personally will not advocate that. It will be a mistake. Because a slower program is more sustainable. It is not rushed. This is consistent with the research in Antarctica . We go there every year and do a little research. That is my view on it and I think it reflects NASA's view on it too.

Shadi: Is there any private funding for NASA or any of the space projects and missions?

Dr. McKay: There is private money being spent in developing space hardware, none of it to support NASA's goals. In fact, there is private money for lower earth orbits. Like the Spaceship X which was funded by private money. There are also people who are developing rockets which will go into Earth's orbit and come back. There is currently no private funding available for anything that goes beyond the lower earth orbit. There is obviously private funding for satellites. For example, when you use a phone you are using satellites which have been sent up on private rockets.

Shadi: I would like to switch gears, and ask you about another one of your interests. You mentioned research in Antarctica . I know you have headed a number of projects and research on Earth in places with extreme climates. Would you tell us a little about it?

Dr. McKay: I do a lot of research in places on Earth that are like Mars. I want to understand the possibilities for life on Mars, and one way to do that is to go to places on Earth that are very cold or very dry like on Mars and to try to understand life on these Mars-like places. That has taken me to Antarctic for many years and to Atacama Desert in Chile , the driest place on Earth and a couple of other places, to understand the limits of life on Earth under Mars-like conditions.

Shadi: What have you found so far in doing research in these extreme climates?

Dr. McKay: What we have found and confirmed is what we and others knew—that liquid water is important for life. Ice does not work. We need water. The other thing which we have found is that when we go to extreme climate which resemble Mars, life becomes patchy. It is no longer everywhere. There are little patches of life in environments which are otherwise barren. It becomes very hard to find. You go to places like the Atacama Desert and you move ten feet and the amount of life changes radically. There are patches of bacterial life in an ocean of otherwise nothing. The other thing we have found in these harsh environments is that it can be very hard to find evidence of life. So, we have come to believe that we need to develop our instruments here on Earth to look for life. If we can not develop instruments here to detect life in places like Antarctica or the Atacama Desert we will not be able to do it on Mars.

Shadi: I want to ask you a broader question about the future: in terms of where you want us to be, your hopes; what do you want to see, let's say, in 10 to 20 years; and for the next generation, who will continue your research?

Dr. McKay: I guess there are two lines related to that. There is one related to going back to the moon and the other is going to Mars. In 10-20 years, I would like us to have research bases on the moon like what we have in the Antarctica . In 10-20 years, I would like us to have the capability to explore Mars, in more detail with robots that have the ability to drill deeply down into permafrost and to have the sophisticated rovers and instrumentation on the surface and so on. That's what I hope we can achieve in the next 10-20 years. Further exploration of Mars, humans on the moon and let's throw in a mission to Europa in there too.

Shadi: Thank you, this has been such an interesting and fascinating conversation. Thank you for speaking to us.