About science; About space exploration
This is about science produced by the California Institute of Technology and originally broadcast my station KPP see Pasadena California. The programs are made available to the station by national educational radio. This program is about space exploration with host Dr. Peter less a man and his guest Dr. Robert McGregor the end of the Jet Propulsion Laboratory. Here now is Dr. Les on one of man's earliest here races the Explorer. Since time immemorial he has been the subject matter of myth legend and reality. We see him staed first at the venturing out in flimsy ships off fragile spacecraft or opening doors to understanding in the quiet and intense tempo of the research lab voyages of discovery over perilous seas to uncharted lands. The Voyages of science are many and varied moving in time from the fleeting micro-second life of the elementary particles to the millions of
years in which the earth was formed and varied in space from the microscopic distances of the molecules to the equally unimaginable millions of miles in which our universe is measured. Today we discuss one of the most Olympian of all voyages that TASC quite godlike in its scope exploring space and asking how it started and who is living with us in our solar system. Our speaker is particularly well qualified to discuss these matters which are his day to day concerns. Dr. Robert Freeman gravely and is currently manager of the Space Sciences Division at Celtic's jet propulsion lab. He did his undergraduate work and served in the US Navy aboard carriers during the war and then obtained his Ph.D. in aeronautics from the California Institute of Technology. He worked for some years at the Oakridge Laboratories and is author of a book on reactor
analysis since 1958 doctor regrettably and has worked for Cao takes Jet Propulsion Lab and among his many and varied activities is that of host. On the radio show about science. And now with a poetic turn of justice he becomes the victim interviewed on his own show. Now Bob let's talk a little bit about exploring space. Well I like to think of it in terms of three major elements. Peter was a rather grand introduction as a matter of fact. To begin with the question of exploring space involves a matter of developing a strategy. How do you go about the business. You mentioned the explorers of the frontier the physical frontier. This too is exploration of physical frontier but
most of the explorers will be sitting here on Earth and remotely Manning or operating or commanding complex systems in vehicles far away hundreds of millions of miles away. So there's a question of developing a strategy to do this since the objects to be explored and a space in between is very large and there are very many choices. In other words we should have some idea of what we're looking for before we set off. We need to know what we're looking for. We need to know or to specify the questions we would like to ask the questions we would like to answer. We would like to know the techniques of obtaining answers to these questions and moreover we would like to know where to ask the questions namely what planets or objects in the solar system we would like to ask the questions. So there are these three major elements of space exploration as we see them today. Presumably we choose our nearest neighbors if it came to wondering what planets were
going to look at. Yes that's both convenient and in a way fortunate convenient in a sense of course that it's much easier to go to the nearest neighbors the moon as our closest the moon is also very interesting from a purely exploratory nature in that it appears to be an object in our solar system which has elements of primordial material. Maybe also the two nearest planets Venus and Mars have characters characteristics which are. In some way similar to that of the earth. The in the case of Mars for example the temperatures seem reasonable. It's not like the earth but not too far afield from that on the earth. And in the case of Venus we have a fairly substantial atmosphere although the temperatures appear to be at the moment rather large. But in any case there is some
similarity earth which makes it rather attractive to us because if this be the case then the prospects of finding interesting things there is somewhat enhanced. So these planets are much more like the Earth than the more distant ones as far as we know. Yes I think based on our present knowledge the planets further away Mercury closer to the sun appears to be very hot indeed to our knowledge today. A rather modest atmosphere. If you move in the opposite direction beyond Mars you run into Jupiter and there you have a very massive body which appears to be quite cold. And from the expert exploration point of view these are interesting objects in themselves but based on some of the objectives of the space program as presently envisioned Mars and Venus appear to me most attractive. Well what would be the natural things that you would first look at on Mars and
Venus Bob. Well there are several objectives that have been laid down as representing the interest and consensus of the scientific community. And these were spelled out about two years ago by the National Academy of Sciences where there was an extensive study which they sponsored at Woods Hole in Massachusetts in the summer 65. Which many people were in bright and experts in a variety of scientific disciplines and they came up with extensive documents and reports which spelled out a logic and an approach to this entire matter. And three specific scientific objectives were laid out by them for the space program. The first was to determine the origin and evolution of the solar system and the second was to determine the origin and evolution of life in the solar system. And the third was to determine the processes which formed the terrestrial environment our own planet and the moon complex. And the space program is presently
being constructed in the context of those objectives. So I thought then is to attempt to lay out a systematic approach to accomplishing those particular objectives. Now I guess that the foundations to that approach have already been laid by the spacecraft of the Jet Propulsion Lab up to date. Yes I think some progress has been made by the missions carried out by the Jet Propulsion Laboratory. Of course other major institutions in the country have contributed in an important way and we can mention some of these shortly. It's important to note however that we are in a relative way we know so little about the solar system relative to what we expect and know that whatever you do in the beginning adds to your knowledge and measurably so that although you try to be as logical and considerate in your approach as possible in the beginning most anything you do adds to your knowledge. However as the information accumulates in the facts
and the observations are piled one upon the other then one is pressed to correlate this information to bring it together in a. Cohesive manner. In a coherent manner I should say. And from this don't begin to construct a. General theory or a general representation of the toll system. And when you get to that stage you are then pressed with the problem of which questions do I ask now and what order sequentially and in scientific priority becomes more complex as you gain knowledge. Yes in other words once you've learned a few things you are realize that there are some points which are not really worth exploring and that having built your models you see that there are some other key factors which really must be investigated to to verify your model or not. That in fact that's the approach that's in consideration namely to construct models to carry out the investigation.
In the case of the first two objectives I mentioned and I think it applies also to the third. I can mention some of these in the case of the question of determining the origin of the solar system. First of course we recognize that this is a process which leads in time to a more realistic representation of the facts. You never really know how that sort of system originated but at any one time you think that your understanding is better than it was previously. You construct a model and you construct a model of how the solar system came into being. And the model will encompass processes and physical conditions of the solar system. That is to say it began at a certain time in a certain way from a certain physical state nucleosynthesis when all the elements were form. There were certain processes through which the original elements and the way in which they collected together formed led to a new state. This in turn went through certain other processes and led to another state and eventually we arrive at our present
configuration which is nine planets the sun the asteroid belt the comets and so on. So there's a series of processes and states and at each point there are certain crucial points I should say. Which can be in effect tested. Questions can be asked about these different points and depending upon the answer you can determine the validity of the model if you like. In other words you set yourself up with not being irreverent to some sort of great God scientist and say if I had to build this well I would not give in 7 days but given many eons. This is what I talk with and this is how I go about it. And every couple of million. Yes I had as it were open the oven door and expect to find that a certain thing it happened. And this is what we are going to endeavor to see if this has in fact happened. I think in a sense that's quite true Peter. In fact what you do is you set yourself up a model and you test against the facts observable
facts in physics they call them observables. And by checking against the observable as you determine whether or not your model is valid and the facts deny your model then you discard your model and construct another and eventually you will arrive at a model which generally satisfied the observables within your capability at that time of your knowledge. Of course much of the work on the origins of the solar system at many of those questions will have to be oncet by astronomers. Bob is this true. Well this strawman is a certainly concern themselves with this question for a long time and I think that most of our theories today stem from the astro physicists and astronomers who generally concern themselves. I think that we are entering a period however in which the space explorers if you like whether they go in literally or through their unmanned spacecraft. Aren't going to be making important contributions. I might add here that in developing
some of this rationale for the exploration we've picked in fact Mars and Venus as our first objects targets for exploration and we've made a few ventures one to each In fact the best that the entire human race has accomplished today. And in time we will be venturing a more frequently to these planets and certain questions ought to be asked. With regard to the matter of the origin of the solar system you might ask such a question as the following. Are the planets formed. Were all the were all the planets formed from the same material the same cloud. The present thought is that the planets were created or condensed from a cloud of gas and dust in the field of the sun. The gravitational field of the sun. This is the present thought. We don't know if this is true and if it is true whether the cloud was captured by the sun from some alien space or if it was something that came from the sun itself.
But one could ask the question are indeed the planets generally of the same chemical composition. And you might as disc answer this question by testing at each of the planets. So we've already identified here that answer this question you have to go literally to each other planets and by some process determine the biochemical composition because you can't do that directly. We can even do it on the earth. But there are indirect means in which you can determine this. So having done this then you can get a yes or a no in one fashion or another to the question. And this then indicates to you that indeed some aspect of your model represents the facts. And from there you can progress. So as you point out Bob the astronomers have been looking at these things and hypothesizing for years and finally we have come to the point where we can not only look but we can touch and think. However I expect that we won't may never be expected to bring a piece of those back we are going to be forced simply to touch and feel and radio the messages back to Earth. I imagine
that is the program at the moment. Well. At the moment the missions that are being planned the space missions being planned to the planets are unmanned missions by and large and I think there is anticipation of an opportunity to send men. And I think there are members of the scientific community who feel rather strongly that man in fact does have a role in space but also this role should be a logical one. That is that as you asked these Friday of questions that there was some state at some stage at which man is best able to participate and help answer the question. When you send a man if it's essential that he be there after all a man is a very exceedingly flexible sensor computer and mechanical device if you like more so than anything you could conceive. So there must be at some point in some distant future when the resources and national capability is such that you can send a man and a man it's the right thing to send to get
that answer. We have a lunar program which involves a man today. He will play a role. In fact he will bring back samples Perhaps someday man will bring back samples from the planets. Although it's not out of the question that automated devices could bring back samples. Well there are just basic ideas of rocketry show us that one needs a enormously larger device to get there and to contain the systems which will get you back. So I expect that for many years we will be content with putting out transmitters up there and abandoning them when their function is over. I think that's quite right Peter. Even in the case of the moon with the present manned program that after the arrival of man on the Moon and his return with samples which would be extensively analyzed in our laboratories here on Earth. That one would it one expects and in fact there are plans being formed today in which a man would return along with
many unmanned spacecraft. So as to cover them in an extensive and thorough fashion. One can envision that you would not wish to send man to certain spots on the moon because it's hazardous even Surveyor 3 which just landed last week ran into some difficulties that landed in a crater and bounced around a few times. And one can easily imagine it having arrived and feel the boulders and might not have fared so well. You would not like to risk a man in certain kinds of situations. Moreover to get a thorough exploration of the moon to help answer some of the questions that we've alluded to you would send many spacecraft to many points to do a systematic survey and you need not send a man for all of them. So there is a way in which the unmanned systems can contribute indefinitely I think as a matter of fact probably Jet Propulsion Laboratory is entirely unmanned in the concept of
spacecraft are they not. That's quite right Peter. The role of the laboratory is to contribute to the deep space exploration program. We have been engaged in both the lunar and the planetary program to date. I think that with the present expectations innovations at the laboratory will be asked to do that the emphasis will be towards a planetary programme. And the reason for that incidentally is that there is the great desire to determine whether or not there is life beyond the Earth. Yes this of course is one of our most fascinating topics. We have dismissed any possibility I take it of life on the moon but we are definitely looking at our planet and looking for life in prison for life and the planet. Well the most likely candidate appears to be Mars. And for the reasons we mentioned namely that it has an environment which is not like the Earth
not very dissimilar. I mean it could be attractive if it weren't really as hard as we think it is although there is debate about that question. We've not really touched down on Venus to determine literally the temperature and the thermodynamic sense. We have indications that it's hot so it's appears to be less attractive but that idea again is going to be tested a few more times before we convinced that it's really that high. Mars is attractive because it appears to be temperate in its environment and relatively easy to reach. And. Size comparable to the earth solar flux would be down by what a factor of 4 isn't. Which means that the normal end of the environment is not unlike that of the earth. Now there are those in the scientific community who think that the origin of life is a natural step in the evolution of a planet given a set of environmental conditions. And you can't
avoid it. And if Mars in fact has gone through a series of evolutionary steps as it developed from this cloud of dust and gas that if the right situation came along eventually in physical conditions of the planet for life to evolve life would have evolved. Now the expectation also is that if there is life in the things we know that it will probably on a microbial scale. So the thought is to go to Mars and to test to see if in fact it is an abode of life. Of course Bob the interesting thing about life is that the science fiction addicts always attack the true scientists by saying. You just say that life cannot exist because the conditions are unlike what we expect life would want on earth. But what about the type of life. That thrives in those conditions. And yet I imagine the fact of the matter is that we have discovered that as far as we can see the laws of physics as we observe them on the earth apply to all the planets and all the space
exploration that we have done so far. Well that's certainly entirely true. We have some ideas of what characteristics life on Mars might have. This is of course without a doubt based on what we know about terrestrial life but there seem to be some scientific arguments in support of this. For one thing if we found life on Mars our expectation or a reasonable assumption. Let me say would be that it would be based on carbon water chemistry carbon compounds and water matrix. And the reason for this there are several reasons but one is that carbon is among the most versatile of the elements in the periodic table. It attaches itself and most complex ways with other atoms. Therefore it can build up large complicated molecules and this is necessary in the final analysis for information content. After all the information retained in our bodies in ourselves and in various elements of the cells are tied up in a way in
which molecules are arranged and certain items are located. So you need complex geometric configurations of molecules to retain information. And carbon appears to be very good for this. Other elements can do it but they're not as versatile in the temperate environment that is to say they don't remain in stable configurations the molecules break up. Another thing you might expect of life on Mars is that there should be a photosynthetic species present that is to say one species that draws its energy from the sun the sun in terms that a solar system is an inexhaustible source of energy. If energy is to be taken from whatever source is available and adapted to the use of the living thing that ought to be quite stable source within the history of the species. There might be other species present which don't depend upon the sun but there ought to be at least one species present because there will be other species would feed upon the species which derives
its energy from outside. Another thing consideration is that it ought to have a characteristic shape form morphology if you like a form which has adapted to the environment of Mars it should be recognizable whether it's in a microbial scale or a macroscopic visible to the eye will have some form just be quite specifically Bob work what do you mean by that for why you think it was some growing creeping moss that might be a possibility most likely and I think most possible would be microbial. On the microscopic scale as as we say this is certainly the most abundant form of life as we know it here. It would be certainly most adapted to the environment. More complex systems would require I think
more complex evolutionary path perhaps more benign conditions and conditions on Mars are not entirely benign although if there is life it must have obviously adapted itself to them. How would we go about the take microbial form. Well you can do it both directly and indirectly. First I would regard to the indirect approach if there is life in the environment. It would have an effect on the chemistry of the surface and on the atmosphere. For example there is life on the earth we affect the atmosphere. There are certain constituents chemical stent constituents in the atmosphere of the earth which are due to the presence of life that needs no explaining to someone from Los Angeles probably right. The same thing would be it would apply in Mars. That there would be certain effects on the surface material and there would be certain effects in the atmosphere. For example if we went to Mars among the questions we would ask to begin with certainly in our more modest
first venture is would be to test the atmosphere to see what the chemical composition is. One can determine from the physical condition of the atmosphere its temperature its pressure in the solar flux and so on. And given the principal components what the balance between these ought to be how much nitrogen should there be how much this that or the other. And if one finds Now a particular species that appears to be out of equilibrium then one is confronted with an interesting question how come among the explanations would be that there is some life present which is producing this species and is the source of this particular chemical into the atmosphere. And there would be therefore an inference and direct that something else is going on bitesize pure you know organic chemistry. The direct measurement of course would be that one could test for metabolic products. One could test for growth. One could test for.
Visual observation microscopic observation. So there are direct ways of course. So that's one of the ways in which we could we could test for life and as you point out we might probably be doing this on Mars. What about the other. Subject which is sometimes mentioned about some of our own spacecraft having brought earth life on Earth microscopic particles on to the planets. Do you have any views on that. Well that's a subject which is has which has been of considerable concern and a concern stems from the following. One would like to determine if there is life on these planets. One would like to be certain that the life we discover there is not something that was put there by ourselves inadvertently and then subsequently rediscovered that if we find life there we want to be certain that it's indigenous to the environment and not something that has propagated from some previous venture.
This is then to make a close and very conclusive scientific experiment that we are very careful in our considerations not to contaminate as we say and questions of planetary quarantine and so on have been raised and the debate right now is what the risk should one take in allowing certain the possibility that certain kinds of life for certain amounts of life might be transmitted and placed on a planet and thereby contaminate that environment and subsequently compromise future measurements. So we must keep make sure that all our craft are sterile before we send them off. That's right. What are some of the really big things that we will be looking for in these planets. Very briefly in the next decade. I think the first and foremost question which fascinates the scientific community is that the search for life. I think that's number one. That's my opinion but I think it's one that's shared by many members of the scientific community.
- About science
- About space exploration
- Producing Organization
- California Institute of Technology
- KPCC-FM (Radio station : Pasadena, Calif.)
- Contributing Organization
- University of Maryland (College Park, Maryland)
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If you have more information about this item than what is given here, we want to know! Contact us, indicating the AAPB ID (cpb-aacip/500-5x25fs3n).
- This program focuses on space exploration.
- Interview series on variety of science-related subjects, produced by the California Institute of Technology. Features three Cal Tech faculty members: Dr. Peter Lissaman, Dr. Albert R. Hibbs, and Dr. Robert Meghreblian.
- Media type
Guest: Lockheimer, F. Roy
Host: Hibbs, Albert R.
Producing Organization: California Institute of Technology
Producing Organization: KPCC-FM (Radio station : Pasadena, Calif.)
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University of Maryland
Identifier: 66-40-49 (National Association of Educational Broadcasters)
Format: 1/4 inch audio tape
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- APA: About science; About space exploration. Boston, MA: University of Maryland, American Archive of Public Broadcasting (WGBH and the Library of Congress), Boston, MA and Washington, DC. Retrieved from http://americanarchive.org/catalog/cpb-aacip_500-5x25fs3n