This is a transcription of a slide presentation given by Dr. JIM PAWELCZYK Asst. Professor of Kinesiology presented on March 16, 2001 to the class members of STS497 I, "Space Colonization"; Intructor: Dr. Chris Churchill; technical aspects of presentation by Bob Jones; location: Wartik 108 at Penn State. Transcription by Dr. Jane Charlton. Future plan is to include the slides on a web page. ------------------------------------------------------------------------- At least from what I've heard so far it seems that you all have already given my presentation so I don' know if there is too much more for me to say. But what I want to do is to give you my perspective of how I see space flight and some of the issues that are related to the human condition and what that is going to mean for long duration space flight. This is more the typical view we are used to seeing when we see space flight now these days. And I think that they said it best on the Simpson's when they said that we go from the Earth to the area around the Earth and unfortunately we don't go much further than that. But I think really this is more the view that we would all like to see and that is really something we aspire to and that is to move on to the red planet. Now what I'd like to do is to take a few minutes today and review how that process might occur. And once we have a clear picture of that then kind of identify some of the key physiological challenges, so this will echo some of the things that you have already heard this morning. The general approach for heading to the planet Mars or beyond is that really the technology is within our grasp. And Bob Zubrin did a great job with some of his Mars direct plans of explaining or at least identifying a pathway of how we might do that. The Mars exploration plan which has been developed by NASA/Johnson Space Center has borrowed a lot of those themes and we'll hit on some of those themes in just a second. But let me just take you through what that whole process might look like. So essentially what we are looking at here is a shuttle-derived vehicle. So you see the regular external tanks - solid rocket boosters and then some derivative of the space shuttle that is predominantly a large cargo vehicle that allows us to move a lot of payload up to low earth orbit. Something of the order of a hundred ton mass. In combination with the space station at least this was the plan until the Bush administration decided otherwise a week or two ago would be that we would be able to assemble some kind of habitat or trans-Mars vehicle using the international space station. The trans-hab of course has been cancelled now with some of the cut-backs with the ISS and that is a pretty big loss from a scientific perspective for all of us. But this was the general idea that we'd assemble a trans-hab and once we had that vehicle ready that we would then put that together in the trans-Mars vehicle leaving then low-Earth orbit and heading off to the planet Mars. Now that process is going to take about six months. By the time we're going to get there six months later of course there are going to be a fair number of physiologic changes that we are going to see. Now this is where things get kind of exciting. So heading into Mars orbit by aero-braking. Never been done with human vehicles. Presumably if we get the English to metric conversion correct it will work and then landing of course a vehicle on the surface of Mars. Now the size of that crew could vary considerably but typically it is thought right now that it would be about a six person crew. The whole key to making this process work then is being sure, before we even get a crew there, we have a fully fueled and functional return vehicle. And the only way we can do that, given current technology, is to mine the Martian atmosphere for the constituents we need for the fuel to get home so that we don't have to carry everything. We are not going to do the massive 75 person huge expedition that was envisioned by von Braun. This is a very small and focused expedition. There you see our international crew. Now, the idea of using a Mars transport vehicle actually comes in three different flavors: one would be a transit or habitat type of vehicle that includes predominantly an out-bound living facility, also a lander shown here and then some kind of surface habitat. It is also possible to take the same configuration vehicle and make it a unpiloted version, a robotic version, that would be just a cargo vehicle. This would then include the ascent vehicle for return and a in situ fuel production facility. The other type of vehicle we could see is a trans-earth vehicle. One that includes an Earth-return vehicle and has orbital parking capability. So essentially what we do is we head out in a transit habitat. We land on the surface. There we'll find pre-situated needs that will have already been delivered by our cargo vehicle. Then when we ascend we meet with our trans-earth vehicle, with our earth return, and we'll head on back. Now that is pretty complicated situation, but the advantage to it is that it allows us to pre-position a lot of materials in orbit. In essence what we do is we build up a gradual colonization process if you will so we can pre-position a lot of resources. So in the most ambitious scenario that has been envisioned for this it would have happened around a 2007 time frame. That is when we first go into some favorable positioning with Mars and Earth so we can actually send a vehicle out. Essentially what you see then is launching a trans-earth ejection stage and a return vehicle. Once we have that in position then we follow that up with the ascent stage which is going to land on the Martian surface. We develop a little bit of redundancy by putting up a second vehicle as well. So by the time we are ready to launch a crew we've got something to return to and we've got two ascent stages already on the planet. We talk to those vehicles and make sure everything looks good. In fact, we'll even put a second one up there. And then we're just about ready. We get another ascent stage so now we've got three on the Martian surface. And now we're pretty much ready to go with piloted transit surface habs. And so if you look at it what we've got is one, two, three surface habs. We've got a couple of return vehicles in orbit. And once these are in place there is no reason that the components of these can't be used by future visitors. So we've got habitats in place, and we've got in situ capabilities for propellant. And we'll talk a little bit about that in just a second. So this is a really sensible way to approach things. Now for the human capability of it our most favorable window comes in 2014. And so the way this would basically look would be an Earth departure about Jan. 20 heading to Mars, getting there about 6 months later. Now here's the real trick. You have two choices at this point. You can stay on Mars for less than 30 days and get back home real quickly, or what you do is stay for about 2 years and then return to Earth. And the generally favored position for this is to spend the time, since you already got to Mars, spend the time there, live off the land, and then return. So we're looking at a total time of two and a half or three years depending actually how you do this. So this is a pretty serious endeavor - two and a half to three years in zero gravity or a low gravity of just over one third g. But here's the problem. What this summarizes is our complete experience as a human society with long duration space flight. So these are all human space flights that are greater than two weeks in duration. We have lots and lots and lots that are two weeks or less. But you see that beyond two weeks, once we begin to get up to six months things or so things begin to drop off precipitously. And this is a combined human and Russian space flight experience that we're seeing here. So we see out here at fifteen months we have Valerie Polykov who has been the longest duration person in space. So if you look carefully you see there are only about eight people who have gone beyond eight months in space. We're talking now about 2.5 or 3 years. We have this huge window between 15 months and 2.5 to 3 years. We know nothing about what is going to be the adaptation of a person in that time period. That really represent for us a very big challenge from a research perspective, that if we are going to do these very long duration space flights how do we get from 15 months to 3 years. Some of the challenges you might identify would be changes to bone, to muscle, to cardiovascular system, neurological changes that are associated with space flight, immunological changes as well, in addition to the psychological aspects of being cooped up in this can for a couple of years, radiations, how we're going to provide adequate food and nutrition during that period of time, what environmental conditions we're going to provide given the Martian atmosphere, life support conditions and then of course medical. Now just consider for medical alone, if you look at just the odds of having six people confined together for a three year period. Just off basic statistics, one person at least is going to have a major medical event. And so we have to have a crew that is trained to handle any of these things including things up to the point of minor to major surgery. So these are serious challenges that we have to face, and how are you going to do that and have all of that combined capability in one crew. OK. Let's look at some of the problems we face then, and just quickly characterize the Martian environment. So gravity if you look at earth as 1g, Mars is about 0.38g's. We have no idea whether 38% of normal earth gravity is enough to prevent loss of bone and muscle that we see in zero gravity. We just don't know what 38% g really means in terms of maintaining normal physiology or not. So our assumption is that it is not going to do anything for us at all. It is not going to help us and it is going to act just like zero gravity. And that is a reasonable conservative assumption to take at this point. Temperature is going to be a real big issue. When you consider average Earth normal temperature we have about 16C if you take a world-wide average. The average temperature on Mars is roughly -18C and it swings much more dramatically because there isn't a thick buffering atmospheric layer. So we're going to see extreme environmental conditions as well: high wind conditions, tornados, dust devils that have been documented now on the Martian surface. All of these are going to present pretty serious challenges to anybody who is going to want to get out and ambulate around. If you look at the atmosphere, again here on Earth we are about 79% Nitrogen, 21% oxygen, and 1% of argon and a few other minor constituents. When we look at the Martian atmosphere, essentially what we're looking at is about 95% carbon dioxide and about 5% other constituents. Now, this is both a advantage and disadvantage to us. Obviously carbon dioxide isn't something we can breath, however, it does provide a rich source of carbon. Carbon is something that we can make good use of. And we can make good use of it to produce rocket fuel. So the idea of in situ propulsion simply means that we mine the Martian atmosphere for carbon. Hopefully if we can find sufficient water as well we can mine that for hydrogen and then using the ??Sevadeye?? reaction we can simply produce methane as a rocket fuel. Now methane is not a very elegant rocket fuel, but that's OK. We got to the Moon on kerosene. But it works well enough that it should provide sufficient specific impulse that you can get people back home. Now also if you look at the atmospheric conditions here. There is actually a line here, I didn't forget one. If you are looking at 1000 millibars for normal earth atmospheric at sea level, are down in the range of 5 millibars at the Martian surface. So what we're looking at is a very thin atmosphere with a high concentration of carbon dioxide. Not much there for use to use in terms of breathable atmosphere but a pretty good source of carbon. Now let's look at some of the conditions that we're going to be dealing with. Osteoporosis is one you've heard about already and I'll give you my perspective on osteoporosis as a problem for long duration space flight. Here you see nice normal healthy cancellous?? bone, has this nice trebecular?? network to it. On the right you see osteoporitic bone. You notice all this thinning in the trebecular?? network. In some cases it actually breaks and fractures and ultimately this is what leads to bone fracture. What is the problem with space flight? With spaceflight we see increased resorption of bone and decreased formation of bone. One of the best examples we see for looking at increased resorption of bone actually comes from Skylab data that was analyzed by Scott Smith, a guy who is a Penn State grad. He published this just a couple years ago. What he did is to look at a new technique that is a product of ??collagen crosslinkings urinary entillo pectide excretion which was not available back in the days of Skylab. However, Scott has the distinct advantage of being the person at Johnson Space Center who is the owner of all blood and urine that was ever collected throughout the US space program. So the Skylab urine sample still exists. He was able to fly out with some of those samples, analyze them for urinary entillo pectides, and this is what you see. You see an increase in urinary entillo pectide excretion until you are about 200% of normal, getting out here to about 8 weeks of space flight. Then things tend to level off. Notice though things are leveling off that does not mean you have a stabilization of normal bone resorption. That means that you have augmented bone resorption that is continuing at 200% of normal. You continue to resorb bone for as long as we've been able to measure in space flight. So we don't know what that limit is for when you are going to stop resorbing bone. And that is one of the things that we have to figure out. One the Skylab astronauts returned you see over the couple weeks back at home they are right back to control levels. So let's see what might be that worst case scenario: how much bone you might lose in long duration space flight. Well, here's how we can do it. These data come from Adrian LeBlanc who is down at Baylor in Houston. He has been the guy who has a lot of the bone mineral analyses for astronauts for a number of years now. And these data are from the Shuttle Mir Program, the Phase Ib Program. And what he did was to look at losses of bone mineral at different points along the spine. Now what you'll see is that there is actually an increase in bone mineral that occurs in the head as a result of space flight. And so if you've heard that astronauts come back with big heads I guess that is true. And then if you look as we travel on down and get into regions of the spine that are loaded with gravitational force we see that these losses are greater. Looking right here at the ??thumberal neck, you're looking at a loss of about 1.6% of bone mineral per month. Now just to give you some perspective on that. For a post-menopausal woman what you're looking at is a loss of about 1% of bone mineral per year. So we're looking at a rate of bone demineralization that is 15-16 times greater for astronauts in flight than it is for a post- menopausal woman. And again, we have no idea where that plateaus off and stops occuring. Well, let's work with that number, let's say worst case scenario if we're losing 1.5% per month. And if we're assuming that the Martian gravitational field isn't going to do any good for us, where does that project out for us? Essentially what that means is that you are going to lose over this thirty month period about 45% or so of your bone mineral. Is that reasonable to say that we are going to lose 45% of our bone mineral. I think it is and here's why. I've shown in the right hand column patients who have diminished gravitational loading of their spines here on the ground: parapalegics and quadrapalegics who have been confined to bed for essentially all of their lives, so with a traumatic injury that they are unable to get up out of bed. So lying in this transverse axis they do not get this load on their spine. When you compare their bone mineral to age-matched control people what you're looking at is essentially about a 33 or 34% difference. So what that means is that you can roughly say that gravity confers about 30-45% of our skeleton upon us, and that without that we are going to have about 45% less skeleton. So that is what we're dealing with. Essentially making a person with a long duration space flight equivalent to a quadrupalegic here on the ground. Where does that fall out? Well, if you actually look density of the trocanter?? or the ephemeral?? neck and look at how that compares to the lifespan essential you see you are going to move at this point with the lifespace, 20 years, down to this point, 80 years. And at this dotted line, this is about the point that we define as clinal osteoporosis, typically at about 75 years. In yellow are the lines drawn from the space flight data. So this is the density that we would expect. So there are a couple things to learn from this. On the average, the upper and lower limits here define one standard deviation from the mean population. On the average you can see that by age 80 nearly the entire US population has osteoporosis, a large large fraction of them. And also clearly anyone who participates in long duration space flight is going to have clinically significant osteoporosis. We've got osteoporosis as a problem. Of course the big risk is translating that into fracture. If we have a major traumatic fracture on Mars that is not a good thing. It is not something that you can get home quickly for. What's the real risk in terms of translating that loss of bone mineral into an increase of fracture? Well, here's looking again at bone mineral density and looking at fracture risk per thousand population. And what you see, what you can learn from this is that if you look at young people, under 45 years of age, and look over a wide range of bone mineral density, you can see that there is not much increase in fracture risk. However, as you become older and older, that a loss of bone mineral translates into a greater and greater risk of fracture. And so age and bone mineral density are independent contributors to risk of fracture. Well, think about it a little bit. Some of the things that occur with the aging process are in addition to the loss of bone mineral, a loss of balance, a ??vestibular problem. So you are more likely to fall as you become older. If you are more likely to fall and you have a loss of bone mineral you are more likely to have a fracture. The younger groups don't have as many of those compounding problems, so even though they have a lower bone mineral density, they don't have an increased propensity for falling. Now, what about our astronauts on the planet Mars. Well, they are certainly going to have that loss of bone mineral density. Are they going to have an increased likelihood of falling? Probably, at least for a period of time, and if you fall wearing a 300 pound EVA suit (that is only going to be the equivalent of 100 pounds on the Martian surface) that could be a pretty significant fall for you. So one of the thing you are going to want to do is to stage your landing scenario so that you don't have as many types of activities that would cause you to fall until you are comfortable and have your Mars legs. So perhaps for the first week or two on the Martian surface that you are simply going to have people inside the vehicle and getting comfortable with the Martian gravitation before they are going to hear outside. You now that would be a relatively easy way to handle things. Just simply a staging process. Now one of the things that has been proposed for helping out crew members for long duration space flight has been exercise, and lots of it. I had the opportunity to talk to Yuri Romanenko?? one day, who was the first person to go for a year in space. And Yuri was a famous exerciser where he exercised something on the order of six to eight hours per day in flight. And I asked him what he thought of that. And he said, "well, you know if I wanted to exercise that much I should have joined a gym". And for him, he viewed it as a very unproductive use of his time, but he thought it was necessary to stay healthy. And if you think about it basically at 3000 dollars a minute to keep a person in space, that is a very expensive gym membership. So is this what it is going to take to be the new Martian? So you can see we have a long way to go. So these are some of the other things we deal with when we look at an exercise program. Here I'm looking at just looking at the consumables needed to support an expedition to Mars and to support the exercise program for the crew members, either exercising for an hour a day, or exercising for a half hour three times a week. And what we are looking at then is the mass of our consumables in metric tons. So essentially what we are looking at is food requirements that are going to be on the order of one metric ton, water requirements that are going to be about one and a half to two metric tons, and then oxygen requirements that are going to be on the order of two and one half to three and a half metric tons. So adding that up we are looking at seven metric tons of consumable supplies just for exercise. That's a lot. So we're going to need some serious recycling of resources, and some ability of in situ production of things like oxygen. And obviously getting down to the least common denominator for what its going to take for minimum requirements for exercise is important, because if we can go down to something like the 30 minutes a day 3 times a week there is a savings of about two metric tons. And that is considerable. That's what we can turn into payload then for real science. Now we know that space flight in general reduces work capacity. These are some data that we developed over three different life sciences missions that were done aboard the shuttle. And this is looking at maximal oxygen intake which is simply an indicator of cardio respiratory performance. And what you can see is moving from preflight measurements to immediately post-flight you can see a reduction in work capacity for maximal power output and it is a significant decrease. However, you'll notice that by about six days out that is essentially fully recovered. So in terms of just work performance we do see a significant reduction. However, by about a quarter or so at the worst and it is something we can probably recover fairly quickly. More of concern though is that activity fails to prevent the loss of bone mineral. So this is a series of bed-rest studies that have been done looking at 8 to 20 weeks of bed-rest. And here we are looking at calcium balance. If we are in positive calcium balance we are gaining bone since that is where most calcium goes. If we are in negative calcium balance then we are losing bone. And you look at all these different types of activities that have been done: exercise, simply compressing the legs, or looking at lower body suction where we suck on the legs, they are simply impacting the yield, or simply impacting the heels. All these different ideas. But unfortunately all of them still result in a negative calcium balance, still result in a loss of bone mineral over this long period time. And remember the data I showed you from the Phase Ib program, 1.6% a month. That's also in the face of aggressive counter program that includes one and a half to two hours of exercise per day. So people aboard the Mir have lost up to 25% of their bone mineral and unfortunately even now four and a half years after the Phase Ib program has ended still half of those people still have not fully recovered their bone mineral at this point. So the bone mineral loss is a serious problem. We can't yet prevent it with just exercise intervention. And we are going to have to continue to work on that particular problem, probably in combination with some drug therapy which has been showing some pretty good promise. The other big one that has been mentioned is ionizing radiation. So here again basically the problem is that once you get out of Earth orbit you are dealing with high energy events. High energy events then also contacting things like spacecraft or skulls can produce lower frequency ionizing radiation which then of course leads to a larger potential risk for cancer. Now let's put this in some perspective for what we're dealing with. Here is what we are anticipating for a Mars mission radiation exposure also assuming that you are going to get at least a large event during that period of time. Here's what we are looking at. We are going to concentrate on three different tissues: on the skin, on the eyes, and on the blood forming organs. These are the ones that turn over a lot of cells. And so when you start to introduce mutations the cancer risk is always in the high turnover cells where you have problems. So these are the limits that have been put on your dose in REMs in green for radiation workers here on the ground. Here on the ground we with the idea of ALARE?? limits which is basically as low as possible limits. So basically anything that would cause a cancer risk is unacceptable for radiation workers here on the ground. We use a different idea for space flight. And what we accept for spaceflight is an overall increase in your lifetime cancer of 3%. Now let's put that in some perspective. For all of you sitting here your lifetime risk for developing cancer is about one in four. So look around. Of four people around you, one is going to have cancer in their life. A pretty amazing statistic. What we say for astronauts is that rather than a 25% risk, we'll accept a 28% risk. And if we do that for ISS limits for a 35 year old that puts us up here at a cumulative dose of about 150 REM. And you can see that adding up for galactic cosmic rays, large flares, and typical flares that for any of these tissues we (at about 50 REM) never even get close to these ISS limits. And so it appears, although there has been a big deal about radiation, that the radiation risk may not be as large as we think. There is a little bit of a caveat there though. We really don't know much about the high energy events. We know a lot about low energy events. The only time we learn about high energy events is looking at people who have lived through nuclear explosions. There is not a large pool of candidate subjects that are going to participate in those experiments. So we really can't say with certainty at this point whether these estimates are on target or not. In fact some of these will vary by as much as an order of magnitude. So you have to take these with just a little bit of a grain of salt. So the strategies that we can use to limit radiation exposure: shielding of course and hydrogen rich is usually the best shielding source. Of course minimizing the time in deep space, getting there as quickly as you can and this influences then somewhat what type of propulsion technology you are going to use. Obviously if you use nuclear technology you can get a lot bigger delta V and get there a lot quicker. And then using the idea of "safe haven". So regions of the spacecraft that are going to be relatively more shielded than others. And perhaps the best example is to simply say that in the area where you are storing water, leave it an open part in the center and use that as a safe haven and use water as a good shielding capability or a good shielding strategy. That is probably the best way to go. When you know there are solar flares coming get to your safe haven and minimize your overall exposure risk. OK. So overall here is what I think we are looking at for the Martian risk. For environmental, regenerative life support is probably going to be essential. So you saw some of the consumable requirements. We just can't take that much mass up there. And so biological life support is a good option here. Physical -- I think we are going to require some pharmacological manipulation to maintain bone. And again using some of these ??phisphosphenate compounds seem to be looking pretty good right now looking at some of the bed rest deconditioning studies. There has been pretty good bone mineral maintainence in those. And I think we'll start to see those go into clinical trial now on the International Space Station hopefully within the next year or so. Radiation -- trying to limit to that 3% increase in cancer risk, and again that is a fundamentally different strategy than the way we approach cancer risk here on the ground and approach radiation risk. And so this really becomes a crew issue. Is this something that is acceptable to you as a potential crew member to go and run that increased cancer risk over your lifetime. And of course some of the psychological issues: distance and time from family and friends and providing not just busywork, but providing meaningful work that is going to keep people actively engaged in the process. So I think that is pretty much the overall summary. And we'll open it up to questions a little bit here. Hopefully someday we'll get this Martian mission off. When I talked to astronauts down at JFC this was always one of my favorite questions to ask them - when they thought we'd go to Mars. And I would say that the general consensus of people is that we're looking at thirty to fifty years. Now that's obviously a lot longer than I think any of you and I would like to see. But still, that's within our lifetime. So hopefully if it is faster than that maybe it will be one of you. Hope it will. Thanks. QUESTION/ANSWER Q: My question is about Space Colonization. You talked about what happens to people's bones when they are born on Earth. But if we are able to reproduce on Mars, I wonder if you could speculate on how babies would grow up into adults, what effect would that have on their skeletons. PAWELCZYK: I think I'd have to leave that speculation to Kim Stanley Robinson. I really don't know. And none of us know if fact because we haven't done generational studies in microgravity. We have the most complicated species that we've flown. We have flow a few monkies and we've flown a lot of rodents but we've never done a generational study. The most complicated generational study that we've done in space is with a dwarf wheat plant. So that's one of the big goals for the International Space Station is to be able to keep rats up there for multiple generations and see just exactly how that process is going to occur. Unfortunately because of the cutbacks that are occuring in ISS it is very possible that those facilities are not going to make it on the Space Station and that would be a huge loss. Q: I was thinking that humans could adapt to that environment if they grew up on Mars. So that over periods of years their bones would be normal for Mars. They probably couldn't come back to Earth but they could live normally on Mars. PAWELCZYK: Again, we have no basis to even begin to speculate on that because we don't even have a simple skeleton based species where we've done a multiple generation study. I just can't answer that one for you. But I hope we don't lose that capability. Q: From experience with long term space flights like Mir, we have seen that some of the astronauts have trouble just functioning when they come back into the gravity environment because of the skeletal and the other systems degrading. Is there much of a risk after a six month space flight entering the one third gravity of Mars? How well are they going to be able to function in that environment given the six months of system degradation? PAWELCZYK: Well, again, given that we don't have this experience of working in a 38% gravity field it is a little hard for me to speculate. But we can extrapolate a few things from long duration space flight here on Earth. Let's assume that it is going to be as bad on adaptation as it is occurring here on Earth. People are going to be certainly weakened, but most importantly experiencing pretty profound vestibular symptoms for on the order of three days to two weeks depending on the individual. There are a number of people coming back from Mir and they are literally doing great in three days. They are weak but they are up there walking. There are also people coming back from Mir who literally spent their first week back on Earth puking and couldn't move their head one bit because they just had such profound vestibular symptoms. I don't know if any of you saw Dave Wolfe?? when he first came back. It was in his post flight interview. He literally sat there with his head pinned against a chair and he just looked at people back and forth. And he explained if he moved his head at all he felt like he was moving into the next room. And high frequency stimuli to the vestibular system like brief accelerations are all the things you are missing with spaceflight. And so the sensitivity goes up, at least what we were able to measure on our flight, but a factor of ten to a factor of twenty. Until that system gets toned down again then you are going to expect to see pretty profound motion sickness. Q: In Zubrin's plan he used, when they were flying to Mars, that part of the rocket booster would come off and then would be on a tether and then the space shuttle and the rocket booster would spin around creating artificial gravity. What are the possibilities of doing that both in space and on having some sort of centrifuge machine on Mars? PAWELCZYK: Two different ideas there for artificial gravity: flying a centrifuge, and using a tethered space craft where it spins about an axis. That one is I think originally a Buzz Aldrin idea. Of course every space idea is a Buzz Aldrin idea. The issue with tethered spacecraft is that you have to have things about 56 meters apart to rotate at about four to five revolutions per minute which is about all you can encounter or all you can adapt to within becoming more of less permanently motion sick all the time. That's a pretty long tether that you are dealing with. The other problem with it is that it works great as long as your head remains completely fixed oriented along that axis. Once you begin to move your head out of line with that gravitational field you begin to develop what are called Coriolis effects and you get tumbling sort of phenomena. So potentially people are going to get really sick from some type of counter measure like that. The third issue with using a tethered spacecraft, as you know from some of the NASA experience, is that tethers can break. And if a tether like that would break you have a big problem. And so for the engineering challenges of it, and the questionable return in terms of physiologic performance, I think people are thinking that tethered spacecraft are not a good idea. Now, centrifugation. Definite maybe on that one. We have a centrifuge capability on the International Space Station where we will have animals in microgravity who will be undergoing long term centrifugation to see if we can prevent some of the losses of bone mineral. We'll begin to learn a lot about whether or not that is a good technology to use. There is some suggestion based on some of the experiments that were done on our mission, that in fact that does prevent some of the problems you see with vestibular adaptation and motion sickness afterwards. But I think probably the biggest consensus is that if we can fix this with a modest amount of exercise and drugs that we are going to save ourselves a whole lot of power consumption and a whole lot of upmass and that is probably the most sensible way to get a reasonably sized mission to Mars. Q: At the end of your talk, you mentioned the pharmacological aspects of stopping bone loss. Are you aware of any current research that is going on there? What kind of success there may have been or may be? PAWELCZYK: Yes, those studies are underway right now with Linda Shackleford and Adrian LeBlanc down in Houston. They are doing sixteen week bed-rest studies combinations of velendronite?? which is one of these ??bisphotphenate compounds and exercise both alone and in combination. And it appears that the combination of velendronite and exercise that we are not seeing any loss of bone mineral with people over a sixteen week period so it looks pretty encouraging. Velendronite alone seems to be doing a good job by itself. Usually what we see with bed-rest is a rate of loss of bone mineral that's about half of what we see with space flight. So we're not looking at as big a change as what we see with space flight, but still we're preventing it so again within about one or two years these should be coming into use with astronauts on the ISS and then we will start to know something. Q: This is more of a personal question. If you could go to Mars within the next couple of years, would you want to go on that mission and would you be willing to do that knowing all these physiological effects? PAWELCZYK: Would I want to go, yes. Would I go? I don't know. I'd really have to look at how robust the system was that was transporting me there. And then for me weighing the family issues would be a huge component on that. Personally yes I'd be very interesting in it, but I'm not going to do it taking on an unacceptable amount of risk in my position. Just out of curiosity, what would the risk be of spaceflight? Does anyone know what would be the general risk determination for major loss of life or limb on the Space Shuttle? 1/256 right now. And that is an improvement over what we had pre-Challenger which is about 1/143. So there is a real risk there. That is for total failure that leads to people dying. Q: I was wondering earlier, are you still on the active roster? I don't know if active roster is the right term, but if there is another mission are you among the potential astronauts to be considered? PAWELCZYK: I'm free to apply like anybody else. Payload specialists are brought on board really to bring skills to one particular mission. So if another mission comes up that would need my particular set of skills then I'm free to apply just like anybody else. Q: How did you get interested in becoming an astronaut? Is it something that you had wanted to do from a young age? Is it something you just sort of fell into as your studies progressed? PAWELCZYK: You know it is something I always wanted to do from a very young age. It was either going to be an astronaut or an entomologist. I ended up sort of going down the science route, but I always kept close to some space flight related things and did a lot of space flight related experiments in my own science area. So when this opportunity came up I actually started with that particular flight as an investigator onboard mission. I not only got to do the kind of science I like to do but I got to do it in space so it was the best of both worlds. Q: I know you were pretty busy on the shuttle mission, but did you get a chance to look at the Earth and what was that like? PAWELCZYK: I did get to look at the Earth and that was probably the best experience of the mission was to get a chance to look down on the Earth. It is just so incredibly beautiful. A whole host of colors that you would never expect. Anything from the greens you can see from shallower parts of the ocean looking around the Caribbean, to deserts which I found were probably some of the most beautiful areas of Earth. You sort of expect them just to be big tan expanses, but when you see an incredible dust storm in the Gobi you can actually see it lifting up into the atmosphere so as you are coming up on it oblique you kind of see this tan cloud sitting up there and then as you come up around you see these swirls of these incredible deep russet reds that are just absolutely spectacular. So there is this huge spectrum of color and its an incredible view. Q: I have another scientific type question here. We'd talked earlier about changes to the circulatory system and changes to blood volume to the heart and stuff. What would that mean to the astronaut in terms of the risk to suffer a heart attack or stroke? PAWELCZYK: Probably not much. You look at the adaptation that occurs in the cardiovascular system with space flight. It is probably appropriate for the gravitational field that you're experiencing. So I believe as you guys pointing out that much of the initial volume loss of space flight probably occurs on the pad. So you are sitting there in this Trendelenburg?? position with your feet up in the air which tends to increase fluid return to the heart and increases stretch on the heart which initiates all these reflexes which cause you to decrease red blood cell production, increase urine formation and filtration. So by the time you are done with space flight of a couple weeks duration your total blood volume is down on the order of between a half a liter and a liter. Now, if you actually look at filling pressures during that time, they actually while you are in flight they come back to your Earth normal position. And in fact they are roughly not quite Earth normal but you come to about the position in terms of heart volume, stroke volume, and blood volume as what you would find in a person who is seated on Earth in about a 30 degree recumbent position. So essentially what that says to me is that in fact the lazy boy position is in fact the comfortable space flight position so if you all want to train for space flight get in your lazy boys, kick back 30 degrees and you've got it just right for space. Q: When you are in space, how does it feel like heart-wise? Does it feel like your heart is more relaxed in terms of how fast your heart is beating? Does it work the same way when you move? Do heart rates increase? PAWELCZYK: Heart rate increases are exactly the same. Resting heart rates are exactly the same. Blood pressure measured over long periods of time is about the same or slightly elevated. The nerve activity that constricts blood vessels is slightly elevated in space. The thing that is different is that when you unload the chest wall - so normally the position of our lungs and our chest is determined by a combination of a couple of things one being the elastic recoil of the lung in combination with gravity pulling down on the chest wall versus some muscular capability to lift the chest wall out. You take all those things balance them out. That is what determines the position of the chest wall. Now, you go to space - you take away the weight of the chest wall. And what happens is you got one of the things that is pulling in that is gone - your chest wall lifts up. So everyone seems to have this big barrel chest feeling in space and that is probably the most noticeable thing that is different. Q: Was it a surprise when Bush cut the funding for the transportation to Mars, or did you see it coming because there is a decline in peoples attitudes and government support for the project? PAWELCZYK: In fact President Bush did not cut funding for Mars. That was cut during the Clinton administration and so it has been gone now for about four years. Much of the kind of things you see about Mars planning design are groups of people who are donating their time because they find this interesting and they'd like to see this happen. But what President Bush did do was to limit cost overruns on the International Space Station and probably the biggest loss associated with that was the crew habitation module because what that means is the ability to go to a six person crew is now gone. So we are doing to have a three person crew instead of a six person crew. Our overall time availability of crew members for science capability - we really got some significant crew time when you went to a six person crew. It takes about three people nearly a full day to keep the space station going. So now what we have is three people who can stay up their and maintain the space station and not have much time to do science. To give you an example of that, the first increment on the International Space Station had 171 crew hours budgeted for them to do science. Ultimately with different problems, overruns, rescheduling, replanning, the total time that they had available to do science in that four month time in space was about 17 hours. So that is a little disturbing to me as a tax payer. If our reason for having a space station is to prepare for long duration spaceflight essentially we are in a situation right now where we have built a house, but we didn't plan enough to put a kitchen in it. So how usable is it? Q: That was actually something that I'm curious about. I'm in the STS 200 class. And I find this amazingly fascinating stuff. With all the problems that we have right here on this planet in meeting sustainable living resources and energy resources and how can we justify it in the larger society? PAWELCZYK: Well, I think here is how we do it. What is the NASA budget? Roughly 14 billion dollars. So that is less than 1% of the federal budget. Now, compare that example to the department of defense which is about 20% of the national budget. I think it is easy to justify when you look at the fact that NASA is not a big component of the way we spend our money nationally. And in fact if you look at the overall cost trends of the money that has gone to NASA, NASA declined from 1966 from the Apollo era and did not even reach that level in just plain dollars not adjusted for inflation until 1991. So NASA has taken a huge hit. Yet despite that they continue to provide new technologies for airports, for general aviation, for interplanetary mission, for human space flight programs. So I think it is an incredible deal for the taxpayer in terms of all the different things that come from NASA. And remember that NASA's mission, what it was charged with under the space act of 1958, is to provide new and enabling technologies. If you look at some of those technologies that have been provided they have been a huge economic boom to our society. And a classic example of that would be digital fly by wire. Every commercial aircraft in use today uses digital fly by wire, uses electronic control technology. That did not exist until NASA developed it. NASA doesn't get a dime for that. But I guarantee you that every major aircraft manufacturer has made zillions of dollars off of that. So I think there has been incredible economic spinoff, incredible economic return, still a reasonably efficient operation, and at the same time this ability to inspire society in ways that I don't think many other federal agencies don't have the ability to do. So I think it is worth it. Q: I was wondering what is it like to perform daily routines in zero gravity environments for example like when you move your hand to scratch your head you might apply too much force, and other routines like eating, going to the bathroom, these kind of things. PAWELCZYK: A reasonable way to understand the overhead of living and working in zero gravity is if you've ever been long term winter camping. The things that you have to deal with in terms of all the extra problems and precautions you have to take to live when it is very cold out, that is about the same amount of overhead that you have to life when you are working in space. So you are right that you have to do everything differently. So using the bathroom is a cumbersome thing, but you learn how to do it. Eating is relatively easy in space so there is no problem there. One of the big advantages is that in space you can put your pants on two legs at a time not just one leg at a time. Q: In the photo your face looked heavier than you look now. Were you heavier or was that an effect of microgravity? PAWELCZYK: That is microgravity. My colleagues always commented on my Clint Eastwood vein right down the center of my forehead. And that stayed throughout the flight. And in fact a pretty noticeable headache throughout the flight as well just with that increase in cephalic?? pressure. And that may be part of what drives that increase of skull mineralization that occurs with longer duration space flight. But if you look at every astronaut in flight you'll see that. You'll see that swollen face. Q: What advice would you give to students who are interested in space flight? PAWELCZYK: The two basic words I would give are math and science. Those are clearly the two fields that are most needed in relation to space flight. When you look at the requirements for the astronaut office there are five different categories that usually people are hired under as astronauts. Four of them are engineering related. One is sort of a mish-mash of everything else that includes veterinarians, physicians, and PhD's in a whole variety of fields. So usually you'll see people that have complementary degrees. You might see physicians who have undergraduate experience as engineers or vice versa. Something like that. So versatility is a key component. People who are really experts in their fields and have a clear demonstrated interest in aviation or space flight. So you'll see a lot of private pilots, a number of people who come out of the military. If you have all those things there is no guarantee that you will make it as an astronaut. But I think it is a pretty good guarantee that you are going to have a pretty fun life. /end/