 Right, now that certainly was the most significant and exciting of all the things that I've done in space. I mean, both as an astronomer and an astronaut to put my two hands on the greatest telescope in the world up in space. I mean, what a thrill. Boom, what's up, everyone? Welcome to Simulation. I'm your host Alan Saakyan, very excited to still be at MIT in Cambridge in Massachusetts. We are at Building 33. We are going to be talking about being a NASA astronaut and also space systems design. We have Dr. Jeffrey Hoffman joining us on the show. Hello. Hi, good to be with you. Thank you so much for coming on. It's such an honor and a pleasure. We're very grateful to be able to sit down with you and talk to you. Looking forward to it. Thank you. Thank you. For those that don't know, Dr. Jeffrey Hoffman is a former NASA astronaut flying in five missions with over 50 days of time in space. He was inducted into the Astronaut Hall of Fame in 2007 and is now a professor of aeronautics and astronautics at MIT, co-director of the Massachusetts Space Grant Consortium, and author of an astronaut's diary which contains excerpts of original recordings he made with a pocket tape recorder. And you can find his link right below in the bio. Jeff, let's start things off with one of our favorite questions. We like asking people, we find ourselves as stewards of Earth. What is your current take on the state of humanity? Well, it's interesting that you mentioned stewards of Earth because one thing that you do get as an astronaut is a new perspective on planet Earth. You know, before I went up, I grew up, I was in school in the 60s, the birth of the ecology movement, Earth Day, all that. I mean, I always knew intellectually the Earth is finite. We have to protect our resources, all the things that we talk about, problems that have only become worse in the subsequent 50 years. But somehow, when you actually go up there and you can see the Earth as a planet, and you feel the finiteness of the planet because you're going around it every 90 minutes, and you look at the atmosphere, which you go out on a nice sunny day, and you look up at the big blue sky, and it looks like it goes on forever. And you can sort of understand how it was hard for some people to get the idea of the finiteness of Earth, the finiteness of our atmosphere, the fact that if you keep putting more and more carbon dioxide into the atmosphere, eventually it's going to have an impact. But you go up in space and you see how thin that layer of the atmosphere is. It is finite. We can't just do anything we want to our planet and expect that it's not going to have an impact. It's having an impact, and you can now see the impact of humanity from a global, cosmic perspective, really. It's like how many people have seen pictures of the Grand Canyon. It's magnificent, this huge hole in the Earth, and intellectually you understand, you see the strata, you know that that's the history of the last few billion years. But man, when you go there and you're in the bottom of the canyon and you're looking up, the emotional impact is just overwhelming, and that's what comes from being in space. So the current state of the Earth, on the one hand, there's lots to be pessimistic about. Are we really going to be able to get our hands around climate change and stop the sea level from rising? I have great doubts just because there's so many countries involved, the population is still growing. But on the other hand, there's a lot of things to be optimistic about, growth of interesting technologies, the improvements in healthcare, genomics, the ability to cure a lot of diseases. And so, like I suspect most times in human history, there are things to be optimistic about, things to be pessimistic about. I think humanity is going to survive one way or the other. You never know. Back at the height of the Roman Empire, people probably thought that that kind of life and technology was going to go on forever. And who knew? And we kind of imagine our civilization is going to go on forever and just keep on improving. We could have a worldwide famine, we could have famine, disease, wars, pestilence, I mean the four horsemen of the apocalypse, so to speak. So I don't know. I suspect things are going to hopefully be pretty peaceful for the rest of my life. I'm concerned for my grandchildren, but just like we've had to take care of the world in our lifetimes, that gets passed on to the next generation. And all we can do is try to make their job as easy as possible, which we're not doing right now, unfortunately. What a profound realization to be able to take the animals, the humans from the planet, to put them into orbit every 90 minutes and have that perspective for the first time in just the last 50-ish years be augmented to have that style of awe and a comprehension of our place in the cosmos and being able to see the Anthropocene actually happening with some of the deforestation or acidification and things of that sort. Yeah, deforestation. I mean over the course of my five space flights I could see the progressive cutting down of the Amazon rainforest, for instance. It's scary. You see all of the agricultural burning that's going on to create fields where the trees have been cut down. You see how, because of the need for firewood in developing countries, that the vegetation on hillsides, the line of trees goes further up, because as they have to go further up to cut the wood down, harbors getting silted up. I mean there's a lot of problems which you get a different perspective on when you see them from outside. Yes, yes. And we hope and feel as though the millennials and the Gen Z and further are going to take that stewardship very seriously and solve some of these biggest challenges that we have ahead of us. Jeff, let's talk about your journey. So born in New York City and then ended up going through astronomy at Amherst and then PhD in astrophysics at Harvard and then also masters in material science at Rice. Getting involved in getting inspired by science and space, tell us about how that process happened. Well, I was born in New York City and lived there for the first seven years. Then we moved up to the suburbs but frequently went back into the city. My parents were very good about exposing me and my brothers to a lot of cultural aspects in the city. We went to concerts, museums, including the planetarium, the Hayden Planetarium. I don't know exactly what it was, but I guess my dad was kind of interested in astronomy as well. He had a little two-inch refracting telescope and he knew quite a lot. So he enjoyed taking me to the planetarium and I guess he noticed that I seemed somehow to react to it. I was fascinated by how the planets moved and I learning the names of all the constellations. Now that was back in the 1950s. That's how old I am and it was also the dawn of the coming space age. I was a kid before we launched Sputnik but there was a lot of writing in the newspapers and magazines and shows on television about how pretty soon we were going to have rockets that could orbit the earth and satellites and my boyhood heroes were Flash Gordon, Buck Rogers, because there were no real astronauts at the time but that came. I remember I was in junior high school when Sputnik was launched and dad took us out to the high school football field to watch this incredible thing fly over, which now I mean we see satellites all the time. We don't think much of it, but that first time it was amazing. And then when people started to go in space, you know Yuri Gagar and Alan Shepard, John Glenn and I mean it was all over the news everywhere and you know every red-blooded American boy and unfortunately we didn't have the astronaut role models for girls at the time. We do now luckily we have lots of women astronauts but in any case we all wanted to be astronauts when we grew up. Sure why not? I was fascinated by that. However it became apparent pretty soon that all of the early astronauts were military pilots, test pilots mostly and that was not a career for me. But my interest in space you know from the planetarium and just reading and that continued. I did well in school in all the subjects but I particularly liked science and math and astronomy so I went to Amherst College and I took the beginning astronomy course. I still enjoyed it and so I took all the physics and math courses that you need for astronomy which is basically astronomy is physics through a telescope and a few astronomy courses as well and then went to graduate school. The kind of astronomy that I was most interested in was space-based astronomy looking at high energy radiation. I mean we get all our information almost all our information about the universe by electromagnetic radiation light of course is the easiest that gets through our atmosphere as do radio waves but high energy radiation x-rays gamma rays. I mean it was interesting from a scientific point of view first of all because they're created in some of the most energetic parts of the universe really high magnetic field super high temperatures stellar explosions I mean cool stuff basically. So and scientifically it was interesting because it was new we had just gotten to the point of being able to send x-ray and gamma ray telescopes up above the atmosphere and so it had the added in addition to the intrinsic interest in this type of radiation it had the added interest that when you're doing something for the first time you're looking at a new part of the spectrum you're almost guaranteed to find new things and of course the early days of x-ray astronomy were very exciting continues to be actually we're in a golden age of astronomy these days and so I was working basically with with space technology designing telescopes that we launched from my PhD it was carried up by a high altitude balloon I went and did a postdoc over in England at the University of Leicester and there we use sounding rockets that would go up above the atmosphere but only stay up for five to 10 minutes at a time and started work on satellites as well which then I came back and was working at MIT in the Center for Space Research basically designing satellites to put up designing x-ray telescopes to put up in satellites and analyzing data from them and we had some really exciting discoveries probably the most interesting this was back in the late 70s what we call x-ray bursts that was probably the the most fascinating part of my my astronomical career these are you look at these x-ray sources and and they they're they're sort of going along not doing very much and then all of a sudden boom and there's this huge flash of radiation which gradually dies away but then you know a certain amount from minutes or hours or days later on semi periodically boom again and what we finally after a lot of observations unraveled the mystery these are neutron stars which are orbiting around other stars sucking hydrogen onto the surface of the neutron star where it gets compressed by the gravitational field and eventually it's compressed enough that it triggers nuclear fusion so it's it's like a big hydrogen bomb 10 miles in diameter so quite fascinating and you know I was prepared to go on with my astronomy career and and was just about at the point where I was going to be looking for a 10-year track position to become a professor eventually um yeah by that time by the way I was married I I married an English woman when I was living over there and and our oldest son was born in England now we were living in Cambridge I was working in Cambridge we were living in the Boston area thinking you know this would be a nice place to spend the rest of our lives and along came NASA in the mid to late 70s let's let's we'll get there in a moment oh okay you want to know how I yeah I want to know we need to spend a little more time on okay just the in crazy coolness of of of x-ray and gamma ray astronomy because you spent so much time on this seven years yes seven years of time and also it continues to be like you said a big renaissance in astronomy so you're explaining how it's it's like a binary or a triple star system potentially multiple star system and one of the stars is larger than the other star and it's it's one of the stars is not larger physically it's smaller it's yes the neutron star is only maybe 10 miles in diameter but it's got a lot of gravity it has the mass of a big star has the mass right what well what happens is you know you have a star like our son and there's a balance the the nuclear fusion inside the center of the sun creates a lot of heat it wants to push everything out and gravity wants to suck it back in and it's in a nice balance once you use up all the fuel that you've burned your hydrogen you maybe burns burn the helium but eventually you've burned out the fuel then our son will collapse into a white dwarf and at that point it's actually the pally exclusion principle prevents all the electrons from getting into one place and and that creates an outward pressure so the the white dwarf is is much smaller than than our son and that's about all that's going to happen to our son it's going to throw off some some big shells that will eventually burn up the earth and but that's not for a few billion years so don't lose any sleep over it but if our son weighs the mass if our son were bigger if a star is bigger then it has more gravity when it collapses and it can actually push those electrons which were holding apart the white dwarf can push those electrons right into the nuclei and so the protons combined with electrons to make neutrons and you you end up with a huge atomic nucleus 10 miles in diameter that's a neutron star it has to be several times more massive than our than our son it's an I mean an incredible concept that you can have this and and so on the surface of the neutron star the gravity is is quite strong and if it's in orbit around another star like a you know a bigger star with an atmosphere it can actually suck the atmosphere off that other star and as that gas falls onto the neutron star it heats up and gives off it to millions of degrees really and gives off x-rays and you can all you know there's other ways to make x-rays I mean you can if you have strong magnetic fields and you get charged particles moving around in a magnetic field they can create electromagnetic radiation as well and you get a strong enough magnetic field and and and powerful electrons you you can make x-rays as well it's all very high energy high temperatures cool stuff yes and then briefly teach us about how to do x-ray and gamma ray analysis versus this is versus the big old mirror for reflecting the light on a telescope what does it look like on for x-ray and gamma ray well the the early days of x-ray astronomy the x-ray detectors really came out of nuclear physics in fact my phd thesis advisor originally was a nuclear physicist but you know they they adapted these x-ray gamma ray detectors to astronomy and the only way you could figure out where the x-rays were coming from would be to make collimators if you imagine you know like a a gun barrel but lots of them stacked together so that when you look through them it's like looking through a soda straw and so if you see an x-ray you know where it's coming from but it was pretty crude you couldn't get good images for x-rays as long as they're not too energetic it was discovered that you could actually make a mirror that would focus x-rays not by bouncing them off directly like light because x-rays would be absorbed but if you have it at a very shallow angle the x-ray will hit it and then bounce off and if you have just the right shape double mirror parabola and hyperbola you can actually focus an image with x-rays and and that was the real breakthrough in x-ray astronomy that we could take pictures of objects in x-rays and and we had there's been a succession of x-ray telescopes culminating in the current Chandra x-ray observatory which is a a large x-ray telescope and it's just been spectacular and and what we can do now in astronomy which is one of the reasons why why it's a golden age of astronomy is we have these telescopes throughout the electromagnetic spectrum so you can get radio pictures of something and and you know radio waves are created by certain processes and then you can get infrared and optical and ultraviolet and x-ray and gamma ray each of which gives you different type of information about what's going on out there and and so we have this broad spectrum astronomy which we can do now plus much bigger telescopes Hubble telescope which is an important part of my life is still going strong and and some super big telescopes that have been developed on the ground together with the ability to get around some of the distorting image of images created by the Earth's atmosphere I mean it's it's it's almost incredible what what earthbound astronomers are able to do now so it astronomy it's really exciting yeah yeah so it's been like you said it's the big big renaissance happening with a lot of the exponential technology the broad cosmic imaging that's happening across all different parts of electromagnetic spectrum so interesting and also more trips up to space more higher tech equipment better equipment on the ground then you end up being selected by NASA in 1978 well what happened when the early astronauts were selected and I saw that they were all military pilots which was not a career for me I figured oh yeah flying in space that'd be really cool but I never looked out at it as a realistic career prospect you know I was going to be an astronomer and do high-energy astrophysics but along comes the space shuttle which NASA was testing in the mid to late 70s with the the drop tests of the enterprise and getting ready they thought to launch the first orbital shuttle in 1979 and they needed new astronauts but the thing about the shuttle they had a crew of up to seven people and they only needed two pilots and so that's what really opened things up for scientists medical doctors engineers so when I was working at MIT in the late 70s and NASA put out a call for new astronauts and when I saw that they're looking for scientists wow you know this is yeah I always dreamed of doing this and all of a sudden it's no longer an unrealistic it now becomes a realistic goal and I put in my application and I was lucky I got selected the first time around I mean some people I know one of one of my colleagues applied four times before he got selected but I was in the first group of space shuttle astronauts that was the group that came in with the first American women Sally Ride and her colleagues and and all of us flew 35 of us and we all flew at least once I was fortunate I stuck around and ended up with five flights and I was very fortunate yeah and okay so this what does the team this first crew of 35 of you what do you go through what are the operations and the trainings and what does this all look like well when we showed up nobody had flown on the shuttle before and it was very different from when a group of astronauts showed up you know 20 years later because by that time we knew how the shuttle operated we knew how to train people for the shuttle I mean nobody actually knew how to train us we originally we got trained by engineers who had built the shuttle and they would tell us how you know this piece of equipment was made out of 1327 aluminum and and you know these are the kind of rivets we use I mean no we don't need to know that we're operators and actually given my educational background one of the after our initial training we clearly weren't going to fly for a while I mean the shuttle did not fly in 79 it didn't fly until 81 and there were a lot of older astronauts who were going to fly before our group so we were all given on-the-job assignments one of my first assignments was testing out the shuttle software and a software lab out at in in Downey California where the shuttle was was built but another job that I got I think given my educational background and the fact that I had worked at a university was to work with the training people and actually develop techniques for how to train us so I actually wrote one of the training manuals that was for quite a few years was was used just to to show the people you know this is the sort of information that we need as astronauts we are operators we have to have a very broad knowledge of many many different systems and the shuttle or whatever spacecraft we're flying on very different from the engineers who work in mission control where you have you know one person who's responsible for the propulsion system and has to have a really deep knowledge of that system but he doesn't necessarily have to have a deep operational knowledge of how the electrical power system works although that may influence the propulsion because all these systems are interconnected but you know basically the astronauts need a broad but maybe not quite so deep a knowledge as the working engineers we need to know how to operate a system we need to know what kind of failures can occur and then of course what do we do if something fails yes so the major thing is to know the protocols for the operations of space flight and to be very familiar with all of those processes and in many cases when we're working with new systems we have to develop the processes and that that was one of the things I spent a lot of time on was given my scientific background uh I would often be assigned to work with scientists who were designing experiments to be done in space and given my knowledge of the shuttle systems and the environment of weightlessness I could often see things about the way they had designed their experiment you know given that they weren't familiar with operating in space things that weren't going to work properly and and so I could offer ways to to fix them in fact one of one of my most important jobs as an astronaut I when someone would hand me a piece of equipment or a procedure and I would try to break it basically not by hitting it with a hammer but but by you know what what kind of operational problems could we run into because I'd much rather figure that out on the ground when we can actually work with the engineers and do something about it and develop work around procedures rather than wait till we're up in space and time is limited and and you don't want to have something fail up there and then not know what to do about it although that happens as well but the process of having spent a lot of time on the ground working with malfunctions and how to deal with them it equips you better even when something happens up in space that that you didn't expect you have the mindset and the confidence that you can deal with it and that's important yeah yeah and the missions then so 1985 with discovery and that was my first mission and that was to rescue a malfunctioning satellite okay no actually well first I should start the my first flight assignment was to fly in June of 1984 but back in the day shuttle flights were getting canceled all the time equipment was failing flights would get canceled you'd get bumped to another flight so for for various reasons the flight was supposed to go before hours got canceled so so that crew got put on to our flight and then we got moved to a flight in August of 1984 they had a problem on the launch pad in in June so they took the August flight and we got bumped all the way to January of 1985 the satellite that we were supposed to launch wasn't ready so we got bumped to another flight which was supposed to go in March of 85 they had a problem with the shuttle we didn't launch till April the original purpose of that first mission was just to take two satellites up punch them out of the cargo bay of the shuttle and each of them has an upper stage which would then take them up to geostationary orbit because they were both communication satellites is a four-day mission and then go up punch out the satellites and come back home why did it require astronauts to punch out the satellites well that's a very interesting question and the the answer which was determined after the Challenger disaster was that you don't remember that when the shuttle was originally built it was thought that it it could fly a lot more frequently than it ended up being able to fly it turned out it was a much more complex it was reusable vehicle but reusing it refurbishing it turning it around took a lot longer and was much more complicated than people had originally hoped not surprisingly maybe because we had you know we had never built a reusable spacecraft before you would have thought that the first reusable spacecraft would have been a small X vehicle you know follow on from the X-15 something like that so that we could actually learn something about how do you how do you refurbish a spacecraft once it's come back from space no the space shuttle I mean it's huge it was the size of a dc-9 airplane and and you know the fact the idea that that this was the first reusable this huge vehicle and there are you know political and policy reasons why NASA had to build the shuttle that it did it had to satisfy all users because the original idea was the shuttle would replace all expendable rockets and it was considered at the time it was going to be it had so much redundancy in it it was going to be incredibly safe the crew would not need an escape system first time that that was ever done and and so yeah if you had to launch a satellite just put it in the shuttle and yeah there are people there and and so we would we would go through the operations to deploy the satellites after Challenger people realized that despite everything that had been done to make the shuttle as safe as possible you could still have loss of life and so the decision was made no there's no reason to have to have people just to launch a satellite so satellite launches were returned to expendables and more or less we use the shuttle for things where it made sense to have people on board but before Challenger and that was my first flight was we did everything with the shuttle so the the idea was we were just going to go up on a relatively short mission launch these two satellites we had one or two medical experiments that we were carrying out but then come home what happened was that the the first satellite we launched that was fine you know we we launched the satellite then we get out of the way because 45 minutes later the engine turns on and that satellite goes up to geostationary orbit the second satellite we deployed out of the shuttle and that normally is the end of our responsibility but we looked at it for a while and there's a little antenna on the top which is supposed to pop up which we had seen many times in the simulator because we had done this many many times for practice well it never nothing happened after about five minutes you know i i turned to one of my my crewmates there something's wrong here so so i called down to houston uh you know the the omni antenna has not popped up so the suspicion already was um you know something is really wrong inside the satellite they told us to move away from it just in case the engine was going to fire 45 minutes later although we really didn't expect it to fire because the whole timing sequence never started up that that would have popped up that antenna yes so we we moved away and sure enough it didn't fire and then they said well don't move any further away just and and we'll think of think of what to do and you know we didn't know what they were going to come up with and what can we do we had we had no special tools on board we we had no training on what what to do if the satellite didn't work because nobody had ever anticipated that but it did turn out the first thing you look for when something fails is what we call a single point failure because if you have redundancy it's much less likely that that multiple things will fail in the same way but there was one single switch on the outside of the satellite which is normally closed when the satellite's in the cargo bay it's part of the whole timing sequence it's a safety measure you you don't want the engine to fire when it's inside the shuttle that would be a bad day so this switch has to open up when when the satellite leaves the shuttle and and the thought was there's a little micro switch underneath the external big part of the switch and you know maybe it's sticky or something and and so that was really the only thing that we had access to but they basically had us build some special tools I mean it was sort of like that Apollo 13 moment where they they throw all the stuff on the table that that we have on board and they say all right got to come up with a tool to do this and they came up with two objects that that looked kind of like fly swatter so we became known as the SWAT team and and then when they were telling us all about what they were thinking I remember the call coming up saying Discovery Houston we're we're thinking of several different options for what we might do one of which involves a spacewalk and you know that magic word spacewalk because for every shuttle flight two astronauts get trained on how to use a spacesuit and do a spacewalk just as a contingency in case something happens that would prevent the shuttle from coming home and so I was one of those two people and I guess we had gotten good reports from our trainers who had watched us training underwater and they said yeah you know you can you can trust Jeff and Dave to they know what they're doing and so sure enough they had us go out and attach these tools to the end of the robotic arm and that was an amazing experience because I had never I hadn't I mean you always dream about doing a spacewalk if you're an astronaut I mean that's that's the the closest you can come to really be in space you know here's my hand here's a vacuum I mean I'm you're really in space with a big wraparound view with your helmet but what I found was the the value of the training because I'll never forget I I opened the hatch and sort of slid out on my belly I was facing down to the floor of the the shuttle's cargo bay because I had to go over to the toolbox to get the tools I needed for the job and thinking to myself you know that the training was really good because I I felt comfortable I knew what I was doing and it felt really very much like when I was in the water tank which is and the reason we train in the water is because this space suit suit on on the earth weighs about 300 pounds and and so you can't really do anything in it but in the water you float and and they they balance you out with lead weight so you're neutrally buoyant you don't float you don't sink and and so you can actually work in the space suit underwater it's as close as we can come to actually being out in space and so I remember thinking to myself it really feels like when I was underwater that was great training then after I had all the tools I turned around to go back and I looked up and there was the earth and the sky and the stars and I knew I wasn't in the water tank anymore it was that was an incredible thing and and we did the job and and got good good ratings for how we moved around in the space suit and and that turned out you know totally by chance did I happen to be you know after four different flight assignments to be on that flight when that satellite happened to fail and I got to do a space walk and then eight years later when it was time to choose a crew to go up and rescue Hubble because the Hubble telescope repair was such a critical mission for NASA they said only people who have previously done spacewalks are eligible to get a sign to go fix Hubble and I had my union card for spacewalk your union card this was 93 with endeavor that's right and that was my fourth space flight that was your fourth space flight and and because you had your card for going and doing a spacewalk and fixing a satellite that's so interesting and so crazy how back then it you could get bumped and bumped and bumped and now it seems as though the amount of space flights that we're doing and and also not needing crew to deploy the actual satellite but automating that process to potentially save lives and then also I want you to speak even before we get to the Columbia Atlantis etc teach us about the EDL entry descent and landing process because yeah we've heard that it's like going over the Niagara Falls in a barrel and having that barrel be on fire well I would think going over Niagara Falls is well first of all it doesn't take nearly as long and well you would be weightless for for part of that at least so in any case regardless of the of the appness of the analogy yeah I I didn't know what to expect the first time our commander had been in space once before and and so he gave us a little bit of a you know introduction and and he he could actually see the G meter which would measure the the acceleration and and he told me because I was sitting in behind where I couldn't actually see it he said let me know when you think we've got up to about one G and you'll be surprised you know back to one earth gravity yeah so anyway you turn the shuttle around you fire the maneuvering engines to slow you down just a little bit and that drops the far side of your orbit you know 45 minutes away on the other side of the earth your orbit takes you down into the upper reaches of the atmosphere and so after the engines are fired you know you're coming home you're still weightless you're still in space but there's nothing you you're coming home one way or the other of course we have to fire the engines at just the right time so that we end up at the right place because unlike other spacecraft the shuttle can't land in the water it can't land anywhere it can only land in a runway so they never bothered like with jungle training or things like that for us flying the shuttle because you know if you don't land in a runway you don't need to worry about survival training because you're not going to survive there were certain emergency procedures which we did practice you know if if the the shuttle has a hard landing and you have to evacuate things like that but basically so anyway we're on our way back and not too much happens what I would do I I would take a pen or pencil and and just let it float in front of my face and then what you notice very slowly it starts to move down because you hit the very upper regions of the atmosphere and the friction starts to slow you down and that decelerates the shuttle and that's what creates the initial onset of gravity so it gets down I'll pick it up now it's coming down a little faster now it's coming down much fat now I reach over to get it my camera to take a picture out the window these were heavy nike on f4s f5s normally you just touch it with your finger it floats up and you can just maneuver around you go to pick it up oh what's this you know it has weight it's amazing how used you get to being weightless and I want to have a clarification point quick so this is different the Soyuz descent oh the shuttle is is totally different from Soyuz Soyuz is a space capsule and that's and that comes yeah that comes in much steeper and much faster with a much higher g-load which is what they normally do when they return from the International Space Station right now all flights to and from the station are on the Russian Soyuz but even once we start getting the SpaceX Dragon or the Boeing Starliner those are still capsules so yeah they'll they'll have a you know people who some of my colleagues who have have ridden the Soyuz as well as the shuttle will tell you I mean the shuttle is a pretty rough ride on the way up especially the first two minutes when you're burning the solid boosters but it's a very smooth ride home compared to the Soyuz which is particularly when the parachute opens there's a huge shock and then you're swinging back and forth and and then when you actually hit the ground yeah they they do fire retro rock it's just before you hit but it it really is a hard hit they tell people you know keep your mouth closed when you hit the ground because you don't want to bite your tongue off I mean it's it's that much of a shock no the shuttle is much more civilized way to come home from space you know with wings then what happens is when you get down to about 250,000 feet you you first start picking up the atmosphere about 400,000 feet 250,000 feet is when you really start to heat up and that's when looking out the back window of the shuttle which you're looking into the wake just it's just like a motorboat leaves a wake behind it you know the entering spacecraft leaves it leaves a hypersonic weight which is glowing at at thousands of degrees and you have to have a heat shield well that's without that I mean the shuttle is made of aluminum the body which which melts at you know less than a thousand degrees and you've got temperatures of many thousands of degrees out there and do we know what the optimal material is for the heat shield well the heat shield for all previous spacecraft had been expendable it was a what we call an ablative material which gradually melted it was kind of a phenolic resin embedded in a honeycomb and and as it heated up it would melt and that would take the heat away but it was a one-shot only and it was rather heavy so it was a big challenge for the shuttle devising a reusable and very light heat shield and that's what all those ceramic tiles you know they have like upwards of 30,000 tiles on the shuttle and they have to be really light but very very good insulators and it was an amazing development to build those tiles getting them to stick on to the shuttle turned out to be harder than people had imagined but that that was a whole another story they finally did figure that out and it works it works so um post 250,000 feet yeah so I mean I was just mesmerized by this light show going on and you know the the shimmering lines of the wake and between each of the tiles they have these little gap fillers and every once in a while a tiny piece of that would come off and so you'd be looking at the re-entry wake and every once in a while you'd get these little flashes of light you know zing zing and every time I saw one of those I would I would think to myself well I hope that wasn't anything important and it wasn't you know we got to the ground and and then you know I was I was feeling really heavy so I told the commander uh hey uh but we must be up at one g now right so yeah we're about a third of a g you know because after being used to weightlessness for we had been up for a whole week as it turned out um gravity it affects you much more strongly up for a week in zero g right and then yeah you your body gets used to that yeah I mean I wasn't biology changes well it wasn't physically you know in one week uh your body doesn't change that much people spending six months in the space station they they have to be very concerned about changes in their body they have to exercise regularly we had a treadmill on board and um everybody else ran in the treadmill so I figured well I better try it out so in in order to be able to run on a treadmill you you have to put on a body harness with bungee cords to hold you down so that you can run so you know I ran for about 20 minutes and then as I released the bungee cords and floated back up I realized you know while I was running on the treadmill I felt like I was back on earth I don't need that I'm gonna be on earth for the rest of my life I want to be in space and so that's the last time I ever exercised in space which for a week or two I mean you can go without you can lie in bed for two weeks and and you're not going to suffer any undue harm but for six months yeah you have to exercise no question and and they spend two to three hours a day up in the space station exercising I didn't yeah yeah but um there's still when you when you get back into a gravity field strange things happen I mean right after we landed can you teach us about the landing process of your working and then you finally come yeah well what what happens that that that heating phase where you you see this incandescent weight behind you that lasts for about 10 minutes and and then by that time you're you're pretty much up to 1g and and now the the other incredible thing then was we were landing in Florida so as we came over the shuttle the the the California coast one of the things when you're in orbit and you look at the earth going by you it moves at about the same rate as the earth when you're looking out of it an airplane a window you know you're going a lot faster but you're much further away you don't really have any sense of speed because you know there's no vibration there's no wind there's no billboards rushing by you coming over the coast of California though you know now we're we're down you know many times closer to the earth than we were when we were in orbit so now the ground is really screaming by and that's when I first got the sensation of speed was crossing the California coast and then we basically maneuver it's all about energy management you want to get to the runway with a little bit of extra energy just so that you don't want to get there with too little energy it's much easier to bleed off the energy so you basically fly over and then when you get right over the landing field you do a big circle heading alignment circle they call it you line up with a runway and then when you finally go sub sonic you you by the way you have those two booms and you can feel a little shock as you as you're going down lower than the speed of sound and then the pilot takes over manually this is what the pilots have been training to do hundreds of times in the shuttle training aircraft and in the simulators and then they line up with the runway and they of course it's a glider so you only get one shot at landing but that's what they train for and we had a great landing only problem with our landing that time there was a there was a big crosswind and the shuttle was designed so that the nose wheel could steer which is how you keep in the center even if there's a crosswind but there was a problem with the redundancy problem and the potential single point failure which could turn the wheel over hard which would be very bad so in those early days the pilots weren't using the nose wheel steering the way to steer the shuttle and the runway would be differential pressure on the brakes on the rear tires and we had a strong crosswind so our commander had to continually use one brake and and we had the the original brakes at the time they they were subsequently improved anyway the net result it overheated led to a blowout it's the only tire blowout we ever had this was my first flight we had gone through all this incredible stuff with the satellite failure an unscheduled spacewalk the first time nasa had ever done an unscheduled unplanned spacewalk in its entire history a rendezvous in space with the satellite and you know i felt just touching down on the runway you could feel the deceleration the nose wheel comes down gradually you know we were coming to a stop we were just about stopped and i remember thinking to myself wow what an incredible week this mission all these things we did but now it's over nothing can go wrong and everything you know i thought one of the fuel tanks had blown up or something it was the the tire had blown and luckily we were just about stopped so there was no adverse effect so if that had happened at a high speed you could run off the runway what was the speed at landing speed at landing is about 250 miles an hour so much much faster than a normal it's interesting that you can slow it down from orbiting at whatever speed it well this the the slowing down from 18 000 miles an hour in orbit is all due to the friction of the atmosphere we slow it down just a few hundred miles an hour with with the engine firing but that lowers our orbit enough so that we hit the atmosphere and then the atmosphere if the earth didn't have an atmosphere yeah like if we're landing on the moon all that slowing down has to be done with rocket yeah propellant which we don't have that much propellant interesting so we couldn't do it thousand miles an hour down to 250 all by using almost all by using just the atmosphere and of course that kinetic energy is transformed into heat energy yeah yeah and so then um i want to we'll get to the other mission just quickly want to know about the uh we're not using shuttles technology anymore is that right um well we're certainly we're not in the new um vehicles most of them with one exception are capsules are capsules right Sierra Nevada company is building a wing vehicle a much smaller vehicle than the space shuttle and they hopefully will be test flying it in the next year or two so the two are either capsule vehicles which is on the booster or as well as the winged vehicle which is attached to the well actually the Sierra Nevada uh it's called the dream chaser and and that's small enough that it can actually sit on top of the rocket which is where a spacecraft ought to be i mean that's that's weird to put it in the shuttle was so big it had to be on the side and that made it vulnerable to the the phone falling off and hitting the tiles which is what eventually led to the Columbia disaster oh and that's we know that that's what led oh yeah absolutely yeah yeah wow yeah okay interesting so now always on top of the rocket and um interesting capsule versus that wing technology okay so so then um two the uh the Columbia deployed uh a uv astronomy laboratory as is astro one was the deployment nasa um signed up to uh with the european space agency to have the european space agency create the space lab and there were two aspects of space lab there was a module of the space lab which is what most people think of which you could put experiments in and and it had special computers and and that was used for a lot of scientific missions but the europeans also built a pointing system for telescopes which could be mounted uh outside in the shuttle cargo bay and you could do ultraviolet or x-ray astronomy things where you have to be above the atmosphere and as an astronomer i got assigned to the first ultraviolet astronomy mission actually another astronomy colleague who had also gone to amherst college so we had two amherst astronomers on the shuttle and two non-astronaut we called them payload specialists but they were scientists astronomers who had worked on the telescopes that we were carrying up and so we flew them so we had four phd astronomers on that flight we were scheduled i actually was assigned to that flight before my first flight uh went so i i knew already went during my first flight what my second flight would be and we were assigned to fly in march of 1986 in conjunction with hallie's comet because we wanted to get ultraviolet observations of the comet so we would have been the very next flight after the challenger disaster so we were very close to that crew we knew them well it was a i was in the simulator that day um the last nine minutes we come out of the simulator to watch the launch on tv and of course we saw the explosion the disaster and um we didn't go back to the simulator that day but early on we didn't know what the problem was obviously there were a few people who who already knew about the the o-ring seals but we didn't uh possibly it i mean it was a terrible disaster but possibly whatever the problem was could be fixed relatively quickly and so they nasa told us to continue our training and that was really strange the next day we had to go in for an ascent simulation after having watched the challenger disintegrate the day before and so we i remember we told the simulator crew hey how about not giving us any malfunctions let us have a clean run to orbit and and so we did but um we trained for i don't remember a week two weeks but and and then it became apparent that this was a serious problem and we were going to be standing down for a couple of years and so we stopped training and in fact we didn't fly that mission until 1990 yeah and the disaster was again 80 the disaster was was the end of january of 86 86 yeah that was the challenger in the next flight after we would have flown four four years later no two it was in 88 88 was that it was about two and a half years wow yeah well they had to completely not only did they redesign the solid booster seals but they then went deep into the design of all of the shuttle systems and they found a lot of other potential failures um many of which were corrected so the shuttle when it flew again in 1988 was much safer than it was that was probably the safest flight of the that the shuttle ever made because at that point if anybody could think of anything that needed attention they would get management's ear unfortunately as time goes on you you get used to success and we had you know many years of successful shuttle flights and and people then start taking safety for granted and that that's a recipe for disaster and unfortunately that's exactly what happened with columbia where people had seen the foam falling off for many flights but it never really did any serious damage to the shuttle and so you sort of get used to it and you say oh yeah foam falls off don't worry it's happened before until you get a bad luck and the big piece makes a big hole in your wing which nobody knew about and we lost the crew and just to take a moment to you know be with how much uh with them and how much work um and hard work they put into pushing the boundaries of the edge of what we knew and how hard they worked and we're really grateful for them to be able to do that yeah yeah it was uh it was very painful for for everybody not just for the astronauts I mean everyone in mission control and the people in Florida who prepare the shuttles for flight I mean an amazing group of people they I mean the shuttles for them were like living breathing objects I mean they had a personal relationship and yeah they were devastated that the crew had been lost but but they were also devastated that they had lost their vehicles uh you know that they had grown up with and worked with for so many years yeah yeah and then so teach us on um in 1990 when you go up with um columbia to astro one uv yeah well uh the the first flight of the of the astro payload we we had a lot of problems on that mission um there are two computers special space lab computers which control the operation of the telescopes and the very first day of the mission one of them burned up not a nice feeling to wake up in the morning and smell smoke on a spacecraft um and then on the fourth day well we could keep operating with just one computer then on the fourth day of what was supposed to be what was a nine-day mission the second computer burned up um well what they discovered was we didn't know this until after we got back but during all that time the four years that had been sitting on the ground uh periodically they would turn the system on and uh all the computers are air cooled and the air comes through a filter because you don't want dust coming in nobody had thought to clean the filters they were full of dust and so we weren't getting proper air flow over the computers and so the computer is overheated and that's one of the problems when you're in weightlessness there's no convective cooling because hot air doesn't rise and so you have to blow air across the computer with a fan and if you don't have enough air intake it overheats and and uh luckily together with mission control we figured out a way to continue the mission so we we did get some useful science out of it but it was very frustrating yeah and then the Atlantis mission this was with European retrievable carrier Eureka mm-hmm yeah this is a great acronym and the tethered satellite system TSS when I was with NASA and the Italian space agency and this is 1992 with Atlantis so Eureka was designed to be a reusable satellite where you could put experiments on it we deployed it using the robotic arm and just left it in orbit and a few years later another shuttle went up and brought it back but the most complex experiment we had was the tethered satellite which is an the concept of that is that you you deploy a satellite from the shuttle but rather than just let it go free in space it remains attached to the shuttle by a thin electrically conductive cable that's 20 kilometers long that's about 12 and a half miles we would deploy it all the way as this conductive wire moves through the earth's magnetic field it acts like an electric generator and so it generates up to about 4000 volts and using that you can vary the voltage on the satellite by by controlling how much current flows through the tether and that would allow us we had a lot of plasma diagnostic instruments on the satellite which would study the interaction of the satellite with the earth's plasma in the ionosphere fascinating fascinating experiment both the plasma science and the dynamics of the tether which I could spend hours talking about that but we spent a lot and and the fascinating thing nobody had ever flown a tethered satellite and so we had to from scratch develop the procedures the people who originally designed the tethered satellite I think they thought it was all going to be all automatic that you just push a button the satellite would go up our job as astronauts figure out what might go wrong and the more we studied it the more potential problems we came up with all of which required manual interventions so we had to argue strongly over the years to get more and more manual control and in and in the end we got what we needed it was a very frustrating project on that flight we got the satellite out to about 200 meters and then it jammed and they we tried to restart it several times it it was getting out of control at one point one thing you don't want is for the thing to wrap all the way around the shuttle and and so at one point you know we were trying to control the jets on the satellite because it had gone over to about 45 degree angle if it had gone just a little bit more I was going to have to cut the tether push a button and the shuttle commander was trying to fly the shuttle to get back underneath and we were trying to push the satellite I mean it was pretty hairy in the end after several attempts and it kept getting jammed we decided together with mission control you know we don't know what's happening and we just pulled it back and actually when they first tried to pull it back it wouldn't come back either it had gotten jammed in both directions and they had to start preparing for another contingency spacewalk I was going to get a bad reputation there every time Hoffman goes up something goes wrong but in the end they maybe I should say unfortunately from our point of view but they figured out a way to overcome the jam without us going out and doing a spacewalk so we did get the satellite back and we refluid again on my fifth and final shuttle flight where we did get it out almost all the way to 20 kilometers and then again tragically there was a short circuit and sparks and it melted the tether and the whole thing broke and the satellite was lost so very frustrating but fascinating project I'm yeah hopefully we can do another tether satellite system at some point well there's a lot of fascinating things you can do with tethers which is why the initial interest in it and I'm sure someday the technology will come back and be used but you know right now we don't have a shuttle and and there have been some unmanned robotic tethered satellite missions and there's there's still quite a bit of interest in tethers but I don't think NASA at the moment has any plans to do anything with it and then the fourth flight on endeavor you captured service and restored to full capacity the Hubble telescope right now that certainly was the most significant and exciting of all the things that I've done in space I mean both as an astronomer and an astronaut to put my two hands on the greatest telescope in the world up in space I mean what a what a thrill but you know we had lived through all the buildup to the launch of the Hubble space telescope it was it was really very gratifying to the astronomy community to to NASA a lot of publicity before Hubble was going to be put in orbit about the incredible new view of the universe we were going to get the public was was into it I mean there's a lot of a lot of interest and so you know the shock when my god this billion dollar telescope can't focus properly and how long did it take until the first malfunction well the telescope was put in to orbit in the spring of 1990 and the what you do with the new telescope on the ground or in space it's like you pick up a pair of binoculars I mean you take the focus will you go back and forth you try to find the sweet spot where everything is in focus and that's what you do with the new telescope and and so I don't remember exactly but it was it was weeks maybe a little a month or so but it was during that summer of 1990 that it dawned on the astronomers who were trying to get it in focus that oh my god it doesn't focus it had I mean the the images were classically what what's called spherical aberration which which is when the the mirror it it turns out I mean there was a well first of all it was it was an absolute disaster I mean Hubble became the butt of jokes of late night comedians it was denounced on the halls of the US Congress as a techno turkey I mean it was NASA at the time was trying to convince congress to start the initial funding for what would eventually become the International Space Station and of course NASA was not very popular in Congress and the basic message was you know go do something about Hubble and then talk to us about the station and and so it was an absolutely critical mission yes and I remember getting back from my third space flight that was actually the only time I came back from a space flight without knowing what my next flight would be because I had been assigned to the tethered satellite before astro one flew because of the delay in astro one I had started already before 1990 when astro flew I had already started working on the tethered satellite so I knew I was going to be on that mission but after tethered satellite I I didn't know what my fourth flight if anything was going to be I think my wife thought I was going to retire finally from her part of you she had liked my space flight because of the danger involved which is understandable but it took three years though to send you up to make the fix on Hubble well it was actually I came back in August of 92 from the tethered satellite mission okay people had been working on what to do about Hubble you know because the first thing they had to figure out what the problem was they they figured out it turns out the the measuring device which you use when you're actually grinding the mirror had been installed incorrectly long story that I can't go into all the details but but that's what led to the mirror being slightly too flat they took about one micron too much glass off the outside of the mirror one micron one millionth of a meter that's one fiftieth the diameter of a human hair but Hubble's optics are so precise that that made all the difference anyway once once they understood that then optical engineers astronomers mechanical engineers figured out a fix for each of the observing instruments you had to install two tiny mirrors each of them about the size of your thumbnail one of them you have the out-of-focus light coming in that's normally there each camera has a little 45 degree mirror the out-of-focus light bounces into the camera well we had to put one mirror to block the out-of-focus light bounce it off another mirror which is slightly curved to compensate for the lack of curvature in the main mirror and then that light gets reflected into the observing instrument that was the all of those things and and you know there were about two dozen of these little mirrors that had to be going to 24 well what they what they did was I mean it's not just challenging for the optical engineers but then the mechanical engineers had to figure out how to package all these things in one big box yes and they all had to be folded up because you couldn't have them all deployed we'd never be able to put it into the telescope luckily Hubble was designed from the very beginning to be serviced by astronauts so you could take out an old instrument and that left a big hole in the telescope where we could put this big box with all the these folded mirrors inside them interesting once it was inside then automatic automated but the whole thing comes out and opens up like an umbrella sort of and all the mirrors end up in the right place so you could you could it was compartmentalized exactly that that's the way Hubble was designed that's a great design it absolutely was the I mean it was designed for servicing and it was it was unique and huge and we really showed the value of it you know Hubble would have been a billion dollar piece of space junk yeah and we wouldn't have these gorgeous photos of the cosmos yeah yeah and of course because there was so much publicity to the problems that Hubble had there was incredible interest in this rescue mission yes so much so I was told later on by people in the media that more people watched our Hubble rescue mission than any other spaceflight other than Apollo 11 yeah and and that's awesome yeah so awesome so then you went out with with another astronaut to go do the repair this mission was so calm it was most complex shuttle mission that had ever been anticipated yeah how did you how did you capture the Hubble there were so many things that had to it wasn't just the optics the the solar panels had to be replaced the a bunch of electronic boxes had to be replaced there were there were a dozen different things that that we had to do so it was going to require five spacewalks which had never been done before oh you had to go out and then come back in five different days of spacewalking different days and why what's the reason why uh because it took you multiple hours through the first oh it takes time to do these things out there yeah I mean we we couldn't and a space suit you can only stay out for about a little over eight hours maximum we try to plan spacewalks for about six and a half hours so that you have a little bit of you know time built in in case there are problems and what's the and what's the max for six and a half why why well you run out of electrical power probably goes first oxygen yeah yeah and those tethers that the space suits tethered to the we are always attached by a stainless steel wire to the shuttle yes um so that it doesn't have like an oxygen run to it no no it's just a stainless wire everything is contained in the backpack oh wow yeah so it was felt normally you only send up two people to do spacewalks on a shuttle mission but we had five days in a row and it was felt that might be a little much for just two people so we had four spacewalkers and we went out in alternate days so my partner and I went out on days one three and five and the other two went out on days two and four wow and we we cross trained on all the tasks just in case someone was incapacitated and as it turned out we all did our proper spacewalks but it all worked and it all worked out now we what we first of all we had to rendezvous with Hubble how did you do the rendezvous well you know rendezvous was we had done a lot of rendezvous at that point I mean rendezvous was developed first back in the Gemini program because they had to do rendezvous on Apollo and you know basically the the critical thing for rendezvous a satellite is in a certain orbit so the telescope's in orbit you're on the earth and the launch pad and the earth is rotating around and you have to launch right when you're underneath Hubble's orbit because once you're in space changing your orbit takes a lot of propellant which we don't have so so we had to and and that determines your launch time which for December 2nd 1993 happened to be four o'clock in the morning which a lot of my friends said you know why couldn't you launch it at a decent time of day but it's celestial mechanics yes you don't get a choice yeah so you know I remember one of my brothers who was kind of a space nut he said you know a little less than half hour before your launch we saw a Hubble fly over which gave us a good feeling like NASA must know what they're doing yeah anyway so yeah you launch and you launch so that you're slightly behind the object you're going to rendezvous with and so you're in a faster orbit so you gradually catch up to it and then you do burns and and your burns are guided initially from the ground and then on board we have a radar and once we get radar lock our onboard computer tells us when to burn and and gradually and it's really exciting you know you first see this thing as a just a point of light and then it gets brighter and brighter and then finally looking through binoculars you can start to see the shape and wow and then it gets and then in the end when you get really close I mean it's 50 feet from top to bottom so it's it's big yeah and then how do you and then what you have to do then it's up to the the commander flying manually to essentially null out all of the relative motion so now we're flying together at 18,000 miles an hour but it it just looks like it's floating motionless above the cargo bay and now the robotic arm operator yeah has to reach out and grab it without disturbing it and which he's well trained he did it perfectly and then we latch it down onto the the work stand which then allows us to rotate it and tilt it over so we have access to it so it was and so that was the first thing I remember when the command after we grabbed it with the arm and the commander could call down and say you know happy to report we have a good handshake with mr. Hubble's telescope and yeah but that was only the beginning then we had the five spacewalks to do yes and so my partner and I went out on the first day we had to replace the gyroscopes which had failed that's they're a high failure item on on Hubble they've they've since kind of figured out what it was and the new gyroscopes that are in there now because they've been replaced several times hopefully aren't going to fail but in any case we replaced them that was the very first task that we had to do and all I had to do now was to close these big doors and get on to the rest of the work question how many more service missions have there been to there had been a total of five so four after hours interesting and on each operational for 20 years well 30 30 years wow yeah and and and the thing about servicing you know most people when they when they you ask what's the value of servicing well they were able to fix the optics and so they look at it as if something breaks you can fix it but that's not really the most important value of servicing the real value is that every time we visited Hubble we put in a new more powerful observing instrument because the technology of detectors is continually improving it's like Moore's law correct computer memory exactly you want to keep updating it yeah Hubble was launched with 1970s detector technology after the fifth and final servicing mission in about 10 years ago it now has 21st century detectors and it's almost a thousand times more sensitive than when it was launched yes so that's the real value of servicing that's a that's a beautiful way to put it yeah the servicing of the very expensive satellites and that's what we do in the ground I mean you build a telescope on the ground the mirror is good for decades yeah centuries even but the detectors that you put at the focal plane are continually improving yes up until Hubble we didn't have the ability to do that in space and now we do yes yes so despite the this Hubble rescue mission being the most complex mission than that we had ever done with the shuttle and there were many people who thought that it was too difficult that NASA had bit off more than than they could chew so to speak but we did it and so we knew after the fifth day of space walking that we had done everything that they asked us to do we had in fixed all the things that were broken we had installed the new optics and we came home and everybody was happy lots of celebrations but you can't turn on the instruments for a couple of weeks because the new instruments that we had put in little bit of earth's atmosphere sticks to the surface and you have to wait you you can't turn on the high voltage until all that gas has escaped because otherwise you'll get high voltage discharge and you'll blow your electronics so we didn't know if all of those optics were really going to work obviously we we thought they would we hoped they would but the proof is when you get the first images down and they couldn't turn it on you know we got back in the middle of December and they couldn't really turn it on until right before New Year's and I'll never forget New Year's Eve 1993 to 1994 this is like one o'clock in the morning I was cleaning up we had had some people over what a phone rang yeah so it was an old astronomer friend who was working at the Hubble Space Telescope Science Institute that's where they operate Hubble and and he you know we wished each other happy new year he said you know you have any champagne handy well yeah we had a half a bottle still in the refrigerator and go pour yourself a glass I'm not supposed to tell anybody this but it because it's going to be announced publicly in a couple of days after the holiday but we figured that somebody on the crew ought to know that we've just got the first pictures back from Hubble and it works and that was I'll never forget that moment I mean and and that's when you know a history was made it was and Hubble has gone on partly because of servicing to be NASA's most productive science mission ever in terms of the number of papers published PhD theses and incredible groundbreaking new discoveries I mean the the fact that the universe still expansion is accelerating and that we have this dark energy which is 75% of the universe and we have no clue what it is I mean it's incredible it's it's exciting times in astronomy partly due to Hubble yeah yeah that's like you said most successful NASA project and that's that's so beautiful how how many decades and hours and lives were put into to making the successful project and hopefully inspiring a lot of young people to get involved in space sciences with Columbia in 1996 that was you like you said earlier the reflight of the tethered satellite system and also the the third flight of the United States microgravity payload and this was interesting the the tethered satellite we we did get deployed and unfortunately it it broke it did have an interesting effect though that the this 20 kilometer long tether it reflected light the outside was was a white and it actually stayed in a straight line moving around the earth it it eventually after about three weeks it it de-orbited because of the atmospheric friction but for those three weeks you know normally when you see a satellite fly over you see a point of light well this you can actually see a line moving through space there were so many UFO reports during those three weeks and and we actually when we were still up in orbit we we saw that it fly over a couple of times and it's spooky to see a you know a luminous line move through the sky like a satellite but anyway that was the end of the tethered satellite and and but now we we we had these crystals to grow but it was an automated experiment out on the cargo bay however in order to grow the crystals properly they they want to reduce the any vibrations in the shuttle so this experiment was originally designed to be operated only when the crew was asleep so that we wouldn't be moving around well because of the tethered satellite we were a two-shift mission because we had to be up 24 hours a day when the satellite was deployed and and so somebody was always awake so the the microgravity experimenters they were pretty upset they said you know they're going to be moving around and so I said look it's going to be done on our shift give us the read out on our computer of the accelerometers and we will sort of like biofeedback we will train ourselves we we will not make any vibrations we won't bounce off the walls they didn't schedule any other activities for us so for about five days for eight hours a day we had these quiescent periods where the only thing that we could do was to sort of float and look out the window and watch the earths go by I mean it was like being a space tourist it was incredible you know there I was up there and I wasn't allowed to do any any work it was it was incredible fun and they got some good results out of it as well and teach us about the this the images of you when you're out you repairing the Hubble or where you're where you're out doing the space walks you know you gave that profound example of when it was you and then the vacuum of space in your hand teach us about when you're looking at earth and what do you feel when you're feeling this overview effect it's the sense of the earth as a planet what what I I felt very strongly and I think a lot of my colleagues have expressed the same feeling we're in an incredibly hostile environment I mean space is totally intolerant of human error mechanical failures and that's most of the universe is like that it's very hostile to life and so we look down at our home planet which is the one place in our solar system that we know can support life and and it becomes you know almost miraculous maybe not in a biblical sense that depends on you know your own philosophical background but in any case it's a it's a unique and wonderful place and and so I think many astronauts actually come back with much more of an ecological sensitivity than when they went up just because of this experience of you know this this sense of all that at life and and the earth can it was the home of life and it supports life and and you know we need to take care of it yeah yeah and then you spent four years as NASA's European representative in Paris and then you were also inducted into the Hall of Fame in the Astronaut Hall of Fame in 2007 and I know we we have some time to unpack this a little bit and I know we need to get going but hopefully we can continue on another conversation soon but give us the cliff notes on the European representation in Paris and then the Astronaut Hall of Fame yes my last three flights the two tethered satellite flights and the Hubble mission they they all had European involvement the Italians made the tethered satellite the European Space Agency financed a good part of the Hubble telescope and provided the solar arrays anyway I spent a lot of time in Europe NASA ever since the 60s has had a permanent representative in Europe working out of the embassy in Paris the European Space Agency headquarters is in Paris because we have so much scientific cooperation with the Europeans NASA from the very beginning although NASA was putting up satellites the Europeans at the time couldn't put up their own satellites now they can but but NASA wanted the best science from all the world and so they competitively would open up space on U.S. satellites to foreign experiments and there were so many coming from Europe that particularly back in the 60s when we didn't have email and you know so much easy communication it was it was considered wise to have somebody on the ground there and that's continued obviously our communication is a lot better but still it's like diplomacy you want to get to know the people in Europe who are active in the space arena you want to get to talk with people in European governments you know what's happening with space policy what possibilities are there for cooperation between Europe and NASA I got to know the the guy who was the European representative when I was spending all that time over there and he told me that he was getting ready to come back to the States and I thought you know this would be interesting so I applied for the job well I got back from the fifth mission where we had flown the tethered satellite done these microgravity crystal growing experiments not knowing what I was going to do but hoping that maybe I would get the the European job well the head of the Johnson Space Center told me right after I got back he said you know Jeff we got another flight for you we need a space walker trained astronauts because we're going to start building the space station soon afterwards I found out that I had actually been selected for the European job so now they gave me a choice there's all right Jeff you got to choose Paris or space thought about it got a little help from my wife if you can imagine but you know I was not tired of spaceflight I mean I would go up again in a minute if I had the opportunity and I would have loved to have had another spaceflight and spend four years in Paris but that was not an option so we chose Paris and I have no regrets I had five wonderful flights with incredible you know incredible experiences and we had four incredible years in in Paris I really got to know the european space scene yeah had an addition it was you know wonderful living in a beautiful apartment at government expense thanks to all the U.S. taxpayers yes yes and and and I think I was appreciated for being able to because of my my astronaut background I in addition to working with space people over there and the fact that I my French was pretty good and I can speak German Spanish Italian so I did a lot of public relations tv shows radio call-ins that that's a challenge in a foreign language yeah but yeah we had great four years and I had actually maintained certain contacts at MIT all the time I was at NASA I came back on a few occasions and gave talks and the department head in aeronautics and astronautics had the idea that you know we do a lot of work designing space systems it might be a nice idea to have someone who really knows what it's like working up there and so they offered me a chance to come back to MIT and so here I am finally as a professor after all these years my wife you know she kids me you know most people they go into an academic career and within seven years they're a tenured professor why did it take you 30 30 years but I had fun five missions no complaints but I'm really happy here I mean I one of the one of the things that I was really concerned about leaving NASA was not being connected with the space program anymore and one of the wonderful things in our department here at MIT we're very closely connected we do a lot of work with NASA with the Air Force with DARPA and and so I've had a great opportunity to continue my involvement with with space right up to now and and you know now I've got a really exciting experiment I'm the deputy principal investigator of an experiment which is going to go to Mars on the next big rover which is going to be launched in the summer of 2020 yes and this is the moxie experiment moxie is an acronym which stands for Mars oxygen ISRU and that's a nested acronym in situ resource utilization experiment Mars oxygen ISRU experiment moxie and ISRU in situ resource utilization basically means learning to live off the land which since time immemorial explorers have had to do that I mean you're sailing across the ocean you come across an island somewhere well what do you do you put on on shore you you look for fresh water for food we haven't done that in space the astronauts went to the moon they took everything they needed with them but they are they're only staying for three days you go to Mars and you have a lot of requirements among other things for oxygen not only to breathe but assuming that you want to come back home you're probably going to need many tens of tons of oxygen just to launch your Mars ascent vehicle to get off the surface of Mars back to Mars orbit so you can get your ride home bringing 30 tons of dumb old oxygen all the way from the earth you know it takes 15 tons of propellant in earth orbit to bring one ton of anything to the surface of Mars so to bring 30 tons of dumb old oxygen to the surface of Mars we would need to launch 450 tons of propellant from the surface of the earth that's expensive now some things that are going to go to the surface of Mars we have to launch from the earth you know complex habitats you know the rocket to get up but the fuel for the rocket the propellant man if we could make the oxygen on Mars we're way ahead of the game and that's exactly what our experiment is going to demonstrate for the very first time it's a process which has been developed and demonstrated here on earth but if you're going to rely on it for something critical like you know that's your ride home from the surface of Mars you better demonstrate it to just make sure that Mars doesn't have any nasty surprises and that's what we're going to do so we're going to it's a small scale experiment only about yay big and it's only going to make about 10 grams an hour compared to for a real human mission you'd have to make about two kilograms an hour so you know half a percent scale but nevertheless we'll demonstrate the process I was an astronaut I was lucky I had five space flights but I'm never going to get to Mars myself I don't imagine but it's nice to be able to send an experiment there that someday will help humans when we finally do get our act together and get to Mars yeah and this is these are the these are the the components to what the millennials and the Gen Z and Onward will be able to go to Mars with the levels of efficiency that we need to sustain and make the consciousness interplanetary something that I thought was super interesting about that so when we get to summer 2020 is when the Mars rover gets launched there's only a 26 month window for the rendezvous of Earth and Mars and then we arrive in February 2021 and then Mars's atmosphere is 96 percent CO2 this is how we make oxygen it's a very thin atmosphere but we we suck the atmosphere in we compress it and then we put it into an electrolysis unit you know high school chemistry you put these two electrodes into a beaker of water you hook it up to a battery and wow hydrogen bubbles up one side oxygen bubbles the other side you're electrically decomposing water you can do that with carbon dioxide it's a lot more difficult you have to heat it up to 800 Celsius you have to run it over catalytic beds you need yttrium stabilize zirconium electrolyte but nevertheless you can do it and we've done it in the laboratory here on Earth and we just have to demonstrate that it all works on Mars and let's talk on a geopolitical level what do you how do you feel about the future of the space economy balancing out competition but cooperation how do you think we can best do that what do you see well um we're in a new era now particularly in in this country because previously it was only governments that could launch things into space and and bring back humans from space now we have private companies in in the U.S. and and now also in China they're starting up with with private space companies so we now have in addition to the Orion space capsule that NASA is developing uh we have four different human carriers all developed by different companies we have rockets which can now land the first stage of the rocket and recover them spacex blue origin i mean this is flash gordon kind of stuff that's it back in the 50s when i was a little kid flash gordon's rockets landed vertically but nobody ever thought we'd do that for real and now we're doing it so it's exciting times i mean we we have a tremendous amount of innovation going on which would not have occurred if it were just the government i mean there's no question international competition is what got the space age going yes the the race to the moon between the U.S. and the soviet union you know we never would have gotten to the moon without that because of the incredible investment that our country had to make which was done because it was part of the cold war we learned a tremendous amount of scientifically and it was incredibly inspirational for so many people but it was the competition that got us there now we've got a lot of commercial competition you know spacex has figured out how to drastically reduce the cost of launching satellites and the other satellite launchers are really feeling the the pinch even the the chinese complained they said this is unfair competition you know he must be getting some sort of subsidies or whatever man if the chinese are complaining that you're undercutting them in price you must be doing something right yeah yeah the the now with the ability to be able to go uh and take the next steps in in the space economy i think the creativity of what we can do is just about to be unlocked at unprecedented levels it's going to be very exciting we need the dreamers and creators to actually be the executors and to make the blend of of academia and industry and government and geopolitically come together in a powerful way just a couple last thoughts on a governance level i'm very interested to hear your thoughts on this what would be your ideal way to govern mars well until you get a large number of people i think it will be run on a mission oriented basis which means you pretty much have a quasi military type hierarchy where you have a commander of a mission and you know that's that's the way we run missions up to now you know every mission is at a commander we have a commander on the space station the early settlements of mars the missions they'll they'll have a command structure i don't know what the minimum number of people is before you actually are going to get people interested in in self-government yeah you know we we would hope that our western principles of democracy would be adapted on mars but you know the chinese are in the business too and and and they have different ideas about how to organize governments and i i don't really know certainly experience with the early colonies in the u.s was such that you you couldn't just have free-wheeling democracy where anybody could do what they wanted because your survival depended on working as part of a group so there's no question you're going to be in a very hostile environment and there will be certain limitations on individual freedom and ability to i mean you you just can't just open the airlock and go out for a walk anytime you feel like it because you're using up valuable resources for that belong to everybody so you know the question of of you know what are the commons and how do you protect the avoiding the so-called tragedy of the commons that we've seen so many times here that that will be important as well yes yes and then what type of psychometric profiles do you foresee us sending what types of intelligence what types of genders etc what what would be an ideal because you have to live together for years well i think you know gender max gender matches with there will be men and women and everything else that that entails so we'll you know we'll human beings something very inventive of you know dealing with sexuality and that that will work i'm not worried about that in terms of the skill set there are so many things particularly if you in the early days when you you'll have a relatively small crew just because of the limit of how much mass you can send there people are going to have to be trained in in a variety of different skills so you know in the book the movie The Martian you know Mark Watney he was a plant biologist a botanist but he was also a mechanical engineer and you're going to need people who are geologists and engineers and you know electronic specialists and computer specialists and and so you're going to be multiple trained and you know when you're talking about a trip to mars you're talking probably two to three years so you know what are the family circumstances under which people will be willing to commit three years of their lives with not a hundred percent chance of coming back alive either so it'll it'll take a certain breed of astronaut to do that but i have no doubt that there are many people out there right now in the astronaut office you know if you said are you willing to commit three years of your life to go into mars yes sir yeah sign me up you know yes yes you won't have trouble finding people but but you better send the right people the new frontiers yes sending our people jeff how about uh are we in a simulation no i you're you're talking about alternate universe and we're in a simulation of somebody else's universe i don't even know what that means you you tell me what the observable consequence is of being a simulation of some alternative universe that's what constitutes a science theory is is an observable consequence that can be either proven or disproven uh there's a lot of fascinating you know even something string theory which is a very elegant mathematical theory of elementary particles which i'm not an expert in by any means but to my understanding it still has not come up with an observable prediction that would allow us to you know confirm or or disprove it um and so to be a real theory it has to have observable consequences and you know there's a lot of fascinating philosophy about what constitutes a uh you know simulation in an alternative universe but i don't look at it as a question which needs to be answered because you haven't come up with any anything that i can test and as a scientist i i deal with things that i can test and measure and soon soon to potentially change poke with the scientific probe and the last question is what do you believe is the most beautiful thing in the world the most beautiful thing in the world um maybe things that i've seen from out of the world for me and and i mean just the the variety i've always enjoyed watching sunrises and sunsets um here on earth but from space i mean i took so many pictures when when we got back those were the days of film and i i heard from the people who worked in the photography office at nasa they would develop the pictures and the half of these pictures of sunrises and sunsets hoffman must have been on this flight you know so that was and and you know the the beauty of of the um uh this the halo that surrounds the earth at night the the aurora which in orbit you actually fly right through the aurora yeah just so many things and and just being able to look at the stars and from space they don't twinkle stars don't there's no more twinkle twinkle little star because you're above the atmosphere and you can in one nighttime part of your orbit see both the northern cross and the southern cross because you fly from the northern hemisphere to the southern hemisphere you can never do that on the surface of the earth the earth is a beautiful planet there's many beautiful places that i've seen on the earth and try to pick out one as the most but i've been fortunate enough along with about roughly well fewer than 600 other people to have been able to see things from from above it's uh you know like the old uh johnny mitchell song you know clouds i've seen clouds from both sides now even looking at the the and one of the most beautiful things you do see looking at clouds from the top is thunderstorms the lightning propagating around the clouds i mean it's not individual lightning strikes like we see from the ground it's these incredible light shows moving around and that that was probably one of the most mesmerizing things that that we would see looking out the windows where cities sprawl out at night yeah this is these are all gorgeous profound realizations and i'm so grateful that you joined us on the show to teach us about your life and journey as an a** astronaut as well as the space systems design well i wish we had more time we could you know we could talk we'll have we'll have another we'll have a part we'll have another part where we can dive deeper into all of this jeff thank you again so much it's been a pleasure the show we really greatly appreciate you thank you everyone for tuning in we would love to hear your thoughts in the comments below share more content like this with other people go and inspire your friends families online communities co-workers get people talking about space get people talking about what it's like being an astronaut and all of these shifts in our awareness that we can experience and check out jeff's links below also check out the links below the simulation to our show support the artists entrepreneurs and organizations around the world that you believe in and go and build the future everyone manifest your dreams into the world thank you so much for tuning in and we will see you soon peace