• NASA’s Lunar Outpost Plans Taking Shape – NASA (2007)
• Colonization of the Moon -  Wiki
• Kaguya Finds Lava Tube on the Moon — Universe Today
• NASA:  Why We Explore
• Inflatable Structures on the Moon --NASA
• Paper:  Mechanical Equipment Requirements for Inflatable Lunar Structures
• What if We Lived on the Moon – HowStuffWorks
• Earth’s Magnetic Field — Universe Today
• Rotating Wheel Space Stations -- Wiki
• O’Neill Cylinder -  NSS
• Orbital Megastructures — Universe Today
• Transparent Solar Panels — Ubergizmo
• Ringworld books – Wiki
• Babylon 5
• Babylon 5 Tech Manual
• Arthur C. Clarke
• Dyson Sphere — Wiki
• Swarm Satellites – WorldChanging
• Moving the Earth; A Planetary Survial Guide -- New Scientist
• From the *interesting* files:  We Must Move the Earth Now!



Transcript: Future Civilizations

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Fraser: Hello Pamela.

Pamela: Hey Fraser, how’s it going?

Fraser: I’m doing very well. So let’s assume that humans survive the next few hundred years without destroying ourselves or the planet and we actually become a space-faring civilization. What kinds of challenges will we face and what kinds of projects will we build to expand ourselves out into the solar system and eventually into the galaxy–we just need to think big! Alright Pamela, so what would you say the future holds? Now let’s assume, right… we’ve talked about all the ways that we could kill ourselves and the universe is trying to kill us, we’ve got global warming, we’ve got diseases, we’ve got asteroid strikes, you know, mega solar flares, wandering black holes… there’s so many ways to die. But, let’s assume that we make it through that turbulent period and actually move ourselves into the process of becoming a space-faring civilization, beginning to colonize the solar system. What are some of the kinds of projects that some people have thought of that we might be able to build to support that?

Pamela: Well, I think two of the first real super-giant huge in-space structures that we’re likely to see are, first of all just a colony on the moon. It will probably start as the equivalent of a trailer park on the moon, something built down, hollowed into the sides of craters or… the thing that we’re looking for most is a lava tunnel… underground that was left behind as the cool crust of the magma stayed behind while the hot rest of the lava continued to shoot across the surface creating a tongue of lava somewhere else. We want to be underground, and our first mega-structure is likely to be built roughly under the surface of the moon.

Fraser: So we can imagine sort of as we move towards building that moon base we’re going to be launching up, as you said, trailer after trailer down onto the moon, connecting them together, and eventually humans are going to decide, well… it’s time to stay. So they’re going to dig down into the moon regolith and actually build something underground… I guess excavating out a lunar base, something permanent.

Pamela: And this isn’t the most exciting type of structure any of us have ever imagined, you always want to see the big, shiny dome with the skyscrapers underneath the big, shiny dome. That works great in a George Jetson universe, but the reality is we have to deal with radiation. But, if we ever figure out how to deal with radiation without requiring dirt, water, earth… something between us and the solar wind… if we can make that breakthrough, suddenly the doors open to create much more exciting mega-structures.

Fraser: Right. So, what’s the problem with the radiation? I mean, obviously you don’t want to get radiation…

Pamela: It will kill you..

Fraser: But how does that affect… like as you said, you build some great big space station… what’s the problem?

Pamela: In general, they type of stuff you build a great big space station out of… you’d want to have some sort of membrane, something that inflates like the inflatable domes you see covering some football parks. That sort of membrane, that sort of flexible material… we don’t currently know any that’s capable of blocking high-energy particles, capable of blocking radiation, capable of blocking the type of stuff that is shooting through space every moment of every day looking for a piece of DNA to tear apart and cause cancer.

Fraser: Right, so if you lived in a big balloon, you’d have the air pressure that you needed to breathe and against your skin so you’re not getting space bruises, but it’s the radiation… and I guess if you’re out there for long periods of time you’re eventually going to get hit with a solar storm, proton storm coming from the sun… which could deliver a lethal dose in just a couple of hours.

Pamela: The Apollo astronauts were extremely lucky. We managed to have this wonderful window where the sun was quiet while the astronauts were on the moon. Had we not been so lucky, we could’ve lost some astronauts to the radiation. Now here on the planet Earth, we’re protected by our own magnetosphere. We’re protected by the wonderful magnetic field that comes along with the north and south magnetic poles that allow us to navigate. The moon doesn’t have that sort of a magnetic field. In fact, if you get high enough up in the Earth’s orbit, you don’t have enough protection in orbit, either. The astronauts are mostly, but not entirely protected, because they’re so close to the planet Earth. But, people are working every day to try to develop artificial ways to create magnetic fields that are light enough, that are low enough energy drawing that it might be possible to start to protect spacecraft, to start to protect space structures with artificial magnetic fields.

Fraser: But don’t you also suffer the problem of not having any gravity? I know that the astronauts living on board the space station… their muscles and bones start to waste away if they’re not experiencing any gravity. And exercise can help, but it doesn’t solve the problem entirely.

Pamela: Right. This is another long-term problem. But it’s also a problem that lots of sci-fi writers have started to find solutions for. Now, hanging out on the surface of the moon, you can’t do too much. One solution that’s been proposed, that sounds rather horrific to me, is you sleep in a centrifugal chamber where you sort of imagine going to bed in a carnival ride where you’re in a giant drum leaning up against the wall, and the drum starts to rotate, and eventually you’re experiencing one Earth gravity or more. It might be a comfortable way to sleep, I know I managed to fall asleep in one of those rides at Space Camp once as a kid, but I’m a bit twisted. It’s a solution… but it’s not a day-to-day solution.

Fraser: Right, now rotation, though, I think is the key, right?

Pamela: Yes. So while on the surface of the moon it’s kinda hard to build a structure that’s big enough to work in that’s rotating… that same limitation doesn’t exist when you start building space stations. And here there’s some really neat designs out there that go beyond just Babylon 5 and the space station from 2001 where we start imagining what, to me, look kinda like giant hamster habitats rotating in space. But if you build a large enough tube and set it rotating at an angle to the sun, you can have such that the inside part of the tube experiences daylight for part of the day, and is in shadow… is in its own shadow as it exposes the outer part of the tube to the sun for another part of the day, creating a natural day/night cycle for people living in this partially transparent tube.

Fraser: Whoa… ok, so, hold on… I’m kind of imagining a toilet paper tube, right?

Pamela: Well, think more donut in space… but a hollow donut, like one of those hamster trail things that you can get.

Fraser: Right, but you’re living inside it… on the inside edge of this gigantic cylinder. And it’s rotating at the right speed so that you’re experiencing the equivalent of Earth gravity, and at the same time it’s angled so that part of it is in the shade and part of it is in the sun. Then I guess you would cap off the ends of it so that all your air doesn’t get out.

Pamela: Right, so… well, here’s a good way to think of it. Take one of those completely round hamster trail tube things that if you set it on the floor, you can watch your very disturbed hamster running infinitely in circles and circles and circles. Now, take that completely clear tube and roll it like a wheel through paint, so the outer half of it is completely opaque. Now, instead of having paint there, imagine this entire habitrail is something the size of an orbit around the earth.

Fraser: Whoa!

Pamela: And where that paint is, is where earth is… where dirt is… where structures are. And where it’s transparent, well, that orbiting structure is transparent as well, and that’s how the sunlight gets in. Now you take this donut-shaped… this tube that has on the outer rim earth and buildings and structures, and put it at a 45 degree angle to the sun. Well, the inner part of that donut, that tube, is going to get sunlight coming into it during part of the day, but then it’s going to rotate so that the sun is blocked by the dirt so that the sun is actually underground behind your feet for the other part of the day. So you can build something… in fact you want to build something big enough that as it rotates you can have earth gravity, but also as it rotates you can have a 24 hour day/night cycle.

Fraser: Right, but building a structure the size of Earth’s orbit sounds a little complicated.

Pamela: Yeah, you need to go grab yourself a good asteroid and start mining madly away. But, it’s possible. It just takes time, technology, and money. And it’s mostly the money and the ability to stop radiation that we’re lacking right now.

Fraser: And you could imagine, then, a structure like that, just having an enormous amount of surface area for people to live on.

Pamela: And also an amazing ability to collect solar energy. We are starting to reach the point, technologically, where we can build transparent and semi-transparent solar panels. So you can build a structure where everywhere you have a window, you’re also gathering energy. Since you’re building the entire thing from scratch anyways, you can also put opaque solar panels all along the outer rim, the part that’s going to be opaque anyways because it’s covered in dirt, of the structure. So you can build this as a giant energy collection system. It’s a pollutionless form of energy. You can now have a completely electric society that isn’t doing any harm to its completely enclosed atmosphere other than whatever harm comes from having cows that do cow-like things, or other life forms that do life-form-like things.

Fraser: But in theory if you build something that ginormous you can handle the implications of the life forms that you’ve placed inside of it.

Pamela: Right.

Fraser: So like there’s the Ringworld story… is that kinda what we’re talking about?

Pamela: The Ringworld is exactly the type of thing that we’re talking about. Except you can do this on two different scales. What I’m talking about is you build something that you can imaging the entire donut orbiting in a happy-go-lucky way in place of a planet around a star.

Fraser: Right, I see… so it wouldn’t be ringing around the sun at the distance of the earth’s orbit, it would just be sort of floating in space in the same kind of place where the earth is going. But it would just be rolling around the sun as opposed to surrounding the entire sun… so you could make these as big or as small as you wanted, right? You could make one, as you said, as big as the earth, you could make one as big as the moon, as long as you get the… you could make one a couple hundred meters across… there would be some minimum size where the rotational forces would make you sick to your stomach, right?

Pamela: Well, as long as you do the rotation right, it’s always 1-g. The problem is making the 1-g area wide enough that you can survive it, and tall enough that your head and your feet don’t have radically different gravities.

Fraser: That’s right… yeah, I know that’s the problem, right… people talk about these rotational strategies for dealing with gravity where… but what you don’t want is where your feet are feeling one type gravity and your head is feeling a different amount of gravity because of the different rotation speeds. Is there some size where that sort of goes away?

Pamela: Yes. And it’s not that bad of a size. Babylon 5 did all of their calculations right, Arthur C. Clarke did all of his calculations right. So, this is something that is a buildable size, that’s a feasible size, but what’s not as feasible but is still imaginable–not feasible today, but maybe in the future–is starting to build Niven’s ringworlds where instead of having a regular donut inclined to a sun, happily rolling around… rolling around the solar system… Instead, you just build a ring around the sun.

Fraser: Wow.

Pamela: Yeah.

Fraser: So essentially, you’ve then got Earth everywhere around the entire orbit around the sun.

Pamela: Yes.

Fraser: At the earth’s distance from the sun, it’s just planet. But instead of it being a round ball that goes around the sun, it’s just a flat ribbon that goes all the way around the sun. So, then what’s involved with that?

Pamela: Here again, you see in websites and in science fiction this is often described, like you said, strictly as a ribbon. But you actually need to build it as a domed ribbon. Because otherwise the atmosphere will escape. People talk about… well, if you make it big enough you’ll have gravity… no, if you make it big enough… gravity always points towards the center of mass.

Fraser: Won’t it just turn it into a sphere? It’ll try to, right?

Pamela: Well, it will eventually gravitationally collapse under its own mass into a sphere. But, ignoring that structural building problem, if you make the thing massive enough, gravity always points towards the center of mass, so you’re not going to be attracted to the outer ribbon of this thing, you’re going to be attracted to fall straight into the sun, and that’s a bit of a problem.

Fraser: Right, well I thought the trick was that you set it rotating…

Pamela: You set it rotating…

Fraser: And you give it a rim, and then the air, just like people, is experiencing that 1-gravity. The air can’t get over the edge of the rim, so it sticks around inside the ribbon, just like the people do.

Pamela: The problem starts to be that gases collide with themselves, they’re getting berated by the solar wind, you run into all sorts of problems that will cause, over time, the atmosphere to drift away.

Fraser: Right, it’s very different from escape velocity.

Pamela: Yeah..

Fraser: What you would get with the centrifugal force of it turning…

Pamela: And so now it’s a much more complicated system where you will lose your atmosphere, and it’s something to be concerned about. So the easiest way to prevent that is you just put a lid on the whole darn thing.

Fraser: So, build a big dome… so it’s a ribbon with a dome facing the sun. And I guess then you can also put in your shielding because you’re going to have that same problem, right? You’re not going to have the magnetosphere to protect it, and so it’s almost like somebody somewhere is always going to be getting blasted with protons.

Pamela: Right. The other problem with these is that they’re not actually all that stable. Here with our planet Earth we’re always, quite literally, falling towards the sun. But, we have enough velocity that we are falling at the same rate we’re orbiting, which sounds really confusing. The way to think of it is… if I throw a rock, it arcs down towards the surface of the earth. It falls. But, if I throw that rock hard enough, it’s going to be able to get from me here in Illinois all the way to you in Vancouver before it falls and hits the ground. If I throw it even harder, it’s going to make it curving around the surface of the planet all the way to China before it falls. I keep throwing the rock hard enough, it’s going to make it all the way to friends in Britain before it falls.

Fraser: Right. Eventually it’s going to bonk you on the back of the head.

Pamela: Eventually it’s going to bonk me on the back of the head. And if I duck, it’s orbiting.

Fraser: Right.

Pamela: Now, it’s that velocity that it has that keeps it orbiting. Well, if you have a solid ribbon, it’s not really experiencing a forward velocity. It’s just a stationary object that happens to be rotating about its center of mass. So the only thing holding that Niven ringworld in place is, well, it’s gravitationally attracted to the sun and it’s stopped falling. It just happens to have its gravitational center and the sun’s gravitational center in the exact same place. But, it could become unstable very easily, and it could end up rotating in strange ways. Lots of bad things could happen, so you actually have to have stabilizers on this thing.

Fraser: Yeah, it could just buckle and then break apart…

Pamela: Yeah…

Fraser: So you’d have to be watching every little part of it to make sure it’s not rotating too quickly or not quickly enough, or bending inward or outward, or…

Pamela: Or that it doesn’t inadvertently start rotating about more than just the central axle. You can imagine it rotating like a bicycle… that’s a good thing… where you have the axis straight through the center, the ring is perpendicular to it, it’s going around and around and around… life is good. Now imagine coming up and biffing it from the top so that it’s now the entire ring is rotating around and around and around like a top on its end… that could be bad on many, many levels.

Fraser: Well, I think the initial impact would be bad… Now is there mass… is there material in the solar system to build something like that?

Pamela: The calculations that I’ve seen basically say that if you sweep up all the mass, all the mass… all the asteroids, all the planets, all the plutinos, all the Kuiper Belt objects, sweep up the Oort Cloud… yes.

Fraser: Oh really? Ok, yeah… so if you sweep up everything solid…

Pamela: And melt the stuff that’s not, so that you can make the atmosphere that you need.

Fraser: Yeah, get rid of Jupiter, just ’cause we don’t want its gravitational interactions… you know…

Pamela: Well, we need its mass, also.

Fraser: And its fuel.

Pamela: And its fuel.

Fraser: Might as well chew it up for fuel… but, I mean what we’re obviously talking about here is the ability of future civilizations to actually completely control the mass and matter in their solar system, right?

Pamela: Right. And it’s the energy that in many ways is the real reason for starting to build these things because again, with the Ringworld, you’re able to start capturing a whole lot more of the sunlight simply because you’re now exposing a whole lot more area to the sun. And as you start to build more complete enclosures around a star, you start to be able to capture more and more of its energy and do more and more interesting things. We’ve all seen in Star Trek or in other sci-fi movies where they start talking about Dyson spheres–completely solid spheres enclosing a star. And while they have the same stability problems as a Ringworld, they also aren’t as feasible to build because they require a whole lot more mass. But, if you were able to build one, you could then capture and utilize all the energy from a star.

Fraser: Now, let me see if I understand this… you’re talking about… you just go and scoop up again all of the mass in the entire solar system…

Pamela: And from a couple of others…

Fraser: And from a couple of others somehow… or you figure out a way to make it very strong, you turn it into a ball…

Pamela: A hollow ball…

Fraser: A hollow ball, and you just clamp it around the sun. And you’re now extracting all of the energy that’s pouring out of the sun.

Pamela: Other slightly more feasible ways of doing this are brought up all the time. Instead of creating a new surface on which to live, keep the planet Earth… we kinda like it. We may not like it eventually, but right now we kinda like it. And instead build a swarm of light collectors–a Dyson swarm. Encase the sun in these small moving orbiting objects that are hopefully not colliding, but are all scooping up light from the sun and either beaming or otherwise getting that energy back to the civilization that needs it.

Fraser: Right, and I guess you could leave a window, just for the earth…

Pamela: Right…

Fraser: So you could imagine that you take this swarm of solar collectors, move them in to like maybe the orbit of Mercury, so that they’re very… receiving a very strong amount of radiation, and you configure them so that they’re all collecting sunlight except for this little spot where you let sunlight pour out and hit the earth. We wouldn’t even be able to barely tell the difference, right? I mean, we’d look at the sun, and there’d be the sun in the sky and you wouldn’t even see that there’s a big cloud of collectors….

Pamela: Well, you would if you looked in the infrared because these things would glow hot…

Fraser: They would be very bright… yeah, no, absolutely. But the point being that you could still have your Earth and still have your sunlight, and then of course as the sun gets warmer, you’d just be collecting more sunlight and, of course, you could keep moving the earth further and further away if you wanted to. You could get all your benefits… you could still live on Earth and have free energy for everybody.

Pamela: And taking this a step further, one of the coolest ideas that I think I’ve read about is a type of stellar engine where you actually start moving the entire solar system.

Fraser: What?

Pamela: Instead of worrying about building generational spacecraft, you just move the whole solar system to go exploring. The way you do this is you build a GIANT… a GINORMOUS solar sail, something that is able to block a substantial amount of the sun’s light from going off out into space. You place this giant solar sail such that it’s exactly balanced between its gravity pulling it in–it’s mass and the sun’s gravity pulling it in toward the sun, and the radiation pressure on it pushing it out towards the rest of the solar system.

Fraser: Oh… I see.

Pamela: And this giant solar sail is now preventing the radiation pressure from going off in other directions, and is effectively acting to unbalance the forces.

Fraser: I see. Let me see if I understand it correctly… so the radiation pressure is hitting the solar sail and so it’s causing the solar sail to move away but you figure out a way to make sure that the gravity of the solar sail keeps pulling the sun forward.

Pamela: Right.

Fraser: So what ends up happing is the sun…

Pamela: It’s actually its radiation pressure is doing all this pushing and that radiation pressure being unbalanced because it’s being blocked in this one direction. That unbalancing of the radiation pressure in all directions is able to allow you to start moving the solar system.

Fraser: And so you could imagine moving yourself further towards the core to maybe get access to better resources or…

Pamela: Hey, I’d just head towards the first habitable-looking world out there…

Fraser: Right, and then zoom in and double your size, double your stars, take that one apart…

Pamela: “Hey, we came to visit. We brought our own world!”

Fraser: “And our own sun!” You know, just to show that we’re good guests. So you could then, with enough time, and we’ve talked about how the universe has trillions and trillions and quadrillions of years to go before we start to lose stars, that you could imagine some really advanced civilization eventually moving all of the stars in their galaxy around to wherever they want to put them. Put them in a big ring… put them in a big ball… mash them all together into the super-massive black hole in the center of the galaxy and harvest the energy… can you harvest energy from a black hole?

Pamela: Only if you throw things into it…

Fraser: Like stars!

Pamela: Yes…

Fraser: Right, right… so you drop stars into the super-massive black hole and then harvest the energy that pours back out, right?

Pamela: And what’s interesting, is that you start to imagine a future where we’re basically not just terraforming planets but stellarforming galaxies. “Oh, we need more energy. Aah, we’re not using this red dwarf… throw it in!”

Fraser: Right, right… because if I recall correctly, energy coming out of a black hole is actually a very efficient form of energy.

Pamela: Right.

Fraser: Right, you’re getting almost pure energy coming out of that.

Pamela: You’re getting all sorts of different energy coming out of it, but what is good is the accretion disk is able to convert a fairly significant amount of the mass into thermal energy of all sorts of different types, and this gets radiated away as light.

Fraser: You know what’s interesting about this is that like when you first started thinking about these ideas, it just blows your mind. And yet, nothing here is breaking the laws of physics…

Pamela: Right.

Fraser: It’s just time on your hands… we’re not having to come up with any new methods of time travel, or faster-than-light speed, or any of that… as long as time time’s on your hands, and you’ve got a big plan, you can move stars.

Pamela: And this is the perfect type of plan for someone living on an itty-bitty little red dwarf. You’ve got a few trillion years on your hands, you have a planet with a nice stable civilization, you all love one another… You can start to, in this case, start to make the many-generational plans. With our system, our sun doesn’t have that long left, and you can’t really get these suckers going that fast.

Fraser: Yeah, and I think that… although this sounds kinda like insane navel-gazing, you know… run out of interesting things to think about, so let’s think about, you know, really crazy stuff. But I think that there is a real purpose to this which is that thinking of the kinds of things that future civilizations might do to manage their civilizations gives us something to look for from Earth… which is that each of these things that we’ve talked about is gonna have a radiation signature… it’s going to be instantly obvious… if you find it.

Pamela: And this is where people have talked periodically about looking for stars that have excess in the infrared because that excess in the infrared could indicate oh, there’s a swarm… a swarm of Dyson energy collectors, oh… there’s a ring…

Fraser: So, could you explain that a little deeply? Why would we see an excess in the infrared?

Pamela: So, what ends up happening is that these happy little energy collectors… they’re collecting energy across the entire electromagnetic spectrum. Blue light–take it! Red light–take it! They absorb everything… gamma ray, x-ray, it’s all theirs for the collecting. These higher energies aren’t going to make it all the way through the collector and come out the other side. They’re just going to get absorbed, they’re just going to hopefully get converted mostly into energy if you’ve got good efficiency. But the entire structure is going to heat up and heat is the same thing as infrared light. So you have these collectors gathering light, gathering light, gathering light and then that’s on the front… but on their backside they’re going… oh, going to be hot and radiate away infrared energy. So, they’re accepting the blue, accepting the red, and only giving off the infrared. That causes an excess of infrared where you wouldn’t normally have it.

Fraser: Right, so there would actually be a fairly interesting energy signature of a star like that.

Pamela: Yes.

Fraser: You theoretically should be able to detect even with the kinds of telescopes that we have today.

Pamela: It just takes high resolution… well, it doesn’t even take that high resolution spectroscopy, it just takes broad wavelength spectroscopy, very careful analysis, and it has to be very high accuracy because it’s not going to be a lot of an excess, but it’s the type of thing that people are thinking about.

Fraser: Right, and then once again with the solar sail idea you would, you know, be able to detect a… again almost a reflection off of this.

Pamela: Right, so, you end up seeing this very weird infrared signature that is clearly the equivalent of a hot rock rather than a hot star. And what’s interesting is because these things are so big spatially, even compared to the surface of a star, it starts to get to the point where once you find one of these suckers, if they exist, if there’s aliens, if there’s other civilizations nearby… many, many ifs. But if… then you can start to go oh, let me resolve that because we have the technology.

Fraser: Right, right… and give them a clue. So, although this all sounds like wild, dramatic science fiction, searching for these kinds… you can’t hide them…there’s no way to hide a Dyson sphere, or Dyson cloud…

Pamela: Yeah, we don’t know of the perfect absorber.

Fraser: Right. It’s gonna leak out energy in the infrared spectrum and it’s something that would have a very tell-tale signature and we would be able to spot it. That’s the part that is very interesting… it’s another vector, another way for us to search for evidence of alien civilizations. We’re looking for life in the solar system by grinding rocks on Mars, we’re listening for signals from other worlds, and this is another way that perhaps we can search for other civilizations… to look for these specific megastructures out in the universe. That’s really cool.

Pamela: And even if none of them exist, maybe we’ve provided someone with fodder for next year’s NaNoWriMo.

Fraser: What’s that?

Pamela: It’s the “write a novel in one month” competition that’s out there.

Fraser: Oh, there you go… yeah. There’s your idea… give us credit. Alright, well thanks a lot Pamela… that was really cool.

Pamela: OK, sounds good Fraser, talk to you later.

Fraser: Talk to you later.

This transcript is not an exact match to the audio file. It has been edited for clarity.

Shownotes

Major Launch facilities

• Cape Canaveral — Kennedy Space Center, Florida, USA
• Cape Canaveral Air Force Station/Patrick Air Force Base, Florida, USA
• Shuttle and rocket launch schedule
• Mojave Air and Space Port, California USA
• Spaceport America, New Mexico, USA
• Mid-Atlantic Regional Spaceport, Wallops Island, USA
• White Sands Missile Range, New Mexico, USA
• Kourou Launch Facility in French Guiana
• Sea Launch Facility
• Baikonur Cosmodrome, Khazakstan
• Kagoshima Space Center, a.k.a. Uchinoura Space Center, Japan
• Jiuquan, Taiyuan and Xichang launch centers, China
• ISRO launch facility, India

Launch details

• Benefits of launching from the equator
• Vehicle Assembly Building at KSC
• NASA’s crawler-transporter system
• Rotating Service Structure
• Launch Complex 39-a and 39-B
• Water Sound Suppression System
• “Walk Down” tour of the launchpad with Jen and Andy Sheer — Astronomy.fm
• 3-D Video of NASA’s launchpads
• IMAX movie, The Dream is Alive
• Space Food
• Spaceflight Meteorology Group
• Shuttle launch profile
• Shuttle countdown timeline (STS-129)
• Ep. 127 — Scott Miller’s trip to KSC
• Shuttle Landing Facility
• Shuttle Emergency landing sites
• Alternate Shuttle Landing Sites
• Video of Shuttle riding “piggyback” on a 747
• Virgin Galactic SpaceShip 2

Transcript

Coming Soon!

Shownotes

• NASA’s Constellation website
• Overview of Apollo missions
• Discussion on BAUT Forum on comparing Ares I-X with Saturn V
• Compare pictures of Ares I-X with Saturn V and Delta IV
• Expanded views of Ares I and Ares V (pdf file)
• Ares I overview
• Ares V overview
• Orion overview
• Altair Lunar lander overview
• What NASA’s Return to the Moon May Look Like — New Scientist
• Lunar Reconnaissance Orbiter
• LRO’s images of the Apollo landing sites, Apollo 12 site (imaged later)
• LCROSS
• Participate in watching LCROSS impacting the Moon
• Canada’s Avro Arrow project
• Ares D-M Motor test — scheduled for Sept. 10
• NASA’s Ares I-X Blog
• Ares I-X test scheduled for Oct. 31
• The Augustine Commission:  The Review of the US Human Space Flight Plans
• Houston Chronicle:  Obama’s NASA Dilemma in a Nutshell

Transcript: Constellation Program

Download the transcript

Fraser Cain: You’re back from another couple of trips and we’re once again recording on schedule.

Dr. Pamela Gay: I only have two more trips to do to you. I will be at Dragon*Con.

Fraser: That’s the important one.

Pamela: At Dragon*Con there will be a Star Party for Cancer to raise money in honor of Jeff Medkeff who was the blue-collar scientist.

Fraser: Also just to mention last week we talked about Facebook and Twitter and I was expecting a flurry of Facebook friends but both Pamela and I have Facebook pages. Feel free to friend us.

I barely use mine. Pamela uses hers all the time. Same deal with Twitter feeds, Pamela uses her Twitter like crazy; I barely [laughter] send any tweets. We have them and subscribe to them and maybe at some point people can make some suggestions.

This week it has been more than 40 years since humans last set foot on the moon. Plans are in place to return humans to the surface of the moon and maybe even to asteroids and the planet Mars. New rockets, landers and flight technology are all under development.

Humans are pushing out into space again and this time we’re going to stay. Let’s take a look at NASA’s new Constellation Program, what’s been developed so far and what’s coming up. Hopefully most people sort of know where the Constellation Program came from but why don’t we kind of refresh everyone’s memory. What is it?

Pamela: This is one of these times where we have to thank President Bush.

Fraser: Thanks President Bush.

Pamela: George W. Bush on February 4, 2003 said that “the cause of exploration and discovery is not an option we choose. It is a desire written in the human heart”. With these words and later he went on and January 14, 2004 to say “Americans will make these words come true”.

He set forward a new ideal for NASA that was funded – which is always a good thing that we were going to put men back on the moon by 2020.

Fraser: And women, people, humans!

Pamela: And women – I’m using generic. Sorry, humans put humans back on the moon by 2020, and to look out beyond the moon, Mars, the asteroids and to build with that larger vision in place. With this Congress and the Congress budgetary office started figuring out what needs to happen. How do we keep NASA growing and looking out to new human horizons of exploration?

We can’t do it with the space shuttle. The space shuttle doesn’t really get very far off the planet. It gets about 300 miles up. That’s a hair’s breadth away from the surface when you start looking at how far away the moon is from the planet Earth.

We need something that can lift heaver weight, that can lift humans – not necessarily the same spacecraft to do both – and we have to retire our nice friendly pick-up truck of a space shuttle in order to fund this new vision of exploration. That’s okay because the space shuttle was only supposed to make it to the year 2000. It just kept going like the pick-up truck that never dies.

Fraser: Or Hubble.

Pamela: Or Hubble.

Fraser: We’ve got the space shuttle being phased out. They put a hard date on that right? It’s the end of 2010.

Pamela: Yes and we still don’t know if that’s for certain. People are fighting the 2010 deadline because part of our new vision of space exploration requires us to not start from scratch in building rockets but to build something completely new out of the pieces we’ve got.

The new set of rockets they’re looking at, Ares I and the Ares V, we haven’t even tested one of them yet. We’re looking to do that end of August but we haven’t even tested one of them yet. You have to get them human ready.

What we’re looking at right now is we’re going to retire the space shuttle at the end of 2010 and we’re hoping that no later than March 2015 we’ll have humans into orbit on the top of an Ares I rocket.

That’s five years that NASA has to figure out how to support the International Space Station while our government-funded space agency doesn’t have a mechanism to get anyone up to the International Space Station.

Fraser: Currently, the space shuttle is the only human-rated vehicle for launching people up to the space station.

Pamela: In the United States.

Fraser: Yeah, exactly. There are really only two other options. There are the Russians and the Chinese.

Pamela: Or the commercial space agency.

Fraser: But they don’t have a human-rated rocket yet.

Pamela: Yeah they’re still working on it too. What’s unknown is if they’re going to get there before NASA does. The reason that they might be able to get there first is NASA is building a suite of spacecraft that work together.

If you’re working in isolation, if you’re building something strictly for your own needs or for one specific goal, you can go a lot faster. You can work in a much more streamlined fashion.

With the combination Ares I – Ares V system they’re building rockets that in some cases have interchangeable parts. They’re both building on the technology used to build the solid rocket boosters for the current space shuttle.

They’re incorporating that same technology into the new launch vehicle so that they can build all the parts in one factory. They’re also making it so that you launch humans on the Ares I and you launch stuff on the Ares V. You have to figure out how to rendezvous these two spacecraft in orbit.

Fraser: Right this is for safety reasons? This is what we saw was the tragic failure of the space shuttle design is that you’re carrying cargo and humans together on a very dangerous vehicle. We saw the loss of Challenger and the loss of Columbia showed the catastrophic failure that can happen.

In this situation you’ve got the Ares I which is really well rated, very safe – as safe as a rocket can be that’s great for carrying humans and that’s it. Then you’ve got the Ares V which is built with less safety issues and can carry huge amounts of cargo up into space.

Once you get up in space humans and cargo will meet and will dock together and away the spaceship will go. I like it a lot. I like it because you’ve got Ares I has so many redundancies, so many ejection systems, so many ways to bail out. It has very tried and true technology. Ares V is going to be a monster. [Laughter]

Pamela: It’s the same size pretty much as the Saturn V.

Fraser: It’s got a larger launch capacity than Saturn V, doesn’t it?

Pamela: That’s the thing is you stick them side-to-side and they’re about the same height. When you start looking at that little ejection bit on the top of the Saturn V that was used if they had to grab the nosecone filled with people and launch it separate from the rest of the rocket because something is going horribly wrong, that little extra bit makes the Saturn V a nose bit taller.

When you look at them side-by-side the Ares V has the two extra side rockets like we have on the space shuttle. The two solid rocket boosters on either side of the main fuel tank and it is all fuel. Where the Saturn V got narrower as you got up, it’s one large giant column ready to be filled with cargo.

The Saturn V could launch about 118,000 pounds whereas with the Ares V we’re looking at 188,000 pounds. That’s a good difference. The Ares V is going to be able to get a 5ish percent command module of stuff into space to meet up with the human beings going up on the Ares I. That’s going to allow much larger crews to land on the moon.

Fraser: That’s 85,000 kilograms is the launch mass.

Pamela: A hundred and 88 tons is the maximum payload capacity to low Earth orbit. If we’re then looking to go to the moon it has 71 tons to the moon because you need more fuel.

Fraser: The cool thing about this is that with the Ares V you’ve got the capacity to launch not just to the moon you could go to asteroids. If Bob Zubern is correct that’s enough to get you to Mars and back.

It could also be used for launching commercial satellites. I think of all of the development the Ares V is the one that is just the raw technology upgrade that gives so much potential for space exploration.

It could be used for anything. You can put a ton of weight, amazing space telescopes, incredible landers, rovers the mind just boggles. I’m really looking forward to the development of the Ares V.

Pamela: The thing that really did it for me is I saw a NASA presentation where they were talking about the future of space telescopes. One of the things that we really struggle against right now is when we’re building things to put into space they have to be super, super lightweight.

Ounces instead of pounds when you can start comparing space systems to Earth-based systems, they have to be extremely fuel efficient. There is no extra from Earth to orbit fuel to launch the fuel needed to get to Mars.

We could right now if we wanted to take Gemini, one of the largest Geminis – north or south pick either one – one of the largest telescopes in the world, plunk it in the cargo area of the Ares V and off she goes.

Fraser: Right [laughter] there you go – space telescope.

Pamela: Exactly we don’t even have to worry about thinning the mirrors. We don’t have to worry about using special fold-out anything just put it in the cargo hold. Now it’s not going to have any mechanisms to control it, but it would fit. It would work. It would launch.

Fraser: Yes, space telescope. Problem solved – done.

Pamela: Yes, useless space telescope if you launch Gemini but it amuses me nonetheless.

Fraser: So I think people are starting to kind of wrap their heads around this. We’ve got these two rockets there, Ares I and Ares V. Ares I launches up, crew onboard, maybe they go to the International Space Station. Maybe they just go in orbit.

The Ares V launches up with whatever you want, lunar landers, lunar base, and Mars rovers. They dock in orbit, the excess parts all blow away and you’re left with some kind of vehicle which will then go to the destination.

The destination that is really being talked about most is the moon. How is this all going to work?

Pamela: What’s neat is this all feels like plug ‘n play space technology. You have the Ares I which the lower segments of its engines are basically identical to the solid rocket boosters we currently use on the space shuttle.

We’re just reusing technology. It is five segments, reusable. It is tested through the space shuttle program. We know how to make these and factories exist. The upper part is then based on Saturn technology. We took the old Saturn I – these J2S engines and we brought them into the 20^th century or hopefully the 21^st century.

Those are then used on liquid oxygen, liquid hydrogen upper set of stages. It launches, it launches, it launches and it gets to orbit and then either goes on rendezvous with the International Space Station or it rendezvous with whatever came up on a parallel flight of an Ares V.

This is where the cool plug ‘n play part comes in. The Ares V has two solid rocket boosters on either side of it that are again these exact same engines that were used on the space shuttle that are being used on the Ares I. They launch straight up.

They started off planning to use space shuttle engines but realized that they could actually build much better engines that were much more efficient. They’re still working on the engine designs, finalizing everything.

They also have for the main parts of this a central booster that has multiple booster separation motors. It goes up, goes into different parts a lot like the Saturn V did. They’re actually again reusing the J2S simplified version of the Saturn 1B engines as they launch with the big Ares rocket.

You have in different numbers in different compositions on both the Ares I and the Ares V – the exact same pieces. You put more pieces together you get to either heavier stuff in space or you get to a higher orbit. It’s just kind of cool. It’s Legos of spacecraft.

Fraser: Right but let’s talk about the cargo part. Let’s talk about what’s going to go to the moon.

Pamela: This is where we have the Altera program. There are some neat, not-to-scale artist’s renderings on the NASA website that what’s cool is the new command module that they have. It is kind of traveling in luxury.

It is still cramped; you’re still in space suits but it now has its own solar arrays so you have more power as you’re flying to the moon. It docks itself up with the Altera lander which is basically a three-story habitat that you land on the moon and you’re set with all of your supplies for you and a bunch of your buddies for about a week.

The original idea is you go, you land, you stay put and explore. They’re working on developing a rover. It looks a lot like a bug right now. It has this forward crew cabin that’s all windows. It really looks like the head of an ant. Back behind it is a much more cylindrical habitat where you go and sleep and stuff. It looks kind of like the body of an ant. It has a ton of wheels.

You land the Altera, go off and explore with your little rover that might have landed ahead of you. They’re still working out those details. Then you come home. In a way you start and end with your mission the same way.

It used to be with the Apollo you and your lander all fly from Earth to orbit to the moon in one piece. Making the system a little bit more complex – which I know makes some people nervous – with the new system, you take off in your rocket, and your lander takes off in its rocket. You dock in outer space.

You go to the moon, land on the moon, take back off, rendezvous potentially again with whatever is needed to get you back to Earth. Then you land. There’s more work but we can get more weight.

Eventually the idea is we’ll also start building stuff on the moon. The first thing that we’re set to build which is part of an international collaboration is a communications network.

We’ll be putting a string of relay nodes out across the surface of the moon. Then hopefully more permanent habitats are to follow.

Fraser: I think that’s the key difference. This time around the plan is to stay. To figure out how to live on the moon for not permanently but in the same way that astronauts are at the space station.

You’re not going to walk around, take a few steps and then pick up some rocks, shoot a few golf balls and then get back in your lander and take off. There is going to be over time a permanent research station on the moon that astronauts will go and stay for extended periods of time, right Pamela?

Pamela: This is where the current Lunar Reconnaissance Orbiter and the matching LCROSS mission are so important. The Lunar Reconnaissance Orbiter is capable of imaging the surface of the moon in roughly one meter resolution; one meter per pixel.

This means that most tall individuals if they lay down like they’re sunbathing on the moon you’d be able to see them across more than one pixel.

Fraser: Yes it’ll be able to see the landers and the rovers.

Pamela: We already actually have images.

Fraser: Ha! We didn’t land on the moon! [Laughter]

Pamela: We can see the paths from people walking around on the surface. We can see the landers. What’s amazing about the LRO data – Lunar Reconnaissance Orbiter data – is as people look through it one image at a time we suspect that we’ll be able to find lost missions.

Imagine sitting at your desk in your office slacking off or sitting on your sofa at home watching TV with your family flicking through images of the Lunar Reconnaissance Orbiter and seeing in those images some weird splat that looks like it has metal bits.

You wonder what it is and you report it. It turns out you just found some long lost Soviet mission crashed on the moon because you’re looking through Lunar Reconnaissance Orbiter images.

Fraser: Or, alien spaceships.

Pamela: I’m betting more on lost Soviet missions. [Laughter]

Fraser: Alright then interesting mineral veins, that kind of thing?

Pamela: Right and the cool thing about the Lunar Reconnaissance Orbiter is when it went up it took the LCROSS mission on the same rocket with it. LCROSS is the little robot that kills itself. It is an imaging mission that took with it part of the rocket that they flew up into space together in.

It’s throwing ahead of it that empty fuel part of the rocket, crashing it into the surface of the moon and then flying through the debris that gets sent up looking for water. It is looking to see what is the chemical composition of that stuff that gets splashed into space with the collision?

Then LCROSS in its final dying act is going to follow that rocket shell straight into the surface and make its own impact. This is going to be visible to North America and the westernmost coast of Europe.

That’s coming in October where all of us can go out and watch a new crater being made in real-time.

Fraser: And watch that little flash on the moon if we’re lucky.

Pamela: These two missions are helping us figure out if the stuff we need to live on the moon is there. If it is, then where should we land?

Fraser: What changes have happened from the Obama administration now that – I mean it was George Bush that came up with the plan, it was [laughter] it was George Bush who articulated the plan, helped encourage funding for the plan (I’m sure there were a lot of hardworking people at NASA who came up with the plan – I apologize to all of you please don’t e-mail me). [Laughter] But what happened with the change of the administration?

Pamela: Obama is currently going through the U.S. books looking for excessive spending. It’s what we all have to do now and then. I know I’m looking for excessive spending right now. The economic times in the United States aren’t good.

Constellation is an expensive mission. It’s doing everything it can to use existing technology to build on things that we know work. We’re not recreating the wheel but it takes time. Because we’re still flying the space shuttle money is being deviated for that.

At a certain point some really harsh decisions are going to be made. Are we going to keep the Constellation program on schedule by gutting the science mission directory; removing money that would otherwise be used to explore the planets, to build space telescopes to look at the stars and the galaxies.

Fraser: Absolutely not.

Pamela: Are we going to abandon funding for the International Space Station? We have international treaties committing us to different programs.

Fraser: Intriguing.

Pamela: Then we have Constellation itself which is not cheap. Constellation was originally budgeted at about 28 billion dollars. It’s looking like it’s going to be closer to 44 billion today.

Fraser: Hmm what a surprise. What are the chances of that it is going to cost more than people are expecting? When you first saw the budgets for this the way they were planning to do it was to keep the shuttle going and tail it out to keep the space station going.

They were planning to fulfill all their commitments and then as well be developing this all new technology in the background. People called it out as being a little ridiculous back in the day. Here we are and now it looks like the budget is going to be high. It’s too late to go back now, right?

Pamela: Yeah, it’s sort of like saying oh yeah, well the backhoes are out there putting in the new pool, let’s also build an external garage. We already have all the tools.

Well yes but it’s a little harder than you might think. That’s an unfair assessment. NASA is trying hard but I don’t think anyone really realized the complexity of what they were doing. They dreamed large.

Fraser: I don’t think that’s true. I think anybody…

Pamela: Okay, anyone budgeting it [laughter]

Fraser: Well even that I think there were certain things that had to be said to make certain people happy and those things were said and people signed off and the project moved forward.

It’s just like you get a contractor who’s going to put a new addition on your house and sets a price. Then when he tears it open and realizes that termites have eaten away at a part of your house, and then it’s going to cost more money.

Anyone who has been project manager knows that stuff always happens. I’m a little skeptical on that front, I think. I don’t know anything about this and I would have expected the budget would go over budget.

I think people said what they had to say to move things forward. I’m really glad that they’re moving forward. I really wish that the money could be found. The way this usually happens right is you just stretch out the timeline. Instead of you getting there by 2020 you get there by 2025.

Pamela: The biggest concern we’re dealing with right now is that 2015 humans to the International Space Station. We finally almost finish building the thing – we will have finished building the thing when we lose the space shuttle.

Doesn’t it hurt your stomach to think about it’s finally done and now we can’t get there anymore?

Fraser: Sure we can. Just hop on the Russian Soyuz rockets and away you go or Chinese rockets.

Pamela: Yeah and it gets complicated because NASA still has to pay to use those.

Fraser: Right, you know it’s cheaper than developing it. I’m the Canadian here so [laughter] I don’t know. I don’t have any emotional investment on where the rocket got built.

It doesn’t bother me. Launch on an Avro Arrow – Canadians know what I’m talking about. [Laughter]

Pamela: As it stands Obama is in August of 2009 where we stand right now is doing an inquiry into the funding of the Constellation program and trying to figure out what is the best way to move forward. The House of the U.S. government chopped half a billion dollars from Barack Obama’s request for NASA funding.

We’re dealing in a constrained situation during hard economic times. I think this is a mission that the scientists are behind because we can launch really big telescopes if it just stays. We can launch really big rovers. The manned space flight people are in favor of this.

Fraser: Don’t you mean the human space flight people? [Laughter] Sorry.

Pamela: Yes I mean the human space flight people. [Laughter]

Fraser: I’m sorry, we get so many e-mails about why do you say the word manned?

Pamela: Because it’s shorter! [Laughter] It has fewer syllables.

Fraser: We are gender-equal here on astronomycast.

Pamela: Yes, but as I was saying, even the logo for Constellation has a vision. It’s the moon, Mars and Earth in silhouette showing the three bodies that this mission is hoping to help facilitate the exploration of. We just have to get it done.

Fraser: One of the neat ideas was to land on an asteroid. Is that moving forward at all?

Pamela: It’s not one of the things that you see on the NASA website. There are things you can do with the spacecraft – once you have it – and then there are the things that it is built for.

One of the really common things that we do in astronomy is we build something for such reason and then we use it for everything else under the sun. Hubble Space Telescope was built to figure out what are planetary nebulas and what is this expansion rate of the universe that keeps baffling us from the surface of the planet?

We’ve gotten a long ways on both of these questions. We’ve also used it to explore so many other questions, to explore so many different ideas. Constellation is being built with moon, low Earth orbit with heavy stuff and hopefully Mars as its mission.

Once you have it, who is to stop some commercial agency wanting to go mine an asteroid giving all of the launch money needed, give me one?

Fraser: Hmm and some astronauts.

Pamela: That’s no different than today when we do commercial launches with the space shuttle.

Fraser: Right they’ll pay to put their satellite in the cargo hold of the space shuttle and then it gets launched as part of the mission or as the only mission.

Pamela: Right.

Fraser: Although it’s been too expensive, right that’s the problem. It has been poor use of money to launch on the space shuttle.

Pamela: Hopefully by giving up on the idea of a fully reusable craft we will figure out how to save money. This is one of the strange cases of reusable really wasn’t useful. It did a great job but it spent a whole lot of money for what it has done.

Fraser: Yeah that’s a whole other show. [Laughter]

Pamela: Orion, the capsules are each usable for about ten missions. The engines are reusable for a few missions. We are still green but acknowledging that one craft does need to get retired sooner than later.

Fraser: Before we wrap up the show, let’s give some people some important dates. Or at least let’s give them timeframes. When is the first test launch of the Ares rockets?

Pamela: Test launch? I haven’t been able to find a complete date on. What I know is a test firing of the whole shebang. An Ares they are calling X-1 is set for the end of August.

Fraser: When will astronauts probably be flying in them?

Pamela: In March 2015 is the “we will be done by then or else date”.

Fraser: March 2015?

Pamela: Yes we have awhile.

Fraser: Right and then when should we probably see humans setting foot back on the moon?

Pamela: They’re saying no later than 2020. I’m not sure anyone believes that but they’re saying no later than 2020. We’d like to believe it I think.

Fraser: That’s like ten years.

Pamela: I know but it’s

Fraser: It went from zero to men on the moon – sorry humans – on the moon with the Apollo program. [Laughter]

Pamela: Yeah but we’re building really cool rovers that you can rove for massive distances in. The Altair system that is like a three-story lander; it is huge and you can live in it for a week happily.

It’s the difference between building a nice friendly hut out on a hill with your friends and building the world’s tallest building. One takes a bit longer than the other.

Fraser: There you go and that’s where we stand right now. I’m sure we’ll do more shows in the future as the technology works its way out and actual launches start happening and we get closer to the end of the space shuttle.

Then the first Ares launching and eventually if we keep doing this show we’ll do a special on the first landing on the moon. That’s it everyone has to hold out for another ten or twelve years of astronomycast so we can do that show. Keep listening.

This transcript is not an exact match to the audio file. It has been edited for clarity. Transcription and editing by Cindy Leonard.

Shownotes

• Sirius – EarthSky
• How long would it take to get to Alpha Centauri? — EarthSky
• 9.8 meters per second squared — Glenbrook Schools
• Specific Impulse – Northwestern U
• Possible transporter technology breakthrough?
• Different propulsion systems -- Overview by NASA
• The Physics of Space Travel — UC
• How Rocket Engines Work — HowStuffWorks
• How Do Rockets Work? Cornell U
• Ion Propulsion FAQs – NASA
• NASA’s Dawn Mission, info on its ion engine
• How Solar Sails Work – HowStuffWorks
• Atomic Rockets (Thermonuclear Rockets)
• Gravitational Slingshot
• Antimatter spacecraft – HowStuffWorks
• New Horizons Mission to Pluto
• Questions Show discussing a “flashlight drive”
• Rail Guns for Space Launch -- Next Big Future
• Robots Vs. Humans in Space – NSS
• Research in protecting humans from radiation in space — Space.com
• Magnetic Bubble Could Protect Astronauts in Space – Universe Today
• How To Avoid Space Madness — Universe Today
• Faster Than Light Travel (ain’t gonna happen) — Wiki
• Wormhole – Internet Encyclopedia of Space
• Quantum Tunneling
• Drake Equation – SETI
• V’ger (Star Trek Movie) — Memory Alpha
• Voyager Mission
• Pioneer Mission

Shownotes

• SpaceElevator.com: From concept to reality
• Space Elevator Blog
• Liftport
• Space Elevators on Facebook
• How Space Elevators will work – HowStuffWorks.com
• Space Elevators — Wiki
• Space Elevators, Physical Principles by Ranko Artukovic
• Konstantin Tsiolkovsky
• “The first person to think of the basic idea was Konstantin Tsiolkovsky, a Russian scientist. Visiting Paris in 1895, the remarkable Eiffel Tower made him think about a spire that reached all the way into space. In Tsiolkovsky’s vision, a “celestial castle” would be built at the end of a cable 35,790 kilometers long. This put the terminus of the structure in geostationary orbit.” — Technovelgy.com
• Geostationary orbit -- WiseGeek.com
• Carbon nanotubes – Wiki
• Post about space junk on the Space Elevator Blog
• Science Central article about space elevators, with video
• Conservation of Angular Momentum -- UTK
• The Space Elevator Challenge – Spaceward.com
• Space Elevator Games 2009
• Discussion of space elevators on Mars — Physicsforums
• Lunar Space Elevator – Wiki
• Space Elevator:  Build It On the Moon First – Universe Today
• Japanese Space Elevator Association (in Japanese)
• Article about Japan’s space elevator efforts — Times Online
• Skyhooks — Wiki

Transcript: Space Elevators

Download the transcript

Fraser Cain: Hi Pamela. Space elevators – we had a bunch of people ask us to do a show on this. And we live only to serve. If you want to travel into the solar system, you have to get off the Earth. Traditionally, that meant blasting off in a rocket. But there is another strategy for escaping the Earth’s gravity. Just climb to the top of an extremely tall tower and just jump away. That is the idea behind space elevators.

Theoretically possible, but practically infeasible, space elevators have gotten new life thanks to new super strong materials. Alright, so then, why don’t you explain the problem first that I guess the space elevator is trying to overcome.

Dr. Pamela Gay: Well, in general, getting to orbit is difficult. You have to attach yourself to a giant…

Fraser: Energy intensive.

Pamela: It’s energy intensive and that energy just kind of goes away. So, you fire chemical engine and once you’re in orbit all those chemicals have gone away. You’ve spent lots of money and you’ve destroyed what you flew into space with. It’s kind of sad.

Fraser: Right, you have to get from zero to tens of thousands of kilometers an hour going around the Earth. It costs at least $1,000 a kilogram, more like $10,000 a kilogram to launch stuff into space.

Pamela: So you have severe weight restrictions and it’s just dangerous. Who really wants to attach themselves to end of giant, uncontrollable fire?

Fraser: This is a total tangent, but I did an interview with astronaut Story Musgrave. He’s one of the most-flyingist space shuttle astronauts ever. I asked him “did you find it fun? Did you enjoy your launches?” and he was like “No, no, I didn’t like it at all. It was very unpleasant and very scary.” [Laughter]

He was very aware that he was attached to an explosion and he didn’t like it one bit. So then the solution here is the space elevator. Who came up with this?

Pamela: It’s one of these things where Americans may not realize this, but the idea actually came out in Russia a long, long time ago. Russian scientist Konstantin (and I’m going to mispronounce this and I speak Russian, but it’s written in Latin letters while I’m looking at it) Konstantin Tsiolkovsky came up with the idea that we should build a giant tower where the end of the tower is in geostationary orbit.

His idea was let’s start at the ground and build our way up with basically scientific Tower of Babel reaching up to geostationary orbit. The problem is that it is hard to build.

Fraser: What is geostationary orbit?

Pamela: The only problem is trying to build something that like is 36,000 kilometers tall is a bit difficult. Things tend to flatten like pancakes when you attempt to do that.

Fraser: We haven’t even built a building a building on Earth that is one kilometer.

Pamela: [Laughter] Right, right. Currently we don’t have any materials that we can build up and the materials won’t fall apart underneath their own compression.

Fraser: In theoretically though, if you went out and built a Sears Tower or a CN tower and got all the way up to 36,000 kilometers, then, if you could stand on the top of that tower you could just jump and drift away from the Earth.

Pamela: Exactly. Or at least drift into a different orbit around the Earth. You’d hover there.

Fraser: You would drift into a sort of widening orbit around the Earth, right? Ever widening the harder you push. The point is it is easy to get away from the Earth at that point.

Pamela: Exactly. Having realized that building up is not so good, different people look for different strategies and maybe reversing the idea. The next logical idea was to put something in space and drop a cable down. This is where the original idea of a space elevator came in where the top of the elevator is one way of envisioning it was as an orbiting castle.

This was another Russian idea where you basically have a giant castle attached a tether here on the surface of the Earth. The idea of a castle or an asteroid or some giant something is you want the center of mass of your entire cable to be the geostationary point. That way, you end up with a giant long-armed object that naturally keeps itself constantly in pace with the place on the Earth that it is orbiting over.

You have long tether that reaches all the way down to the surface of the planet. The longer you make it, the more it weighs. Some estimates have this coming in at 18,000 tons. That’s a lot. Then as you build up, you need to balance all of that mass. You stick either more cable past geostationary orbit, or you just build a giant space station, you tether a rock there. You need something to balance out all of that mass.

Fraser: Right, some kind of counter balance. You would, depending on what the number of actual weight of the cable is, you would take that cable, and you would drop it down from some geostationary orbit down to Earth. Then you would need to counter balance that weight by the rock or extend something the other way. Kind of like a teeter-totter, right?

Pamela: Right.

Fraser: The geostationary orbit is the middle point of the teeter-totter, and then the one side of the teeter-totter is down to the Earth. The other side of the teeter-totter is out into space to balance out the weight. You could put a heavier weight on the far side of the teeter-totter, but on the close side you’re going to need cable getting down to the Earth.

Pamela: Right.

Fraser: Okay. That sounds about as easy as building a tower 36,000 kilometers tall.

Pamela: [Laughter] The problem is we don’t currently have anything that is strong enough to deal with this. Let’s imagine that we can use the lightest weight per amount of strength thing that we know of, and that is carbon nanotubes.

With carbon nanotubes you start to be able to imagine making a single ribbon that just very carefully, not really capable of carrying anything, but a single ribbon that spans from the surface of the Earth all the way up to geostationary orbit.

That ribbon, not really capable of carrying anything, is going to weigh 18,000 kilograms. It’s still not strong enough, we think. We are still working on figuring out how to build things out of carbon nanotubes, this is completely new technology.

Fraser: Yeah. From what I understand, people haven’t gotten carbon nanotubes lined up longer than a few centimeters, right?

Pamela: Right. And we’re looking at needing to have something that is about 200 times stronger than steel to make this successful. You can, we think, do that with carbon nanotubes.

This is where we start getting into really strong, stronger than diamond, materials are needed.

Fraser: Right and I know that one of the ideas is that you make it thicker towards the middle point and you thin it out as you go. The end that is actually hitting the Earth is quite small.

The point being that the part of it that is right next to the midpoint has to be holding up everything below it. As you get closer and closer to the Earth, it doesn’t have to be as strong, right?

Pamela: Right. The other thing that you also unfortunately have to deal with is, this cable is getting used to basically yank, not just up, but also in a horizontal velocity whatever sort of elevator car you have going up and down.

The car, when it starts off at the surface of the Earth isn’t moving as fast in the direction parallel to the surface of the Earth as that counterweight way above the surface of the Earth is moving. As it goes up it has to complete every 24 hours a bigger and bigger and bigger circle.

To gain that velocity the cable has to be able to yank it along. If you’ve ever tried to yank something even at a few tens of feet per second, it requires a lot of force. In fact, it is a really good way to break a rope.

We’re looking at having to get something going many, many hundreds of kilometers per hour and you need to have all of the strength to yank it sideways and carry all of the mass at the same time.

Fraser: Let’s say that you could overcome the structural issue and you could overcome this horizontal movement. What would sort of the space elevator then kind of look like, and how would it function?

Pamela: There are basically two different models. In both cases you need to connect it to someplace exactly on the equator of the Earth. That way whatever your counterweight is it stays exactly over it.

One of the things we don’t think about very much is, you can have something that is constantly over the same north/south line on the planet of the Earth that goes around the planet every 24 hours, but as it does it goes up and down, up and down that north/south line. To get something to stay exactly over the exactly same point of the Earth, you can only do that over the equator.

Somewhere along the equator you drop the cable down. There are two different ways of doing it. You either drop it down to the top of the mountain and this is a reasonable idea because it allows you to not have to build as much cable. There are mountains out there that are kilometers tall. You just build on top of one of these mountains and save yourself the extra weight and the extra trouble.

The problem is there is junk in space. If you’re attached to a solid point on the planet Earth and you don’t really get more solid than the top of a non-volcanic mountain, you can’t move your platform and orbit around it all to get away from space junk.

The other idea is let’s instead attach it to someplace out in the ocean. Let’s attach it to a mobile platform of some sort. While this allows you to avoid space junk, it gives you added problems of how do you get power to it?

You’re adding now I have to go across the ocean and then go up. That just adds stress. Then you have the added weight of having to get all the way down to sea level instead of just getting to the top of the mountain.

Fraser: You would have some kind of ground structure, be it on a mountain or be it on the ocean, where the cable is actually affixed to it?

Pamela: Yes.

Fraser: Say you had some cargo you wanted to take into orbit, you would drive to it or take your boat to it, and then you would put it onto some kind of an elevator, right? Some kind of climber?

Pamela: That’s exactly what they call it. Some sort of a climber. These are somehow symmetric about the cable to make it a little bit easy. You still want to keep it as lightweight as possible because the heavier the object you’re lifting, the more energy is needed. You still have to compensate for having one gravitational potential energy when I’m standing on the surface of the planet and I have a completely different gravitational potential energy when I am high off the surface.

You have to give all of that energy via work whatever it is you’re lifting. You have to increase its velocity so that is increasing kinetic energy. You have to add all this extra energy into whatever it is you’re lifting. It’s easier if you do it a small load at a time.

You take your hopefully fairly lightweight whatever it is and load it onto the cable and start heading it up. As it goes up, one of the cool things is conservation of angular momentum actually says that the rotation of the Earth is slowed down minutely as the one object goes up.

When it comes back down the rotation of the Earth is then put back to where it was if the same amount of mass comes back down. But it is still kind of neat to think about that if we slowly but surely sent enough mass into outer space we could slow the rotation of the Earth noticeably.

Fraser: How long would the journey take then? I guess it depends on the speed of the climber, right?

Pamela: It depends on the speed of the climber. I haven’t seen anything on that but you’re traveling 40,000 miles. Well, 36,000 basically. You’re going a long ways. It’s going to take a long time.

Fraser: Right. You’re going to take days, or even like a week to get up to the top of it…

Pamela: Right. But we’re looking at a few hundred dollars to get up there instead of per kilogram and spend thousands or tens of thousands of dollars per kilograms.

The cost savings is great. Unfortunately, we don’t have the materials to do it yet.

Fraser: Although I am sure we’re going to get a bunch of angry e-mails from people who claim otherwise. I think there are a lot of people who differ on whether we can do it or not. We look forward to your e-mails.

Pamela: [Laughter] There are a lot of people working towards the many different prizes around the planet that. The X PRIZE is set up to encourage cheap vehicles that are capable of going up multiple times in short periods of times. That was what was won by Spaceship One a few years ago. There is an X PRIZE to get to the moon. There are all sorts of really cool X PRIZEs around.

Fraser: There is an X PRIZE just for who can make a climber that can climb up a ribbon the fastest using solar power and even beamed laser power from the ground.

Pamela: That’s how they are looking to be able to fuel these things. The lasers are looking like one of the best options for getting energy onto one of the climbers.

There are people working very hard to try and overcome the how we build a strong enough, long enough cable. What is really cool is there is a company here in America, Liftport, that their eventual goal is to be constructing these carbon nanotube fibers basically to build us all the way into space one string at a time.

While they work on developing the technologies necessary to do that, they are building all sorts of other products that are funding their research. It’s cool to see that there are people thinking about how to do this, and thinking about how to do this in a commercially viable way.

Japan is sinking lots and lots of effort into this. Many countries are thinking about how to do it. There are some companies working very hard in that direction.

We’re still figuring out carbon nanotube fibers. It’s a brand new technology and progress is being made. Hopefully in the next few years this will go from we don’t know quite know how to do this to yeah, this is easy. Let’s go build one.

Fraser: Now there are a bunch of risks to this situation. Obviously, what happens if the cable breaks?

Pamela: That’s a very bad, bad, thing.

Fraser: You’ve got a cable that is longer than the diameter of the Earth, right?

Pamela: It’s actually very close depending on how they build it. If you use the giant floating castle as your counter balance, then you have less length coming down toward the surface of the Earth.

Fraser: You’re talking 36,000 kilometers. The diameter of the Earth is about 40,000 kilometers.

Pamela: Some of the cables they are looking at are 100,000 kilometers long because they are planning to counter balance the cable with more cable. In which case, you now have a giant cable falling toward the Earth for who knows what reason, capable of wrapping itself twice around the planet along the way creating tidal waves. Creating new valleys where valleys didn’t use to be. Shredding cities in fascinating ways.

Fraser: Yeah. [Laughter]

Pamela: Kim Stanley Robinson talks about this in detail in his Red Mars series, where he goes from building the space elevator, to space elevator tragically gone wrong due to terrorism.

That’s a feature that I have to admit scares me a great deal. While I love the concept of space elevators, I’m a fan of space elevators with really large military safety precautions.

Fraser: think one of the issues is where it breaks. If you have actual tension in the elevator that it wants to pull away from the Earth, then wherever it breaks the part that is above the break is just going to drift away from the Earth.

The part that is below the break is going to fall down and wrap around the Earth. I think you’re really only looking at the atmosphere and below. What if a hurricane comes through and tries to tear up the cable? Or what if …

Pamela: A micro-meteor hits it and severs it in the wrong place. That’s where you really have to start being afraid. What if the sucker gets knocked by an asteroid in just the wrong way?

Fraser: I think for a lot of the other, as you said, terrorism is the same thing, right? If you go up to one kilometer and you try to chop the cable or even explode it from the ground, the cable is just going to drift away, right?

Pamela: Yeah. It’s when you get control of that counterweight and you move the counterweight.

Fraser: Yeah, these are gigantic engineering issues and could have some gigantic risks. I think that a space elevator is the most feasible way to get enormous amounts of mass off of the planet and out into space.

Pamela: At the end of the day you still have to wonder is it more feasible perhaps to go out and grab an asteroid and instead of taking mass from the planet Earth and putting it into space, to start mining space itself and move the construction workers into space. These are the debates we’re going to have.

Fraser: But even people, right? Large amounts of people. I could almost afford at $100 a pound, if I really save my money.

Pamela: [Laughter] Sell your house.

Fraser: Sell my house. I’m never going to be able to afford $10,000 a pound to leave the Earth, right?

Pamela: Right. The going rate is $3 million with the Russians. A few hundred thousand if you get your seats now for Spaceship 2.

Fraser: Yeah, exactly. Now what about space elevators in other places? I know the Earth is very high gravity, but there are some other places we can put them.

Pamela: Right this is where Kim Stanley Robinson’s idea of attaching one to Mars was such a straight-forward idea. It’s a lower gravity system. Grab yourself a moon, start mining it and dropping down toward the surface.

In these lower gravity areas you don’t need to have as thick of cable. Suddenly it becomes much easier to weave together enough carbon nanotube fibers.

Fraser: Or spectra or some regularly available stuff.

Pamela: You also don’t need as much energy to get from the surface of the planet to a geostationary orbit when your geo belongs to Mars instead of the planet Earth.

Fraser: One of the big, big issues with Mars we’ve talked about this a bit in the past, landing heavy payloads on the surface of Mars. This is going to be really dangerous, and really scary to do it.

If we’re going to be serious about colonizing Mars, then maybe that makes a lot of sense, right? Build a space elevator there at a fraction of the cost that it would be here on Earth, lower things down.

Pamela: One of the ideas that came forward in Kim Stanley Robinson’s book, which apparently I am just going to keep plugging. I love the book.

Fraser: Yeah if you haven’t read Kim Stanley Robinson’s books. Which one, he did the three Mars books, are you talking about something different?

Pamela: No. This is again all the Red Mars series. But all his books are good.

Fraser: Yeah, Red Mars, Blue Mars, Green Mars.

Pamela: The idea he had was let’s use the space elevator to get colonists from space down to the surface. Then use space elevators to get mine substances, to get basically goods from the surface of Mars back out to orbit. You have this exchange of mass going on.

Fraser: Another really good place for a space elevator is the Moon.

Pamela: There you actually start looking at why we don’t start thinking about sky hooks which isn’t something we haven’t really talked about. Instead of having a nice friendly hanging non-moving elevator, the sky hook idea is you put something in lower orbit and you set it spinning.

You essentially fling yourself into higher and higher orbits on this set of interconnecting hooks. You get caught off of an airplane, spun into a higher orbit.

You get caught by different hook in a different orbit that just happened to line up at the right moment. You get almost a set of interlocking orbiting gears that go in and out of phase with one another and allow you to fling yourself into deep space.

Fraser: I actually did an article a few years ago about an elevator on the moon, same idea. You put an elevator on the moon facing directly towards the Earth. What you can do is put a counterbalance in, there is a Lagrange point in between the Earth and the moon. You could put your counter balance in there and it would be almost like you’re floating something off of the bottom of the ocean. That it floats up and pulled the cable tight because of the way it would sit in the Lagrange point.

It’s the same deal. You could mine helium three off of the surface of the moon and then drive it to the space elevator, take it up the space elevator and then once you’re up to the top, fly over to Earth You could move towards the big space station where you’re going to be harvesting solar power, right? [Laughter]

That, as you said, there are lots of ways we could get the resources from space, and then there are a lot of options then.

Pamela: What is crazy is we’re essentially imagining a future where we’re weaving our own space highways where Buck Rogers and the 21^st Century rocket ship is getting replaced with little spiders climbing between all the different special locomotion places.

They’re climbing between the Lagrange points, between the geostationary obits. Then we have little shuttles that get you between these places. Other than that, you’re stuck on the ribbons.

Fraser: Yeah, yeah. But it allows you to make these changes from gravity walls at theoretically the lowest possible cost. That would be a true space faring solar system civilization.

Pamela: [Laughter] and it always comes down to the economics.

Fraser: Economics. But, hopefully, if the prices come down and if there’s money to be made then boy, sky’s the limit.

I’m sure we’re going to get an e-mail from the Liftport folks telling us how far along their progression is and we’d love to hear from you.

Pamela: And we are supporting what you do.

Fraser: Absolutely.

Pamela: This year it’s not getting built.

Fraser: No, we are absolutely enthusiastic about the concept of space elevators. They are not as crazy. I think that’s the thing is that they are not as crazy as you might think.

Pamela: Yeah.

Fraser: Build a cable from Earth to geosynchronous orbit. That’s insane. But, when you actually sit down and you do the math and you do the costs it’s not outlandish. There are mega projects that get built on Earth that would cost more money.

Pamela: I just want a giant security system.

Fraser: Sure, sure. I don’t. Let’s just make it happen.

This transcript is not an exact match to the audio file. It has been edited for clarity. Transcription and editing by Cindy Leonard.