Sometimes a trilogy needs four parts. We’ve looked at the history and modern era of space stations but now it’s time to peer into the future at some space station concepts still in the works. Most of these will never fly, but the ideas are important. We can’t call ourselves a true spacefaring civilization until humans live permanently outside the Earth.
Astronomy Cast episode 299 for Monday, March 25, 2013 – Space Stations, Part 4: Future Space Stations.
Welcome to Astronomy Cast, our weekly facts based journey through the cosmos. Where we help you understand not only what we know, but how we know what we know.
My name is Fraser Cain. I’m the publisher of Universe Today and with me is Dr. Pamela Gay, a professor at Southern Illinois University Edwardsville, and the Director of CosmoQuest.
Fraser: Hi Pamela, how are you doing?
Pamela: I’m doing well. How are you doing?
Fraser: Good! How you liking this weather?
Pamela: Oh my gosh. It is stunningly beautiful and stunningly allergy inducing outside right now. But it is leading to some really great photos.
Fraser: I heard a rumor that you are so nervous of this you don’t even ride your horse outside.
Pamela: No. It’s not that I’m nervous of this. I ride my horse inside because inside he cannot jump outside of the arena. That’s a completely different fear.
Fraser: Right. Right. Having him jump in unexpected ways.
Pamela: He’s mostly a good boy.
Fraser: I went on my first big mountain bike ride of the season and ruined myself.
Pamela: (Laughing) Oh no.
Fraser: Yeah. I went for 25K.
Pamela: Oh that’s nothing.
Fraser: I know. It’s up hill. It’s up a mountain. Typically I’m riding like that and during the middle of the season I ride a couple of times a week. First ride of the season absolutely destroyed my legs. I’m still sore. So hopefully I’ll be back. I’ve got to get back at it. I’m a little over due for my first ride.
Pamela: I’m almost ready to start riding my horse outside. I just want someone with me in case my horse decides he’s terrified of sheep. He’s made that decision before.
Fraser: It’s a perfectly rational fear.
Pamela: It is. It is.
Fraser: So sometimes a trilogy needs four parts. We’ve looked at the history of modern era of space station but now it is time to peer into the future at some space station
concepts still in the works. Most of these will never fly but the ideas are important. We can’t call ourselves true space-faring civilization till humans live permanently outside the earth. And I think as we were noting going into this episode I am extremely excited about this topic. I was throwing links at you right and left. “Oh, and we should talk about this” and “Oh and these video games, we should talk about that.” Yeah. I am super excited. As soon as we move into the world of speculation that’s when I get to my happy place.
Pamela: Yeah. And unfortunately the reality of what we can fund takes me to the unhappy place. I have this unfortunate habit of living within budgetary constraints.
Fraser: You think about 1969. Humans have walked on the moon. The future of space exploration is so bright and here we are, 40 years later. It’s like none of that stuff has happened. When you thing of these really cool ideas for space stations, part of you wants to ask, ‘How are we ever going to pay for this? It’s never going to happen.”
Pamela: My generation growing up in the United States, when we were in middle school I went to space camp back in 1987 the year after the Challenger disaster. I remember seeing on one of the walls the plans for Space Station Freedom. At that point in my life I still thought maybe someday I will go into space. The adults who were training us kids were saying, “Oh yeah. All of the interesting stuff will be done by the time you are old enough to go to space.”
It’s like, no, no. We still haven’t done it, and yeah, I’m an adult now thank you. It’s just too many broken dreams at a certain point.
Fraser: Oh I love that you went to space camp. That is awesome.
Pamela: I went four times.
Fraser: You went four times to space camp? Do they still run space camp? Can I take my kids to space camp?
Pamela: (Laughing) Yeah totally! It’s down in Huntsville, Alabama. It’s still going strong.
Fraser: Oh we should totally do it. I will totally sign them up. Will they like it you think?
Pamela: Yeah! Totally.
Fraser: My kids specifically will probably love it. Alright. I think before we get into the crazy wacky concepts that I am super excited about we should talk about the near future. What will happen to this existing program? Do we have a pretty good chance of maybe almost happening?
Pamela: I think the one to really watch, the one that really is likely to happen is the Chinese Space Program. They have two more. I apologize. This falls into the category of things I will mispronounce. They have two more Tiangong Space Stations planned that are basically single launch capsules to go up, they have the solar arrays that are deployed. The next one that is slated to go up has 20 days of life support. The next one will last a bit longer and allow multiple crews. Then after that they are going to be working on building a multi module space station that starts to resemble what we are used to with Mir and the International Space Station. It’s still not named. They are currently calling it the Esoteric Project 921-2. But they are asking their people to brainstorm or crowd source a new name for this future space station they will be constructing.
Fraser: As we discussed on the last show, looking at something that is following less expensive – a practical method of getting this space station going by learning from the lessons of what’s happening with the Americans using Russian hardware. I think the long term objective of the Chinese is to reach the moon. They stated they plan to set some feet on the moon. So this is an interesting way point for them.
Pamela: They’re doing this with very nice incremental design. They’re not wasting their time by saying they’re going to innovate everything in one step and go from zero to 10,099. They are instead doing the nice slow and gradual that allows them to test and innovate, and test and innovate. That’s really a safer and lower cost way to do it because it’s easier to do incremental designs than do the whole thing all at once. While they are building on the old Salyut technology, they have completely renovated it, and made it their own. It’s similar to when a country singer takes a pop rock song. It may have some of the old bones inside of it, some of the same core transitions and words but it gets completely redone in a new way. So what they are doing really is their own innovation on the older designs.
Fraser: We talked about Bigelow Aerospace and their plans to build bigger and bigger inflatable habitats and eventually dock them to the space station. And of course the International Space Station is going last out until the 2020s right?
Pamela: Right. That is what we currently think. There are also potential plans as the Russians and Bigelow are both looking at commercial habitats. Various people are talking about building things out at Earth-Moon Lagrange Points orbiting the moon. So the question is, “Where are the needs? And where are the dollars?” As we look toward the future we’re trying to define both how to make space exploration self-funding and also what are the things we need to do to take that next great leap in our own exploration.
Fraser: Let’s talk about the needs then. I think we’ll avoid the dollars from here on out. We’re in speculation land and there is no need to talk about where the money is going to come from.
Pamela: Oh man. (Laughing)
Fraser: So let’s talk about the needs. Why is it important for there to be space stations and what are some missions they can do for us?
Pamela: That’s where it starts to get kind of tricky because that’s where it gets kind of hard to justify a space station beyond the peace keeping image it has. The basic needs are to run a variety of different microgravity experiments ranging from chemical reactions to crystal growth. There has always been the idea that maybe the next breakthrough in cancer research or in refined products is going to come from what we could create only from under microgravity scenarios. At the same time we ask why we cannot do all this in canned sets. Why do we need human beings doing that? So what we do require is basically human thumbs is fixing things on orbit. This is one of things the space shuttle was particularly good at from rescuing solar max and repairing it to servicing the Hubble Space Station to building the International Space Station. Over and over this space shuttle proved that human beings on orbit can grab things, fix things and allow them to last longer and not be as expensive as long as you ignore some of the overpriced shuttle launch costs, but not be as expensive to maintain on orbit.
Fraser: So you’re imagining a future space station and being some kind of maintenance yard where…
Pamela: Yeah, it sounds kind of bleak but that’s what we actually need is that platform from which we can send out grabber robots. NASA was actually working on developing these in the early 90s –spacecraft that would go out, latch onto things and move them around. This was initially conceived as a way to catch space junk and move them around. It would also work to grab spacecraft, bring them back to a repair platform and put them back where they need to go when you’re done fixing them.
Fraser: I just dropped off my computer at the repair shop and I imagined that. A super-duper crazy repair shop with tons and tons of spare power systems and wiring and boards and crazy tools, but working in zero gravity, the scientists are one half computer techs and one half astronauts, test pilots/computer techs. Beyond a certain point, future repair missions will be very carefully planned out but there will still be this need of all these parts they can repair things. Getting things to and from the repair station is going to be pretty complicated. Satellites have a different orbit that for them to come together to land on one of these or be connected to one of these space stations is going to be pretty expensive in terms of fuel right?
Pamela: That’s where once you have something on orbit that can go and do the grabbing for you is not as bad. The majority of the launch costs and the majority of energy goes into getting out of earth’s gravity and getting into lower orbit. You can stick something like this in mid orbit and that would give you an easy platform to have helper robots, grab the things you need and then put them back where they belong. With the space shuttle we used payload assist modules to raise things to higher orbits and the space shuttle could detain itself. That’s how Chandra got into its highly elliptical orbits is it had to fire additional rockets. So it got carried up, launched from the bay of the space shuttle and then fired its own rockets to make it where it needed to go. So this is not outrageous of an idea and it does take much less fuel to make those smaller variations. We need tow trucks.
Fraser: You can imagine one hanging around a geo stationary orbit and slowly moving around the geo stationary ones. You can have one that’s getting pull orbited and one in a lower orbit. Satellites will be launched into appropriate paths so they can be picked up, docked, repaired and upgraded. That sounds great and a really good thing. Then I guess the other thing is a fuel weight point where you can assemble a space craft for further missions. You may launch all the parts up to the space station and they get to hang out at the space station for a few days while they dock everything together, refuel it and head off to mars or something.
Pamela: Part of that is also the construction of things on space, on orbit to go out into deeper space. So you can imagine, it’s not just a fuel depot but it’s where you start assembling things, it’s where things are coming to be refurbished so you can have basically that gas station in space where the guy is in the back building his own cars. This allows us to consider a lot of times when we launch rockets the final stages make it most of the way to orbit, they could make it all the way to orbit. There have always been plans that various people put together as a cost saving measure to utilize the upper empty stages to start building things.
Fraser: Also there are these free obits that transfer you from planet to plant, from moon to moon. You can imagine once you’ve got a space craft in orbit, you don’t need to bring it back to any gravity. You can have it go to Mars, drop people off, come back from Mars, dock at the space station, pick up more people, go back to Mars and shuttling back and forth being these weight point stations. As we get more and more infrastructure in the solar system you can imagine a great and greater need for these weight point space stations.
Pamela: It’s kind of like the most ludicrous people mover to get on and off of rides you have seen at Disney World. You have these space craft that are in these continual orbits that resonate between earth and Mars. They simply are ejecting capsules and capturing capsules as they get closer to the two planets and as they depart. It’s one of those times you can’t actually stop the moving walkway because someone got stuck. It does open a much more continual pathway to travel between planets.
Fraser: What about resources. You can imagine in the future we will want to mine asteroids. Tons of companies are starting to look at mining asteroids. I’m sure a lot of
that work is going to be done by robots. But you can imagine a future you will need to stockpile and gather these resources.
Pamela: One of the issues as you start looking at more and more of these large space station designs they require a lot of metal. When you start imagining how to launch that into space with all the fuel costs, you also have shipping all of the earth’s metal into space. It’s not a renewable resource. If we can get the metals and minerals we need by mining asteroids that saves the resources for the surface of our planet and it also means we don’t have to expend fuel getting things off the surface of the planet which means fewer greenhouse gasses and fewer other wasted resources.
Fraser: So you can imagine more and more of this infrastructure that gets built in space the more resources they will need, the more they are going to be parking these tiny metal asteroids nearby their space stations and tearing them apart. Trying to raise metal from the earth to space is crazy talk when there is all that metal out there raining down on us as we’ve seen.
Pamela: Some of the space station designs that are out there are hundreds of thousands of tons. That starts to become unrealistic when launching a single astronaut costs 70 million dollars. It’s a lot to think about. It’s not a cheap future. I know you want to ignore costs but we have to get metals from somewhere.
Fraser: This is Fraser’s mad imagination episode and we no longer need to worry about costs. So let’s keep scaling this up because you can imagine. It’s really this chicken and egg problem. Once you get this rolling you’ve got a repair facility and the repair facility needs raw materials and it needs to be able to fuel. People will need their families nearby so you will need living space. What are some of the larger future space stations that are proposed? A lot of these ideas came out 40 years ago. We saw them in 2001.
Pamela: Some of the realistic side we have the inflatable multi module ships that are getting planned by organizations like Bigelow. Or they are looking to use inflatables that have the lowest weight per volume that any of the craft we’ve been able to design. They basically have thick walls, a variety of different phones and high strength materials. They seem to be fairly puncture resistant but we are still testing them out. And that seems to be the realistic way to go. But when you start looking at some of the realistic ways to go in the near term future, there has always been that dream of the space station you can walk around with regular gravity. That rotating wheel, rotating cylinder. The reason why these are so much harder to put together in practical reality they have to be huge. In order to get that one gravity experience for your feet you have to build something that is tens and tens and tens of meters in diameter because if you try to build something that is just a 20 meter diameter, something that is roughly house-sized for a really big house, your feet will be experiencing normal gravity and your head will be experiencing 80% gravity. And that’s disconcerting when you feel the weight of an object noticeably change as you pick it up off the ground.
Fraser: That would be so cool
Pamela: It would be so creepy.
Fraser: It would get tired fast for sure.
Pamela: It’s only once you get the point that your space craft is 300 meters. So it’s more than three football fields in diameter. That’s the difference between your feet and as high as you can lift with your arm is only a couple of percent.
Fraser: Right. And then you can imagine the forces involved to have something that’s moving fast enough at 300 meters so that it can hold together is going to be really tough and require even more metal.
Pamela: Yeah. It’s also a matter of how do you put it together and maintain its stability. Sure things that are rotating are fairly stable. But you have to get it rotating without getting it wobbling. There are a lot of complexities getting something like this going. So far we have not taken this on as a reality we want to consider for the future. Personally, rather than building a wheel and get that wheel going, Babylon 5 had the right idea to build a nice large cylinder and have the outer walls of the
cylinder rotate. That way you can have your central zero G region which you’re stuck with anyway. You have a more stable structure to begin with that’s doing the rotation.
Fraser: And you’ve got other ideas where you have the space station in some kind of counter weight and everybody lives in this space station and there is a long cable between the space station and the counter weight. But then that is fairly difficult to get to it and dock with it because you have got all this motion going on and the strength of this cable. In the end for us to live in space for any long period of time, we will need some level of gravity and rotation is the only feasible method of artificial gravity that we can come up with.
Pamela: So the question is do we need to rotate the entire space station or do we just need to rotate where the astronauts sleep. If you just rotate where you are sleeping you can basically build that small ride they have at almost every amusement park where you get plastered against the walls to relax. Then of course there are crazy chicks screaming. That might be more feasible but you have to figure how you not rotate everything while you are rotating the one thing; you have counter rotation; conservation and angular momentum is a pain. It gets tricky quickly. It is all first year physics. It’s all something any engineering student should be able to do. But turning these equations into a stable reality is a challenge.
Fraser: There were some great concepts proposed in NASA and even to the public back in the 1950s and 1960s. There are some great pictures on the internet.
Pamela: There is a lot early space art that is dedicated to imagining that future where we all live in space. There were actually people trying to figure out how to put cities into space – ideas ranging from the Bernal Sphere to the Bishop Ring Cylinder. Let’s just take care of all of the geometries. All of these different plans had a couple of core concepts. They used mirrors to get sunlight into the inside of walls of their rotating architecture. They planned things so large that you could have multi story buildings inside where people experienced negligible changes in gravity as they went from one level to the other. In some cases it was the rotation alone that kept them in the atmosphere so no ceiling was required. In all these cases it was a problem it would require multiple asteroids worth of metal to build the realities that were being envisioned. Then, how do you get the dirt, how do you get the water, how do you get all these things up to build these hundreds of kilometers in size – islands in space. They were fabulous science fiction and it was a few 100 years off I think.
Fraser: Yes. Some of them are just amazing. There was this one called the Stanford Taurus. I’m going to try to post a picture for the people who are watching. It was just amazing stuff and really big. Like you said, 100 kilometers long that would house hundreds of thousands of people. These are serious space-faring construction projects. But as you said, that is the far, far future.
Pamela: In the near future what we are looking at is, ‘let’s grab ourselves an asteroid and hollow it out and live in it. You are the one that said this earlier today, live in it while we are mining. This is along the lines of one of the projects NASA currently has in its budget as put forward by the White House. We don’t know if this budget will be adopted, we don’t know if this will actually move forward but currently there is 105 million dollars set aside to just scope out what would be necessary to catch a near earth object and bring it back home. That’s just weird.
Fraser: I think that solves a lot of problems when you think about it. Many of these asteroids will possibly have pockets and sources of water underneath the surface so they will have a ready-made place for fuel, water, air. That will all be available. They are going to be made of metal or stone, probably some combination of both. So you’re going to have access to some of the resources we require. You can dig into them so you can hide from radiation and from micro meteor particles. They are a safe place to go. They can handle a certain amount of rotation if depending on if they are just a loose ball of rock or if they have some cohesion so you can start them rotating. You could then go inside and create that artificial gravity. They aren’t going to have a certain size that’s required. Eventually if you are feeling you want to use them, just put some engines on them and hit the road.
Pamela: The real quandary is figuring out which ones are the ones to grab. You described an ideal asteroid that may not exist – one that has readily accessible water that was deposited there through some comet impact; and also has a high metal content. Most asteroids are dirt, mineral, rocks. They are interesting but not necessarily building materials. Trying to find those rare rocks that have water that doesn’t have to be taken out of minerals through an energy intensive chemical reaction and also has metals that are accessible in seams that are mineable – we don’t know how to find those objects yet.
Fraser: You can imagine bringing it together. You find the right rock and then bring in those little metal rocks that give you additional metal. You can bring in something that might provide water and ice like a smaller comet and just crash into it if you need to and use that to help with the rotation if you need to. The point being you don’t need to find the one thing to serve all those purposes. You’re going to find a good place to live and then you’re also going to find and access other resources as well. I think this is great. We’ve only just begun my imagination journey. I’d like to go bigger and talk about some really cool space station concepts in science fiction. You already talked about Babylon 5, a 10 kilometer long space station that rotates and provides artificial gravity. Another classic one is from the Mass Effect video games which is about my favorite video game series. There is the Citadel Station in that. Then of course everyone is talking about the Halo Video Games. I know you haven’t played much Halo. These are rings that are built around worlds. In fact there is a new movie coming out. I forget what it is called but it is the same thing of some futuristic space station in orbit. Then there is the Ringworld, stories by Larry Niven which people have taken a crack at the physics and it has come up pretty lacking.
Pamela: Yes. (Laughter)
Fraser: And then I think the grandest concept is like a Dyson Sphere.
Pamela: That’s what we’ve talked about in past shows. How do you make it without having it collapse in on itself during the process of building it? It requires you to take massive multiple planets and spread it out into a sphere surrounding a star. That is difficult. Then you have to set it spinning. You only have gravity that is maximal on the equator and you will have no gravity when you get to the poles. It’s one of those really great science fiction concepts, but the reality of constructing and setting something like that spinning starts to become more of a challenge. At the end of the day we have to remember that space is mostly empty. If you try to fly through our actual asteroid belt, it is not Hans Solo asteroid belt. We’re not dodging and weaving between rocks. If you’re on one asteroid, most of the time you might have a moon asteroid you can see, but it’s not like you can see all the other asteroids on the asteroid belt. You are just on the rock you were on floating like the lonely prince. Trying to turn one asteroid into a home and then going out and grabbing others that may be vast distances away, it is fuel intensive, time intensive and a lonely prospect.
Fraser: There’s one concept of a space station, Elysium by Neill Blomkamp that is coming out in August. There is an idea you may have not thought of. People can use space stations as a way to communicate and demonstrate there are alien civilizations on these stars.
Pamela: We also brought this up in the same Dison Sphere Episode awhile back. There are some ideas similar to Dison Sphere where instead of completely enclosing a star, you have a variety of things in orbit, basically Dison Swarm…
Fraser: Dison Cloud…
Pamela: This would change the color of the light of the star where you would see more infrared but lose a lot more of the optical. By carefully studying the spectrum and the continuum from stars you might be able to see that there are these advanced solar system-altering civilizations out there. So far none of them have been detected. People have looked.
Fraser: We did an article on Universe Today about five years ago. Someone proposed building a series of Mylar Triangles that you would put in orbit around your star and it would give off a signature of light that was absolutely a clear signal that some intelligent civilization had created this because it is not a natural formation. But it wouldn’t be super expensive and cheaper than trying to send messages or receive them.
Pamela: And that gets into the whole philosophical debate that Stephen Hawking has brought up, “Do we really want to find the aliens right now?” But that is a completely different topic.
Fraser: We actually just covered that one with the Firmy Paradox, there are very good reasons why you don’t want to necessarily let the aliens know we are here. I think this is great. I thank you very much for falling into Fraser’s speculative mind. I appreciate that. We’ve wrapped up our four part episodes on the space stations. That was great.
Pamela: So who knows what we’ll discuss on Monday but we will be back with more science.
Fraser: But it won’t be space stations. Thank you very much Pamela.
This transcript is not an exact match to the audio file. It has been edited for clarity.