I finally got a chance to watch the episode of the National Geographic Channel’s “Known Universe” that filmed partly in my Cornell research lab. The episode is about how we currently build stuff in space, and how we might build more advanced or complicated structures in the future. Naturally, my flux pinning research fits into the “future” part of the show. And, at my research adviser’s suggestion, I was the guy on camera with the host. (Probably due to my propensity for putting research stuff on YouTube!)
This whole thing was a really interesting and fun experience for me. It all started with some idle speculation on space battles, which turned into one of Gizmodo’s hottest articles in December ’09, which ended up with a Nat Geo producer calling me on the phone. To my immense grad-student pleasure, he asked me what my research was about. And ta-da, our lab got featured on one of their shows!
Kids: let this be a lesson to you about what happens when you have thoughts and put them on the Internet in a blog!
We spent the better part of a month preparing equipment in our lab for the TV shoot, and an entire working day doing the actual filming, all for a five-minute segment in the episode. I have to say, I’m impressed with how well our topic got covered in such a short time, given how long I usually spend explaining it and how much material we spent filming! There’s a lot to be said for having professional editors who want to tell your story. If you caught the episode last Thursday (it will re-run soon; I believe tomorrow at 3 PM is one slot), you saw me show the host, Johns Hopkins physicist David Kaplan, three features of magnetic flux pinning that we feel could make it the basis for a future in-space construction technology:
- Pinned magnets and superconductors can attract one another and stick together without physically touching. David best demonstrated this when he held a superconductor in one hand and a magnet in the other, and the magnet jumped across a distance of a foot or two to lock back onto the superconductor.
- This effect does not necessarily require any power or control inputs. I explained at one point during filming that, although we have to supply liquid nitrogen or power a cryocooler in order to get flux pinning to work on Earth, a spacecraft might only need to shield its superconducting elements from sunlight. (That detail didn’t make it into the final segment.)
- Flux pinning can not only lock structures into place, but it can also form the basis for reconfigurable multiple-module space structures that change their shape in response to changing mission goals. Our research group likes to think about morphing space telescopes, planetary orbiters, or solar power satellites, but there’s no reason why human-habitable space stations are out of the question! (If you provide flexible tubes for inhabitants to get from module to module, of course.)
If I had to criticize this TV episode, I would say two things: first, that I wish it had done a bit better job at putting everything in context (I guess I prefer my science shows to make their driving questions more explicit…) and second, that I wish more of my explanation for point #3 had made it into the edited segment. What the final show was missing in regard to that point is something like this:
If a space structure is held together by flux pinning, then it depends on magnetic fields. These fields are actually something that we can manipulate – specifically, we can introduce electromagnets or other permanent magnets to change the shape of the flux-pinned fields. Doing that actually changes how the different components of a structure interact: by turning on and off electromagnets, we could lock components together, release them, or even turn them into flux-pinned hinges. The property of a magnetic field that governs whether two flux-pinned space modules are completely locked together or have some unconstrained degree of freedom is the presence of symmetry in the magnetic fields. In the video below, my fat cryo-gloved finger demonstrates that a cylindrical magnet is stiffly pinned in five directions (three translation directions and rotations about two axes) because its field is rotationally symmetric, but a square magnet is locked to a superconductor in all six possible translations and rotations because of its asymmetric field.
If I sound a bit nitpicky here, it’s only because this was my research for several years! And I think it’s important. The bottom line here is that we can turn a space structure into a space mechanism – and back again – by flipping switches! That is not something you can do with ordinary docking adapters unless you build complicated (and potentially fragile!) mechanisms into them. You could also build your magnetic field sources in such a way that a “universal” connector could form many different kinds of joints (hinges, sliders, cylindrical joints, …almost whatever you want) or lock modules together, or even attract new modules, all depending on which settings you choose.
In other words, if you want to build a space transformer, you will get some advantages from making the connectors out of flux pinning instead of mechanical joints.
That’s the jump between David and me playing with magnets and superconductors and the air-levitated satellite mock-ups going from a line to a box and back again in the second half of our segment. And now, I’m going to move from talking about the research depicted on the show to the experience of filming!
When the production company approached us about shooting in our lab, they asked us to share with them photos and movies to give them an idea of the kinds of demonstrations we could stage on camera. One of them showed an example of two square modules that could start off pinned side by side, turn their connection into a hinge, use an electromagnetic impulse to start rotating, and pin together again in a different configuration.
Now, here’s the thing about university research: conceiving and developing the theory behind something like this is the Ph.D.-level work (i.e., my contribution). A master’s student put together the demonstration. And after that, it’s not really an interesting research problem any more. We know how to do it, in principle. We’ve demonstrated the concept in a laboratory setting. Actually building this is “just” a problem of optimization! On I went to more theoretical things, with the idea of shape-morphing spaceships in hand.
“That looks great,” said the production company, “and we love the idea of transforming a spacecraft from one shape to another. When we come to film, can you set a demo of that up for us?”
“Sure,” said we.
“And can you make it look something like this?” they asked, and pointed us to this video, which I had crudely animated up a couple years earlier when prospective grad students visited the Cornell campus.
“Um,” we said to ourselves. We thought about it, and answered, “well, we have two devices that float around on an air cushion and flux pin to each other. We could make two more, and set them up like our other hinge demo so that they push off each other with electromagnets and turn from a 2×2 square into a 4×1 line and–”
“Great! See you in a month.”
And thus began a month worth of frantic labwork while I was trying to finalize my dissertation.
We really struggled to get those air-floated satellite mockups going. But, with a final effort the night before the shoot, we got the four levitating modules to the point where all four air systems worked, all the superconductors could be chilled with nitrogen, and all the electromagnets could fire on remote command to trigger the transformation maneuver. Just so you know I’m not making up stories, here is a video of the electromagnetically actuated, flux-pinned hinge working. However, perhaps this video does a better job of capturing the mood in the lab at the time:
So, with everything finally shipshape, we went home and got up the next morning to meet the producer/director, host, and film crew. (I know what you’re thinking. Wait for it. I have made this mistake before.)
We spent a full work day filming. First, we took the crew to our lab (a version of my favorite lab-tour opener, “all the cool physics happens in basements,” even made it into the show!) and showed them what we could do. We did the superconductor-magnet pinning demo and pointed out all the satellite mockup hardware, all before any cameras started rolling. Kaplan, a physicist, had heard of these effects but, as he put it, his job on the show is to ask all the questions that the audience wants to ask – and the editors would then make me, the “subject matter expert,” look like the smart one.
Here was where we encountered our first surprise about filming with a TV crew. We got out our liquid nitrogen, yeah yeah, we work with this all the time, it’s just our means to an end, all very blasé and casual, and then suddenly someone on the crew remembers that liquid nitrogen can freeze stuff. And that you can smash the frozen stuff. We kind of rolled our eyes – not that smashing unexpectedly smashable things isn’t fun (it is), but we were more keen on showing off our research! Still, for the first half of the morning, we put together some footage of David discussing with me the physics of making things cold and brittle and, under the camera lens, many racketballs and a couple bouquets of carnations met their splintery, frozen ends. I was a bit relieved to see that our lab’s appearance on Known Universe didn’t waste any time on the nitrogen stuff and got right down to the superconducting physics!
Still, all that was good practice for me! I have given many lab tours. I like giving lab tours. But I’d never given a lab “tour” to a camera crew while wearing a mike, and I’d never had a director before! The first major impact on my tour shtick was that, though you see many different camera angles in the edited episode, there was only one cameraman. So, out of necessity, we filmed the “lab tour” in pieces and each bit had to be repeated three or four times: once for an overview shot, once for a close-up on David, once for a close-up on me, and once for a close shot of whatever we were doing on the lab table. I got used to hearing the director, Scott, say: “Okay, that’s enough information for now. Let’s hit the same beats, but close-up on Joe.” At that point, David and I would stop our somewhat natural interaction and try to hit the same questions, answers, and demos as we had a during the last run. (Some of the same jokes, too.) Once or twice, Scott stopped us if we accidentally covered new information, so that we could make sure they had all the material they would need. Sometimes he stopped me to have me repeat a line with different emphasis, or gave me suggestions about how to explain things, position myself, and so on.
I had to get a bit used to this. In fact, the interference between my usual explanations and the TV modus operandi led to one of the quips that did make it on air! We had just explained how the superconductor’s special properties only occur below a critical temperature, and that we have to cool it down with liquid nitrogen to get it to interact with a magnetic field. David asked me, “well, aren’t you going to make something happen?” and I turned to Scott and said, “so, here’s where I would like to set up the magnet and cool the superconductor down.” He suggested that I just answer David with something like, “Oh, that would spoil the surprise,” and David repeated the question. Boom: TV was made! And David got a good excuse to look surprised when I pulled the magnet’s supports out from under it and it started levitating. That part of the shoot was a lot of fun.
In the afternoon, though, we had to do our demo with the four interacting modules. And Murphy’s Law showed up.
The end product looks great, and as far as we are concerned, the science content of the episode is just fine. As I said before, in principle this concept works – and we even have (on our own dinky cameras!) demonstrations of all the constituent components. But getting all four air-levitated, electromagnetically interacting, wirelessly commanded modules to behave for National Geographic’s HD cameras was more than those devices wanted to contribute! First we couldn’t get the air system working, and two of the modules wouldn’t float. Then that was fixed, and a nitrogen container sprung a leak. Then I substituted a backup container, and the air system broke again. Then that was fixed, and the electromagnets cut out. And so on…
The maneuver broadcast on TV, in which the line of spacecraft mockup modules moves from a single-file line into a square formation and back again, is the result of two lines of effort: careful editing, and good old-fashioned laboratory jury-rigging.
First of all, the episode seems to show a smooth maneuver, but the camera angle transitions between a couple of different points for dramatic effect. As I said before: only one cameraman! Those were actually entirely separate runs of the demo. Of course, this would have happened anyway, because the editors would have wanted all those camera angles at their disposal. But given the way things were working in the lab that afternoon…they got to creatively pick those angles that best showed off what was going on. You know…those angles, and those experiment runs, in which most of the hardware worked!
Second, though, we had way too much trouble with the electromagnets and, in the interest of expediency, eventually just gave up on them. Instead, we relied on a different non-contacting force to move the modules from one shape to another: gravity! If you take a close look at the picture of David and me above, you might notice that my right hand is holding something just off the table. What I am cleverly concealing is, in fact: a screwdriver. (What can I say? Only a week before, I’d officially become a Doctor!) Behind the modules, David is holding another screwdriver wedged under the glass sheet on his end. On a signal, we both levered the glass up slightly. The two modules in the middle had their air systems off, but the modules on the end were active and so they slid frictionlessly away from us – but, thanks to the flux-pinned hinges, they swung into their proper positions! (See? We didn’t gimmick the flux-pinned hinges; the most science-fictiony part of our setup worked on its own!)
To get the modules to swing back into line from their square formation, the show’s narrator explained that we used the air system to mimic the forces provided by thrusters on a real spacecraft. True! But our thrusters didn’t actually appear on camera. 😉
Remember, all this was to demonstrate the concept of a modular structure that could change its shape at different points in its mission. Here is how National Geographic’s CG artists presented the concept:
Look familiar? The Nat Geo production company really focused on that concept. And I have never seen any of my concepts done with better CG! Secretly, though, I was just a little disappointed. Why? I don’t think this concept is ambitious enough!
I put together my animation in about a day, in Matlab. Yes, Matlab! Renderman it is not. My original animation is a careful sequence of pieced-together kluges: while the concept of a structure that transforms by turning “rigid” components into hinges is correct, my animation did not actually include any simulations of the physics or implementations of the control systems that would govern the spacecraft. (That took me two more years and another couple dissertation chapters to develop.) No, my animation was based on the easiest way I could illustrate the concepts at the time I put it together, and it is not necessarily easy to animate stuff in Matlab. I bet a professional animation studio has access to much better tools. So, in fact, I wish the CG artists had taken more liberties with my concept!
You see, my own vision for how flux pinning could be implemented in modular space structures is even broader than what appeared in the show. I think that “transformable” structures could be extremely versatile: whenever you want new modules, or different modules, you could add them. Your whole spacecraft could morph its shape to incorporate new modules with new capabilities. And these new modules need not be added one at a time, either: two different spacecraft could meet up, in the depths of space or above a planet, and merge themselves into one big mechanism-structure. These modular spacecraft could also split and send various sub-ships off to separate destinations. This whole space future would behave like a Lego universe!
At one point during our afternoon of filming, David commented to one of the crew that a tricky thing about interviewing scientists is that they always want their science to be presented correctly, and sometimes this makes getting nice definitive statements difficult. He pointed out, as an example, that this phenomenon is one reason why it was so hard to get a physicist on TV to say that no, the Large Hadron Collider is not going to create a black hole that will swallow the Earth – because there’s always that tiny, scientific-notation-small, 0.0000001% chance of a black hole forming, and then a similarly small chance of it lasting long enough to do damage before decaying! That may be good enough as a “no” for a scientist, but a some people hear “the chance is astronomically small” and think “that means there is a chance it will happen!” Not an hour later, David and I were on camera and he commented, “and all this docking and reconfiguring is happening without any power usage!” I looked across the table, caught my research adviser’s eye, and let out a rousing “…yessssss…” which got everybody laughing. David got the hint, and on the next take the comment was that it all “uses very little power!” Yes.
So I didn’t really expect our segment of the show to be perfect, and I knew in advance that there was no way they could reasonably cover everything in detail. But I have to say that for the length of time we got in the final episode, I’m impressed with how well our research came across! Most of the major points are there, and we got in some dramatic demonstrations. Perhaps our lab will even get a bit more media attention now.
And, hey, it’s just pretty cool to see this stuff on TV: a nice capstone to my graduate school experience!