Project RAMA: Reconstituting asteroids into mechanical automata
Jason Dunn, Made In Space, Inc.
National Institute of Aerospace 2016
http://livestream.com/viewnow/NIAC2016/videos/133901534
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Introduction
Hi everybody. This is a presentation for our phase 1 NIAC study. RAMA stands for reconstituting asteroids into mechanical automata. At Made in Space, this is a visionary type of idea to look into. When we first proposed it, we weren't even sure if this was possible. So the study was really to look into the feasibility of doing this. And it's a lot like the artwork shows in the image, we want to turn an asteroid into a spacecraft or generally turn asteroids into mechanical machines that can be used for different sorts of missions.
Team
Before I get into it, really the idea and why we are doing that, I want to talk about the team. This project would be nothing without the team. Eric Joyce, Max Fagin (orbital mechanics lead), Michael Snyder (co-founder and chief engineer and a lot of the idea of RAMA comes from Mike), Jason Dunn, Phil Metzger (technical advisor from the Florida Space Institute). Phil comes from NASA with some experience on the ISRU backend.
Space manufacturing
So what's really kind of the vision for this? At Made in Space, we are really focused on a future where everything can be made in space and we don't have to lauch things from the gravity well of Earth. So we're constantly thinking about the day when the resources we manufacture things with, also come from space. We're excited about the asteroid mining companies and the lunar mining companies.
The big question we have always had is, how do these asteroids and near-earth objects get to the mining outpost of the future where they will be mined? For us, we want the resources. We want to know how we're going to get the resources to build our things we need. So we're really interested in how these resources go throughout space and make it to their mining location.
We also know there's a lot of objects out there that are great candidates for mining. There's the Pennhat database which shows 1763 near-earth objects that are all great candidates. The question, then, is really how do these different candidates get to a mining location? For the study we're looking into, we're looking into a location at the earth-moon L5 point where one day there would be a mining activity.
Self-replication and mechanically repurposed asteroids
The other piece of inspiration that drove us to this idea is the idea of self-replicating machines in space, like von Neumann machines, Freeman Dyson's astrochicken, etc. Now, this idea is technically not the self-replicating machine. There's a lot of inspiration behind it, though. In the company when we talked about that idea, one of the big questions was how do you take today's most intricate machines and make them self-replicating? That seemed really hard. How do you replicate electronics and processive units and so on? And that's when we had this concept that, you know, there are types of machines that could be potentially easy to self-replicate, and those would be mechanical machines, very basic analog type devices. The probem is that if you have a small mechanical machine, like one that might sit on a desk, it's not very useful for too much. But what if the machine itself was the size of an asteroid? What could you do with a mechanical machine that large?
And that really kind of spawned this idea that, you know, if you can turn an entire asteroid into a giant analog computer, you could do lots of interesting things with it. One of those ideas is to have it become its own spacecraft, and fly itself around the solar system. So we're leveraging the advent and kind of the future roadmap of additive manufacturing, along with ISRU. And with this idea that we can actually turn the asteroids into spacecraft, they have some basic catapult type technology to propel their own mass and gain delta V.
This idea for an asteroid spacecraft starts with a seed craft built on earth. A very advanced spacecraft, which I will talk about in a moment. The seed craft is launched to an asteroid target where then it begins to convert the asteroid into a spacecraft. For this study, we had proposed an asteroid target 2001:UY19. I will go into that in a moment, why that one was chosen. Before I do, I'd like to give just a little kind of a background on what Made in Space Does and why this would be an important study to us.
3d printing on the International Space Station
We're pretty well known for not just having a big vision, we all believe that what we're doing in the ocmpany is what will help enable people to permanently settle outer space one day. But we're very practical in how we do it. We're focused on building things that fly to space near-term. And we have products and services that we provide there.
We have two 3d printers on the International Space Station. That's operational today, every day we're doing different types of manufacturing projects in space. This is a picture of Butch Wilmore holding a 3d printed ratchet that was printed a few hours after we sent the digital information to the printer.
In our lab, we have been taking that same microgravity manufacturing technology and we made a technique to 3d print with regular simulants... so there's a picture of a gear, printed out of JSC1A, and we also have a program with NASA through a public-private partnership called the Archinaut program, where we're developing a spacecraft with Northrup Grumman and [...] subcontractors on the project. Developing a spacecraft that will go into space, and build very large structures. So imagine the archinaut program spacecraft gets itself to space, and it builds itself a giant aperture, or it builds itself a giant backplane or a new space telescope.
Just three snapshots of what we're doing in the company, but we have microgravity manufacturing, in-situ resource utilization slash manufacturing, and designing a spacecraft that will go into space and build things there. So those are three important parts of what we're doing.
Mechanical contraptions and non-electronic analog 3d printers
Going back to RAMA, we're finding a lot of inspiration in the mechanical machines. These are technologies that have existed for a long time. Catapults, from 400 B.C., the antikytheramechanism which existed in 200 B.C., a very complex type of computational device, but 100% mechanical. The large industrial gears from the beginning of the industrial revolution, showing that you can make very big mechanical devices. And then fast forwarding to things that are happening right now. 3d printing is showing that you can make 3d printed analog computers, and even more interesting is that some groups have shown that you can make an analog 3d printer. So they have taken, they are printing with a concrete mix, very similar to how we're printing with regolith today, but it's entirely mechanical type of printer, with no software, no electronics, it's a machine with belts and pulleys and weights and it's printing structures. So imagine a seedcraft gets to an asteroid, and one of the first things it does is builds more mechanical-type 3d printers to build other things.
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Design of asteroid spacecraft and seedcraft
So the way we're looking at how you design an asteroid spacecraft is very much how any of us in this crowd would design any other spacecraft, we start with a functional block diagram. And the only difference is that our functional block diagram is a little bit different when we dive into the details. We have 3d printing computer for avionics, we have printed flywheels to store power, and then some sort of mass driver, some sort of simple catapult-style mass driver for propulsion.
The goal in this study is not just about how do you convert an asteroid into a spacecraft, but really at the end of the day it's what is a seedcraft. How does the seedcraft work? That's the piece of technology we have to invent in order to have asteroids be converted. The way we're looking at that problem is that we start with the end-goal in mind. The end goal is we need asteroids that can fly themselves where we want them. So what we want, we start with the mission. This is what we're doing today. We're analyzing what that mission looks like. What is the asteroid type that would be available at the right time period we're looking at, and so on? That defines the requirements on how, what do the mechanical systems on the asteroid need to do. And then we're looking at how do we do that. What are the mechanical systtems? We hope to end up with a set of requirements for a seedcraft which will allow us to design a technology roadmap in the next few decades on how you would build such a seedcraft.
Mission analysis and asteroid target selection software
Diving into how we're doing the mission analysis, this is the bulk of the work so far has focused on this. We started with the NHATS database from JPL, so you have a huge list of near-earth objects targets over 1700, and we're trying to refine those targets. So we built a software application that takes in that data and starts to refine it based on different assumptions. We're using some assumptions from asteroid redirect mission in terms of seedcraft power, delta V, ISVs, it's very similar metrics to what ARM looks at. We have to come up with some assumptions on the driver velocity, that when the asteroid is propelling its own mass off itself, what's the velocity at which it's propelling that mass? And then we're creating another constraint, once the seedcraft gets to the asteroid, how much time does it have to convert that asteroid into a spacecraft? And that conversion time fits into our software and helps us understand and downselect targets. In some cases, based on these constraints, we might start off with 1700 targets, and we end up with 6.
The software is-- it's a pretty cool application that we have created. We can put in all that information that we have created, and get out the acceptable targets. When you hit go, you get a nice table. One of the points I'll point out is that, UY19 is in this example in this table, that's where we started when we proposed this. Now that we're diving into this software application that we have created in the past couple months, we're realizing there are a lot of other targets that are really interesting, partly because for instance UY19, in the time frame that we're looking at for going to it in the late 2030s, we would only have about 4 days to convert UY19 into a spacecraft. So just our hunch is that 4 days might not be enough time. Maybe we'll come up with some new insights, though. So now we're looking at other targets that would have a longer conversion time over a month.
From that, we can think about the trajectory. How does that work? In the beginning, it looks a lot like asteroid redirect mission, we did the parcher from ARM is once you converted the asteroid, no longer do you need to carry the propellant and the delta V needs from earth, the asteroid does the rest of the work. The seedcraft is launching from earth, very similar to the ARM mission, it has the same delta V and the same power, and then there's the departure, when we get to the asteroid we convert it, and then the asteroid flies itself back to L5.
There's, this table in the bottom of the screen is showing the delta V needs at different stages in the mission. Probably the most important point is the blue circle, which is circling the delta V needs for the RAMA spacecraft when it's flying itself to the mining outpost. So that's, that number for UY19 is 446 meters/sec. That's how much delta V that UI19 will need to fly to L5 insertion. And that's a really important number because that number places the most constraints on what the specific technology RAMA needs to have. It gives us a sensitivty on the size of the asteroid needs to be; from that number we can back out things like how much of the asteroid gets consumed by the propellant, and so on. As we look at these different asteroid opportunities, that one number, the delta V, drives a lot of our decision making.
What we end up with is this really nice 3d plot that we can plot different asteroid targets on. In the z-axis is the total delta V needed to move that target to L5, and the x-axis is the driver velocity that the target would need to propel mass at, and the x direction is the amount of asteroid mass that is consumed in that process. UY19 is blue circle. You can see it has this 446 meters/second, which gives a driver velocity just around 450 meters/sec, notice that for UY19, we're consuming little over 60% of its mass in order to get the other 40% or so to the mining outpost.
One of the concepts is that, well, if you do a trade analysis, can, you know, can we just make sure that the 40% that gets there is the most useful 40%? And maybe the 60% is mostly useless mass, and now by the time the asteroid makes itself to the mining outpost, perhaps it's been "pre-refined" so that of the mass that does make it to the mining outpost it's mostly useful stuff.
That's one concept; the other is just to find better targets. On this list right now, we're still diving into the data. We have two other targets that are interesting. At the bottom of the kind of most ideal is SG344. Some of you may know that that is assumed that it might actually, that SG344 might be an Apollo upper stage. We're not sure if it's actually an asteroid. If it were an asteroid, it becomes very interesting to us because it requires a very small amount of delta V to get to L5, and a very small amount of mass actually has to be removed.
Asteroid hopping
We also interested in this idea of asteroid hopping, which is if the seedcraft can refuel itself on the asteroid, then the seedcraft can go to other asteroids and continue to do this over and over again. And now the mining outpost will just have this constant influx of new mining resources coming in, from different near-earth objects. So in this idea of asteroid hopping, just walking through it, the seedcraft would go to UY19, it would begin the conversion process, once the asteroid is converted into a spacecraft, the RAMA seedcraft would depart from UY19, and UY19 flies to L5, and the seedcraft would fly to the next target like FR85 and begin that process again, and then FR85 becomes the next asteroid spacecraft going to L5.
Brainstorming
I am going to end really quick on the next thing we've been doing. Now that we have a really good idea of what the mission might look like, what the targets are and so on, we've been thinking about how do you convert that into a spacecraft. How do you take that initial functional block diagram and come up with the ideas there? Whenever in the company we have the chance to be really conceptual, we have a really big brainstorming session with everyone with post-it notes and everyone can vote on their various ideas. So we did this for the functional block diagram, and there's too many ideas to list on one screen, but we've come up with lots of different ideas.
propulsion: diurnal thermal catapult, drone swarm selective albedo control, controlled ablation/outgassing with solar concentrator, electrostatic dust rocket, regolith ion engine, pressurized volatiles monopropellant rocket, water ice LOX-H2 rocket, water-ice steam rocket, pulsed laser ablation, solar sail, gravity tractor, rail gun, pneumatic catapult, spring catapult
energy: day/night thermocouples, thermal batteries, bimetallic spring diurnal generator, volatile pressed pneumatic tank, ISRU photovoltaics, slag flywheels, printed springs, solar concentrator, seedcraft RTG, seedcraft photovoltaics
C&DH: solar shadow clock, abacus, mechanical "punch card", mechanical logic processor, 3d printed mechanical computer, ISRU TTL semiconductors, asteroid sourced silicon circuitry, seedcraft based, bring flight computer from earth
GNC: insolation triggered despin RCS, selective albedo RCS, 3d metallic e-sail wires, reshape asteroid for spin stabilization, selective explosive ablation, water/ice steam RCS, thermal sun tracker, despin tether/counterweight, fly wheels, seedcraft avionics
subsystem connections: seismic, light/shadows, pneumatic linkages, gear & chain belts, conventional electronics
tech gaps: microgravity metal refining, ISRU photovoltaics, mirror fabrication in space, asteroid mining, computer on a chip, archinaut technology, autonomous rendezvous and proximity ops, dust mitigation, printed bimetallics, remote NEO composition characterizatio, printable raido comms
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.. different ways you do with propulsion, energy, C&DH. One of the most interesting to me, although on the crazy end, is how do subsystems talk to each other? How does the mechanical computer tell the propulsion system to deploy mass? One idea that wsomeone had was to create seismic activity on the asteroid, and have the seismic activity on the computer tell the computer to tell the asteroid to propel mass. Really interesting ideas came out of the brainstorm. I will always recommend that.
We weren't sure if it was possible, but now that we're diving into this, it seems that it would be feasible, especially on the timeframe. We have a cheesy dad joke to share. How does Made in Space turn an asteroid into a spacecraft? Ready for it? With RAMA-terials. Alright, thank you.
Questions
Q: This is fascinating. Have you considered the possibility of turning one asteroid into two spacecraft?
A: Ah, interesting. I am going to skip to... just going to leave this on the screen. We have thought of it. We have also thought of some other interesting missions. I think that's the really cool thing about this, there's a lot of different missions you could do. We had to come up with one, for the study, but we are looking at-- there are some that we think could be better missions for RAMA.
Q: John Cramer. About the .. tails... you showed really shallow teeth. Can you make a real gear instead of one with just little bumps there? Was there some problem with having a gear with real gear teeth on it?
A: We're doing a lot of work right now on separate project, but doing some material study on different ways to manufacture with regolith and how to get the right strength properties. We think we came up with a way to do that, to get really high strain. It's pretty preliminary.
Q: I have had experience with mechanical devices that do computation, for example I once had a mechanical calculator that would do square roots. I am probably the only person in the room that ever had one. If you look inside these things, they have not only gears but lots of springs. I was wondering whether you have a technique for making springs out of regolith or whatever materials, because I think you're going to need a lot of them.
A: That was one of the original, we kind of have a list of really big challenges. The going idea right now is that if you can manufacture the spring with the in situ resources, the seedcraft itself would load up the compression in the spring, so it's a two-part analysis. Everything we're doing now is helping to drive the requirements for the seedcraft would have to have. Once we figure out how to make the spacecraft work mechanically, then the next challenge is is there a way to get a seedcraft that can actually be created in this 2030 timeframe that can actually go off and do that?
Q: Third question is, there's a difference between a bucket of parts and a really working device. Do you envision printing the thing already assembled, or do you have to have something that puts the parts together to make the device?
A: It might be too early to say. My hunch right now, and maybe it's too much of a cop-out, but it's that the seedcraft would be the assembler of the parts.
Q: Little hands to put things together?
A: In the much more near term, we are working on a spacecraft today that does assembly in orbit. So take that technology and move it forward a decade or two, and maybe it's conceivable.
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