Tailored Force Fields

PART 1: The Radiation-Shielded 1-G Habitat

The Original NIAC

Back in the 1990s, NASA set up NIAC, the NASA Institute of Advanced Concepts. It was perhaps intended to allow space for grand dreams such as those that led to the Apollo and Solar System exploration missions. It was a “Paper-Free Institute”: everything from proposals to reports was electronic and based on the Internet. It was also set up to be “at arms-length” from NASA managers, for fear that otherwise, projects would be driven to align with existing NASA projects and missions and serve to fill their “cost growth”. Thus it was managed by the Universities Space Research Association (USRA) under a NASA contract.

(Irreverent Note: Today’s version, that came up after the original was cancelled in 2006, maintains Conservation of Acronyms but stands for NASA Innovative Advanced Concepts. The ill-informed might well wonder what Advanced Concepts are not Innovative or vice versa. The ‘Innovative’ tag is required because today an explicit condition is that each proposal be set in a Mission Context. The original one emphasized Long Term and High Risk; the present one turns down proposals saying “there is a lower risk way”. Why fly when one can get there by bicycle, as dictated by Systems Optimization.. But let us not digress).

NIAC’s original slogan was “Do not let your preoccupation with reality constrain your imagination!” They insisted that advanced concept proposals (limited to 15 pages and 600kB total file size) should not propose “New Physics” – but were to aim for projects that could not be done in the next ten years (a condition that today would be satisfied by just about anything by scheduling enough Decision Making Meetings..). I had one proposal turned down citing precisely that: they said that “this team will get this done in 5 years, which was the Kiss Of Death. What a kind and sweet rejection! 🙂

I attended an NIAC meeting in the late 1990s because it was free. They showed off the tall NIAC Mug, the Real Prize. I wanted that! And then I saw that they had funded a project on Quantum Teleportation!! (Actually quantum communications, not zipping people instantly to the Andromeda Galaxy). If I could be one of THAT gang!

The Island One concept from Professor Gerard O’Neill. Courtesy Space Studies Institute, Princeton, NJ. The original high-resolution image can be found by clicking this.

Our Phase 1 Project: Show How To Build The O’Neill Cylinder Automatically

My team proposed to solve the ancient (1960s) problem of the O’Neill cylinder. This is the dream of living in a shirtsleeves environment in 1-G artificial gravity, in one of Professor Gerard O’Neill’s spinning-cylinder cities: Island One (1 mile circumference per SSI caption) or Island Three (Two cylinders 20 miles long and 4 miles diameter) in orbit which per SSI, is the official O’Neill Cylinder. The ancient problem was that long-duration habitats in Space had to be radiation-shielded, which meant a layer of soil, 6 feet (2 meters) thick to stop cosmic radiation. Our generation of Earth-born humans are also “designed” to operate in 1-G gravity (9.8 meters per second-squared). Exposure to micro-gravity does bad things to us: don’t believe the happy smiles on all those heroic government employees cavorting in gorilla suits on their trips bought with tickets that cost the taxpayer $24000/kg of their mass just to launch. Nausea is just the beginning: 33% of astronauts, after years of brutally intense training, get very sick on their first space flight, as insiders explained to me. Muscle loss. Bone loss. Blood clots. If you have seen pictures of Soviet Cosmonauts carried on the shoulders of the soldiers who got them out of their landing capsules, that is not just because they are heroes: they had trouble standing up.

Radiation is the real problem. A metal shell is a death sentence: High energy cosmic rays striking a metal shell will send out a lethal storm of alpha particles on the other side, cooking anyone inside! Instead you need either 2 meters of soil, or about 0.25 meters of water, or some large depth of compressed hydrogen, to slow down the energetic particles and absorb the rays. Water is nice, but has to be carried up from Earth. And- whatever the shell is made of, it cannot be built by humans exposed to Space radiation for any length of time. It requires automatic/ robotic manipulators.

1G artificial gravity requires that you be on a Station that is spun at some speed. You can calculate the speed. At the rim of a 1-km diameter station, rotating at 1 RPM, you experience 0.5V**2/R = (Pi*D*(RPM/60))**2/D. There is also a saying in books that humans suffer disorientation because the fluid in the inner ear becomes severely displaced if they are in something that spins faster than 1 RPM. Obviously, 6 feet of soil placed at the rim of something spinning fast enough to have 1G radial acceleration, also “weighs” as much as it does on Earth, so the structure holding it must be just as strong. Lifting all this mass from Earth is just impossibly expensive. So it must be built from extraterrestrial material.

We came up with two fundamentally different approaches. The Low Risk approach was to build the Cylinder from lunar material, at the Earth-Moon Lagrangian Point L-1 or L-5. The method was something that we could justify proposing. The other was the Force Field Tailoring approach based on a “gleam in the eye”, from our flight experiments on Acoustic Shaping in Microgravity. I will go into that, called “AcLev” for short, after briefly explaining the first 1km Cylinder in orbit.

The Ignatiev Lunar Power Plant

Our plan started by landing automatic solar-cell generators on the lunar surface. Professor Alex Ignatiev, director of the Vacuum Epitaxy Lab at University of Houston, had developed (under another NIAC project) a scheme to “grow” a solar photovoltaic power plant on the Moon. His small robotic crawlers carried lenses to focus sunlight on to the regolith, melting it. They would also deposit whatever ‘dopants’ they use to make solar PV cells, and form the contacts, and keep crawling slowly over the surface, generating PV cells. The perfect Vacuum Deposition Facility to build PV arrays! Over time we calculated that a 2GW power plant could be built. Problem 1 solved: we had electric power!

Next, an open-pit mining/processing plant would bootstrap itself. The metal to build it would be gradually dug up and refined again by sheer heat and vacuum: there is research done, to prove that reducing Iron Oxide found on the Moon to iron is best done by intense heating in vacuum: the heat is free there, from the Sun, and can be concentrated to achieve metal-vaporizing temperatures. Everything would be robotic. Some essential instruments and tools would have to be landed there from Earth, but many orders of magnitude of mass would be dug up from the Moon, than had to be landed there.

Once the metal plant was working, the job of building an electromagnetic launcher would proceed. It’s mostly just rails and metal windings, all buildable on the Moon.

1km diameter habitat formed from lunar regolith

Electromagnetic Launcher Built On the Moon

Electromagnetic Launch: Railcar-Sized Container Full of Regolith Speeds Towards Construction Site

A sequence of such loads will be launched. In fact, 314,122 of them, over a 10-year period, to build the 1km cylinder.

Electromagnetic Launcher View

Lunar Processing Plant

Construction Spider builds the outer rim of the 1km cylinder, welding railcar-sized metal containers full of regolith, making a strong shell with 2m of regolith as radiation shield and 2m of soil to grow trees. Storms are not a concern inside the 1km cylinder.

Construction Spider Builds The 1 km Cylinder

PART 2. The Way Into NIAC: Acoustic Shaping in Micro Gravity

Many of us have seen Science Fair experiments where styrofoam in a vertical tube is “levitated” by a strong sound field. Back in 1996, Sam Wanis, then a sophomore, called me during his lunch break at his Co-Op job (at Delta Airlines) and asked if I would be faculty advisor to his team of 4, to write a proposal under NASA’s new “Reduced Gravity Student Flight Opportunities Program”. The program was also known as the Vomit Komet program in honor of the old KC-135 tanker aircraft that took a Zoo-full of undergrads in a padded cell through nauseating parabolic flights over the Gulf of Mexico. I did what any sensible advisor would do: tried to politely ‘bounce’ the request so I could go back to whatever had me scrambling in the lab that afternoon. I asked him to check the library for any info on what sorts of things NASA was interested in doing in microgravity. As I hung up the phone I remember being sure “That’s the last I will hear from those guys! Ha!”

Acoustic Shaping: Styrofoam on the NASA KC-135

Acoustic Shaping: Styrofoam Forms Walls on he NASA KC-135.

I couldn’t have been more wrong. He came to me next day carrying a big book titled: “NASA’s Interests in MicroGravity”. I had a sinking feeling imagining the horrors of sending sophomores on a flight experiment. But there was something in there on Acoustic Positioning: a single droplet suspended inside a cubic container using “fingers of (ultra) sound”. Triggered memories of Acoustic Modes from my graduate student days, when I did survive a sequence of 3 grad courses on Acoustics: I remember the top score on the final exam on the 3rd one being 61/100 – and who got that. 🙂 But it was enough for an A, and kept me in the PhD program.

Hollow Aluminum Oxide Spheres forming walls in an acoustic resonator in reduced gravity

So we proposed to see what would happen if not one, but a multitude, of particles were put in a container which was driven with higher-order modes by acoustic speakers, with gravity removed. Would they still congregate to The Point Of Minimum Potential? Or, as I hoped, would they move and stand along the compex-shaped walls denoting surfaces of minimum potential (nodes)? I remember agonizing over the Safety part of the proposal, but being thankful that I had stayed away from any experiments involving combustion, fuels or sharp objects. Survive a 9-G crashlanding without any external breakage or generating sharp edges that might hurt flying undergrads! Later experience made me very glad I had worked through that.

Team members Andres and Ron on their first zero-gravity flight

What’s going on in the picture of Andres (flying higher) and Ron? There are two big black Pelican Cases open in front of them. Look on the far wall: the open door is to the cockpit of the KC-135. There are 2 oxygen cylinders strapped on the wall, and there is red display that you right above them that you don’t see: that displays the ‘G’s down to 1 or 2 decimal places. Like 0.1. It wasn’t really ‘microgravity’ for very long on this plane because of the turbulence and the fact that the engines and control surfaces are active (not to mention flying undergrads inside). Call it ‘deci-gravity’ or maybe ‘centi-gravity’.

The open Pelican case in front of Andres had the Signal Generator and video displays, I think. The plexiglass resonator with the LOUD(!!) sound was packed and sound-protected inside the closed Pelican case in front of Ron. Ron is reading the value of frequency to set on the signal generator, for each parabolic flight. Andres is stylishly adjusting the frequency down to resolution of (+/-) 1 Hz. And watching the video. We trained hard for this for months. Fear energized us, not least because the program required us to get a Journalist on our team. No, not the campus rag reporter (we tried that!) A real pro. And did they get one!! Kevin Salwen, Southeastern Editor for the Wall Street Journal!!! Mr. Salwen asked me several times: “Professor, so do you think this will work?” (talk about terror..) He went on the first flight with the team (4th member other than Sam Wanis, team leader). And wrote a fantastic article about his experience. Center of the front page of the WSJ on a Wednesday. Yes I am acutely aware .. it could have been far, far worse….

Image Gallery