To my great surprise, this page got slashdotted. It was neet to bump into people I know and have them tell me they saw me on slashdot.
If I had known that so many people would see this page, I would have at least read the notes over before posting them. In response to the slashdotting, a number of people pointed out fixes that I have incorporated below. I would like to thank Jim Van Zandt and Monte Davis, who probably spent more time reading the notes and correcting than I spent writing them.
I integrated the comments with as little effort as possible. Jim sent a diff file, so I just diffed (and checked that the changes were apropriate). Monte sent comments per speaker, so I just added "Monte Davis adds" lines everywhere.
Here are my notes from the Third Annual Space Elevator Conference. It was quite a fun conference to attend. It was interesting to see how more and more independent people are starting to seriously look at aspects of the space elevator. Ben Shelef is looking at deployment scenarios, and chatting with him, I found that we have been doing a lot of thinking along common lines. Larry Bartosek has been doing some really interesting work on designing the drive elements of a climber. Lots of other interesting things are going on of course, see below.
As usual, the big hurdle is the materials for the space elevator. So far no breakthrough, I think we are still at 3.5 GPa. Individual nanotubes have been better characterized, and strengths of 150 to 200 GPa are typical, now we just (big just, I'll admit) need to figure out how to make a good composite out of them. So far, it appears that very small imperfections in a fiber will cause failure. Quality control on the ribbon material is going to be a key issue. Ben Shelef and I both suggested methods by which we could avoid splicing the ribbon in space.
Some other issues caught my mind. The number of impacts by 10 to 100 micron particles is a few impacts per year and per square meter of ribbon. This number isn't new, but it came up a couple of time during the conference. It underlines how important transferring the load between broken fibers is. Another interesting issue is how twisting motion in the ribbon can cause the ribbon's temperature to vary between 100 and 300 K in a matter of seconds depending on the angle of incidence of the Sun on the ribbon. This could have some annoying dynamic and fatigue issues. Finally, I am still eager to find out if the interconnects will be able to handle the large amount energy that is dissipated when a fiber snaps.
I'm not so interested in the political and economic side of things, but there were plenty of talks along these lines. Not much evolution since last year, though. For now, ISR has a couple of million dollars promised to it, but they are still trying to get it from Marshall Flight Center. That may explain why the space elevator doesn't currently have a prominent place on the ISR website, and why things have been moving slowly since the previous conference.
Nice slow first conference day. The registration desk opened at 5pm, and by 6pm twenty to thirty people were assembled for an informal ice breaker. I enjoyed the opportunity to see a lot of faces that were in Santa-Fe, and I was happy to be recognized by most of the ISR and Los Alamos folks. I also bumped into Ben Shelef, who seems to be doing a lot of interesting analysis in his free time. We discovered that we have been doing a lot of thinking in similar directions, and both of us have been frustrated at not having anybody to bounce ideas off. This might be the start of an interesting collaboration...
I picked up a copy of the Space Elevator Challenge 2010, an X-Prize like challenge to help in space development. The goal is to have a 250 kg climber climb a 16 km tether.
Brad mostly talked about conference organization issues.
Brian started by explaining why we need to start thinking about design and engineering of an SE as soon as possible: so that we can start building as soon as the SE becomes technically feasible.
SE very much like the transcontinental railroad. Construction of transcontinental railroad started as soon as the necessary surveying had been completed. A number of differences though. The railroad was not completely unproven technologically and economically. With the SE, we can do small scale demonstrations, but the full scale implementation is fundamentally different from any small scale testing. Like the railroad, the SE would be a paradigm shift in transportation. It would reduce costs, increase launch rate and reduce risk.
At LANL, Brian's hierarchy is behind him and he has been given money to write grants. Next conference with a SE flavor is the Space Exploration conference in New Mexico, in April 2005.
- SE is very ambitious idea. If realized would revolutionize space. He will talk about what is going on in his department, in relation with Bush's space new space vision.
- Bush's vision is good. Wants humans in space. Goal is an ongoing space exploration program.
- Policy is less succinct than Kennedy, but is still a very tight vision. Has long term goals, intermediate steps and detailed tactics.
Projector died. Talk went on without it.
- Program calls for robotic exploration, search for extra-solar planets, robotic then human exploration of mars, lunar exploration, etc.
- Need building block capabilities for space exploration, so that technology can be reused. Currently being implementing by NASA.
- John Mankins works in the Department of Human and Robotic Technologies. A lot of work related to building up the technology readiness level of technologies that will be needed.
Monte Davis adds: "Orchard" metaphor for NASA today: planting, culling and pruning (through "spiral development" process) -- keep our eyes on the fruit, not on maximizing the number or size of trees
Projector came back up.
- In order for space vision to last, need for it to be accepted by both political parties. Need set goal, with modest budget requirements. Current space budget around $15B per year. The new policy should try to work within or close to this limit to be viable in the long term. Need to make tough decisions: close down Space Shuttle, slowly pull out of ISS. This way all funding can be directed towards exploration missions.
- In the near term, development of crew exploration vehicle (first spiral). First flight with crew in 2014. This would be followed by later spirals of development the details of which will be modulated by the outcome of the previous spirals.
- The innovation model for NASA is to develop new concepts as well as new technologies, with more focus on new technologies, but must still keep innovation as a goal.
Lots of budget talk that I would do a horrible job of writing up.
- In 60s, lunar mission cost $4-5B. In the 80s, more reusable technology, lots of infrastructure, still very expensive. Today to go to the moon we would probably redo Apollo with some corrections for new technology. Now we have to develop something sustainable for the new space vision.
- Need to work on margins and redundancy, reusability, modularity, autonomy, long term human presence in deep space, in-space assembly, reconfigurability, robotic networks, affordable logistics pre-positioning, energy-rich systems and missions, space resource utilization, data-rich virtual presence, access to surface targets.
- Conclusion: New technology is critical for space activity. Will go on for years to come.
- Will talk about nanotubes and how they will apply to SE, not nanotube SE.
- Why develop CNT composites? Useful in a lot of other areas. Promise of multifunctional materials (strength, thermal and electrical conductivity).
- 150-200 GPa being measured for individual nanotubes. Need good stress transfer to make a strong fiber. Alignment of nanotubes is critical. Defects have to be eliminated for the fiber (as strong as weakest link).
- Nanotubes have high surface area compared with carbon fibers, how can we use this?
- Can bond to CNT with van der Waals forces. But forces may be too weak. Covalent bonding is possible; stronger, but risk of weakening nanotube.
- Shi's group is activating/etching MWNT surface. Then deposits polystyrene on the nanotube. Got improved material properties.
- Shadler's group. Does carboxylation on the CNT to get functional sites on the side of the CNT. You can then bond larger molecules at those sites to get better adhesion to a matrix.
- He has been doing similar things, different polymers and functional groups.
- Fibers with 20% CNT by weight. Big problem is CNT sticking out at sides of fiber; causes week points.
- Baughman, 60% by weight of SWNT. 80 GPa modulus. 1.5 GPa strength.
- Kumar. 1 to 10% nanotubes. Sees increased modulus, toughness, strength. Put nanotubes into PBO. 3.5 GPa. Now being used in applications.
- Conclusion: Nanotubes are strong enough. Should allow 100 GPa composites. Still many challenges to get the composites made, but things are going fast.
- Question about conductivity vs. strength. Both don't necessarily go together.
Monte Davis adds: alignment of fibers should be within 5% -- beyond that, stress generates new defects. Conductivity *does* go up with strength in "traditional" carbon fiber, but may be uncorrelated or even inversely correlated in CNTs.
- Proposes 10 micron fibers, with about 10 micron fiber spacing. Coated with metal or some composite.
- So far they are considering the 0 to 1000 km altitude range. Ribbon cm to m wide, crescent shape. Made of a single row of fibers.
- Threat: Atomic Oxygen. Depending on binder material, fiber could be eaten away in a matter of days. Coating can improve this by orders of magnitude. Considering SiO2, Metals (Al, Ni, Au), CNT.
- Threat: Debris from 200-1000 km. Used ORDEM2000 model for impact statistics. Quotes a 0.2% chance of severing probability. Will have to check paper to see what this number means. Trying different ribbon structures to try to improve this probability.
- Talking about varying fiber diameter with altitude to optimize for various threats.
- They are doing quite a bit of simulation, having problems with necessary computation power.
Monte Davis adds: atomic oxygen concentration peaks at 80-120 km
- Will be talking about production and processing of fibers.
- Many methods to make nanotubes. CVD is most popular. Typical result is a highly tangled aggregate of CNT. Post-processing needed to make fibers. He is going to show a continuous process to make CNT fibers.
- Inject Ferrocene, Thiophene into H2 stream. Run through a furnace. End up with strands of CNT in the furnace. Produces a "sock" of CNT at exit of vertical furnace.
- Added winding mechanism to avoid the "sock" bunching up and cutting off the gas flow through the furnace.
- Diameter of fiber is not consistent. Length of fibers is limited.
- Can twist fibers together to make ropes.
- Making coatings by spin coating objects.
- Can select between single and multi wall nanotubes by varying temperature and composition.
- To get good spinning need oxygen containing molecules in the composition.
- Different composition gives different tensile strength / extension to break properties. So far goes up to about 1 GPa.
Monte Davis adds: we get large variations in spun-fiber diameter, length and mechanical properties -- but old hands in the business tell us that's quite typical for experimental fiber
- Ground based laser powering for first elevator commonly accepted. Could solar power be used later on?
- Can space based solar power be used for powering climbers?
- Where: GEO? Easy to locate hardware there, but can't beam to climbers at all heights. Power needs to be beamed further than from the ground. At the counterweight? Centrifugal force means a lot of structure would be needed.
- Need 2.4 MW to each climber.
- If power beaming from space, need very high reliability. Radiation there means operation has to be autonomous.
- After considering a bit, beaming from space is a bad idea for Earth, but might be a good idea for a Mars elevator.
- Presented concept for Mars elevator. Uses concentrated solar power. Big advantage is that you do not need to have support infrastructure on the ground.
- Explained elements of typical free electron laser. Cost around $500M. Design completed, would take 5 years to build.
- At 0.84 microns, there is a transmission window for the atmosphere that corresponds to high efficiency for GaAs "solar" cell.
- Need compensated adaptive optics to get high intensity of beam once it has travelled through the atmosphere.
- Need to maintain beam diameter on solar cell when the climber climbs. Change radius of primary focussing mirror with altitude.
- Need 15m telescope to get necessary focussing.
Monte Davis adds: ideally, adaptive optics should be able to get 96% of FEL output power through the atmosphere
My talk went great!
- With 63 GPa and 1300 kg/m3 an untapered tether is possible.
- With a stonger ribbon, an inverse taper (wider at the bottom) is possible.
- Concept: Use an inverse taper during deployment: add gradually wider ribbon at the bottom, let the previous ribbon lift the new ribbon into place.
Steven Patamia, Analytic Model of Real-Time Large-Scale Elastic Dynamics of a Single-Cable Space Elevator
- Will present analytic method. Will give example of solar event. Tension assumed constant. Fixed at Earth end. No damping. Highly conductive tether.
- Only transverse vibrations considered. Only large scale forces and responses (100th of length of cable).
- Linear wave equation.
- Transfer function approach; spatial and time.
- Expands into normal modes.
- Will take example of solar storm event to test the model.
- Large amounts of power involved (compare with locomotive)
- Optimizes mass lifted per unit time
Great talk, I was paying too much attention and forgot the notes.
Monte Davis adds: 20-ton climber at 100m/sec: near earth, that's 20 MW or four locomotives' worth Can't dump waste heat into ribbon -- contact area too small and transient Why climb the ribbon at all? Consider a continuous feed of ribbon from the base, pulled out by centrifugal force -- high ribbon consumption, but you get *all* your lift energy -- altitude as well as orbit velocity -- from the angular momentum of the earth-SE system.
- Electrical properties depend a lot on how the ribbon is made.
- CNT can be conductive/semiconductive. Comparable to copper possible.
- Matrix not conductive.
- Final composite: your guess is as good as mine.
- Causes of electrical phenomena. Ionosphere/storm clouds.
- Ionosphere, current flow along ribbon is additional path to ground. Equatorial electrojet interaction. Triple-point effects when climber passes through ionosphere.
- Resistance is function of resistivity. Estimate ribbon equilibrium temperature.
- AIAA has a technical committee that deals with tethers.
- Space tethers have been flown before. As early as Gemini 11.
- Technical committee was created to promote tethers, which are currently not being pursued enough.
- Detailed nomination requirements to be on the committee.
- People on committees: Brian Gilchrist, Rob Hoyt, Enrico Lorenzini, Sven BilÚn, ...
- NASA will organize prizes to stimulate innovation and competition in space exploration areas.
- Goal is for competitors to spend the money, rather than the government.
- Will stimulate public.
- Need to tie back to NASA goals.
- Challenges involving tethers are high on the lists.
- Looking for help to select goals.
- We need a very strong ribbon that can additionally be bonded in space. This is a tough requirement. For good quality you need very repeatable process conditions. This is not the case in space.
- Replace continuous ribbon with a modular structure and mechanical connectors.
- Attaching segments of ribbon together can be done effectively without any quality problems.
- Have about 100 km lengths of ribbon. Can replace any one of them individually.
- Explained neat replacement method.
- Could start SE construction in low earth orbit, deploy ribbon upwards.
- Would require thrust at the top of the ribbon.
- Orbital period would start at 90 min and gradually lengthen as CG rises.
- Keeps most activity in low orbit, below the radiation belts.
Cool talk, he's clearly done his homework.
Marvin Bumgardner, Analysis of Forces and Environmental Conditions in the Operating Regions of the Space Elevator
- Look at wind loading. For 8cmx10umx1km ribbon segment. Conclude it is not a problem. Model is simplistic, though; in particular no dynamic considerations.
- Atomic oxygen: data from NASA MSIS-E90 model. Maximum effect around 100km. 150 to 300 microns per month erosion for a couple of polymers. For metals, the situation is much better.
- Ribbon must account for wind loading, because geometry makes big changes to wind load. Must take atomic oxygen into account.
- About 9000 big chunks. 500 are active satellites.
- Surveillance network: Space Control Center, Space Surveillance Network, GEODs, ...
- SSN does spot checks to make sure that satellite is where it is expected. It has happened that satellites have been lost. Must be careful because a re-entering satellite look like an ICBM re-entering.
- Showed example of a phased array radar. Can track 200 targets at a time up to 35000 (??) miles.
- SE control center will need access to all existing tracking facilities + new facility to extend detection down to 1cm range (object size).
- Possible solutions to "intersection" between satellite and SE: move SE, move the satellite, deorbit obsolete satellites, widen/twist the ribbon, zap the junk.
- Future work: work more on collision models.
- Did study to assess orbital debris problem between 200 and 2000 km.
- Various experiments have been run.
- Used ORDEM2000 code to determine debris flux on elevator.
- Showed a bunch of plots.
- At 10 to 100um particle sizes, appear to be collisions on the order of once a day per square meter of ribbon.
- Talked about the Space Foundation
- Challenges: Funding, for related work and specific SE work.
- Regulatory problems: insurance and law, ownership, (...)
- Many federal agencies will have to be involved in this project.
- How do you make this project international without having the ISS effect? How do you go and convince people about it?
- Need to overcome the "giggle factor". A paradigm shift usually creates more enemies than friends (at least initially).
- Examples of paradigm shifts that were initially ridiculed: telephone, railroads, gasoline, heavier than air flying machines, landing on the moon.
- The SE has a solid foundation. Engineering, credible advocates, growing government interest, (...)
- Need to do: continue to build scientific case, identify credible articulate advocates, publicize, identify opportunities to get involved (national security policy, vision for space exploration, ...), begin to work on regulatory hurdles.
- Key stake holders need to be engaged early: congress, NASA, DoD and intelligence community, universities and other who design launch access, potential international customers and partners.
- Advocates need to be recruited to help impact the stake holders.
- Get good information into the stake holders' hands.
- The media has been picking up the SE as a story. This is a great thing. In particular, stake holders who do research will find that the space elevator is a well accepted concept.
- Conclusion: Progress being made. Try to move the space elevator to mainstream policy making process. Prepare for attacks once the "giggle factor" dies off. Engage the public interest through the media.
Monte Davis adds: Bush's Moon/Mars proposal represents good news (openness to big initiatives in space) and bad news (decision makers may not be open to your alternate/competing big initiative). Get good information into the stake holders' hands... and get *samples* of best current ribbon candidates into their hands.
- There won't be a space elevator until there is a market to support it.
- Freight is the way to go initially.
- Top ten keys to Space Transportation: The SunSat Act (make a congressionally appointed company to develop solar satellites), (...), SpaceX, X-Prize, lunar development authority, commercial satellite market, personnel space travel; moon, mars and beyond; telepresence.
- Long talk about the effect of increased CO2 production. More than a dozen slides about its effects. I think I know what makes this guy tick now! The nice countryside background for the slides made me suspicious from the very start.
This talk was done with James over the phone.
- Biggest challenge for Bush's space policy is political. Political sustainability is critical. Has to survive multiple presidency, congresses and generation.
- For Space Elevator, the same stumbling blocks apply.
- The political frame is critical to the success of a project. Need a political frame that will easy get over to the public.
- Wrong frames for the space elevator: glamour of manned space exploration, the public that is captivated by this frame is already captivated, will not move the persuadable skeptics.
- Proposes a better political frame: new energy supplies, better intelligence gathering capability, better defense capabilities. All this better, faster, cheaper.
- A good frame helps get existing institutions on board: government agencies, private interests, international collaborators.
- Do we need an Abraham Lincoln for the Space Elevator? No. The charismatic figure can sometimes add "noise" to the debate. Need spokespersons representing appealing political stereotypes.
- Summary: Daunting technical challenge, but political challenges may be bigger. Good political strategy will be essential for success.
- Many issues: overall design, drive system, durability, efficiency, mass, power system.
- Has been working on a non-functional model to get a better idea of the various issues. See how the components fit together.
- Jack Buffington won the climber competition in San Francisco. He is now constructing a more advanced climber for ISR.
- How do you keep the climber going straight up the ribbon (tracking)? Active or passive? Need to consider efficiency, mass, lifetime, wear of ribbon, contraction of ribbon (that is being detensioned as the climber passes).
- Have started to put together a passive tracking system. Have belt that can be driven at high speed, and doing experiments.
- Considering Belt/Pressure plate system for driving the ribbon through the climber.
- Microwave guide power system being kicked around. Possibility of using ribbon as a waveguide, flat or tubular. Only becomes efficient as of tens of meters in size.
- Question: have people in the auto industry been questioned about experience with treads/belts. Looks like not many contacts yet, but this is planned.
Monte Davis adds: in climber design, "everything is exponentially dependent on everything else". [my comment: CNTs may tame the ugly exponential of the thickness and taper ratio... once built, the SE removes the ugly exponential of the rocket equation... and Brad's done a great job with the bonded-tape "bootstrap" method, but ugly exponentials keep trying to sneak back in with every extra pound, kW, or day of construction time on the initial "spider" climbers as we see here]
- Goal: design 230 construction climbers to build up the ribbon.
- Objections to Brad's design. Need to have a pressure plate if you are going to use a belt drive system. Worried about making drive belt that will survive over the whole length of the ribbon.
- Proposing pairs of wheels. Metal will not have durability issues.
- How can you increase the top speed of the climber?
- Fatigue is a major issue. A 20 inch diameter wheel needs to rotate almost 63 million times to get to the top of the elevator! Smaller wheel, more revolutions.
- The traction comes from squeezing wheels. The more you squeeze, the more you will be fatiguing them.
- Considered two failure modes: cracking of a wheel axle and rolling fatigue. Difficult because all the industry fatigue analysis is done for 50% confidence of failure. We need near 100% reliability!
- Assumed coefficient of friction of 0.1. Need a force of about 5 tons on the wheels.
- Larger wheels reduce contact stresses for fatigue. (...)
- Did FEA on a proposed wheel design. Found one bad and one good design.
- Developed CAD model of the climber. Nice pictures. Shows the wheel compression mechanism. A spring stack forces the wheel against the ribbon. Can actively control tracking of climber by varying forces on either side of the wheel.
- Mass budgets for two different choices of motors. Ends up with about 3 times too much mass.
- Conclusion. Mass of design too high, and needs to be made space worthy. Many components still need design. Friction between wheels and ribbon is the key issue. Fatigue is a killer issue requiring a lot of analysis.
Monte Davis adds: Steel is a "magic metal" for fatigue resistance. It heals microcracks in use, so for many purposes you can assume infinite lifetime. BUT-- it's heavy, so you think of lighter non-ferrous metals. No one has ever asked non-ferrous metal rollers to turn that often, so no fatigue data anywhere near our needs. Everything about the drive train depends sensitively on coefficient of friction
Gary Campbell, A Tropopause Way Station and a Mirror Solar Power System for the Climbers: A Refinement of the Space Elevator Concept.
- Over the past 20 years there have been some periods of convection in the proposed anchor location. Related to el Nino. Worst case was 6 months of cloudy conditions. This is a problem for the power beaming.
- Tropopause base station idea. Have a base station in the Tropopause, supported by buoyancy, not the ribbon.
- Various back of the envelope calculations. The speaker had not realized how heavy the laser would be.
- Considered solar power with a concentrator.
- Space radiation isn't present enough in the public awareness. Space is a very dangerous environment for people in fact.
- Presented basic radiation units, and gave orders of magnitude for biological hazard. Presented regulatory limits. Presented sources of space radiation.
- He will mostly talk about radiation existing in Earth's magnetosphere. Presented various plots of radiation levels for protons and electrons at various energies.
- An aluminum shield would need to be about 20 cm thick.
- Speeding up doesn't help much, unless very fast (like the Apollo astronauts, who got doses of .5 to 1.5 Rads).
- Magnetic shielding would take about 7 MA. Maybe with superconductors?
Didn't take very good notes here, but the bottom line is that this is a massive issue for the transport of humans.
Monte Davis adds: so far only 21 Moon-bound astronauts have passed through the Van Allen belts -- and they were going 36,000 kph ( <30 min. exposure). If SE is going 200 kph, exposure becomes very serious. Very rough calculations suggest SE occupant going to GEO would need 10-12 INCHES of aluminum to keep whole-body dose down to Apollo astronaut levels.
- STP owns the spare capacity on all Air Force space launches.
- To get DoD support to fly an experiment in space, need: show military relevance, have a sponsor (who does not have to supply funding). Then you get into the competitive selection process.
My talk went great!
- ISR has six tasks. Systems engineering, high strength materials, ribbon dynamics, ribbon design, prototype climber, distribution of results.
- Systems engineering. Full list of trade-offs. Full interconnection analysis of system. System of systems approach. Formally address Pre-phase A and phase A requirements.
- Ribbon design. What cross-sections at what altitudes?
- Considering disk-laser, solid state laser system for power beaming.
- Working with Marshall to get independent cost analysis, technology readiness level analysis, CNT research and space environment research.
- Trying to fit into NASA's new space exploration program. The timeline and requirements are suitable.
Monte Davis adds: "Current Status...": pushing hard for 10-20 GPa in bulk in 2005 Risks of "analysis inertia": so many dependencies that you may stop looking at innovation because its effects would ripple too far
- Systems engineering is a disciplined way to understand complex systems. Efficient way to design and manage the fabrication process. Spread misery evenly across different parts of project. Owns the error budget.
- Gave example of systems design: nanotubes, deployment scenario, space segment, climber technology.
Michael Laine asked a question about whether a speaker from the previous conference had had some results. It transpires that there seems to be a breakthrough, but it won't be public for a few months. Intriguing...
- "Engineering" covers the design.
- "Architecture" includes the "squishy stuff": licensing, finances, environmental impact, safety, etc.
- Mega project: more than 10 years, more than $1B. Need to have the big picture.
- Some examples of mega-projects. ISS, Commanche Helicopter, Akeshi bridge, Big Dig, lots of others.
- The SE needs some common standards - for example, to accommodate multiple suppliers of climbers.
I have trouble doing justice to these architectural talks in my notes; they make me zone out...
- Information without order is chaos. Seek is there to impose some order.
- Need to distribute information because the workforce is distributed. Need to focus on collaboration between all these people. Data gradually made available to the public.
- Will use MS Access and MS Project, as well as DORS (Telelogic) to keep track of system requirements.
Laura Pullum, Resolving Cognitive Conflict During the Technology Development Process for the Space Elevator
- Systems engineering has to be able to extract individuals knowledge and synthesize to get best solution. Individuals don't have same goals as overall project.
Monte Davis adds: Get those responsible for various subsystems to agree on relative priorities: difficult, but vital
- Scalability and leverage are vital to getting economics of scale.
- With the SE, we have mass production of climbers / ribbon. We have continuous production. We have dispersed work overhead. Low cost energy.
- SE is only system for access to space with economics of scale and leverage.
Monte Davis adds: one vivid example of scalability + leverage: adding two 200-ton SEs gives you 200x the cargo capacity of initial 20-ton SE for only 2.67 times the investment
- Requirements for SPS to deliver 1 GW to the power grid? Assume there is a SE, consider solar cell technology, launch costs, construction schedules, power beaming, transportation, land costs, lack of power storage. Amortize costs to get a net positive income.
- Considering optical rectenna, thick film and thin film photovoltaics.
- Combined the various technologies he liked best from the conference and presented his favorite space elevator version.
- Some thoughts on economics of space elevator.
- The only problem with the elevator is the name. Names really matter. Elevator does not inspire respect.
- Elevator reminds of: Elevator shoes, Charlie and the great glass elevator, uninspiring, don't have names...
- Need an alternative. Link to inspiring transport projects, indicate the profound nature of the project, indicate it will be reliable, indicate it will be scalable and high volume.
- His choices: space bridge, space way, space rail. Asked for contributions from the audience. I think space bridge won.
Check out http://www.healthspace.ca/spacebridge/danglingparticiple for his blog.
- Comment on how space elevator like concepts appear to the popular imagination (tower of babel, jack and the beanstalk).
- The SE would be sweeping in and out of the solar wind, could be used to measure.
- SE dedicated to science. Could instrument a length of it, could buy a new or used elevator.
- Unique linear geometry allows measurements that are impossible with other means.
- Troposphere. Could measure temperature, pressure, wind, humidity, composition, ...
- Stratosphere. Same measurements plus ionization level. Monitor mixing layer height of the atmosphere.
- Mesosphere. Unreachable by research balloons except lowest part. Can measure temperature, pressure, degree of ionization, compositional makeup, ...
- Thermosphere. Start to make more plasma-like measurements.
- Magnetosphere. Same measurements.
- Would be nice to have these measurements before building the SE, because many of these things are hazards to the elevator...
- Conclusion: SE would be useful for in-situ measurement of earth environment.
- Brad commented that biology experiments could be done at all kinds of microgravity levels on a SE.
- The elevator is a surprise to the world. This is not an imitation of nature, there are no small scale versions. Idea is counter-intuitive.
- The elevator has not appeared often even in science fiction - e.g. the Borg don't have one.
- A ribbon demonstration is necessary. The public has to believe that really strong ribbons exist.
- The campaign. It will not be centrally planned or coordinated. Many different audiences. General population, politicians, lawyers, venture capitalists, science savvy.
- Educating the general public. Showing how it works is not easy. Need a 30 minute infomercial narrated by an appropriate celebrity. Multiple languages and video formats.
- What needs to be presented: How it works, what are the rewards, ... Need to change from the usual order.
- Need to correct the gargantuan impression that science fiction has given. When the SE falls, it doesn't cause a big bang.
- For the SE to be successful, the public has to be educated. As important as getting the right CNT material.
Great talk, full of insight, easy to follow and well presented.
- Need to test space elevator technology before we build the real thing. Existing cable cars have limitations due to material and geometry of cable. Looks like a good place to use SE ribbons before the SE is built.
- Suggested name: "ribbon rider".
- SE is a tempting target for terrorists.
- Define various defense radii.
- Space-Borne Attack. Considered a whole bunch of scenarios. Too many to fit readably on a slide.
- Air-based Attacks.
- Sea Surface Attacks.
- Sub-sea Surface Attacks.
- Delivery/Platform Infiltration.
- Payload Tampering (Bomb or tracking device to guide other attack).
- Discussion of asbestos history: insurance, government regulation. For CNT that history has yet to begin. No data, no regulations, no standards, etc.
- Asbestos exposure. Primary source (millers and miners), secondary source (industrial and commercial use of asbestos), tertiary source (environmental or para environmental).
- Particle sizes. Nano (<100 nm), fine (.1 to 3 um), respirable (<3um for a rat, <5um for humans), inhalable (10 to 20 um for humans).
- Will consider effects both on environment and on lab workers.
- Quick poll of people in the room who have been handling CNT and whether they were taking precautions. Be careful, we don't know the hazards yet.
- Public health worries about risk to the general public, then to the environment, and only then to the lab researcher. It is really up to the lab researcher to protect himself.
- Need to build the ribbon so that it is non-toxic, but first need to study the risks so that we have a basis to design from. In the mean time lab workers should take precautions.
- Currently we have no evidence for how fibers this small will behave in the body. We do know that if they look like asbestos, they will probably cause the same problems.
- Some good news: not easy to aerosolize, slippery so may not stick to skin.
- Better to design a ribbon that will fall in gram size chunks to avoid approaching asbestos sized pieces.
- Experiments on Bass have shown brain damage when exposed to CNT. Are aquatic systems more susceptible than land ones? Need to know BEFORE we build the elevator.
- The natural environment already has some C60 and nanotubes, generated by forest fires.
- Summary: we don't know much. This is pretty normal. Cause for concern: Bass brains and Rat lungs don't seem to like CNTs. We don't want to make things asbestos like.
- Nanoscale mechanical process to make nanotubes. Intends to use macroscopic rollers with nano-scaled features. Cookie cut a graphene sheet and roll up into nanotubes.
- This is a simple process that will make the SE possible.
- First step: form graphene sheet material. Deposit on mylar sheet.
- Second step: use cutter rollers to cut the graphene sheet. Can even control chirality. Roll up the strips into nanotube. Because of the dangling bonds, will form up into nanotubes spontaneously.
Looks really cool, but I see a lot of hurdles to feasibility. I asked the guy a bunch of questions at the end, but didn't get enough data to determine whether this has been studied well enough or not.
Panel made up of Brad Edwards, Tom Rogers, Robert Sackheim, Donna Shirley, Paul Spudis, George Whitesides.
- He has a unique perspective on the SE. He got involved 5 or 6 years ago. Started looking at the problem when he read that it had been deemed impossible. Was lucky that NIAC decided to fund his proposal. Good short term opportunity. Didn't expect this size conference to happen so soon. Didn't expect how much CNT would evolve. Didn't expect the media blitz; he hasn't put any effort into promotion, the press coverage just happens. He gets lots of email. For example "if God had wanted us to get into space, he would have laid a path for us" or "alien bacteria will climb down the elevator". Others say "thank you" or "this is incredible, how can I help". He talks about it to children, gets through 3 slides and is stopped by the barrage of questions.
- He is going to tell us about how to get the money. The commercialization of space should be the number one goal of the space exploration program. The space elevator needs money, it has to be a part of the exploration program.
- Constituency is a critical word. Not used enough in the civil space area. Space is not high on the list of top priorities for the general public. Space elevator proponents have to fight to increase the constituency for the civil space program.
- Markets. The SE is targeting low cost, and need to target very large markets. Other than GPS, telecom and intelligence, what is there? Need to work as much on developing markets as on the technology. Space solar power is a candidate, but too expensive and too much vested interest in the older methods. Space tourism is another great example. Opening markets would also increase the constituency. Telecom industry is currently bringing in $100B per year. The taxes on this alone covers the current NASA budget.
- He represents the National Space Society. Is going to say how he can help us and what strategies we may want to adopt.
- The NSS can help get its members excited about space.
- There is a lot of press coverage of SE, but there was coverage of space tourism in the 60s. How do we use the press?
- Need to accumulate intellectual property to attract private investors.
- High risk usually requires government investment. Politics is a huge issue here.
- Has just opened the Science Fiction Museum in Seattle.
- The new space vision sucks because it is being done by NASA.
Did a poll of how many people in the room are related to NASA projects. Only 3 or 4 were.
- She doesn't trust infrastructure, at least not public infrastructure.
- Took example of Paul Allen as possible funder.
- Small window of time before baby boomers retiring take up all our resources.
- Need to involve rich guys. Willing to take more risk than most people.
- The pubic isn't as important as Bob Munck thinks.
Missed the first few minutes.
- Goal of Bush's vision is to create a robust space-faring ability.
- Currently everything in the space program is a one-time thing. The space vision wants to start building up, creating wealth. Bush wants to use space resources.
- Moon is important stepping stone for resources. We don't want to be lifting fuel from the Earth, we want to be getting it wherever we need it.
- Don't lift solar arrays to the moon, make them on the Moon with Moon resources.
- Bush wants to industrialize space.
- Humanity is doomed if it remains stuck on Earth. Sooner or later a meteor large enough to kill us will hit. We need to have people in many places so that we can go on.
- Space vision was thought up by considering what could be done with slightly augmented current budget.
- In polls, public is split 50-50 on space. Not a sign of unpopularity, a sign of indifference. Need to change that indifference. Shouldn't screw up too often, shouldn't cost too much.
- Bryan Laubscher: Is the DoD a good source of research money? Response (Tom): SE is fully useable launch vehicle. Isn't this exactly what everybody wants? People in defense DO consider dollars. (Robert) Won't happen without the DoD.
- ??: Space did not start without the military. This statement is wrong. Was started by Goddard and space society. First applications were also civilian (mail). No individual can afford a Mars mission. Moon is a great test bed. A lot of the problems, but not as tough.
- Andy Price: There are long term reasons to get into space. But how do we, today, fund the nanotube research so that we can get the materials we need? Answer (Donna): DoD has more money than NASA. NSF is real hot on nanotech. (Brad) Upcoming NASA BAA has a materials section. (George) Centennial challenge program is a great way to get attention. Need to lobby NASA for a prize in nanotubes. (Robert) Materials are critical in any space endeavor. It is the enabling capability. University is a good place to look. (Donna) Worried that NASA will not use results of prizes. (Tom) Markets, markets, markets, markets, markets!! Wall street doesn't know what to do with all its money. When Boeing wants to make a new airplane, they ask the airlines. We need to start wondering about all the questions beyond the engineering. Need a spaceline company. They will know what the customers want, they will be able to coordinate money. Markets, markets, markets. (Brad, joking) Next conference will be at Wall Street. (Robert) If there is a market, people will find it.
- Bob Munck: The general public may not matter, but 1% of the public is 1M people. And 1M people is a huge political force.
- Jonathan Kruzel: Aldridge commission not very specific, but stated that heavy lift was important. Seems contradictory with SE. Answer: (Paul) Not contradictory. For next 10 years, all we have is rockets, and in that period, we do need the heavy launch capacity. (Robert) Agrees.
- Jerome Pearson: Really wants to see the project succeed. Moon might be easier environment. Would be a good test bed. Could work with much weaker ribbon material.
- Eric Westling: The elevator has a number of consumables. Can we win the industry over to our side by telling them they will be able to make money building those. (...)
- ?? (organizing the 2010 SE challenge): How does she collaborate with NASA for the prize without loosing control to NASA's other agendas? (Donna) Keep control of your project! (Tom) SE is great for NASA because it enables things they can't do so far. The X-Prize competitors will be rewriting the books on space because they are independent. Need to start thinking about true economic business independence.
- Michael Laine: Appreciates the fact that panel is very pro commercialization. Donna, what do you think about markets markets markets markets? How to contact people like Paul Allen? (Donna) SpaceShip 1 launch good opportunity to get them together. They don't tend to clump together.