Category Archives: Conferences

Space Horizons 2017 — Destination: Alpha Centauri

“Space is caffeine for learning.” A.C. Clarke

Space Horizons 2017 — Destination: Alpha Centauri was held February 15th and 16th at Brown University in Providence, Rhode Island. The annual Space Horizons conference covers almost-ready-for-flight space topics. The subject  was centered around sending swarms of tiny, postage-stamp sized spacecraft to our nearest neighboring star systems.

This report includes a general proposed architecture, the workshop schedule, some take-away observations and my initial design research output from the lunchtime poster session.

As always, Professor Rick Fleeter (Brown/La Sapienza) organized the workshop, this year with student lead Kat Pisani. The format varies some years, but this year it followed the pattern of a Wednesday early-arrivals talks followed by an intense, all-day workshop on Thursday consisting of panel discussions, talks by professionals and . The official website is  https://spacehorizons2017.wordpress.com/


General Proposed Architecture

Destination: Alpha Centauri examined proposals, research and funding to develop and fly swarms of postage-stamp sized spacecraft called WaferSats or ChipSats at relativistic speeds (0.3c is commonly cited) to the Alpha or Proxima Centauri (Rigel Kentauri) star systems. Rigel Kentauri is the current most-interesting target due being the closest star to our own Sun and confirmed to have planets.

Generally, a large phased-array laser Directed Energy (DE) cluster in the 100-300MW power range would be installed on the lunar Farside in such a way that it can’t ever face Earth or our geosynchronous satellites. The propulsion laser is automatically going to be perceived as a “weapon” so it needs to be emplaced cautiously for policy purposes. The laser array boosts each individual WaferSat to 30% light speed (.3c) in ten minutes and can propel about 40,000 chips per year in a continuous stream that extends between the stars. The result, in theory, is a massive, low resolution, interferometer stretching across several lightyears that contains the needed sensors to image planets and moons in the star system(s) they pass through. At .3c the WaferSats require about 20 years transit time to fly by the closest target stars.

Additional uses for the laser propulsion system include power transfer to other spacecraft as part of a space-based beamed-power network and for boosting much heavier payloads like crewed capsules. A 1-gram WaferSat can achieve .3c, a 10-ton capsule can be accelerated to get to Mars in a few weeks instead of six months, using the same system. Professor Fleeter describes this as, “The opposite of missions is infrastructure.” The technology advances could include in fiber laser amplifiers for photonics applications and system-on-a-chip devices for everything from aerospace to medicine to environmental monitoring. “There’s a lot to be done along the way and the more it has other uses the better.” according to Jordin Kare.

The teams working on various aspects of this include The Breakthrough Foundation, Dr. Lubin’s Experimental Cosmology Group at UCSB, Dr. Cahoy from MIT’s StarLab and LaserMotive, among others. Breakthrough has a budget of $100,000,000 dollars in overall funding between Starshot, Listen and their other space projects. This massive injection of private capital is important as it circumvents any protesting over government funding plus they award prizes to researchers doing useful work. UCSB’s Phil Lubin is developing WaferSat spacecraft and the phased-array lasers to drive them. Dr. Cahoy models communication systems at light-year distances and poses questions such as “How many photons do you need to form a bit?”. Jordin Kare of LaserMotive is turning his work on space elevators and laser-powered quadcopter drones toward the practical aspects of launching these relativistic WaferSats.

Other proposed technology paths and questions include using a diamond-wafer particle accelerator or other particle beam instead of lasers, using larger CubeSat-scale craft and whether each chip should communicate with Earth directly or intercommunicate in the swarm first.

Two Wafersat Prototypes, courtesy Phil Lubin, UCSB Experimental Cosmology Group. It’s not every day that you get to hold two space probes in one hand. These are flight-ready prototypes, Lubin’s lab continues to refine the devices and laser propulsion.

The schedule

  • Wednesday February 15
  • Michael Walthemathe, Ruhr-Universität Bochum, on importance of extending human reach beyond the solar system
  • Phil Lubin, UC Santa Barbara, on progress toward realizing interstellar missions
  • Thursday, February 16
  • Larry Larson: Welcome
  • Rick Fleeter : Introduction to Space Horizons
  • Pete Klupar: 2017 Keynote Address
  • Jim Head: The Science Imperative
  • Philip Lubin: ChipSat and laser propulsion
  • Ruslan Belikov (NASA Ames), Gregory Tucker (Brown University), Pete Klupar (Breakthrough Foundation) and Emily Gilbert (University of Chicago) on: The value of going to Alpha Centauri plus remote observation from near Earth
  • Panel: Going There vs. Observing From Here
  • Lunch and student posters
  • Kerri Cahoy: Communication link from a low power chipsat 4+ light years away
  • Zachary Manchester: Flying ChipSats
  • Jordin Kare: Separating Power Source and Vehicle
  • Michael Walthemathe: engaging society in exploration
  • Panel: Societal impact of interstellar exploration

Observations

“Low reliability ideas, high reliability hardware.” – Rick Fleeter

Professor Fleeter pointed out that there are thousands of ideas about what to do in space but only a few of which ever actually fly. This appears to scale with the extreme reliability of space hardware.

The main point of the workshop was that we could do this right now but some components are to expensive for it to be practical. A few more years and some developments in manipulating laser light and it will be affordable. This could create the next leg of a transportation network for developing our solar system while exploring neighbors like Rigel Kentauri. Such a DE array could help build massive space telescopes and provide a range of technical advances to any industry that uses lasers. The people developing the first trip to the stars are clearly focused on the technical and economic journey and it’s inspirational potential more than a single end goal. The amount of time, money and careers going into this project require long-term thinking.

Some combination of ChipSat swarms and phased-array laser clusters are probably the best way to fly. Separating thrust from craft is probably essential as Dr. Lubin had a presentation that showed how getting matter to relativistic velocities requires propulsion with relativistic exhaust velocities. This mostly excludes putative fusion drives and leaves only antimatter and Directed Energy as propulsion source candidates.

Example of COTS in this type of research. This 19-element phased-array laser uses standard DSLR camera lenses to provide focus for fiber-optic lasers. Courtesy, DeepSpace Lab at UCSB, J. Madajian and A. Cohen.

Much of the focus is on commercial-off-the-shelf hardware (COTS). For example, Dr. Lubin’s test arrays use standard DSLR camera lenses hooked up to fiber optic lasers. One issue made clear by all the researchers involved is that fiber laser amplifiers need to become much cheaper for Destination: Alpha Centauri to make economic sense. A goal of $1 or less per watt seems achievable, Dr. Cahoy pointed out that the fiber amplifier in a DVD drive costs about ¢.10 for the 1-watt element. Mass-produced, space-rated fiber amps should be able to be priced within an order of magnitude if enough are being made.

At Space Horizons 2016, Dr. Phil Metzger presented an idea of a boot-strap outer space industrial economy of self-replicating machines. At first, they just make low-efficiency solar panels or other simple objects. Over the course of several decades, the machines create an exponentially increasing industrial base. This topic came up separately this year as a way to enable interstellar flights through automated manufacturing and assembly.

Directed Energy boost creates in-system superhighways for nearby payloads to Mars and other destinations. DE may turn out to be a preferred means of propulsion, electricity and process heat for future inner solar system development, especially of Mars and Lunar craters.

A potential research point I’d like to see addressed before hardware is completely specified is whether microwaves, specifically in the 2.45 and 5.8 GHz ranges, can achieve similar results to a laser array. This would be specifically for integration in a putative Space-based Solar Power (SBSP) demonstration network.

Wafersats might be able to be propelled by a demonstration-level Solar Power Satellite (SPS) in Earth Orbit. This would involve a 100-300 kW beam-forming microwave antenna, likely in polar orbit and powered by solar panels. An assessment should look at recent advances in phased-array microwave sandwiches and life cycle assessment of both systems as part of an integrated beamed-power system. The analysis would look at the trades between lasers as an end output of a power system whereas the SPS would be part of the power system. There should be an effort to include power-beaming in some form in whatever external propulsion system is developed.  One immediate issue is beam-focus and whether active beam-forming could address some of the concerns without also flying relativistic mirrors as proposed by Dr. Forward in Vulpetti, Matloff and Johnson (2008). Proposed microwave “sails” have footprints that are orders of magnitude larger than proposed light sails.

Development of the Wafersat system could potentially benefit from this sort of integration with a beamed power network beyond supplying a Farside laser array with electricity. The SPS satellites could potentially serve as a DE propulsion system that can’t work as a weapon.


Design Research Exercise: Technical & Social Imaginaries of Destination: Alpha Centauri

Instead of a poster, I ran a simple design research exercise during the lunchtime poster session. The exercise consisted of a SWOT Matrix and an I Like/I Wish/What If list. SWOT stands for Strengths, Weaknesses, Opportunities and Threats; it is a very fast and efficient method for dissecting an idea, situation or scenario. I Like/I Wish/What If is a technique utilized by Stanford’s D.School for team ideation. Participants filled out each section, then ranked all the entries with dot stickers to indicate what they thought were most important in each category.

Results:

The most important Strengths of the concept were the vision and inspiration it can provide for children, the infrastructure aspect of multi-use directed energy arrays and having that kind of high-energy laser technology for other applications.

The greatest Weaknesses cited include the very large upfront costs and the possibility of the laser location not being under US control, which was also cited as an opportunity.

Opportunities behind Destination: Alpha Centauri include routine, fast access to our own Solar System (again, infrastructure that plays many roles) especially “student ChipSats of infinite types”, technical spin-offs, public engagement and interstellar dating. Several allusions to social networking with aliens were made across the exercise but ranked low. Everyone involved seems to hope the project will help us find life or even intelligent, technical species but aren’t holding those hopes to high. The last opportunity that was ranked by another participant was the so-called Overview Effect, the change that people experience in seeing the world from space.

Threats cited include the perception of these tools as weapons and their potential to spark a space arms race and the loss of interest should the first project fail.

Participants Liked that the laser arrays would likely be a multi-use,  multi-party piece of infrastructure. One entry suggested piles of large, unmarked bills.

Participants Wished that there was a near-term and smaller scale space-based test “to start playing with photon delta-V”. This is in some ways an obvious stepping stone between laboratory benchtops and megawatt facilities on the Lunar Farside but is also the exact kind of policy nightmare regarding space-based weapons that no government would allow to fly, private mission or public. One unranked idea that was discussed elsewhere in the workshop was “brakes” of some kind at the destination star. As it is, the individual WaferSats pass through the target star system in a few hours traveling at relativistic speeds. The advantage to Dr. Lubin’s proposal is that thousands of these craft make that journey in a continuous mesh.

What If questions included “What if I could change the gravity constant” and whether there are aliens and how that would impact the project and our understanding of our place in the universe.

Complete dataset:

These process photos include the final results, two development pictures and one of researchers participating in the exercise. In my experience, space scientists and engineers are often surprised and excited when designers bring our research tools to help them analyze their chosen fields and projects.

Final data snapshot. Participants wrote ideas for each category then ranked all the ideas using dot stickers.
Wall test, any wall will do.
Initial slide of concept, shared with colleagues online for feedback.
Dr. Phil Lubin and Peter Klupar interacting with the exercise.

Space Horizons is always an interesting conference. Professor Fleeter knows all the interesting people in the space sector and brings a keen sense of understanding what is nearly possible and about to happen in space projects. This year’s topic was closing a circle as the first Space Horizons was about ChipSats when they were a completely new concept. Now the discussion isn’t whether ChipSats or Wafersats for Dr. Lubin’s team are possible but whether they are appropriate as our first interstellar emissaries.

Real action is happening on this right now at deepspace.UCSB.edu, Breakthrough Foundation, Lasermotive and other labs across the US. This concept, whether as StarShot or another team, presents enormous commercial and academic opportunities along with workforce development, youth inspiration and the potential of a new  “Earthrise” moment from 4 lightyears distant.

Apollo 8 Earthrise. Image courtesy, NASA.

References

  • Vulpetti, G., Johnson, L., & Matloff., G. L. (2008;2009;). Solar sails: A novel approach to interplanetary travel. New York, NY: Springer-Verlag. doi:10.1007/978-0-387-68500-7

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NAS: Integration of STEM, Arts and Humanities

Washington, DC – December 2, 2015, Carnegie Endowment for International Peace.

The National Academies of Sciences, Engineering and Medicine’s Board on Higher Education and Workforce hosted a one-day workshop on Integrating Education in the Arts and Humanities with Education in Science, Engineering, Technology and Medicine that included multiple members of the Alliance for Arts in Research Universities or A2RU. The workshop brought together members of government including the President of the National Endowment for the Humanities and congressional staff, academics from R1 and other research universities along with faculty, students and deans from a range of institutions.

The workshop was structured as an integrated design exercise with periods of small group discussion separated by lectures and panels.  Other sessions included a creative piece around the life of a young medical student, discussions on how employers see integrated education experiences especially companies like IBM and Oracle looking for “T-shaped professionals” and a structured brainstorming wrap-up. We would have been hosted at the NAS but instead were at the Carnegie Endowment because of an emergency meeting on CRISPR gene-editing technology which Ben Hurlbut of ASU provided an update on.

My role was as student on a panel hosted by Rick Vaz, Dean of Interdisciplinary and Global Studies at Worcester Polytechnic Institute (WPI). Others on the panel included graduate students, an undergrad in nuclear and mechanical engineering and a recent bio-medical technology student. We discussed the needs and experiences of students already doing the types of transdisciplinary research the workshop is interested in prescribing to universities across the US.

The workshop goal was to further refine what is sometimes called “STEM-to-STEAM” or how to make STEM education more effective and inclusive of the rest of the Academy. When John Maeda coined the term STEAM, he wanted the Arts and Design community to lead the way for the rest of the academy. He probably wanted to prevent what one participant at an A2RU conference in 2014 referred to as “Science with Stickers!” Academy would be a better A in STEAM. This specifically addresses the concerns of anthropologists, writers and library sciences professionals along with the arts by incorporating all aspects of a classical liberal education.

The interest seems to be in what Giard (2009) refers to as “delta knowledge” or Simon (1976) calls the “sciences of the artificial” in the making and embodied knowledge around making that can only be learned by doing. Simon goes on to describe “a science of the artificial will be closely akin to a science of engineering—but very different.” Giard specifically recommends the corporate partnership over the student design competitions or sponsored design projects as a solution for design students to develop this delta knowledge of doing. These are the roots of what is now called design thinking as well.

One specific avenue for integrated education is to have instructors and teaching assistants in crossing fields — a Literature TA can bring up the writing level of an engineering or graphic design class, for instance. Projects like InnovationSpace at ASU that bring together and cross-train students across multiple fields is another way to bring realistic teams together to work on these complex or “wicked  problems” according to Brown et al (2010). Wicked problems are ones that defy disciplinary and national boundaries such as access to clean air and water, protection from pandemics and war, etc. These problems require people trained to think, interact and do in comprehensive teams, not just know and perform a specific task.

A key contrast is that some schools, like Worcester Polytechnic Institute and Lafayette College, have been conducting integrated engineering  education since the 1970s with good results that run counter to the specialization proposed and largely implemented from the 1955 Grinter Report. Grinter was part of the Cold War focus on technicians solving fairly straightforward problems and represented what Miller (2015) refers to as a “sea change”. Compared to contemporary wicked problems, the industrial and military issues of logistics and throw-weight from the Cold War are simple. Some of those wicked problems are related to the shortsightedness of that time, too.  Despite issues around metrics and quantifying more versus less integration in education, there is a demand for it, especially at the high-end. Another sea change seems needed for American education to tackle world problems in the 21st Century.

Schools and programs of special attention from the literature provided for the workshop, primarily Stewart-Gambino (2015),  is ASU’s School of Arts, Media and Engineering (AME), along with Stanford’s CS+X, U Utah’s Entertainment Arts program and California Polytech San Luis Obispo’s Liberal Arts and Engineering program. Daniel (2015) specifically refers to AME as “gaining traction”.  Each of these has in some way reintegrated Arts and Humanities back into some form of STEM education.

Key Takeaways from the December 2 Workshop, adapted from organizer Thomas Rudin’s debriefing, Rudin, T. (personal communication, December 7, 2015)

  • Continue this conversation at all levels.
  • Measure the efficacy of STEM/Humanities/Arts integrated programs and curricula.
  • Develop recommendations for multiple audiences — colleges & universities, K-12 schools, government agencies, non-profit organizations, professional education and disciplinary associations, and others.
  • Preliminary educational results like InnovationSpace and top corporate hiring at IBM and Oracle suggest the value of these kind of  integrated education experiences. Systematic metrics need to be created to capture the value of these experiences.
  • There are enough model programs in higher education to suggest that educators believe this more holistic approach works. This means there are plenty of programs to measure and see what works.
  • A committee centered around the NAS is forming to organize recommendations.

Conclusion:

The workshop was a wonderful experience. It was great to see A2RU’s efforts fit with the National Academies’ needs around higher education and workforce development. The key take-away of the workshop pointed to a growing recognition of the need for students and future workers to have deep and broad skills that help them cross boundaries and stay flexible while solving 21st Century problems.

References:

Daniel, Alice, 2015, “Full STEAM ahead”, Prism, March-April 2015

Giard, J. (2005). Design FAQs. Arizona: Dorset Group.

Harris, J, Brown, Valerie A, Russell, J. (2010). Tackling Wicked Problems. Routledge.

Miller, R. (2015) Why the Hard Science of Engineering is No Longer Enough to Meet the 21st Century Challenges. Retrieved from:   http://www.olin.edu/sites/default/files/rebalancing_engineering_education_may_15.pdf

Simon, H. A. (1996). The sciences of the artificial. Cambridge, Mass: MIT Press.

Stewart-Gambino, H. and Rossmann, J. “Often Asserted, Rarely Measured: The Value of Integrating Humanities, STEM, and Arts in Undergraduate Learning.” National Academies of Sciences, Engineering and Medicine, 2015.

 

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Space Horizons 2016 – International City on the Moon

Above, RISD pedal-powered moon rover featuring 13 second deployment time and hand-made tweels.

Space Horizons 2016International City on the Moon was held February 19-21 at Brown University in Providence, Rhode Island. This year’s topic on building an international base on the Moon was approached as an iterative design workshop involving for separate but related tracks: Business & Technology, Politics, Science and Infrastructure.

Space Horizons is an annual conference founded by Professors Rick Fleeter and Ken Ramsley that focuses on near-term but still generative subjects around space with a special focus on relevant topics to students. Past years included Desktop Delta-V which focused on lab-safe propulsion for CubeSats, ChipSat focused on circuit board spacecraft and other topics.

In the past it has been a 1 1/2 day conference, this year was a three day workshop run by a student committee and hosting about 80 students and space professionals. It featured the usual faculty from Brown such as Jim Head, Rick Fleet and Alden Richards, a recorded video welcome from the Director General of the European Space Agency, and mentors including Jim Muncy, Olga Bannova, Phil Metzger, Brent Sherwood of JPL, German theologist Michael Waltemathe and others who generously donated their time and talent.

Unlike prior years when I have been the only designer involved, this year Professor Michael Lye along with industrial & graphic design students from RISD attended. The designers were critical in creating the dialogic system that enabled rapid iteration across a wide range of subjects that all need to be synthesized for this kind of space project or the workshop itself to happen. The design-thinking techniques employed are based around IDEO practices and include How Might We, the 7 rules of brainstorming, affinity diagramming and others. Two ASU students, myself and Chad Stewart (Aero, ’16) were in attendance.

The workshop was structured around having multiple small teams inside each track performing separate ideation and fact-finding while periodically rotating around the room to critique and confer. Teams fluctuated on Saturday as participants somewhat self-selected. Friday afternoon the professional mentors set the stage with a series of talks, Saturday was the main workshop and on

Sunday the ~20 teams presented along with more lectures including Dr. Bannova talking about old Soviet moon plans. Brent Sherwood presented on why Solar Power Satellites are key to further space development by providing Earth with unlimited green energy and energy for space manufacturing and propulsion.  Dr. Phil Metzger discussed how to build a self-replicating industrial infrastructure in space that scales like Moore’s Law of computer processing power.

Some of the themes that came up in student and mentor presentations included managing the dust, providing base power systems, recycling of technological and organic nutrients,  building domes and other large structures using local materials and techniques such as 3D printing using D.Shape or spinning up a dome using SuperAdobe construction.

Specific teams had some interesting results from the research. One Business & Technology team produced a Net Present Value (NPV) rating of an arbitrary-sized Moon base (not full city) of around US $65 Billion. This number can be used as a valuation of potential future value to draw loans and fund aspects of the project. Infrastructure Team 5, consisting of three industrial designers including myself and a medical doctor, produced a planning timeline that tried to bridge the gap in defining the user case between the period when there are 4 government astronauts temporarily on the lunar surface to grow to a community of 16, 32 and 108 permanent residents from different supporting entitites. Our tool tracked base preparation, power systems and mental & physical health evolution as the Moon Village grows from what we called “camping” into “the Shires”.

Space Horizons is an annual event, the topic for next year will be announced soon.

Infrastructure Team 5 presenting results on our Moon Village planning timeline. Sunday, February 21, 2016. Photograph by Dr. Phil Metzger.
Infrastructure Team 5 presenting results on a Moon Village planning timeline. Sunday, February 21, 2016. Photograph by Dr. Phil Metzger.

 

http://www.spacehorizonsworkshop.com/#2016

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Solar Power Satellites and the issues going forward after WiSEE 2015.

December 14-16, 2015 was the WiSEE conference on Wireless for Space and Extreme Environments, hosted by University of Central Florida in Orlando and the Institute of Electrical and Electronics Engineers (IEEE). WiSEE included tracks on Space Solar Power, passive wireless sensors and space internetworking. Here is a summary of ideas behind Solar Power Satellites and some of the issues that are holding up progress.

Solar Power Satellites (SPS) are a conceptual form of Space-Based Solar Power (SBSP or SSP) that collect sunlight, transform it into microwaves or lasers and transmit that energy to locations on Earth or in space that need electricity. The receiving equipment is surprisingly simple, building these systems creates jobs and technical skills, and the end product is the greenest form of electricity generation ever invented.

SPS has a dual effect on spaceflight economics that can open up development of the Inner Solar System; it requires many rocket launches driving per-flight costs down while being able to provide kilowatts to gigawatts for in-space receivers for propulsion and industrial use. While eventually providing unlimited green power for Earth, SPS enables our next steps out into the Solar System.

SPS is the only known form of power generation that can provide the entire world with abundant electricity while maintaining the heat balance of Earth’s biosphere. SPS has an extremely low carbon footprint, less than 1/100th of terrestrial solar and around 1/10,000th that of combined cycle natural gas. Most currently proposed systems (by Mankins, Jaffe, Kaya) use gigahertz microwaves at 2.45 Ghz or 5.8 Ghz, 5.8 Ghz being nearly transparent to water, very important for heat balance.

Older SPS concepts typically involved massive metal space-frames covered in solar panels with mile-wide steerable transmitters, assembled by hundreds of astronauts. Modern concepts like Mankins’ SPS-ALPHA use a composite sandwich structure module with amorphous thin-film photovoltaics above a direct current bus leading into a flat phased-array antennae across the bottom. The modules are launched in stacks on conventional rockets and can either self-point at a target or be docked together into a large flotilla of panels, orbiting in geosynchronous orbit (GEO). Together the phased-array antennae beam-form to create pulses that generate current in the receiving antennae or rectenna. Rectenna are typically a large metal mesh suspended above the ground. Higher density signals and smaller receivers are possible under this flexible schema that would provide point-to-point power for in-space transportation along with Earth-based industrial and military applications. Several safety measures are built in, the largest security issue is rectenna and ground transmission lines. Ranching or solar panel fields can utilize the land under the rectenna mesh.

Trained professionals — An issue that is directly related to the IEEE and workforce preparedness is that there are relatively few researchers actively working on what has until recently been an intractable problem. The basic techniques are well-established; the real issues in deploying SPS systems may be a workforce ready to finish developing and build these systems. The number of researchers with current demonstrations can be counted on one hand. People ready to design the circuits, structures, software and enterprises to operate these systems is lacking. Developing what are currently exotic microwave receivers for Earth and space is both a technical and political issue. Integrating these systems with existing rockets is likely the simplest part.

A cohort of engineers trained in this new type of space system, designers and managers able to synthesize the new requirements and policy specialists willing to tackle these issues are needed to make it viable.

Policy — The case for space solar power and SPS systems needs to be made convincingly to both the public and political institutions. This should happen through both grass-roots teaching using devices like Dr. Jaffe’s demonstrator and through coordinated moves to encourage sympathetic policies.

Making young professionals into effective voices for positive change is essential to this effort.

Technology readiness — Many elements of a functional SPS system are at middle Technology Readiness Levels, defined by NASA as TRL 1-9 with 1 being an observed phenomenon and 9 being off-the-shelf hardware. Jaffe has performed vacuum chamber tests at NRL on a complete SPS sandwich module. Marzwell has demonstrated an end-to-end analog system with solar photovoltaic collection providing electricity to a transmitter, received on another mountain in Hawaii. Dr. Kaya has performed multiple lab, public and suborbital rocket demonstrations.

Mankins estimates that it would take around 15 years to go from the current state of the art to flying a power-generating demonstrator (TRL 8) and an equal amount of time to scale up to a 5GW plant in geosynchronous orbit (TRL 9). Currently critical subsystems are stuck between TRL 4 and 6 and some have uncertainty about where to develop further.

New labs and startups with this new cohort of young professionals can drive these subsystems to higher readiness.

Transmission Issues — There is a minimum strength power beam needed to trip the threshold voltage of a typical 20^km rectenna, or any receiving antenna. Ground tests between mountains by Marzwell and separate demos by Kaya and Jaffe show the principle works at smaller scales. Finding the right sizes of rectenna and beam characteristics is important, especially for in-space propulsion and mobile or smaller terrestrial applications such as a military forward operating bases or atop cargo container ships.

For stationary rectenna powering urban cores, much of the technology is fairly simple and can be located nearby on the ocean, desert or farmland. In that case the biggest transmission issues are communication interference from sidelobes and getting over the minimum transmission requirement. Inflatable or deployable rectenna with much higher beam density may be needed for in-space receiving.

Transmission issues are heavily dependent on system implementation and usage details that need to be further characterized as various SPS systems come online. Finding the right scales for in-space, limited/mobile terrestrial and baseline terrestrial beams is an avenue of currently needed research.

Financing & Business Development — The financial hurdle to fund a working SPS is mostly in funding the research & development and proving out the technology subsystems. The operational system can be earning money after the first launch and scales to literally out-of-this world markets.

An operable SPS system might be financed using commercial methods with a payoff time around 10 years after completion for sale of power to high-price markets. The goal is to achieve around $9 per installed kilowatt of capacity (2011 dollars) for a fully operational system. Some have argued that prototype units could be used for in-space propulsion to boost other client payloads but this is currently a small market.

While the payoff to electricity users (both industrial & residential) and to government (in taxes, military lives saved and new space colonies) is potentially quite large, the 15-40 year process of development toward those goals has proven daunting. Financing further technical readiness steps is also daunting as some of them involve spaceflight. NASA, JAXA and the Naval Research Lab have provided much of the previous funding due to the obvious potential but are neither mandated nor properly equipped to finance or run this type of project. Some kind of public-private partnership with loan and purchasing guarantees may be needed.

As SPS systems become viable, a business case must be made to current electricity providers, especially in coastal and desert regions. As with the development of wind and terrestrial solar, new construction sectors will need to evolve to build rectenna, ground transmission equipment and the factories to make thousands of these satellites. Development of one or several new companies will be needed.

Deeper modeling and trade studies are an opportunity to find the minimum viable products of this technology.

Orbits Utilized — The prospect of gigawatts of carbon- and heat- free power for terrestrial applications is compelling but comes at a cost. Most proposals for SPS systems place them in geostationary orbit (GEO), competing for orbital ‘slots’ with the proliferation of world telecommunications satellites. Orbital slots at GEO are precious, limited and nearly full. Multi-kilometer structures with unique control dynamics may not be allowed based on telecommunication needs.

Options include placing telecom transmitters directly on an SPS, beaming power to new, larger telecom satellites or to operate in other orbits. Prototypes, in-space beaming and high-power applications may benefit from flying in a sun-synchronous ‘high noon’ polar orbit. Final system options include Medium Earth Orbit below the GPS constellations or halo orbits around Earth-Moon Lagrange points if GEO slots are unavailable.

Space-based solar power in general and SPS in particular have tremendous potential environmental, technical and industrial benefits, costs to users that could rival terrestrial power sources, provide world energy security and fast in-space propulsion. SPS can be an enabling technology for lowering rocket launch and spaceflight costs. Convincing the US and international community’s citizens, regulators and politicians of this utility will require hard work and dedication among a new cohort of professionals who can practice an integrated approach to engineering these new systems.

 

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