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SSP Workshop – Presentations

SSP Workshop – Best Paper/Presentation Award: “Hypermodular Distributed Space Solar Power -­ Technology Option for Near-­‐Term LEO Demonstration and Geosynchronous Utility-­‐Scale Plant ”, Martin Leitgab
SSP Workshop – Best Paper/Presentation Award “SSP: Hearts and Minds”, Brent Sherwood

Links to Presentations as PDF Files


Presentation Abstracts (as available)


Professor Koji Tanaka,  The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan, Tel: 050-3362-7027 :27027) Fax:042-759-8464

ABSTRACT Tethered solar power satellite (Tethered-SPS) consisting of a large panel with a capability of power generation/transmission and a bus system which are connected by multi-wires is proposed as an innovative solar power satellite (SPS). The power generation/ transmission panel is composed of a huge number of perfectly equivalent power modules. The electric power generated by the solar cells at the surface of each module is converted to the microwave power in the same module. Since the modules are controlled by the bus system using wireless LAN, no wired signal/power interfaces are required between the modules. The attitude in which the microwave transmission antenna is directed to the ground is maintained by the gravity gradient force. The tethered panel is composed of individual tethered subpanels which are loosely connected to each other. This configuration enables an evolutional construction in which the function of the SPS grows as the construction proceeds. A scale model of the tethered subpanel can be used for the first step demonstration experiment of the SPS in the near future.


Hu Davis and Gordon Woodcock - The SolarHigh Group, Houston, Texas.
E-mail:, Phone: (210) 698-6896
Hu Davis was a manager of Apollo spacecraft power and propulsion systems at NASA Johnson Space Center(JSC), and for four Lunar Modules (including LM-5, the Apollo 11 lunar landing vehicle). After Apollo, he served as JSC Future Programs manager, working on the Inertial Upper Stage and Shuttle C Heavy Lift vehicles, and SPS Reference Study.
Gordon Woodcock is a well-known contributor to spacecraft design and to studies of space exploration and technology development. He worked in the Future Projects Office at NASA Marshall Spaceflight Center on lunar and planetary missions, launch vehicles, and propulsion and at Boeing on the space shuttle preliminary design and managed several design study contracts for NASA, including key contributions to Boeing’s work on the SPS Reference Study, and to space station Phase-A, Phase-B and technology studies. Gordon has published more than 100 articles and books, including Space Stations and Platforms, Krieger, 1986, and Space Exploration: Missions Engineering, Krieger, 2011. Former President of the L5 Society; Former Chairman of the NSS Executive Committee

SolarHigh’s work on Space Solar Power  has improved upon the NASA/DoE/Boeing Solar Power Satellite Systems Definition Study, showing that.

  • The concept is credible, requires no new science and can be implemented with present technology levels. Emerging technologies will improve it.
  • System safety that was previously established has been confirmed.
  • Microwave transmission of baseload electrical power at 5.8 GHZ is technically sound
  • A new space infrastructure is required that will provide low costs and provide other space transport capabilities.
  • This infrastructure will include a new, fully reusable space launch fleet capable of 8 or more flights per day, large solar-electric space tugs , further development of manufacturing in space and orbital propellant depots.
  • We find it to be highly probable that this revised concept can close the business case for SBSP.


Gail Tverberg, is Director of Energy Economics, Space Solar Power Institute, Atlanta, GA  Office: (407) 443-0505.  Ms. Tverberg is a Fellow of the Casualty Actuarial Society and Member of the American Academy of Actuaries.  Gail’s blog is  She is also a frequent contributor and editor at
ABSTRACTHow High and Rising Oil Prices Can Lead to Limits to Growth


Brent Sherwood, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena CA, 91109  JPL Solar System Mission Formulation, Jet Propulsion Laboratory, Cell  818-653-2985
ABSTRACT:  The Space Solar Power concept, and its promise of clean, inexhaustible energy for Earth, has struggled through three generations of perception among cognoscenti: clever but not technically feasible (1970s-1980s); increasingly feasible but not economically viable (1990s-2000s); and now, grudgingly acknowledged to be increasingly viable economically, but not aligned with the space course set by the international political-industrial complex. Unless the context for acceptance and championship changes, SSP is unlikely to be implemented in time to help avert social disruption and environmental devastation as the post-petroleum energy economy takes shape. Clearing a path for conceptual acceptance of SSP is as vital to success as is further technical refinement.  Based on a serial argument developed and published since 2010, and on fundamental principles of strategic development, I present a framework for changing the conversation.

  • Know the competition – NASA invests $1010 per year on human space flight, and largely determines international space-futures goals. While the HSF investment could pursue four distinct goals, it is now fixated on Humans to Mars, not Space Power for Earth.
  • Know the customer – The essential champions are not amenable to technical suasion. For them, electricity “comes from the wall,” externalities are abstract, and logic is not primary. Communication must be properly targeted and designed to be effective.
  • Do our homework – SSP advocates are drawn more to aspects that interest them than to those that interest key stakeholders (e.g., more work has been published on phased-array beam forming than on safety of high-power transmission). Challenges pivotal to widespread acceptance must be embraced and centrally addressed.
  • Learn aikido – SSP would touch virtually every person on Earth, and boost an unprecedented cross-section of industrial and public interests. If recognized and subtly guided, stakeholders’ inherent interests can be manifested through an SSP roadmap.
  • Start small – While large-scale SSP implementation would be a $1011 program on the same scale as the US. National Highway system, an end-to-end demonstration would cost only $108, the scale of a NASA Space Technology Mission Directorate (STMD) Technology Demonstration Mission.

Advancing all five areas is likely to prove enabling for the SSP vision to be significantly realized.


Current Briefing from the FAA Commercial Space Transportation (COMSTAC) Business / Legal Working Group

Chris Kunstadter,  Chair, Federal Aviation Administration's Commercial Space Transportation  (COMSTAC) Business / Legal Working Group, Senior Vice President, Aerospace Insurance, XL Group, One World Financial Center, 200 Liberty Street, 3rd Floor, New York, NY 10281  Office: 212-915-6387

  • GEO and Non-GEO Space Transportation forecasts
  • Development of a legal framework for private exploitation and utilization of space resources
  • Maximum Probable Loss (MPL) methodology review. The MPL is a dollar value assessment of government and third party properties at risk of damage from launch-related activities or conduct, requiring insurance or similar financial escrow.
  • Waivers for many payloads and other Part 440 ModsLong-term extension of third-party risk-sharing regime
  • Strengthening of informed consent protection from unrestricted second-party litigation
  • Inclusion of spaceflight participants in third-party indemnification
  • Draft Recommendations Overview for Launch Vehicle International Standards and Best Practices for Human or Freight only


Michael Contreras, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena CA, 91109, Voice (818) 354-4283   Fax (818) 393-5886

Within the past decade, the Space Solar Power (SSP) community has seen an influx of stakeholders willing to entertain the SSP prospect of potentially boundless, base-load solar energy. Interested parties affiliated with the Department of Defense (DoD), the private sector, and various international entities have all agreed that while the benefits of SSP are tremendous and potentially profitable, the risk associated with developing an efficient end to end SSP harvesting system is still very high. In an effort to reduce the implementation risk for future SSP architectures, this study proposes a system level design that is both low-cost and seeks to demonstrate the furthest transmission of wireless power to date. The overall concept is presented and each sub-system is explained in detail with best estimates of current implementable technologies. Basic cost models were constructed based on input from JPL subject matter experts and assume that the technology demonstration would be carried out by a federally funded entity. The main thrust of the architecture is to simply demonstrate that any amount of solar power can be safely and reliably transmitted from space to the Earth's surface; however, maximum scalability limits and its effects on return on investment are discussed.


Wireless Power Transmission for Space Solar Power Generation

Dr. Amir Mortazawi, Associate Professor, University of Michigan

Space solar power via wireless power transmission proposes solar-generated, DC power to be converted to microwaves and beamed to earth using a large antenna array. The beam would be captured using an array of rectifying antennas and converted back into DC power for terrestrial electrical grids. This addresses wireless power transmission by means of spatial power combining oscillator arrays that employ high power semiconductor devices. The goal is to design a highly stable and efficient oscillator array that is tolerant to multiple device failures. The proposed solar power transmitting system consists of optical-link distribution networks, phase correction loops, and extended resonance oscillator arrays. The beam scanning capabilities of the large array antenna are investigated. Extended resonance technique is applied to the design of coupled oscillator sub-arrays and external injection locking is employed in order to create a stable and coherent high power microwave beam.


Speaker: Michael Brown, Naval Research Laboratory (Retired)

NASA’s “Fresh Look” in ’95 – ’98 produced two designs(1) that remain state of art SSP concepts: the integrated symmetrical concentrator and the modular sandwich microwave system. Both have problems blocking their implementation. The symmetrical design shows two parallel 1,000m diameter PV arrays placed perpendicular to the earth-facing 1,000m diameter microwave system panel. This solves the problem of sending enormous currents through sliprings between the PV and microwave systems in NASA’s 1979 “Reference System Concept,” but conductors’ mass remains a problem. The sandwich eliminates long conductors by placing a 1,000m PV disc directly above the microwave disc. But in this configuration the only thermal waste radiators are the faces of the two discs, an area insufficient to keep the microwave system temperatures at acceptably low level.

NRL solves both problems by replacing the sandwich module with an open-top cone called the step (power conversion) module(2) The cone’s wall has a step configuration: horizontal surfaces are PV panels, vertical surfaces are reflective film. The concentrators direct sunlight into the top of the cone. Microwave devices are on external radiator panels adjacent to PV panels, arranged so PV and microwave radiators do not interact. The cone is an inherently stiff structure, unlike the flat sandwich module.

A major issue for SSP investment is the size and mass (cost to orbit) of proposed structures. Modern buildings achieve great heights because of a basic structural element: the steel I-beam; no such element exists for space structures. A NASA report(3) shows the most efficient beams (grams/meter for given column load) for space to have continuous (no hinges) longerons of ultra-stiff graphite composite; but how to stow them? NRL has developed a design of a deployable isogrid (tube) beam, based on earlier designs of truss beams(4). This is made as an isogrid “fabric” of highest modulus graphite, in a fully automated process, that rolls up for stowage.  Over 10,000 meters (260kg) could be carried into space in a roll 2m diameter. In space the fabric is deployed into tubes and cut to required lengths. Fittings are attached to tube ends, creating beam elements that can be integrated into a structural system. The deployment system’s feed mechanism is copied into  “beam crawler” platforms that move along deployed beams, carrying material and work devices. Nearly the entire reflector support structure and the conversion module cone can be built this way. Tube fitting connections contain thermally activated shape memory composite material, allowing decoupling for system reconfiguration.


Speaker: Gregory Durgin, Associate Professor, Georgia Tech

This talk presents the results of a large, semester-long project at Georgia Tech requiring student teams to design original space solar power systems – a technology mostly associated with Japanese science and engineering. The project results are archived online and surveyed in this article. As a result of participation, over 68% of surveyed student participants developed increased interest in the fields of RF engineering and electromagnetics (notoriously difficult but necessary areas in which to foment student interest); over a third of the surveyed participants expressed a desire to study space solar power beyond the course.


Darel Preble, Executive Director, Space Solar Power Institute, Atlanta, GA

Our global economy is dependent on reasonable energy prices, especially oil. Many energy alternatives have been explored and subsidized, yet our dependency has grown; while prices escalate, our per capita incomes, our energy, economic and environmental security continues to decline. To sustain a reasonable standard of living, while protecting our environment, we must rebuild our energy supply.

A careful examination of the pros and cons of primary energy sources now available, shows Space Solar Power(SSP), to be a clean, dispatchable, and virtually unlimited energy source with many critical advantages. These include low CO2 output, zero fuel cost, low water use, and a very high 99.3% capacity factor avoiding the intractable intermittency of the leading electric power alternatives windmills and ground-based solar.

Existing US energy polices continue to ignore SSP.  SSP is commercially feasible using key legislation we call the Sunsat Act. Just as the Comsat Act of 1962 created our robust commercial satellite communications industry, the Sunsat Act would create a commercial power satellite industry - SSP. Lowering the cost of orbital transportation is essential. No existing US corporation has the patient financial resources, technology and charter to initiate SSP today.
SSP appears to be the only market with the high launch volume essential to creating the low cost launch market necessary. The latest commercial Reusable Launch Vehicle (RLV) alternatives will be briefly surveyed. Similar situations exist for other necessary SSP hardware such as thin-film photovoltaics, which is a major reason the Sunsat Act is needed. 
Japan and China have already embarked on SSP development and are expected to bring it to the global electric power market ten to twenty years from now.


Paul Werbos, National Science Foundation, Program Director, Office of Emerging Frontiers in Research & Innovation (ENG/EFRI)  Email:, Phone (703) 292-8339 Fax: (703) 292-9147


SSP and International Disaster

David Dunlop, Chair International Committee, National Space Society,


The Earth presents an unending series of disasters to humanity which affect both advanced economies as well as economically undeveloped areas. SPS is a potential mechanism to provide power to areas in which a grid has been seriously compromised or where no gird exist. Building on the Foundation of the UN SPIDER Program this potential application may provide a transparent mode of pragmatic demonstration of the practical value of a solar power satellite and one consistent with the UN COPUOS as a mechanism for coordination.


Seyed (Reza) Zekavat, Professor, Michigan Technological University,

Traditionally, SSP has been designed for GEO stationary orbit. However, recently different alternatives for the implementation of the SSP in LEO orbits have been introduced in the literature. This presentation compares different orbits and their implementation technologies and associated performance and costs.