26-03-2011, 04:12 PM
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Solar Powered Satellites
ABSTRACT :
Space-based solar power (SBSP) (or historically space solar power (SSP)) is a theoretical design for the collection of solar power in space, for use on Earth. SBSP differs from the usual method of solar power collection in that the solar panels used to collect the energy would reside on a satellite in orbit, often referred to as a solar power satellite (SPS), rather than on Earth's surface. In space, collection of the Sun's energy is unaffected by the day/night cycle, weather, seasons, or the filtering effect of Earth's atmospheric gases. Average solar energy per unit area outside Earth's atmosphere is on the order of ten times that available on Earth's surface.
KEY WORDS :
Solar power satellite, Solar Energy, Thermal Power.
Solar Power Satellite :
The collection of solar energy in space for use on Earth introduces the new problem of transmitting energy from the collection point, in space, to the place where the energy would be used, on Earth's surface. Since wires extending from Earth's surface to an orbiting satellite would be impractical, many SBSP designs have proposed the use of microwave beams to transmit power wirelessly. The collecting satellite would convert solar energy into electrical energy, which would then be used to power a microwave emitter directed at a collector on the Earth's surface. Dynamic solar thermal power systems are also being investigated.
Many problems normally associated with solar power collection would be eliminated by such a design, such as the high sensitivity of conventional surface solar panels to corrosion and weather, and the resulting maintenance costs. Other problems may take their place though, such as cumulative radiation damage or micrometeoroid impacts.
Producing electricity from sunlight in space is not a new or untried technology. Many space faring craft are covered in solar cells, such as rovers and shuttles, and hundreds of operating satellites use solar energy as their main source of power. What has never been tried before is transmitting that power back to Earth for our use.
Being a clean and safe energy design, space-based solar power has the potential to play a significant role in solving global energy and environmental problems. It utilizes space outside of Earth's ecological system, and may essentially produce no by-products.
History of Solar Power Satellites:
The SPS concept, originally known as Satellite Solar Power System ("SSPS") was first described in November 1968. In 1973 Peter Glaser was granted U.S. patent number 3,781,647 for his method of transmitting power over long distances (e.g., from an SPS to the Earth's surface) using microwaves from a very large (up to one square kilometer) antenna on the satellite to a much larger one on the ground, now known as a rectenna. Generation of Solar power on Earth:
Glaser then worked at Arthur D. Little, Inc., as a vice-president. NASA signed a contract with ADL to lead four other companies in a broader study in 1974. They found that, while the concept had several major problems -- chiefly the expense of putting the required materials in orbit and the lack of experience on projects of this scale in space, it showed enough promise to merit further investigation and research .
Between 1978 and 1981 the US Congress authorized DOE and NASA to jointly investigate. They organized the Satellite Power System Concept Development and Evaluation Program. The study remains the most extensive performed to date. Several reports were published investigating possible problems with such an engineering project. They include:
• Resource Requirements (Critical Materials, Energy, and Land)
• Financial/Management Scenarios
• Public Acceptance
• State and Local Regulations as Applied to Satellite Power System Microwave Receiving Antenna Facilities
• Student Participation
• Potential of Laser for SPS Power Transmission
• International Agreements
• Centralization/Decentralization
• Mapping of Exclusion Areas For Rectenna Sites
• Economic and Demographic Issues Related to Deployment
• Some Questions and Answers
• Meteorological Effects on Laser Beam Propagation and Direct Solar Pumped Lasers
• Public Outreach Experiment
• Power Transmission and Reception Technical Summary and Assessment
• Space Transportation
The Office of Technology Assessment concluded
Too little is currently known about the technical, economic, and environmental aspects of SPS to make a sound decision whether to proceed with its development and deployment. In addition, without further research an SPS demonstration or systems-engineering verification program would be a high-risk venture.
More recently, the SPS concept has again become interesting, due to increased energy demand, increased energy costs, and emission implications, starting in 1997 with the NASA "Fresh Look". In assessing "What has changed" since the DOE study, this study asserts that
Another important change has occurred at the US national policy level. US National Space Policy now calls for NASA to make significant investments in technology (not a particular vehicle) to drive the costs of ETO [Earth to Orbit] transportation down dramatically. This is, of course, an absolute requirement of space solar power.
SERT
In 1999 NASA's Space Solar Power Exploratory Research and Technology program (SERT) was initiated for the following purpose:
• Perform design studies of selected flight demonstration concepts;
• Evaluate studies of the general feasibility, design, and requirements.
• Create conceptual designs of subsystems that make use of advanced SSP technologies to benefit future space or terrestrial applications.
• Formulate a preliminary plan of action for the U.S. (working with international partners) to undertake an aggressive technology initiative.
• Construct technology development and demonstration roadmaps for critical Space Solar Power (SSP) elements.
It was to develop a solar power satellite (SPS) concept for a future giga watt space power systems to provide electrical power by converting the Sun’s energy and beaming it to the Earth's surface. It was also to provide a developmental path to solutions for current space power architectures. Subject to studies it proposed an inflatable photovoltaic gossamer structure with concentrator lenses or solar dynamic engines to convert solar flux into electricity. Collection systems were assumed to be in sun-synchronous orbit.
Some of SERT's conclusions include the following:
• The increasing global energy demand is likely to continue for many decades resulting in new power plants of all sizes being built.
• The environmental impact of those plants and their impact on world energy supplies and geopolitical relationships can be problematic.
• Renewable energy is a compelling approach, both philosophically and in engineering terms.
• Many renewable energy sources are limited in their ability to affordably provide the base load power required for global industrial development and prosperity, because of inherent land and water requirements.
• Based on their Concept Definition Study, space solar power concepts may be ready to reenter the discussion.
• Solar power satellites should no longer be envisioned as requiring unimaginably large initial investments in fixed infrastructure before the emplacement of productive power plants can begin.
• Space solar power systems appear to possess many significant environmental advantages when compared to alternative approaches.
• The economic viability of space solar power systems depends on many factors and the successful development of various new technologies (not least of which is the availability of exceptionally low cost access to space) however, the same can be said of many other advanced power technologies options.
• Space solar power may well emerge as a serious candidate among the options for meeting the energy demands of the 21st century.
Solar Powered Satellites
ABSTRACT :
Space-based solar power (SBSP) (or historically space solar power (SSP)) is a theoretical design for the collection of solar power in space, for use on Earth. SBSP differs from the usual method of solar power collection in that the solar panels used to collect the energy would reside on a satellite in orbit, often referred to as a solar power satellite (SPS), rather than on Earth's surface. In space, collection of the Sun's energy is unaffected by the day/night cycle, weather, seasons, or the filtering effect of Earth's atmospheric gases. Average solar energy per unit area outside Earth's atmosphere is on the order of ten times that available on Earth's surface.
KEY WORDS :
Solar power satellite, Solar Energy, Thermal Power.
Solar Power Satellite :
The collection of solar energy in space for use on Earth introduces the new problem of transmitting energy from the collection point, in space, to the place where the energy would be used, on Earth's surface. Since wires extending from Earth's surface to an orbiting satellite would be impractical, many SBSP designs have proposed the use of microwave beams to transmit power wirelessly. The collecting satellite would convert solar energy into electrical energy, which would then be used to power a microwave emitter directed at a collector on the Earth's surface. Dynamic solar thermal power systems are also being investigated.
Many problems normally associated with solar power collection would be eliminated by such a design, such as the high sensitivity of conventional surface solar panels to corrosion and weather, and the resulting maintenance costs. Other problems may take their place though, such as cumulative radiation damage or micrometeoroid impacts.
Producing electricity from sunlight in space is not a new or untried technology. Many space faring craft are covered in solar cells, such as rovers and shuttles, and hundreds of operating satellites use solar energy as their main source of power. What has never been tried before is transmitting that power back to Earth for our use.
Being a clean and safe energy design, space-based solar power has the potential to play a significant role in solving global energy and environmental problems. It utilizes space outside of Earth's ecological system, and may essentially produce no by-products.
History of Solar Power Satellites:
The SPS concept, originally known as Satellite Solar Power System ("SSPS") was first described in November 1968. In 1973 Peter Glaser was granted U.S. patent number 3,781,647 for his method of transmitting power over long distances (e.g., from an SPS to the Earth's surface) using microwaves from a very large (up to one square kilometer) antenna on the satellite to a much larger one on the ground, now known as a rectenna. Generation of Solar power on Earth:
Glaser then worked at Arthur D. Little, Inc., as a vice-president. NASA signed a contract with ADL to lead four other companies in a broader study in 1974. They found that, while the concept had several major problems -- chiefly the expense of putting the required materials in orbit and the lack of experience on projects of this scale in space, it showed enough promise to merit further investigation and research .
Between 1978 and 1981 the US Congress authorized DOE and NASA to jointly investigate. They organized the Satellite Power System Concept Development and Evaluation Program. The study remains the most extensive performed to date. Several reports were published investigating possible problems with such an engineering project. They include:
• Resource Requirements (Critical Materials, Energy, and Land)
• Financial/Management Scenarios
• Public Acceptance
• State and Local Regulations as Applied to Satellite Power System Microwave Receiving Antenna Facilities
• Student Participation
• Potential of Laser for SPS Power Transmission
• International Agreements
• Centralization/Decentralization
• Mapping of Exclusion Areas For Rectenna Sites
• Economic and Demographic Issues Related to Deployment
• Some Questions and Answers
• Meteorological Effects on Laser Beam Propagation and Direct Solar Pumped Lasers
• Public Outreach Experiment
• Power Transmission and Reception Technical Summary and Assessment
• Space Transportation
The Office of Technology Assessment concluded
Too little is currently known about the technical, economic, and environmental aspects of SPS to make a sound decision whether to proceed with its development and deployment. In addition, without further research an SPS demonstration or systems-engineering verification program would be a high-risk venture.
More recently, the SPS concept has again become interesting, due to increased energy demand, increased energy costs, and emission implications, starting in 1997 with the NASA "Fresh Look". In assessing "What has changed" since the DOE study, this study asserts that
Another important change has occurred at the US national policy level. US National Space Policy now calls for NASA to make significant investments in technology (not a particular vehicle) to drive the costs of ETO [Earth to Orbit] transportation down dramatically. This is, of course, an absolute requirement of space solar power.
SERT
In 1999 NASA's Space Solar Power Exploratory Research and Technology program (SERT) was initiated for the following purpose:
• Perform design studies of selected flight demonstration concepts;
• Evaluate studies of the general feasibility, design, and requirements.
• Create conceptual designs of subsystems that make use of advanced SSP technologies to benefit future space or terrestrial applications.
• Formulate a preliminary plan of action for the U.S. (working with international partners) to undertake an aggressive technology initiative.
• Construct technology development and demonstration roadmaps for critical Space Solar Power (SSP) elements.
It was to develop a solar power satellite (SPS) concept for a future giga watt space power systems to provide electrical power by converting the Sun’s energy and beaming it to the Earth's surface. It was also to provide a developmental path to solutions for current space power architectures. Subject to studies it proposed an inflatable photovoltaic gossamer structure with concentrator lenses or solar dynamic engines to convert solar flux into electricity. Collection systems were assumed to be in sun-synchronous orbit.
Some of SERT's conclusions include the following:
• The increasing global energy demand is likely to continue for many decades resulting in new power plants of all sizes being built.
• The environmental impact of those plants and their impact on world energy supplies and geopolitical relationships can be problematic.
• Renewable energy is a compelling approach, both philosophically and in engineering terms.
• Many renewable energy sources are limited in their ability to affordably provide the base load power required for global industrial development and prosperity, because of inherent land and water requirements.
• Based on their Concept Definition Study, space solar power concepts may be ready to reenter the discussion.
• Solar power satellites should no longer be envisioned as requiring unimaginably large initial investments in fixed infrastructure before the emplacement of productive power plants can begin.
• Space solar power systems appear to possess many significant environmental advantages when compared to alternative approaches.
• The economic viability of space solar power systems depends on many factors and the successful development of various new technologies (not least of which is the availability of exceptionally low cost access to space) however, the same can be said of many other advanced power technologies options.
• Space solar power may well emerge as a serious candidate among the options for meeting the energy demands of the 21st century.
