The Lunar Plasma Environment: Real time navigation and communication will be especially difficult... more The Lunar Plasma Environment: Real time navigation and communication will be especially difficult in the lunar polar regions, with heavily shadowing, at best oblique sunlight and frequent lack of line of sight to the Earth or any high-altitude communications relay. Unlike the Apollo surface Extra-Vehicular Activities (EVAs), where direct line of site was maintained between astronauts and either a lander or rover in direct communication with Earth, future astronauts on polar surface EVAs will need means to communicate and perform local positioning beyond the local lines of sight to radio relays. Here we describe how these problems can be addressed through the use of low frequency radio (in this context, any usage with a radio frequency, f, with 1 Hz . f . 100 MHz). It is important to realize that at the lunar polar regions astronauts will be entering a novel and relatively poorly explored plasma and radio frequency (RF) environment, quite different from the direct sunlight and solar ...
The Plasma Environment at the Lunar Poles: At the lunar polar regions astronauts will be entering... more The Plasma Environment at the Lunar Poles: At the lunar polar regions astronauts will be entering a novel and relatively poorly explored plasma and radio frequency (RF) environment, quite different from the direct sunlight and solar wind encountered in Apollo EVAs. We are developing a unified “LunaCell” system with very small SDR modules for deployment onto the lunar surface, with low frequency radio capabilities both to enable communications beyond the line-of-sight, and as a tool for exploring the lunar RF environment [1]. Table 1 briefly describes the complicated and timevariable plasma environment near the lunar surface. The Moon is in the complicated plasma dynamics of the Earth’s magnetotail roughly 25% of the time, and the remainder of the time will be in the supersonic solar wind [2]. In the lunar wake the e− density is substantially decreased, and the plasma can become non-neutral as the thermal velocities of the solar wind electrons are higher than the bulk wind velocity, ...
Space-beamed solar power (SSP) is a concept based on a solar power satellite, that is, a solar pa... more Space-beamed solar power (SSP) is a concept based on a solar power satellite, that is, a solar panel…
Introduction: With the recent expansion of plans for lunar exploration there has been increased i... more Introduction: With the recent expansion of plans for lunar exploration there has been increased interest in support of operations at and near the Moon (i.e., in Cislunar Space), including robotic and crewed missions to the lunar polar regions. Real time navigation and communication will be especially difficult on the heavily shadowed lunar polar regions, given the bad lighting, the frequent lack of line of sight to the Earth, the extreme Geometrical Dilution of Precision (GDOP) for any use of terrestrial GPS and the lack, at least in the near term, of continual overhead satellite coverage. Unlike the Apollo surface Extra-Vehicular Activities (EVAs), future astronauts on polar surface EVAs will need local relays to communicate with the home base, and to perform local navigation, and communication beyond the local line of sight to a central lander.
Planetary Science Vision 2050 Workshop, Feb 1, 2017
Extra-terrestrial space elevators are technically feasible with current materials and can be part... more Extra-terrestrial space elevators are technically feasible with current materials and can be part of a transportation network to fulfill NASA's strategic exploration goals for the next three decades.
Introduction: The Deep Space Gateway (DSG) proposed for cis-lunar space offers an opportunity to ... more Introduction: The Deep Space Gateway (DSG) proposed for cis-lunar space offers an opportunity to both improve tests of fundamental physics and to develop chronometric navigation techniques for the human exploration of Mars and beyond. Here we outline how the DSG, equipped with highly accurate optical atomic clocks and optical phase coherent links with the Earth and other spacecraft, can used to develop and apply the science of chronometric geodesy and navigation, where the clock-spacecraft system is used to both position the spacecraft and measure adjacent gravitational fields. It appears likely that the DSG will be placed in a lunar Near Rectilinear Halo Orbit (NRHO), which offers many advantages for access to the lunar surface and the Earth, while minimizing or even eliminating both solar eclipses and terrestrial communications blackouts [1, 2, 3]. For definitiveness, we assume a 4:1 synodic resonant Halo orbit with a perilune radius of 5600 km and an apolune radius of ∼75,000 km.
Introduction: A Schumann Resonance is an electromagnetic oscillation excited in a closed waveguid... more Introduction: A Schumann Resonance is an electromagnetic oscillation excited in a closed waveguide formed by multiple reflecting layers at or near the surface or interior of a planetary body. The waveguide, for spherical bodies with uniform reflecting layers, is a resonant cavity with a fundamental wavelength ∼ the circumference of the body. The terrestrial Schumann Resonance, predicted by W.O. Schumann in 1952 [1], is formed by the cavity between the ionosphere and the surface of the Earth, with a fundamental frequency ∼7 Hz and the resonance primarily being excited by lightning. A Schumann Resonance was detected on Titan at ∼36 Hz by the Huygens probe [2], with the resonant cavity being formed by Titan’s and subsurface ocean and the excitation thought to result from currents in the ionosphere induced by the advected Saturnian magnetic field [3]. The same mechanisms should apply to Europa, leading to a prediction of a Schumann resonance between near-surface charged particles and th...
Instrumentation located on the Earth for monitoring, tracking, and communicating with satellites,... more Instrumentation located on the Earth for monitoring, tracking, and communicating with satellites, sp…
It has been proposed to use microwaves to beam down power to Earth from space based solar power s... more It has been proposed to use microwaves to beam down power to Earth from space based solar power stations in Geosynchronous Orbit. However the Rayleigh diffraction limited optics requires enormous antennas, typically a few kilometers in diameter, and huge power levels, of 5GW to 10GW. A much lower cost of entry investment (100x lower) is afforded by use of optical or infrared lasers with much shorter wavelength, hence much smaller system size, e.g. 10MW, with one meter size collimator mirror diameter. Since there is no "grid power" in space, most spacecraft today use solar power sources, mostly photovoltaic solar cells. Powering lasers requires high levels of power. PV solar cells are usually less than 25% efficient. This multiplied by a typical 20% “wall plug” efficiency of lasers results in overall a mere 5% efficiency (95% waste heat!). This strongly motivates interest in solar pumping of lasers to greatly increase overall efficiency; theoretical efficiency of about 38% ...
The concept of a space elevator dates back to Tsilokovsky, but they are not commonly considered i... more The concept of a space elevator dates back to Tsilokovsky, but they are not commonly considered in near-term plans for space exploration, perhaps because a terrestrial elevator would not be possible without considerable improvements in tether material. A Lunar Space Elevator (LSE), however, can be built with current technology using commercially available tether polymers. This paper considers missions leading to infrastructure capable of shortening the time, lowering the cost and enhancing the capabilities of robotic and human explorers. These missions use planetary scale tethers, strings many thousands of kilometers long stabilized either by rotation or by gravitational gradients. These systems promise major reduction in transport costs versus chemical rockets, in a rapid timeframe, for a modest investment. Science will thus benefit as well as commercial activities.
What are the important benefits provided to the United States and other countries by human spacef... more What are the important benefits provided to the United States and other countries by human spaceflight endeavors? The ability to place humans in space is exciting to the public, and demonstrates the technological maturity and stature of each spacefaring nation. Such a visible and peaceful demonstration of cutting edge technology fosters foreign policy by showing strength without engaging in conflict i . Human spaceflight sparks the imagination and serves an instinctive need to explore. Astronauts are ambassadors for all of humanity in a very personal way. Men and women in space suits inspire people – of all cultures and demographics – to achieve excellence, to believe in a common cause and to pursue a noble goal. Furthermore, humans in space have unique abilities and attributes (eyes, fingers, and onsite reasoning) to pursue scientific research and commercial development that cannot be achieved by robotic means. American leadership, as demonstrated by the continuous success of human...
The Lunar Plasma Environment: Real time navigation and communication will be especially difficult... more The Lunar Plasma Environment: Real time navigation and communication will be especially difficult in the lunar polar regions, with heavily shadowing, at best oblique sunlight and frequent lack of line of sight to the Earth or any high-altitude communications relay. Unlike the Apollo surface Extra-Vehicular Activities (EVAs), where direct line of site was maintained between astronauts and either a lander or rover in direct communication with Earth, future astronauts on polar surface EVAs will need means to communicate and perform local positioning beyond the local lines of sight to radio relays. Here we describe how these problems can be addressed through the use of low frequency radio (in this context, any usage with a radio frequency, f, with 1 Hz . f . 100 MHz). It is important to realize that at the lunar polar regions astronauts will be entering a novel and relatively poorly explored plasma and radio frequency (RF) environment, quite different from the direct sunlight and solar ...
The Plasma Environment at the Lunar Poles: At the lunar polar regions astronauts will be entering... more The Plasma Environment at the Lunar Poles: At the lunar polar regions astronauts will be entering a novel and relatively poorly explored plasma and radio frequency (RF) environment, quite different from the direct sunlight and solar wind encountered in Apollo EVAs. We are developing a unified “LunaCell” system with very small SDR modules for deployment onto the lunar surface, with low frequency radio capabilities both to enable communications beyond the line-of-sight, and as a tool for exploring the lunar RF environment [1]. Table 1 briefly describes the complicated and timevariable plasma environment near the lunar surface. The Moon is in the complicated plasma dynamics of the Earth’s magnetotail roughly 25% of the time, and the remainder of the time will be in the supersonic solar wind [2]. In the lunar wake the e− density is substantially decreased, and the plasma can become non-neutral as the thermal velocities of the solar wind electrons are higher than the bulk wind velocity, ...
Space-beamed solar power (SSP) is a concept based on a solar power satellite, that is, a solar pa... more Space-beamed solar power (SSP) is a concept based on a solar power satellite, that is, a solar panel…
Introduction: With the recent expansion of plans for lunar exploration there has been increased i... more Introduction: With the recent expansion of plans for lunar exploration there has been increased interest in support of operations at and near the Moon (i.e., in Cislunar Space), including robotic and crewed missions to the lunar polar regions. Real time navigation and communication will be especially difficult on the heavily shadowed lunar polar regions, given the bad lighting, the frequent lack of line of sight to the Earth, the extreme Geometrical Dilution of Precision (GDOP) for any use of terrestrial GPS and the lack, at least in the near term, of continual overhead satellite coverage. Unlike the Apollo surface Extra-Vehicular Activities (EVAs), future astronauts on polar surface EVAs will need local relays to communicate with the home base, and to perform local navigation, and communication beyond the local line of sight to a central lander.
Planetary Science Vision 2050 Workshop, Feb 1, 2017
Extra-terrestrial space elevators are technically feasible with current materials and can be part... more Extra-terrestrial space elevators are technically feasible with current materials and can be part of a transportation network to fulfill NASA's strategic exploration goals for the next three decades.
Introduction: The Deep Space Gateway (DSG) proposed for cis-lunar space offers an opportunity to ... more Introduction: The Deep Space Gateway (DSG) proposed for cis-lunar space offers an opportunity to both improve tests of fundamental physics and to develop chronometric navigation techniques for the human exploration of Mars and beyond. Here we outline how the DSG, equipped with highly accurate optical atomic clocks and optical phase coherent links with the Earth and other spacecraft, can used to develop and apply the science of chronometric geodesy and navigation, where the clock-spacecraft system is used to both position the spacecraft and measure adjacent gravitational fields. It appears likely that the DSG will be placed in a lunar Near Rectilinear Halo Orbit (NRHO), which offers many advantages for access to the lunar surface and the Earth, while minimizing or even eliminating both solar eclipses and terrestrial communications blackouts [1, 2, 3]. For definitiveness, we assume a 4:1 synodic resonant Halo orbit with a perilune radius of 5600 km and an apolune radius of ∼75,000 km.
Introduction: A Schumann Resonance is an electromagnetic oscillation excited in a closed waveguid... more Introduction: A Schumann Resonance is an electromagnetic oscillation excited in a closed waveguide formed by multiple reflecting layers at or near the surface or interior of a planetary body. The waveguide, for spherical bodies with uniform reflecting layers, is a resonant cavity with a fundamental wavelength ∼ the circumference of the body. The terrestrial Schumann Resonance, predicted by W.O. Schumann in 1952 [1], is formed by the cavity between the ionosphere and the surface of the Earth, with a fundamental frequency ∼7 Hz and the resonance primarily being excited by lightning. A Schumann Resonance was detected on Titan at ∼36 Hz by the Huygens probe [2], with the resonant cavity being formed by Titan’s and subsurface ocean and the excitation thought to result from currents in the ionosphere induced by the advected Saturnian magnetic field [3]. The same mechanisms should apply to Europa, leading to a prediction of a Schumann resonance between near-surface charged particles and th...
Instrumentation located on the Earth for monitoring, tracking, and communicating with satellites,... more Instrumentation located on the Earth for monitoring, tracking, and communicating with satellites, sp…
It has been proposed to use microwaves to beam down power to Earth from space based solar power s... more It has been proposed to use microwaves to beam down power to Earth from space based solar power stations in Geosynchronous Orbit. However the Rayleigh diffraction limited optics requires enormous antennas, typically a few kilometers in diameter, and huge power levels, of 5GW to 10GW. A much lower cost of entry investment (100x lower) is afforded by use of optical or infrared lasers with much shorter wavelength, hence much smaller system size, e.g. 10MW, with one meter size collimator mirror diameter. Since there is no "grid power" in space, most spacecraft today use solar power sources, mostly photovoltaic solar cells. Powering lasers requires high levels of power. PV solar cells are usually less than 25% efficient. This multiplied by a typical 20% “wall plug” efficiency of lasers results in overall a mere 5% efficiency (95% waste heat!). This strongly motivates interest in solar pumping of lasers to greatly increase overall efficiency; theoretical efficiency of about 38% ...
The concept of a space elevator dates back to Tsilokovsky, but they are not commonly considered i... more The concept of a space elevator dates back to Tsilokovsky, but they are not commonly considered in near-term plans for space exploration, perhaps because a terrestrial elevator would not be possible without considerable improvements in tether material. A Lunar Space Elevator (LSE), however, can be built with current technology using commercially available tether polymers. This paper considers missions leading to infrastructure capable of shortening the time, lowering the cost and enhancing the capabilities of robotic and human explorers. These missions use planetary scale tethers, strings many thousands of kilometers long stabilized either by rotation or by gravitational gradients. These systems promise major reduction in transport costs versus chemical rockets, in a rapid timeframe, for a modest investment. Science will thus benefit as well as commercial activities.
What are the important benefits provided to the United States and other countries by human spacef... more What are the important benefits provided to the United States and other countries by human spaceflight endeavors? The ability to place humans in space is exciting to the public, and demonstrates the technological maturity and stature of each spacefaring nation. Such a visible and peaceful demonstration of cutting edge technology fosters foreign policy by showing strength without engaging in conflict i . Human spaceflight sparks the imagination and serves an instinctive need to explore. Astronauts are ambassadors for all of humanity in a very personal way. Men and women in space suits inspire people – of all cultures and demographics – to achieve excellence, to believe in a common cause and to pursue a noble goal. Furthermore, humans in space have unique abilities and attributes (eyes, fingers, and onsite reasoning) to pursue scientific research and commercial development that cannot be achieved by robotic means. American leadership, as demonstrated by the continuous success of human...
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