Lunar space elevators could revolutionize the development of the Moon. The lunar space elevator s... more Lunar space elevators could revolutionize the development of the Moon. The lunar space elevator system allows solar-powered robotic vehicles to climb a high-strength composite ribbon from the lunar surface to beyond the L1 Lagrangian point, where payloads of lunar resources could be released into Earth orbit for major space construction projects. The overall system concept includes the lunar space elevator, a robotic construction system for the components, and robotic vehicles to carry lunar products into Earth orbit for construction and for upper stage propellant, and Earth-orbit payloads to the lunar surface for lunar habitat supplies. The construction system creates building blocks from lunar materials, using automated assembly and wire forming to construct complex shapes. The lunar space elevators provide non-rocket transportation of these lunar products from polar and equatorial mining sites into Earth orbit. This architecture is a new way to create a lunar base for robotic and human operations on the surface. A lunar space elevator using existing high-strength composites with a lifting capacity of 2000 N at the base equipped with solar-powered capsules moving at 100 km/hour could lift 584,000 kg/yr of lunar material into high Earth orbit. Since launch costs twenty years from now may be $1,000/kg, this material would be worth half a billion dollars per year, creating a new era of space development.
The ElectroDynamic Delivery Express (EDDE) is an autonomous space vehicle that can deliver multip... more The ElectroDynamic Delivery Express (EDDE) is an autonomous space vehicle that can deliver multiple small satellites from any low earth orbit (LEO) to any other desired low earth orbit within months, without using fuel. EDDE uses solar power to drive multiampere currents through a multi-kilometer aluminum tape. The tape sees a force normal to both itself and the local magnetic field. The tape is electrically connected to the ambient ionosphere to close the current loop externally. EDDE spins at ~8X/orbit to improve both stability and operational flexibility. Changing the current as a function of orbit and spin phase imposes forces and torques that allow any desired changes in orbit and spin. This allows far higher performance than possible with a hanging electrodynamic tether. For high-inclination orbital plane changes in LEO, EDDE can be more than twice as fast as more conventional high-specific-impulse electric rockets, and has much higher delta-V capability, since it does not exp...
It is commonly accepted now that large debris objects, such as derelict satellites and rocket bod... more It is commonly accepted now that large debris objects, such as derelict satellites and rocket bodies, should be removed from LEO to prevent or at least reduce the frequency of new catastrophic collisions. Such collisions can produce hundreds of thousands of debris fragments in the centimeter range (“shrapnel”) that are hard to track, but could be long-lived and lethal to operational spacecraft. Different technologies are being proposed and developed for debris removal. While it is important to begin the process of debris removal in the near future, it is not less important to assess the sustainability and long-term implications of the proposed debris removal campaigns. In this paper, we describe a high-level statistical model of shrapnel production and use it to evaluate the average cost of a catastrophic collision as the statistically expected loss due to the damage to operational satellites and loss of their functions as a result of future collisions in LEO. The model is phenomeno...
Two methods using long tethers are examined for the disposal of inoperative satellites or debris ... more Two methods using long tethers are examined for the disposal of inoperative satellites or debris in GEO. The disposal method is to move the orbit of the satellite 300 km from GEO to prevent interference with operating satellites. The first method uses a service vehicle with dual 300 km tethers. The vehicle docks with target number 1, then uses rocket thrust to carry the pair to target number 2. The two satellites are extended upward and downward 300 km by the two tethers and are released in turn. After the first release, the service vehicle drifts to the next target, releases the second satellite, then uses a small rocket thrust to rendezvous with target number 3. The second method is to oscillate a single target satellite upward on the end of a 600-km tether into an in-plane pendulum mode with a libration half-angle of 15 degrees. Tether-based disposal is compared in terms of mass required with conventional rockets and with the tumble-orbit transfer, previously proposed by one of t...
The Wright Laboratory is the Air Force center for air vehicles, responsible for developing advanc... more The Wright Laboratory is the Air Force center for air vehicles, responsible for developing advanced technology and incorporating it into new flight vehicles and for continuous technological improvement of operational air vehicles. Part of that responsibility is the problem of acoustic fatigue. With the advent of jet aircraft in the 1950's, acoustic fatigue of aircraft structure became a significant problem. In the 1960's the Wright Laboratory constructed the first large acoustic fatigue test facilities in the United States, and the laboratory has been a dominant factor in high-intensity acoustic testing since that time. This paper discusses some of the intense environments encountered by new and planned Air Force flight vehicles, and describes three new acoustic test facilities of the Wright Laboratory designed for testing structures in these dynamic environments. These new test facilities represent the state of the art in high-temperature, high-intensity acoustic testing an...
A new device is described for measuring the mass of weightless objects in space vehicles, based o... more A new device is described for measuring the mass of weightless objects in space vehicles, based on new techniques. The zero-gravity massmeter measures the mass of an unknown object by measuring the change in center of mass between the object and a connected known mass. The new device has advantages over past techniques that depended on the frequency of an unknown mass on a spring. The device can be used over a large range of unknown masses, making it applicable to measuring bone loss in astronauts and the mass of small specimens such as crystal growth experiments. This zero-gravity massmeter technique can also be applied to measure the mass of fuel tanks and other objects tethered to a Space Station, as well as the mass of the station itself.
T he nearly 2,200 spent stages and dead satellites in low Earth orbit (LEO) – a mass of nearly 2,... more T he nearly 2,200 spent stages and dead satellites in low Earth orbit (LEO) – a mass of nearly 2,000 tons – is starting to act as a slow-release anti-satellite (ASAT) system, randomly targeting valuable space assets. The Cosmos-Iridium collision of 2009 produced an effect very similar to the Chinese ASAT test in 2007: the satellites shredded each other, producing over 2,000 tracked fragments and over 100,000 untracked fragments, a cloud of " shrapnel " potentially lethal to operational spacecraft. These debris clouds have spread out and will persist for decades. The probability of more catastrophic collisions is no longer negligible: it has now reached 8% per year, and will scale with the square of the number of large objects in congested regions of LEO. Given the current launch rates, this collision rate could double within the next 20 years. The Cosmos-Iridium collision involved a total mass of 1.5 tons, which was substantially less than what was statistically expected t...
The ElectroDynamic Debris Eliminator (EDDE) is a LEO vehicle of a new class. It is solar-powered ... more The ElectroDynamic Debris Eliminator (EDDE) is a LEO vehicle of a new class. It is solar-powered and uses electric current in a long conductor to thrust against the Earth's magnetic field. Operating without propellant, EDDE can repeatedly change its altitude by hundreds of kilometers per day and its orbital plane by several degrees per day. EDDE weighs about 100 kg, but it can move multi-ton payloads. We consider three options for debris removal campaigns in low Earth orbit using EDDE. A dozen EDDE vehicles could remove all large debris from LEO in 7 years. They could all be launched on one ESPA ring (two per slot), but phased deployment has advantages. Two EDDE vehicles can be launched each year and retired 5 years later. In 9 years of operation, 2,000 tons of large legacy debris and 97% of the collision-generated debris potential in LEO can be removed, at an average cost of less than $400/kg and an average annual cost of less than $90M. We also consider a campaign that removes...
The ElectroDynamic Delivery Experiment (EDDE) is proposed for a space demonstration. EDDE consist... more The ElectroDynamic Delivery Experiment (EDDE) is proposed for a space demonstration. EDDE consists of an autonomous space vehicle powered by lightweight solar arrays, a bi-directional electrodynamic tether, and batteries for power leveling. The EDDE vehicle can modify its orbit repeatedly without rocket fuel, and can change all six orbital parameters by modulating and reversing the current flow in the conducting tether. The base spacecraft is connected to the service module by a 6-km-long electrodynamic tether, and is designed for 2 kW of power and a total mass of 180 kg. Tether lifetime of several years is achieved with a two-strand caduceus, with the strands connected every few meters. Tether libration is minimized by mass distribution and by active current control. The vehicle and tether system concepts are developed, the operational envelopes are examined, and potential applications are evaluated. The EDDE vehicle is about twice as fast as ion rockets for high-inclination orbita...
2nd International Energy Conversion Engineering Conference, 2004
Electrodynamic tethers produce low thrust through interaction of the electric current in the teth... more Electrodynamic tethers produce low thrust through interaction of the electric current in the tether with the Earth's magnetic field. The thrust is comparable with that of ion rockets and Hall thrusters, and they have the added advantage that they are propellantless, allowing them to produce an order of magnitude greater velocity changes than ion rockets. However, the long conductors of such electrodynamic thrusters typically exhibit unstable behaviors with higher currents. Instability affects both libration and bending modes of tether motion and significantly limits the performance characteristics of electrodynamic tether thrusters. Previous concepts for electrodynamic tethers have proposed stabilizing them by hanging vertically under the gravity gradient, but this passive gravity-gradient stabilization severely limits the current in the conductor, and therefore limits the thrust. Two methods have been developed to stabilize electrodynamic tethers and improve their performance. First, the system spins with an average spin rate significantly higher than the orbital rate, increasing tether tension for a more robust and controllable tether system, and providing a better orientation of the tether with respect to the magnetic field for orbital maneuvering. Second, electric current variation is used to control both the tether spin parameters and the tether bending modes. It is shown that a controlled, spinning electrodynamic tether can consistently deliver a much higher thrust compared with the traditional "hanging" tether configuration. Minimum-time orbit transfers with spinning tethers can be described approximately by a set of relatively simple ordinary differential equations using Pontryagin's Principle. These techniques were developed to control the dynamics of the Spinning Electrodynamic Tether (SET) system. This uses a conductor two to ten kilometers long as an electrodynamic thruster for a low-thrust orbit transfer vehicle. The SET was simulated with a PC-based computer program to evaluate its orbit transfer capabilities. This vehicle is capable of repeated large orbit changes in low earth orbit, totaling >50 km/sec each year for several years.
... On the other hand, there are tropical tornadoes, and EarthA ~_~ Radiation belts ~Orbital towe... more ... On the other hand, there are tropical tornadoes, and EarthA ~_~ Radiation belts ~Orbital tower r 1 ro r, 6378km 42166 km ~I 15 'i28km iO0 Toper ratio I0 ~-n Tower cross-sectional diameter ... A major difficulty in building the orbital tower is the immense volume of material needed ...
Space elevator concepts for low-cost space launches are reviewed. Previous concepts suffered from... more Space elevator concepts for low-cost space launches are reviewed. Previous concepts suffered from requirements for ultra-high-strength materials, dynamically unstable systems, or from danger of collision with space debris. The use of magnetic grain streams solves these problems. Magnetic grain streams can support short space elevators for lifting payloads cheaply into Earth orbit, overcoming the material strength problem in building space
Improved laboratory techniques were developed for the measurement of seismic velocities, elastic ... more Improved laboratory techniques were developed for the measurement of seismic velocities, elastic constants, and loss factors in rock cores. The method used was the forced and free vibration of cylindrical cores in longitudinal, torsional, and flexural vibration modes. The results from Ohio sedimentary rock cores selected from the Brassficld limestone, the Cedarville dolomite, and the Columbus limestone were compared to
The Flight Dynamics Laboratory of the US Air Force is developing analysis, test, and vibration co... more The Flight Dynamics Laboratory of the US Air Force is developing analysis, test, and vibration control technologies for flexible space structures. This program requires the development of low-restraint suspension systems to simulate the dynamics of structures in space. Such ...
... It will be assumed that a model (SINDA, NASTRAN, or equivalent) exists whereby the structural... more ... It will be assumed that a model (SINDA, NASTRAN, or equivalent) exists whereby the structural deformation of the flex-ible appendage resulting from solar heating can be determined from elements of the state vector and time. ...
Lunar space elevators could revolutionize the development of the Moon. The lunar space elevator s... more Lunar space elevators could revolutionize the development of the Moon. The lunar space elevator system allows solar-powered robotic vehicles to climb a high-strength composite ribbon from the lunar surface to beyond the L1 Lagrangian point, where payloads of lunar resources could be released into Earth orbit for major space construction projects. The overall system concept includes the lunar space elevator, a robotic construction system for the components, and robotic vehicles to carry lunar products into Earth orbit for construction and for upper stage propellant, and Earth-orbit payloads to the lunar surface for lunar habitat supplies. The construction system creates building blocks from lunar materials, using automated assembly and wire forming to construct complex shapes. The lunar space elevators provide non-rocket transportation of these lunar products from polar and equatorial mining sites into Earth orbit. This architecture is a new way to create a lunar base for robotic and human operations on the surface. A lunar space elevator using existing high-strength composites with a lifting capacity of 2000 N at the base equipped with solar-powered capsules moving at 100 km/hour could lift 584,000 kg/yr of lunar material into high Earth orbit. Since launch costs twenty years from now may be $1,000/kg, this material would be worth half a billion dollars per year, creating a new era of space development.
The ElectroDynamic Delivery Express (EDDE) is an autonomous space vehicle that can deliver multip... more The ElectroDynamic Delivery Express (EDDE) is an autonomous space vehicle that can deliver multiple small satellites from any low earth orbit (LEO) to any other desired low earth orbit within months, without using fuel. EDDE uses solar power to drive multiampere currents through a multi-kilometer aluminum tape. The tape sees a force normal to both itself and the local magnetic field. The tape is electrically connected to the ambient ionosphere to close the current loop externally. EDDE spins at ~8X/orbit to improve both stability and operational flexibility. Changing the current as a function of orbit and spin phase imposes forces and torques that allow any desired changes in orbit and spin. This allows far higher performance than possible with a hanging electrodynamic tether. For high-inclination orbital plane changes in LEO, EDDE can be more than twice as fast as more conventional high-specific-impulse electric rockets, and has much higher delta-V capability, since it does not exp...
It is commonly accepted now that large debris objects, such as derelict satellites and rocket bod... more It is commonly accepted now that large debris objects, such as derelict satellites and rocket bodies, should be removed from LEO to prevent or at least reduce the frequency of new catastrophic collisions. Such collisions can produce hundreds of thousands of debris fragments in the centimeter range (“shrapnel”) that are hard to track, but could be long-lived and lethal to operational spacecraft. Different technologies are being proposed and developed for debris removal. While it is important to begin the process of debris removal in the near future, it is not less important to assess the sustainability and long-term implications of the proposed debris removal campaigns. In this paper, we describe a high-level statistical model of shrapnel production and use it to evaluate the average cost of a catastrophic collision as the statistically expected loss due to the damage to operational satellites and loss of their functions as a result of future collisions in LEO. The model is phenomeno...
Two methods using long tethers are examined for the disposal of inoperative satellites or debris ... more Two methods using long tethers are examined for the disposal of inoperative satellites or debris in GEO. The disposal method is to move the orbit of the satellite 300 km from GEO to prevent interference with operating satellites. The first method uses a service vehicle with dual 300 km tethers. The vehicle docks with target number 1, then uses rocket thrust to carry the pair to target number 2. The two satellites are extended upward and downward 300 km by the two tethers and are released in turn. After the first release, the service vehicle drifts to the next target, releases the second satellite, then uses a small rocket thrust to rendezvous with target number 3. The second method is to oscillate a single target satellite upward on the end of a 600-km tether into an in-plane pendulum mode with a libration half-angle of 15 degrees. Tether-based disposal is compared in terms of mass required with conventional rockets and with the tumble-orbit transfer, previously proposed by one of t...
The Wright Laboratory is the Air Force center for air vehicles, responsible for developing advanc... more The Wright Laboratory is the Air Force center for air vehicles, responsible for developing advanced technology and incorporating it into new flight vehicles and for continuous technological improvement of operational air vehicles. Part of that responsibility is the problem of acoustic fatigue. With the advent of jet aircraft in the 1950's, acoustic fatigue of aircraft structure became a significant problem. In the 1960's the Wright Laboratory constructed the first large acoustic fatigue test facilities in the United States, and the laboratory has been a dominant factor in high-intensity acoustic testing since that time. This paper discusses some of the intense environments encountered by new and planned Air Force flight vehicles, and describes three new acoustic test facilities of the Wright Laboratory designed for testing structures in these dynamic environments. These new test facilities represent the state of the art in high-temperature, high-intensity acoustic testing an...
A new device is described for measuring the mass of weightless objects in space vehicles, based o... more A new device is described for measuring the mass of weightless objects in space vehicles, based on new techniques. The zero-gravity massmeter measures the mass of an unknown object by measuring the change in center of mass between the object and a connected known mass. The new device has advantages over past techniques that depended on the frequency of an unknown mass on a spring. The device can be used over a large range of unknown masses, making it applicable to measuring bone loss in astronauts and the mass of small specimens such as crystal growth experiments. This zero-gravity massmeter technique can also be applied to measure the mass of fuel tanks and other objects tethered to a Space Station, as well as the mass of the station itself.
T he nearly 2,200 spent stages and dead satellites in low Earth orbit (LEO) – a mass of nearly 2,... more T he nearly 2,200 spent stages and dead satellites in low Earth orbit (LEO) – a mass of nearly 2,000 tons – is starting to act as a slow-release anti-satellite (ASAT) system, randomly targeting valuable space assets. The Cosmos-Iridium collision of 2009 produced an effect very similar to the Chinese ASAT test in 2007: the satellites shredded each other, producing over 2,000 tracked fragments and over 100,000 untracked fragments, a cloud of " shrapnel " potentially lethal to operational spacecraft. These debris clouds have spread out and will persist for decades. The probability of more catastrophic collisions is no longer negligible: it has now reached 8% per year, and will scale with the square of the number of large objects in congested regions of LEO. Given the current launch rates, this collision rate could double within the next 20 years. The Cosmos-Iridium collision involved a total mass of 1.5 tons, which was substantially less than what was statistically expected t...
The ElectroDynamic Debris Eliminator (EDDE) is a LEO vehicle of a new class. It is solar-powered ... more The ElectroDynamic Debris Eliminator (EDDE) is a LEO vehicle of a new class. It is solar-powered and uses electric current in a long conductor to thrust against the Earth's magnetic field. Operating without propellant, EDDE can repeatedly change its altitude by hundreds of kilometers per day and its orbital plane by several degrees per day. EDDE weighs about 100 kg, but it can move multi-ton payloads. We consider three options for debris removal campaigns in low Earth orbit using EDDE. A dozen EDDE vehicles could remove all large debris from LEO in 7 years. They could all be launched on one ESPA ring (two per slot), but phased deployment has advantages. Two EDDE vehicles can be launched each year and retired 5 years later. In 9 years of operation, 2,000 tons of large legacy debris and 97% of the collision-generated debris potential in LEO can be removed, at an average cost of less than $400/kg and an average annual cost of less than $90M. We also consider a campaign that removes...
The ElectroDynamic Delivery Experiment (EDDE) is proposed for a space demonstration. EDDE consist... more The ElectroDynamic Delivery Experiment (EDDE) is proposed for a space demonstration. EDDE consists of an autonomous space vehicle powered by lightweight solar arrays, a bi-directional electrodynamic tether, and batteries for power leveling. The EDDE vehicle can modify its orbit repeatedly without rocket fuel, and can change all six orbital parameters by modulating and reversing the current flow in the conducting tether. The base spacecraft is connected to the service module by a 6-km-long electrodynamic tether, and is designed for 2 kW of power and a total mass of 180 kg. Tether lifetime of several years is achieved with a two-strand caduceus, with the strands connected every few meters. Tether libration is minimized by mass distribution and by active current control. The vehicle and tether system concepts are developed, the operational envelopes are examined, and potential applications are evaluated. The EDDE vehicle is about twice as fast as ion rockets for high-inclination orbita...
2nd International Energy Conversion Engineering Conference, 2004
Electrodynamic tethers produce low thrust through interaction of the electric current in the teth... more Electrodynamic tethers produce low thrust through interaction of the electric current in the tether with the Earth's magnetic field. The thrust is comparable with that of ion rockets and Hall thrusters, and they have the added advantage that they are propellantless, allowing them to produce an order of magnitude greater velocity changes than ion rockets. However, the long conductors of such electrodynamic thrusters typically exhibit unstable behaviors with higher currents. Instability affects both libration and bending modes of tether motion and significantly limits the performance characteristics of electrodynamic tether thrusters. Previous concepts for electrodynamic tethers have proposed stabilizing them by hanging vertically under the gravity gradient, but this passive gravity-gradient stabilization severely limits the current in the conductor, and therefore limits the thrust. Two methods have been developed to stabilize electrodynamic tethers and improve their performance. First, the system spins with an average spin rate significantly higher than the orbital rate, increasing tether tension for a more robust and controllable tether system, and providing a better orientation of the tether with respect to the magnetic field for orbital maneuvering. Second, electric current variation is used to control both the tether spin parameters and the tether bending modes. It is shown that a controlled, spinning electrodynamic tether can consistently deliver a much higher thrust compared with the traditional "hanging" tether configuration. Minimum-time orbit transfers with spinning tethers can be described approximately by a set of relatively simple ordinary differential equations using Pontryagin's Principle. These techniques were developed to control the dynamics of the Spinning Electrodynamic Tether (SET) system. This uses a conductor two to ten kilometers long as an electrodynamic thruster for a low-thrust orbit transfer vehicle. The SET was simulated with a PC-based computer program to evaluate its orbit transfer capabilities. This vehicle is capable of repeated large orbit changes in low earth orbit, totaling >50 km/sec each year for several years.
... On the other hand, there are tropical tornadoes, and EarthA ~_~ Radiation belts ~Orbital towe... more ... On the other hand, there are tropical tornadoes, and EarthA ~_~ Radiation belts ~Orbital tower r 1 ro r, 6378km 42166 km ~I 15 'i28km iO0 Toper ratio I0 ~-n Tower cross-sectional diameter ... A major difficulty in building the orbital tower is the immense volume of material needed ...
Space elevator concepts for low-cost space launches are reviewed. Previous concepts suffered from... more Space elevator concepts for low-cost space launches are reviewed. Previous concepts suffered from requirements for ultra-high-strength materials, dynamically unstable systems, or from danger of collision with space debris. The use of magnetic grain streams solves these problems. Magnetic grain streams can support short space elevators for lifting payloads cheaply into Earth orbit, overcoming the material strength problem in building space
Improved laboratory techniques were developed for the measurement of seismic velocities, elastic ... more Improved laboratory techniques were developed for the measurement of seismic velocities, elastic constants, and loss factors in rock cores. The method used was the forced and free vibration of cylindrical cores in longitudinal, torsional, and flexural vibration modes. The results from Ohio sedimentary rock cores selected from the Brassficld limestone, the Cedarville dolomite, and the Columbus limestone were compared to
The Flight Dynamics Laboratory of the US Air Force is developing analysis, test, and vibration co... more The Flight Dynamics Laboratory of the US Air Force is developing analysis, test, and vibration control technologies for flexible space structures. This program requires the development of low-restraint suspension systems to simulate the dynamics of structures in space. Such ...
... It will be assumed that a model (SINDA, NASTRAN, or equivalent) exists whereby the structural... more ... It will be assumed that a model (SINDA, NASTRAN, or equivalent) exists whereby the structural deformation of the flex-ible appendage resulting from solar heating can be determined from elements of the state vector and time. ...
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Papers by Jerome Pearson