This document discusses using tethers to address the issue of orbital debris. It proposes using tethers to relocate about 1500 large debris objects accounting for most of the mass in low Earth orbit. Tethers could capture debris using spinning nets or cooperative maneuvers with robotic spacecraft. Relocating debris could reduce collision risks for operational spacecraft and provide ballast for high-delta V tether transport systems. A scenario is presented where 12 tether spacecraft could relocate most large debris over about 5 years.
The document discusses the design of magnetic sail (magsail) systems for spacecraft propulsion. It describes a proposed demonstrator magsail with a 200m radius and 25.7kg mass, and an operational magsail with 20,000m radius and 7,060 metric tonne mass. The operational design could accelerate at 0.003185 m/s^2 and deliver over 100,000kg payloads to Mars or Saturn. Future advances in superconductors could enable magsails to deliver payloads of over 400,000kg to Jupiter and millions of kilograms to the outer planets.
The document summarizes a proposal for a fission fragment rocket engine (FFRE) capable of powering spacecraft. Key points:
- The FFRE uses suspended plutonium carbide dust grains that undergo fission, producing fragments that are directed out the nozzle at 1.7% the speed of light, generating thrust.
- Initial designs suggest the FFRE could provide 10s to 100s of pounds of continuous thrust for years, with a specific impulse over 500,000 seconds.
- Preliminary assessments found a FFRE-powered spacecraft could travel faster and with more payload than current chemical or nuclear designs, enabling missions to Jupiter within 8 years round trip.
- While the concept is
This document provides information on 24 different tether missions conducted between 1992 and 2017. It includes details on the mission name, objective, characteristics of the tether used, length deployed, outcomes and lessons learned for each mission. The missions spanned various space agencies and covered objectives such as demonstrating electrodynamic tether propulsion, studying tether dynamics, technology demonstrations and more. While many missions successfully deployed tethers, shortened mission lengths and failures also occurred from issues like protruding hardware, atomic oxygen erosion and communication failures. Overall the document outlines the progression of tether mission technology and research over 25 years.
The mission aims to map space debris in low Earth orbit between 1,000-3,000 km using 6 small satellites. Each satellite will use an infrared camera to image debris and calculate its orbit. The satellites will be placed in 3 evenly spaced orbital planes by a Delta II rocket and slowly lower their orbits over 30 days to map the entire region. Their design emphasizes modularity for low cost and mass, using commercial off-the-shelf components, with a focus on thermal control, power, communications and orbital maneuvering systems to complete the debris mapping mission.
This document discusses various concepts and technologies related to interstellar travel, including:
1) Current rocket technologies are insufficient to reach other stars due to limitations of chemical fuels; multistage rockets and new fuels like nuclear or antimatter could help.
2) The nearest star is over 4 light years away, so travel at current speeds would take tens of thousands of years; new propulsion methods like ion drives, solar sails, and ramjets could enable much faster travel.
3) However, special relativity shows that nothing can travel faster than light speed, posing a fundamental limit to interstellar travel; speculative ideas like wormholes or generation ships may be needed to overcome this.
1. Electrodynamic tethers use the interaction between electric current in a conducting tether and Earth's magnetic field to propel spacecraft. As the tether moves through the magnetic field, a voltage is induced along its length.
2. When current is run through the tether, the Lorentz force from the magnetic field can be used for propulsion. Current can be collected from ionospheric plasma to de-orbit a satellite or an external power source can overcome the induced voltage to boost an orbit.
3. Tethers provide propellantless propulsion and can lower the cost of in-space transportation by reducing the need to launch propellant from Earth. Potential applications include de-orbiting satellites
I'm not the author of this presentation, I'm just sharing it here for better accessibility.
This slideshow was given by Roger Shawyer to NSF (NASA spaceflight forum) member Mullerton for wider distribution.
The document discusses the design of magnetic sail (magsail) systems for spacecraft propulsion. It describes a proposed demonstrator magsail with a 200m radius and 25.7kg mass, and an operational magsail with 20,000m radius and 7,060 metric tonne mass. The operational design could accelerate at 0.003185 m/s^2 and deliver over 100,000kg payloads to Mars or Saturn. Future advances in superconductors could enable magsails to deliver payloads of over 400,000kg to Jupiter and millions of kilograms to the outer planets.
The document summarizes a proposal for a fission fragment rocket engine (FFRE) capable of powering spacecraft. Key points:
- The FFRE uses suspended plutonium carbide dust grains that undergo fission, producing fragments that are directed out the nozzle at 1.7% the speed of light, generating thrust.
- Initial designs suggest the FFRE could provide 10s to 100s of pounds of continuous thrust for years, with a specific impulse over 500,000 seconds.
- Preliminary assessments found a FFRE-powered spacecraft could travel faster and with more payload than current chemical or nuclear designs, enabling missions to Jupiter within 8 years round trip.
- While the concept is
This document provides information on 24 different tether missions conducted between 1992 and 2017. It includes details on the mission name, objective, characteristics of the tether used, length deployed, outcomes and lessons learned for each mission. The missions spanned various space agencies and covered objectives such as demonstrating electrodynamic tether propulsion, studying tether dynamics, technology demonstrations and more. While many missions successfully deployed tethers, shortened mission lengths and failures also occurred from issues like protruding hardware, atomic oxygen erosion and communication failures. Overall the document outlines the progression of tether mission technology and research over 25 years.
The mission aims to map space debris in low Earth orbit between 1,000-3,000 km using 6 small satellites. Each satellite will use an infrared camera to image debris and calculate its orbit. The satellites will be placed in 3 evenly spaced orbital planes by a Delta II rocket and slowly lower their orbits over 30 days to map the entire region. Their design emphasizes modularity for low cost and mass, using commercial off-the-shelf components, with a focus on thermal control, power, communications and orbital maneuvering systems to complete the debris mapping mission.
This document discusses various concepts and technologies related to interstellar travel, including:
1) Current rocket technologies are insufficient to reach other stars due to limitations of chemical fuels; multistage rockets and new fuels like nuclear or antimatter could help.
2) The nearest star is over 4 light years away, so travel at current speeds would take tens of thousands of years; new propulsion methods like ion drives, solar sails, and ramjets could enable much faster travel.
3) However, special relativity shows that nothing can travel faster than light speed, posing a fundamental limit to interstellar travel; speculative ideas like wormholes or generation ships may be needed to overcome this.
1. Electrodynamic tethers use the interaction between electric current in a conducting tether and Earth's magnetic field to propel spacecraft. As the tether moves through the magnetic field, a voltage is induced along its length.
2. When current is run through the tether, the Lorentz force from the magnetic field can be used for propulsion. Current can be collected from ionospheric plasma to de-orbit a satellite or an external power source can overcome the induced voltage to boost an orbit.
3. Tethers provide propellantless propulsion and can lower the cost of in-space transportation by reducing the need to launch propellant from Earth. Potential applications include de-orbiting satellites
I'm not the author of this presentation, I'm just sharing it here for better accessibility.
This slideshow was given by Roger Shawyer to NSF (NASA spaceflight forum) member Mullerton for wider distribution.
This document discusses electrodynamic tethers, which use the Lorentz force from the interaction of electric current in the tether and the Earth's magnetic field to produce propulsion. It provides a history of tethers, explains how they work based on electromagnetic principles, and discusses their applications such as deorbiting satellites. Electrodynamic tethers provide a propellantless option for orbital maneuvers but require stabilization techniques due to inherent instability. They have advantages of being reusable, environmentally friendly, and low-cost compared to traditional chemical rockets.
This document discusses electrodynamic tethers (EDTs), which are long conducting wires that can be deployed from satellites to provide propulsion through interaction with Earth's magnetic field. EDTs work by passing a current through the tether, which generates a Lorentz force perpendicular to both the current and the magnetic field. This force can be used to accelerate a satellite or lower its orbit. EDTs offer advantages over traditional rocket thrusters as they require no propellant. The document outlines the principle, working, applications such as deorbiting space junk, and future prospects of EDTs, concluding that they can provide a cost-effective means of propulsion and power in space.
This document discusses electrodynamic tethers, which use the Lorentz force generated by the interaction between a current in the tether and the Earth's magnetic field to propel or deorbit spacecraft. Electrodynamic tethers can be used to accelerate a spacecraft into a higher orbit or decelerate it into a lower orbit without using propellant. They work by either collecting electrons at one end of the tether and expelling them at the other end, or driving current in the opposite direction. Challenges include stabilizing the tether's motion, but feedback algorithms can help maintain stability. Potential applications include propulsion of spacecraft in low Earth orbit, deorbiting of satellites, and reboosting of decaying orbits.
The document discusses plans for developing tether boost facilities to enable in-space transportation. Key points include:
1) Tether Unlimited is developing technologies like electrodynamic tethers and momentum exchange to provide propellantless propulsion beyond low Earth orbit using tether boost facilities.
2) Facilities would use tethers up to 100km long to boost payloads from LEO to destinations like the Moon and Mars in rapid transfer times of 5 days and 90 days respectively.
3) An incremental development path is proposed starting with demonstrating technologies on suborbital and LEO missions before building operational tether boost facilities to GEO, the Moon, and Mars.
Preparing interstellar travel with ultrafast beam-powered lightsailsAdvanced-Concepts-Team
This document discusses proposals for interstellar travel using beam-powered propulsion techniques. It presents three main classifications of interstellar travel: 1) Relativistic reaction propulsion using nuclear or antimatter rockets, 2) Spacetime distortions requiring exotic matter, and 3) Generation ships. It then focuses on the basics and applications of radiation propulsion, including solar and beam-powered light sails. Models are presented for photon rocket kinematics, single trips to Alpha Centauri using antimatter rockets and beam-powered sails, and a two-stage laser-pushed sail concept for roundtrips requiring much less energy than other proposals.
This document proposes developing an ultra-light solar sail without a plastic backing for use in interstellar travel. It summarizes the proposed scope of work, which includes analyzing the reflectivity and engineering constraints of nanometer-thick aluminum sheets and grids, as well as doped carbon nanotubes. Preliminary analyses show these ultra-light concepts could achieve accelerations over 100 times greater than conventional solar sails and reach distances like Pluto in months or 10,000 AU in decades. The document recommends a Phase II experimental program to fabricate and test nanoscale reflectors and verify their properties.
This document discusses using shepherd satellites to provide guidance, navigation, and control for arrays of microsatellites performing formation flying. It proposes using optical scattering and gradient forces generated by lasers on the shepherd satellites to apply corrective forces to the microsatellite array from a distance. Analytic models predict these radiation forces could provide restorative forces of 10-5 N to 10-4 N using laser powers of 10-10 kW to 100 kW. Potential applications include drag makeup for low Earth orbiting satellites, position control for array formation, and correcting perturbations in geosynchronous Earth orbit.
Mini-Magnetospheric Plasma Propulsion (M2P2) is a proposed method of using the solar wind as a free energy source to facilitate high-speed spacecraft for exploration of the solar system and beyond. M2P2 works by creating a mini-magnetic field around the spacecraft using low-energy plasma injections, which is then carried by the solar wind similar to the interaction of the solar wind with planetary magnetospheres. Computer simulations and laboratory experiments show M2P2 could accelerate a 100-200kg spacecraft to 50-80km/s in 3 months using only 15-30kg of propellant. M2P2 also provides large-scale radiation shielding and has the potential to enable faster
This is the presentation given at the end of the Space studies program at NASA Ames, August 2009. The ACCESS Mars project stands for Assessing Cave Capabilities and Evaluating Specific Solutions (ACCESS) Mars explores the future of robotic and human exploration missions to Mars via subsurface habitation.
Mission statement: "...to develop a mission architecture for an initial settlement on Mars by assessing the feasibility of cave habitation as an alternative to proposed surface-based solutions".
The Cassini Radar system on the Cassini spacecraft provided synthetic aperture radar imaging of Titan's surface. It operated in different modes like imaging, altimetry, and radiometry. Imaging produced BIDR products which showed various geological features on Titan like lakes, dunes, and craters. Analysis of these features provided insights into Titan's methane-ethane based hydrologic cycle and surface processes like erosion. The Cassini mission significantly expanded understanding of Saturn's moon Titan through radar observations over more than a decade.
1) The document discusses a proposed method for maintaining a formation of millions of small spacecraft called "flyers" in orbit around the Earth-Sun L1 point to form a solar shield to counteract global warming.
2) Each flyer would be about 1 meter in diameter and 1 gram in mass, and they would be launched in stacks of 800,000 flyers weighing 1 ton total.
3) Maintaining the formation would rely on randomizing the initial velocities of flyers and using their solar sailing capabilities and differences in solar pressure to keep them separated in halo-like trajectories without using propellant. Failed or malfunctioning flyers could be disposed of without threatening other spacecraft.
The document describes a proposed Direct Aerial Robot Explorers (DARE) concept using guided balloons for planetary exploration. DARE balloons would carry scientific payloads and deploy microprobes to study the atmospheres and surfaces of various planets like Venus, Mars, Titan, and Jupiter over multi-month missions. A key feature is a lightweight trajectory control system that could steer the balloons using small wings to provide more targeted scientific observations than previous uncontrolled balloons. The document provides examples of how DARE balloons could operate on different planets to better understand atmospheric dynamics and composition.
The document describes a proposed concept for a solid state aircraft that has no moving parts. It would use thin film solar arrays to collect energy from the sun, thin film lithium batteries to store the energy, and ionic polymer metal composites as artificial muscles to flap its wings and provide lift and thrust. The aircraft could operate on Earth, Venus, or Mars due to its flexible design and ability to use solar power. It would provide a novel way to explore other planets easily and with minimal cost compared to traditional aircraft.
The document discusses proposals for building a space elevator that would provide cheaper access to space. It would consist of a cable anchored to the Earth and extending over 60,000 miles into space. Key elements would include a ribbon tether made of carbon nanotubes, an anchor station on Earth, spacecraft and climbers to carry payloads up the tether using lasers or solar power, and a counterweight in space. Major challenges to overcome are atmospheric effects, impacts from space debris, and health and technical issues. Proponents argue it could revolutionize space travel by providing cheaper access to space.
This document proposes a mission to send a probe to 1000 AU within 50 years to explore the very local interstellar medium. It would use a gravity assist at Jupiter to eliminate angular momentum, fall into 4 solar radii from the sun for a high-speed propulsion burn, and reach speeds of 20 AU/year. Required technologies include high-Isp propulsion, thermal shields, long-life electronics, and autonomous operation. The proposed concept uses solar thermal propulsion and liquid hydrogen, carried on an Atlas V launch vehicle. The probe would perform in situ measurements of the interstellar medium and escape the heliosphere to study boundary regions.
The document proposes a concept for a realistic interstellar explorer probe. Key points:
- The probe would travel to about 1000 AU, penetrating the local interstellar medium to study it scientifically.
- Technologies needed include high-Isp propulsion for an acceleration at perihelion, thermal shielding, long-range communications, and a radioisotope power source.
- A key challenge is accelerating the probe to high speeds (>20 AU/year) through a perihelion burn near the Sun leveraging its gravity and Oberth effect. Several propulsion concepts are considered like solar thermal, nuclear pulse, or nuclear thermal.
The document summarizes a proposal for a space elevator - a structure that could transport material from Earth's surface into space using a cable anchored to the Earth and extending into space. Key points:
- The space elevator would consist of a carbon nanotube cable anchored to the Earth and extending 62,000 miles into space, with a counterweight beyond geostationary orbit to keep the cable taut.
- Robotic climbers would ride the cable into space, powered by lasers on Earth. Climbers could transport up to 13 tons of cargo at 118 mph.
- In addition to transporting cargo, the proposal suggests the space elevator could transport people to the Moon or Mars using the rotational
Development of a mathematical model describing the motion of the space tether system.
Creation of the program complex designed to analyze the dynamics of the space tether system.
The document proposes a student research project called "Swachch Antariksh" to collect magnetic space debris using an electromagnet onboard a satellite. The satellite would orbit Earth collecting small debris in an aluminum alloy net and periodically depositing it. Collected debris could be disposed of in a graveyard orbit or the South Pacific Ocean. The project aims to reduce risks posed by the growing amount of orbital debris and enable continued space exploration.
This document discusses a proposed mission concept to send a probe to 1000 AU within 50 years using currently feasible technologies. Key elements include:
1) Using a solar gravity assist at Jupiter to eliminate angular momentum, then falling to within 4 solar radii of the Sun to leverage the high speeds for an escape trajectory.
2) The probe would use a high-Isp propulsion system like solar thermal or nuclear thermal to accelerate during a 15-minute perihelion maneuver for solar system escape.
3) Enabling technologies discussed include high-temperature carbon-carbon shields, efficient radioisotope power, and laser optical communications. Follow-on studies are proposed to further develop the concepts.
This document discusses electrodynamic tethers, which use the Lorentz force from the interaction of electric current in the tether and the Earth's magnetic field to produce propulsion. It provides a history of tethers, explains how they work based on electromagnetic principles, and discusses their applications such as deorbiting satellites. Electrodynamic tethers provide a propellantless option for orbital maneuvers but require stabilization techniques due to inherent instability. They have advantages of being reusable, environmentally friendly, and low-cost compared to traditional chemical rockets.
This document discusses electrodynamic tethers (EDTs), which are long conducting wires that can be deployed from satellites to provide propulsion through interaction with Earth's magnetic field. EDTs work by passing a current through the tether, which generates a Lorentz force perpendicular to both the current and the magnetic field. This force can be used to accelerate a satellite or lower its orbit. EDTs offer advantages over traditional rocket thrusters as they require no propellant. The document outlines the principle, working, applications such as deorbiting space junk, and future prospects of EDTs, concluding that they can provide a cost-effective means of propulsion and power in space.
This document discusses electrodynamic tethers, which use the Lorentz force generated by the interaction between a current in the tether and the Earth's magnetic field to propel or deorbit spacecraft. Electrodynamic tethers can be used to accelerate a spacecraft into a higher orbit or decelerate it into a lower orbit without using propellant. They work by either collecting electrons at one end of the tether and expelling them at the other end, or driving current in the opposite direction. Challenges include stabilizing the tether's motion, but feedback algorithms can help maintain stability. Potential applications include propulsion of spacecraft in low Earth orbit, deorbiting of satellites, and reboosting of decaying orbits.
The document discusses plans for developing tether boost facilities to enable in-space transportation. Key points include:
1) Tether Unlimited is developing technologies like electrodynamic tethers and momentum exchange to provide propellantless propulsion beyond low Earth orbit using tether boost facilities.
2) Facilities would use tethers up to 100km long to boost payloads from LEO to destinations like the Moon and Mars in rapid transfer times of 5 days and 90 days respectively.
3) An incremental development path is proposed starting with demonstrating technologies on suborbital and LEO missions before building operational tether boost facilities to GEO, the Moon, and Mars.
Preparing interstellar travel with ultrafast beam-powered lightsailsAdvanced-Concepts-Team
This document discusses proposals for interstellar travel using beam-powered propulsion techniques. It presents three main classifications of interstellar travel: 1) Relativistic reaction propulsion using nuclear or antimatter rockets, 2) Spacetime distortions requiring exotic matter, and 3) Generation ships. It then focuses on the basics and applications of radiation propulsion, including solar and beam-powered light sails. Models are presented for photon rocket kinematics, single trips to Alpha Centauri using antimatter rockets and beam-powered sails, and a two-stage laser-pushed sail concept for roundtrips requiring much less energy than other proposals.
This document proposes developing an ultra-light solar sail without a plastic backing for use in interstellar travel. It summarizes the proposed scope of work, which includes analyzing the reflectivity and engineering constraints of nanometer-thick aluminum sheets and grids, as well as doped carbon nanotubes. Preliminary analyses show these ultra-light concepts could achieve accelerations over 100 times greater than conventional solar sails and reach distances like Pluto in months or 10,000 AU in decades. The document recommends a Phase II experimental program to fabricate and test nanoscale reflectors and verify their properties.
This document discusses using shepherd satellites to provide guidance, navigation, and control for arrays of microsatellites performing formation flying. It proposes using optical scattering and gradient forces generated by lasers on the shepherd satellites to apply corrective forces to the microsatellite array from a distance. Analytic models predict these radiation forces could provide restorative forces of 10-5 N to 10-4 N using laser powers of 10-10 kW to 100 kW. Potential applications include drag makeup for low Earth orbiting satellites, position control for array formation, and correcting perturbations in geosynchronous Earth orbit.
Mini-Magnetospheric Plasma Propulsion (M2P2) is a proposed method of using the solar wind as a free energy source to facilitate high-speed spacecraft for exploration of the solar system and beyond. M2P2 works by creating a mini-magnetic field around the spacecraft using low-energy plasma injections, which is then carried by the solar wind similar to the interaction of the solar wind with planetary magnetospheres. Computer simulations and laboratory experiments show M2P2 could accelerate a 100-200kg spacecraft to 50-80km/s in 3 months using only 15-30kg of propellant. M2P2 also provides large-scale radiation shielding and has the potential to enable faster
This is the presentation given at the end of the Space studies program at NASA Ames, August 2009. The ACCESS Mars project stands for Assessing Cave Capabilities and Evaluating Specific Solutions (ACCESS) Mars explores the future of robotic and human exploration missions to Mars via subsurface habitation.
Mission statement: "...to develop a mission architecture for an initial settlement on Mars by assessing the feasibility of cave habitation as an alternative to proposed surface-based solutions".
The Cassini Radar system on the Cassini spacecraft provided synthetic aperture radar imaging of Titan's surface. It operated in different modes like imaging, altimetry, and radiometry. Imaging produced BIDR products which showed various geological features on Titan like lakes, dunes, and craters. Analysis of these features provided insights into Titan's methane-ethane based hydrologic cycle and surface processes like erosion. The Cassini mission significantly expanded understanding of Saturn's moon Titan through radar observations over more than a decade.
1) The document discusses a proposed method for maintaining a formation of millions of small spacecraft called "flyers" in orbit around the Earth-Sun L1 point to form a solar shield to counteract global warming.
2) Each flyer would be about 1 meter in diameter and 1 gram in mass, and they would be launched in stacks of 800,000 flyers weighing 1 ton total.
3) Maintaining the formation would rely on randomizing the initial velocities of flyers and using their solar sailing capabilities and differences in solar pressure to keep them separated in halo-like trajectories without using propellant. Failed or malfunctioning flyers could be disposed of without threatening other spacecraft.
The document describes a proposed Direct Aerial Robot Explorers (DARE) concept using guided balloons for planetary exploration. DARE balloons would carry scientific payloads and deploy microprobes to study the atmospheres and surfaces of various planets like Venus, Mars, Titan, and Jupiter over multi-month missions. A key feature is a lightweight trajectory control system that could steer the balloons using small wings to provide more targeted scientific observations than previous uncontrolled balloons. The document provides examples of how DARE balloons could operate on different planets to better understand atmospheric dynamics and composition.
The document describes a proposed concept for a solid state aircraft that has no moving parts. It would use thin film solar arrays to collect energy from the sun, thin film lithium batteries to store the energy, and ionic polymer metal composites as artificial muscles to flap its wings and provide lift and thrust. The aircraft could operate on Earth, Venus, or Mars due to its flexible design and ability to use solar power. It would provide a novel way to explore other planets easily and with minimal cost compared to traditional aircraft.
The document discusses proposals for building a space elevator that would provide cheaper access to space. It would consist of a cable anchored to the Earth and extending over 60,000 miles into space. Key elements would include a ribbon tether made of carbon nanotubes, an anchor station on Earth, spacecraft and climbers to carry payloads up the tether using lasers or solar power, and a counterweight in space. Major challenges to overcome are atmospheric effects, impacts from space debris, and health and technical issues. Proponents argue it could revolutionize space travel by providing cheaper access to space.
This document proposes a mission to send a probe to 1000 AU within 50 years to explore the very local interstellar medium. It would use a gravity assist at Jupiter to eliminate angular momentum, fall into 4 solar radii from the sun for a high-speed propulsion burn, and reach speeds of 20 AU/year. Required technologies include high-Isp propulsion, thermal shields, long-life electronics, and autonomous operation. The proposed concept uses solar thermal propulsion and liquid hydrogen, carried on an Atlas V launch vehicle. The probe would perform in situ measurements of the interstellar medium and escape the heliosphere to study boundary regions.
The document proposes a concept for a realistic interstellar explorer probe. Key points:
- The probe would travel to about 1000 AU, penetrating the local interstellar medium to study it scientifically.
- Technologies needed include high-Isp propulsion for an acceleration at perihelion, thermal shielding, long-range communications, and a radioisotope power source.
- A key challenge is accelerating the probe to high speeds (>20 AU/year) through a perihelion burn near the Sun leveraging its gravity and Oberth effect. Several propulsion concepts are considered like solar thermal, nuclear pulse, or nuclear thermal.
The document summarizes a proposal for a space elevator - a structure that could transport material from Earth's surface into space using a cable anchored to the Earth and extending into space. Key points:
- The space elevator would consist of a carbon nanotube cable anchored to the Earth and extending 62,000 miles into space, with a counterweight beyond geostationary orbit to keep the cable taut.
- Robotic climbers would ride the cable into space, powered by lasers on Earth. Climbers could transport up to 13 tons of cargo at 118 mph.
- In addition to transporting cargo, the proposal suggests the space elevator could transport people to the Moon or Mars using the rotational
Development of a mathematical model describing the motion of the space tether system.
Creation of the program complex designed to analyze the dynamics of the space tether system.
The document proposes a student research project called "Swachch Antariksh" to collect magnetic space debris using an electromagnet onboard a satellite. The satellite would orbit Earth collecting small debris in an aluminum alloy net and periodically depositing it. Collected debris could be disposed of in a graveyard orbit or the South Pacific Ocean. The project aims to reduce risks posed by the growing amount of orbital debris and enable continued space exploration.
This document discusses a proposed mission concept to send a probe to 1000 AU within 50 years using currently feasible technologies. Key elements include:
1) Using a solar gravity assist at Jupiter to eliminate angular momentum, then falling to within 4 solar radii of the Sun to leverage the high speeds for an escape trajectory.
2) The probe would use a high-Isp propulsion system like solar thermal or nuclear thermal to accelerate during a 15-minute perihelion maneuver for solar system escape.
3) Enabling technologies discussed include high-temperature carbon-carbon shields, efficient radioisotope power, and laser optical communications. Follow-on studies are proposed to further develop the concepts.
The document discusses the Panel Processing of DebriSat project. DebriSat was a representative low earth orbit satellite that was destroyed in a hypervelocity impact test to generate debris fragments. The fragments were caught by foam panels in the test chamber. This summary discusses how the University of Florida processes these panels using archaeological techniques to maintain fragment integrity, tag locations, and organize large teams of workers. It also summarizes the extensive instrumentation used to document the catastrophic collision of DebriSat during the impact test.
Space Debris and Present Active Debris Removal TechniquesV!vEk@nAnD S
The document discusses space debris and present active debris removal techniques. It provides an introduction to space debris, describing the current debris situation and categories. It then discusses various active debris removal concepts and techniques being researched, such as solar sails, lasers, electrodynamic tethers, and capture vehicles. Some of the challenges to implementing effective debris removal are also outlined, such as the technical difficulties, costs, and need for international cooperation and policy.
This document proposes and analyzes concepts for spacecraft propulsion and power systems using positrons. It discusses two concepts - a solid-core engine where positrons heat propellant channels, and a gas-core engine where positrons heat a gaseous propellant. Thermal and fluid modeling of both concepts shows performance comparable to nuclear thermal rockets. A gas-core design could exceed 1000 seconds specific impulse needed for fast Mars missions. The document also discusses using positrons in a closed Brayton cycle system for spacecraft power.
This document describes the CubeSat High Impulse Propulsion System (CHIPS) being developed by CU Aerospace and VACCO Industries. CHIPS integrates primary propulsion, attitude control, and propellant storage into a single module compatible with CubeSats. It uses a micro-resistojet thruster and cold gas attitude control system. Testing of a prototype showed the resistojet can provide up to 563 N-s of total impulse using R134a propellant. The document discusses propulsion options for CubeSats and why electrothermal propulsion in the 70-400 second specific impulse range is best suited for enabling rapid orbital maneuvers within a day.
The document proposes building a space elevator using carbon nanotube composite materials to provide cheaper access to space. It describes a design for an initial small space elevator with a 20 ton capacity that could transport payloads to geosynchronous orbit in one week for $100 per pound, far cheaper than current options. The design addresses challenges like constructing a strong tether, deploying it into space, powering climbers, and anchoring it on Earth, which could be developed within a decade for under $10 billion. It concludes that a space elevator could transport over 5,000 kg of payload per day and ultimately cost just $10 per kg.
Space debris poses a hazard to satellites and spacecraft. Thousands of small pieces of debris orbit Earth at high speeds and can damage satellites through collision. The risk of impact is increasing as the amount of debris grows. Proposed solutions to reduce debris include attaching rocket motors to slow objects, preventing collision through satellite maneuvering and shielding, and using electrodynamic tethers to deorbit junk. Other ideas are to use radiation pressure from lasers or sunlight to slow debris for atmospheric reentry and removal. With the growing number of satellites launched, space debris will increasingly threaten continued space exploration and use unless addressed.
This document provides an overview of satellite systems, including Iridium, Globalstar, and ICO constellations. It begins with an introduction to satellite systems and their purposes. It then describes the different types of orbits used - geostationary (GEO), medium earth orbit (MEO), and low earth orbit (LEO). The document outlines the Iridium constellation of 66 satellites in 6 orbital planes. It also details the Globalstar system using 48 satellites and its use of LEO orbits. Finally, it compares key aspects of the Iridium, Globalstar, and ICO satellite networks.
Orbital debris poses risks to future space missions. Mitigation is the most effective strategy to limit debris, such as restricting debris generation and limiting time spent in low Earth orbit and geosynchronous orbit. International guidelines recommend no operational or long-term debris creation in these regions. Options to minimize debris include preventing explosions, limiting post-mission orbital time, and removing spacecraft from orbit at end of life.
I. X-ray astronomy will play an increasingly important role in studies of the early universe and large scale structure, but these studies are ultimately limited by sparse photon numbers. There is a need to develop progressively larger collecting area telescopes under increasingly severe mass constraints.
II. The challenge is greater in the X-ray band than optical, as X-ray telescopes reflect X-rays twice, requiring reflectors two orders of magnitude larger than the effective aperture. Large mass is currently problematic for Constellation-X mission.
III. Looking beyond Constellation, a radically different approach is needed based on super lightweight reflectors and perhaps in situ assembly of the telescope. This could enable an ultra high throughput X-
This document discusses the concept of an X-ray interferometer called MAXIM that could achieve micro-arcsecond resolution. It would consist of an optics spacecraft holding multiple flat mirrors in formation with a detector spacecraft to form interference patterns. The goal is to image phenomena like black hole accretion disks and supernovae with much higher resolution than current telescopes. A pathfinder mission is proposed with 100 microarcsecond resolution using two spacecraft separated by 1.4 meters as a technology demonstration.
USAF intercepted a report of a Cuban pilot's encounter with a UFO. In the 1970s, reliable military personnel sighted unidentified aerial objects near nuclear weapons facilities. Though the Air Force said these were isolated incidents, an Air Force document revealed they implemented increased security measures. Newly declassified documents from the CIA, FBI and other agencies indicate unidentified flying objects exist and some pose a threat to national security by demonstrating technologies beyond present human capability. However, the government has misled the public about the true nature and implications of the UFO phenomenon.
This document summarizes the agenda for the NIAC Phase I Fellows Meeting held on October 23-24, 2002. It provides an overview of the presentations and speakers, including status reports on various advanced aerospace concepts from NIAC fellows, as well as keynote speeches from experts in the fields of aerial robotics and the search for extraterrestrial intelligence.
The document discusses the possibility of controlling global weather through small, precise perturbations to the atmosphere. It describes how the chaotic nature of the atmosphere implies sensitivity to small changes and suggests a series of small perturbations may control weather evolution. It outlines components a global weather control system may have, including advanced numerical weather prediction, satellite sensing, and methods to introduce perturbations. It also presents an experiment using data assimilation to calculate perturbations needed to slightly alter a hurricane's track as a proof of concept.
The document discusses observations of various amphibian and reptile species' behavior in microgravity during a flight experiment. It was found that none of the animals vomited, possibly because they did not eat before the flight or because amphibians and reptiles have a weaker vomiting response than mammals. Different species reacted variably based on their ecology and phylogeny. Flexible limbed lizards tended to roll more, while geckos commonly displayed a "skydiving posture" related to their arboreal ancestry. Overall reactions to microgravity varied significantly between species based on both ecology and evolutionary history.
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1. Space Transport Development
Using Orbital Debris
NIAC Phase I Review Presentation
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Tether Applications, Inc.
Oct. 2002, pg. 1
Atlanta, October 24, 2002
Joe Carroll
619-421-2100
tether@cox.net
2. Project Objectives and Payoffs
1. Reduce the creation of collision-generated debris,
by relocating the ~1500 objects that account for
nearly all the mass & area of debris in low orbit.
2. Reduce the direct risk of collision between debris
& operating spacecraft, by clearing many smaller
objects out of the most popular altitude bands.
3. Collect ballast for high-deltaV “sling” facilities.
4. Prove out tethered capture, to justify such slings.
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3. Intro to Orbiting Tether Concepts
Momentum transfer
- Tension transfers momentum & energy
- DeltaVs up to ~4 km/s are feasible now
Electrodynamic effects
- Current in magnetic field causes force
- Connect to plasma to close current loop
Tethered platforms
- Artificial gravity w/low Coriolis effects
- Allows isolation and remote access
Electrons
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Magnetic
field
Force
4. Tethers Are Ready for Real Jobs!
SEDS-1, March 1993
- Deployed 20 km braided Spectra tether
- Slung 26 kg mass into controlled reentry
PMG, June 1993
- Hollow cathodes emit well & collect poorly
SEDS-2, March--April 1994
- Tether was seen by many around the world
- Impact risks are real (cut after 3.8 days!)
TiPS, June 1996--
- Libration damped out over several months
- 2mmx 4km tether is intact after 6.3 years!
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5. NIAC Phase I Tasks and Findings
1. Study LEO debris population and triage options
- Debris is very clustered in inclination & altitude
- Of ~2,000 tons in LEO, 98% is 1500 objects >100kg
2. Explore capture concepts, and make and test models
- Spinning net & two-dog capture both seem promising
3. Study rendezvous, capture, disposal, and contingencies
- It is hard for 100-kg tethers to deorbit objects >500kg
4. Flesh out system architecture & estimate performance
- 12 shepherds might relocate most debris in ~5 years
- Heavy debris can serve as ballast for “sling” tethers
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6. Data on Debris Mass in LEO
0 km 1000 2000 1 km 10 100 1000
Average Altitude Apogee-Perigee
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10 100 1000 1000
Orbit Inclination Object Mass
2
1
1
5
0
Tether Applications, Inc.
Oct. 2002, pg. 6
75% of the mass
is objects >1 ton;
97% is in objects
>200 kg!
2,000
1,000
0 tons
Cum.
Mass
2,000
1,000
0 tons
Cum.
Mass
2,000
1,000
0 tons
Cum.
Mass
Most mass is at
500-1000 km
altitude.
Most LEO debris
orbits are nearly
circular.
2,000
1,000
0 tons
Sun synch
81&83o
71&74o Cum.
Mass
Most is in
near-polar
orbits.
0o 40o 80o 120o 10 kg 100 1,000 10,000
7. Data on 3 LEO Debris Clusters
1000
500
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1000
500
0 tons
71-75o Inclination: 98% CIS
96-102o: US, CIS, other
0 tons
Cum.
Mass
Debris mass estimates provided by
NASA JSC Orbital Debris Office. 81-83o Inclination: 99% CIS
Tether Applications, Inc.
Oct. 2002, pg. 7
0 km 1000 2000
100 kg 1000 10000
Cum.
Mass
Average Altitude Object Mass
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Other Relevant Details
1. LEO debris has 200 acre-years exposure (LDEF<0.1).
2. Most collisions involve large debris, since they are most
of the “target area”. The collision rates are enhanced if
i1+ i2 ~
180o, as occurs with 81-83o and sun-synch orbits.
3. Debris is clustered in inclination and altitude, but the
ascending nodes and apsidal phases are nearly random.
4. The ownership and identity of large debris are known.
5. Intact spacecraft and stages all have launch support
hardpoints that are accessible once they separate.
9. Key Unknowns About Debris
1. Debris tumble rates
- Neither NASA nor DOD records tumble rate data
- But eddy currents can de-spin aluminum in weeks
- And amateur-class videos can detect tumble rates
2. Response of US and other debris owners
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- Are the treaty implications actually clear?
- Is a debris shepherd liable for anything it touches?
3. What can we do about GTO and GEO debris?
- ED tethers cannot easily reach those high orbits
- DeltaVs are low enough for ion-engine shepherds
Tether Applications, Inc.
Oct. 2002, pg. 9
10. Possible Triage Strategy
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1. Objects under ~500 kg
- Drop objects that will burn up into orbits below ISS
- Drop other objects into controlled-location reentries
2. Heavier objects near useful inclinations
- Capture them as they approach nodal coincidence
- Deliver to active ballast assemblers (near 500 km?)
- Or put them in lower-risk temporary storage orbits
3. Other heavy (or dangerous) objects
- Release into controlled reentry (hard to do!)
- Or deliver to larger tethers that can deorbit them
- Or put them in lower-debris-density storage orbits
11. 1989 Tethered Capture Contest
Contest Rules
Open to all MIT.
Soft/light grabber
(don’t break egg).
No practice tries.
Lift “ET” 3 times.
Score=total time.
Prize = $300!
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First Prize: Darryll Pines and Siegfried Zerweckh
Second Prize Design (of 4 designs entered)
12. Spinning Nets for Passive Capture
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Contrast-enhanced frames
from video of net spin-up.
Net was made from bead-chain
for high inertia/drag.
Flight net would use a fine
mesh of high-strength fiber.
Tether Applications, Inc.
Oct. 2002, pg. 12
#1 #2
#3
13. Cooperative “Two Dog” Capture
1. Approach & release
a roving sheepdog
3. Orient sheepdog for
re-capture by tether
(using dGPS, etc.)
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2. Inspect & capture debris,
as tether fine-tunes orbit.
14. Capture Hardware Issues
Basket-catch in net (spinning at ~2 rpm)
- Approach sideways, to slip net under debris
- Net rotates ~60o by time debris falls into mesh
- Nets are light: <50 g for house-size catch area
- Nets can complicate later debris use as ballast
- Nets can foul on shepherd, disabling one end
Cooperative “two dog” capture
- Sheepdog can survey debris before “biting” it
- Sheepdog also usable w/GTO and GEO debris
- Sensors & ops common w/high-deltaV slings
- Hardware must capture and release under load
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15. Is Tethered Rendezvous Feasible?
What could prevent rendezvous?
- Inaccurate relative-navigation sensor data
- Or poor prediction of the tether dynamics
- Or large disturbances (drag variations, etc. )
- Or insufficient control authority or accuracy
What must we do to ensure rendezvous?
1. Use adequate sensors, models, & strategies
2. And reduce disturbances and control errors
3. And ensure control forces are large enough
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16. ED Maneuvering Constraints
Tether force direction
- Push/pull requires 2 collectors & emitters
- Force is normal to both field and tether
- Tether direction has dynamic constraints
Tether dynamics
- IP & OOP libration & bending stimulated
- Control is tricky except at low current
Plasma density
- Large electron collection areas needed
- Narrow tapes collect better than wide ones
- Service altitude varies over solar cycle
Electrons
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Magnetic
field
Force
17. Elements in Architecture
Roving sheepdogs to image, capture, & orient debris
“Leashed sheepdogs” with thrusters & reelable leash
Agile ~10 km electrodynamic tether “shepherds”
(with suitable sensors and lots of software!)
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LEO launches (any orbit)
Capture nets for for 12 ~100 kg payloads.
smaller debris?
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Ground station
18. Possible Scenario for Program
1. Design, build, launch, & test one to prove concept
2. Refine design & build ~12 more debris shepherds
3. Launch as secondaries on any LEO launches
4. Climb high near solar max; stay low otherwise
5. Estimate ~2 weeks per rendezvous + relocation
6. Reassign shepherds as others fail or needs vary
Throughput: ~25 objects/year per shepherd, or
1500 heavy objects in 5 years, using 12 shepherds!
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“Compared to What?”
What limits orbit change rate of tether?
- Mainly, weak magnetic field + resistivity of aluminum
- Also power system mass (for “deadhead” maneuvering)
- And low plasma density (depends on alt & solar cycle)
- In 5 years a tether might relocate ~1500X its own mass
Could high-Isp electric thrusters be competitive?
- They need an Isp >50,000 sec. for similar system mass
- Very high power/thrust is needed to allow such an Isp
- And they must weigh less than their 1-3 ton “payloads”
Are there other alternatives?
- None we know of seem both plausible and competitive
20. Suborbital Capture by Sling
Scenario taken from 1991 TAI study for NASA HQ
Launcher & sling shown every 10 seconds, launch to landing.
Sling is 290 km long and needs a ballast mass ~30X payload.
Payload handoff is 1.2 km/s suborbital, near 130 km altitude.
Launch and landing sites can be within the continental US.
Update for NIAC study
Larger deltaVs seem feasible: 2+2 km/s (sub+superorbital).
>1000 tons of orbital debris may be usable as ballast mass.
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Tether Applications, Inc.
Launch
Landing
Oct. 2002, pg. 20
21. Surprises About Launch Sites
Low-inclination slings allow once-around launches
- Capture and carry launch vehicle with payload.
- Release launch vehicle at nadir 1 orbit after capture.
- Glide east to launch site (~26o earth spin in 1 orbit).
Near-polar slings allow two-launch-port shuttle ops
- Launch north from southern port; land at north port.
- N+0.5 days later, launch southward & return home.
- Required cross-range scales with Abs(DegIncl-90).
(Other inclinations have more complex constraints.)
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22. Surprises About Sling Operations
Sub-orbital capture can be fail-operational
- Missions to GEO or beyond still need 2 km/s after
a successful 4 km/s suborbital-to-superorbital sling.
- If suborbital capture fails, use that propellant to
reach orbit and dock with sling; then refuel and go.
Component masses and throughput
- Reboost power supply will outweigh sling tether,
if net mass flow outwards exceeds ~1 payload/day.
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23. Earth-GEO-Moon-Mars DeltaVs
Hohmann deltaVs in units of 100 m/s,
from 400 km circular equatorial orbits.
Full deltaV is sum of start & finish #s.
Orbiting slings with 1-3 km/s tip speeds
can provide most or all of these deltaVs!
18
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31
36
77
7
11 22
15
16
8
19 4
5
3 6
19
24
GEO
21
35
10
7
24. Conclusions from Phase I Study
Debris
1. Most of the mass is in intact objects weighing 1-3 tons.
2. Most debris mass is near-polar, at 500-1000 km altitude.
3. Intact objects all have unintentional “capture features.”
4. Key unknowns include debris tumble rates and politics.
Rendezvous and capture
1. Good sensors, actuators, and software are essential.
2. 12 shepherds might handle most large debris in 5 years.
High-deltaV slings
1. Slings could use much of the heavy debris as ballast.
2. Such slings could provide up to 2+2 km/s deltaVs.
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25. Possible Phase II Tasks
Debris
- Find tumble rates and typical interfaces & appendages.
- Identify and study possible problems (technical & other).
Rendezvous and capture
- Analyze sensor options and control concepts in detail.
- Test and refine capture/release hardware concepts.
- Analyze survey, capture, de-spin, and other operations.
Architecture and development scenario
- Flesh out shepherd, sheepdog, ballast, & sling concepts.
- Refine throughput estimates for shepherds and slings.
- Estimate key technology needs, schedule, & ROM cost.
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Some References
Orbital Debris
NASA JSC: http://www.orbitaldebris.jsc.nasa.gov/ (site is currently down)
JSC Newsletter http://sn-callisto.jsc.nasa.gov/newsletter/news_index.html
Aerospace Corp: http://www.aero.org/cords/
Europe: http://www.etamax.de/debrisweb/
CD-ROM:: 2000 Earth Orbital Debris, compiled by World Spaceflight News
Book: Orbital Debris : a Technical Assessment, National Academy Press, 1995.
Space Tethers: General Info
Tether Guidebook: www.tetherapplications.com (click on “Review Papers”)
NASA Tether Handbook: http://cfa-www.harvard.edu/~spgroup/handbook.htm
Tethered Rendezvous, Sling, and Space Elevator Studies
Moravec, H. "A Non-Synchronous Orbital Skyhook". J. Astr. Sci., Oct-Dec 1977.
Stuart, D.G., “A Guidance Algorithm for Cooperative Tether-Mediated Orbital
Rendezvous,” MIT Sc.D. thesis, Feb. 1987.
Carroll, J. “Preliminary Design of a 1 Km/Sec Tether Transport Facility,” report to
NASA HQ on contract NASW-4461, March 1991, Tether Applications.
Carroll, J., AIAA paper 95-2895: www.tetherapplications.com (“Review Papers”)
NIAC reports by Bogar, Edwards, and Hoyt, at: http://www.niac.usra.edu/studies/