Abstract: An apparatus for providing optimized power balanced variable thrust transfer orbits to minimize an electric orbit raising duration is disclosed. The electric orbit raising includes a first transfer orbit and a target orbit. The apparatus includes control electronics configured to transfer to a second transfer orbit to reach the target orbit. A variable thrust based on a current electric power balance is determined. The control electronics are further configured to execute a maneuver to transfer from the first transfer orbit to the second transfer orbit according to the determined variable thrust and a predetermined maneuver plan. The predetermined maneuver plan includes a set of compound steering parameters. The set of compound steering parameters are based on an optimized variable thrust and an associated electrical power balance to the optimized variable thrust. An optimized series of transfer orbits minimizes the electric orbit raising duration.

Abstract: Methods of launching a vehicle using impulsive force are disclosed. In one instance, a vehicle is launched easterly with impulsive force in a plane corresponding to the vehicle's elliptical orbital path. In another instance, a method of closing a timing difference is disclosed. The vehicle undergoes a series of forces after impulsive launch. The first force establishes an orbit having a period significantly different from the orbital period of a satellite or desired vehicle location, closing the difference in an integer number of orbits. The second force establishes the vehicle in circular orbit with the satellite or desired vehicle location. In another instance, the vehicle launched impulsively from a first celestial body travels a first path, and the vehicle experiences a second force along a hyperbolic path about the second celestial body and enters circular orbit about the second celestial body.

Abstract: 1. A satellite constellation forming method comprises a satellite deployment step S2, a spacecraft acceleration step S4, a spacecraft orbiting step S5 and spacecraft deceleration step, and the aforementioned steps are repeated in order. In the satellite deployment step S2, deploying one of the satellites into the circular orbit 2 from the spacecraft 10 on the circular orbit 2. In the spacecraft acceleration step S4, accelerating the spacecraft 10 and switching the orbit from the circular orbit 2 to a spacecraft transfer orbit 3 in the same orbit plane. In the spacecraft orbiting step S5, making the spacecraft 10 orbit along the spacecraft transfer orbit 3 a plurality of times. In the spacecraft deceleration step, decelerating the spacecraft 10 and switching the orbit from the spacecraft transfer orbit 3 to the circular orbit 2 in the same orbit plane.

Abstract: Methods, systems, and apparatus for designing, constructing and using instrument landers for in situ exploration of small solar system bodies, such as asteroids and comets. In one aspect, a lander includes a CubeSat-style platform; instrument packaging, wherein the CubeSat-style platform and the instrument packaging are configured and arranged for an uncontrolled descent, hopping landing on a surface of a body in a solar system, where a descending trajectory for the lander is designed based on gravitational force and solar radiation, with no lander-based propulsion; and a mobility mechanism configured and arranged to self-orient the lander on the surface of the body in the solar system.

Abstract: Methods and apparatus to methods and apparatus for performing propulsion operations using electric propulsion system are disclosed. An example apparatus includes means to use an electric propulsion system coupled to a frame of a spacecraft, the electric propulsion system including at least a first thruster and a second thruster, the first thruster adjacent a first side of the frame, the second thruster adjacent a second side of the frame, and means to allow at least one of the first thruster or the second thruster to control the spacecraft without using a chemical propulsion system.

Abstract: A system includes a plurality of satellites including respective antennas and circuitry. The satellites form a satellite constellation and revolve around a rotating astronomical object from which a source radiates interference toward a target satellite for at least some period of time as the target satellite revolves in a target orbit. The satellites' respective antennas may capture the interference when the satellite constellation is substantially in-line between the source and target satellite, and their circuitry may generate respective measurements based thereon. The circuitry may geolocate or cause transmission of the respective measurements for geolocation of the source based on the respective measurements to thereby identify a location of the source on the astronomical object.

Abstract: Methods of launching a vehicle using impulsive force are disclosed. In one instance, a vehicle is launched easterly with impulsive force in a plane corresponding to the vehicle's elliptical orbital path. In another instance, a method of closing a timing difference is disclosed. The vehicle undergoes a series of forces after impulsive launch. The first force establishes an orbit having a period significantly different from the orbital period of a satellite or desired vehicle location, closing the difference in an integer number of orbits. The second force establishes the vehicle in circular orbit with the satellite or desired vehicle location. In another instance, the vehicle launched impulsively from a first celestial body travels a first path, and the vehicle experiences a second force along a hyperbolic path about the second celestial body and enters circular orbit about the second celestial body.

Abstract: A spacecraft propulsion system includes at least one chemical thruster operable with a liquid propellant, at least one electric thruster operable with an inert gas, and a first quantity ‘n’ of pressurant tanks, each of the ‘n’ pressurant tanks having a substantially identical volume. The propulsion system results from assembling a plurality of subassemblies, such that a first selectable number ‘e’ of the first quantity of pressurant tanks are manifolded together with the at least one electric thruster, and a second selectable number ‘c’ of the first quantity of pressurant tanks are manifolded together with the at least one chemical thruster. The first selectable number ‘e’ is an integer in the inclusive range of 1 to ‘n’, and c=n?e.

Abstract: Techniques for deorbiting a satellite include executing an orbit transfer maneuver that transfers the satellite from an operational orbit to an interim orbit. The operational orbit is substantially geosynchronous and has (i) an inclination of greater than 70 degrees; (ii) a nominal eccentricity in the range of 0.25 to 0.5; (iii) an argument of perigee of approximately 90 or approximately 270 degrees; (iv) a right ascension of ascending node of approximately 0; and (v) an operational orbit apogee altitude. The interim orbit has an initial second apogee altitude that is at least 4500 km higher than the first apogee altitude, and the interim orbit naturally decays, subsequent to the orbit transfer maneuver, such that the satellite will reenter Earth's atmosphere no longer than 25 years after completion of the orbit transfer maneuver.

Abstract: A method of following a transfer orbit or a phase of orbital placement of a continuous-thrust space vehicle comprises the following steps: a) tracking at least one GNSS signal and using it to determine at least one pseudorange between the space vehicle and one or more GNSS satellites transmitting the signal; b) using an estimation model to jointly estimate a set of state parameters of the space vehicle comprising a plurality of position parameters, a plurality of velocity parameters and at least one thrust error parameter characterizing a discrepancy between an actual thrust force of the space vehicle and a nominal thrust force by taking the pseudorange or pseudoranges as input datum of the estimation model. An apparatus for the implementation of such a method is also provided.

Abstract: Apparatus and methods for stationkeeping in a satellite. The satellite includes a north electric thruster and a south electric installed on a zenith side. An orbit controller selects a duration of a burn of the north electric thruster proximate to an ascending node that differs from a duration of a burn of the south electric thruster proximate to a descending node. The orbit controller is configured to select an offset of the burn of the north electric thruster in relation to the ascending node that differs from an offset of the burn of the south electric thruster in relation to the descending node.

Abstract: Techniques for deorbiting a satellite include executing an orbit transfer maneuver that transfers the satellite from an operational orbit to an interim orbit. The operational orbit is substantially geosynchronous and has (i) an inclination of greater than 70 degrees; (ii) a nominal eccentricity in the range of 0.25 to 0.5; (iii) an argument of perigee of approximately 90 or approximately 270 degrees; (iv) a right ascension of ascending node of approximately 0; and (v) an operational orbit apogee altitude. The interim orbit has an initial second apogee altitude that is at least 4500 km higher than the first apogee altitude, and the interim orbit naturally decays, subsequent to the orbit transfer maneuver, such that the satellite will reenter Earth's atmosphere no longer than 25 years after completion of the orbit transfer maneuver.

Abstract: A control system for a hybrid propulsion spacecraft, configured for transfer between low earth parking orbit (LEO) and a Lissajous L2 orbit (L2O), including a first control portion communicably connected to a high thrust (HT) engine portion of the hybrid propulsion spacecraft, a second control portion communicably connected to a low thrust high specific impulse (LT-HI) engine portion of the hybrid propulsion spacecraft, the first and second control portions being configured to control both the HT engine portion and the LT-HI engine portion to provide an optimal LEO to L2O transfer trajectory, wherein the optimal LEO to L2O trajectory includes an optimal LT-HI trajectory portion, selected from a stable manifold trajectory, and an optimal HT trajectory portion, and wherein the LT-HI trajectory portion and HT trajectory portion are configured for providing a combined optimal trajectory along the LEO to L2O transfer trajectory, and are optimized substantially simultaneously.

Abstract: Methods and apparatus to methods and apparatus for performing propulsion operations using electric propulsion system are disclosed. An example apparatus includes a frame, a power source coupled to the frame and a payload coupled to the frame, the payload to receive or transmit data. The apparatus also includes an electric propulsion system coupled to the frame. The electric propulsion system is to enable attitude control, momentum control, and orbit control of the apparatus.

Abstract: A gas gun launcher having a pump tube and a launch tube with a first end of the launch tube slidably inserted into a second end of the pump tube. A sliding seal is employed to retain the gas within the launch tube and the pump tube A launch tube alignment system is preferably automatic, again to enhance the accuracy of launches. And an embodiment of the gas gun launcher suitable for use in water such as an ocean or large lake preferably utilizes a neutrally buoyant launch tube and a neutrally buoyant pump tube. And a fast-closing muffler at the second end of the launch tube conserves the light gas utilized for launching a vehicle.

Abstract: A satellite positioning system including a booster configured to launch and subsequently release a plurality of satellites is provided. Each satellite includes first and second stages and an interface to couple the first and second stages. The first stage includes a housing, satellite components disposed within the housing, a first fuel supply and maneuvering components configured to expend the first fuel supply to execute orbital maneuvers. The second stage includes an enclosure, a second fuel supply disposed within the enclosure and thrust elements supportively disposed on the enclosure and configured to expend the second fuel supply to drive a satellite towards orbit after release from the booster.

Abstract: An orbit insertion device for artificial satellite aiming to explore a planet with unknown characteristics. A plurality of sensors send a plurality of measured states of the artificial satellite. A planetary attraction constant estimator calculates a planetary attraction constant based on the plurality of measured states. A drag force coefficient estimator calculates a drag force coefficient based on the plurality of measured states. A rate of convergence calculation unit calculates a rate of convergence based on the drag force coefficient. A fictitious control calculation unit calculates a fictitious control based on the planetary attraction constant, the drag force coefficient and the rate of convergence. A normalized thrust calculation unit calculates a normalized thrust based on the fictitious control. A plurality of thrusters generate a thrust based on the normalized thrust.

Abstract: A method and respective system for delivering cargoes into space by means of preliminary launching cargoes and then capturing cargoes by at least one container spacecraft, accumulating and further transferring to other spacecrafts, wherein the container spacecraft is designed for capturing cargoes as separate portions in the form of a cloud or stream as well as for use of a propulsion system to compensate for container spacecraft speed losses caused by the cargo capture and an aerodynamic drag, wherein the propulsion system being a reactive type with consumption of a part of the incoming cargoes as a working substance.

Abstract: Vehicles with bidirectional control surfaces and associated systems and methods are disclosed. In a particular embodiment, a rocket can include a plurality of bidirectional control surfaces positioned toward an aft portion of the rocket. In this embodiment, the bidirectional control surfaces can be operable to control the orientation and/or flight path of the rocket during both ascent, in a nose-first orientation, and descent, in a tail-first orientation for, e.g., a tail-down landing.

Abstract: A method is provided for controlling a set of at least two satellites adapted to provide a service used by at least one portion of the set of the said satellites at a given moment, in which, continuously or pseudo-continuously, a mean value of the longitudes of the respective ascending nodes of each satellite is computed, and, for each satellite, a correction of trajectory of the satellite is applied by regulating the longitude of the ascending node on a setpoint equal to said current mean value.

Abstract: An aircraft having propulsion units for both conventional aircraft flight in the atmosphere and for high-altitude operation as a rocket. The aircraft is divided into a payload compartment and a compartment containing rocket propulsion unit propellant or fuel, and includes a long transverse wing with a small back-sweep to favour lift in the dense layers of the atmosphere and to thus make it possible to climb to high altitudes at a subsonic speed before using the rocket propulsion units. The return flight portion is performed by gliding or controlled as for a conventional aircraft.

Abstract: A motion of an object is controlled from a geostationary transit orbit (GTO) of an earth to an orbit of a moon. A first trajectory of the motion of the object is determined from an intermediate orbit of an earth to a neighborhood of a stable manifold of a first Lagrange point (L1). A second trajectory of the motion of the object is determined from the GTO to the intermediate orbit. A third trajectory of the motion of the object is determined from the neighborhood to the stable manifold to an L1 orbit, and a fourth trajectory of the motion of the object is determined from the L1 orbit to the orbit of the moon. A trajectory from the GTO to the orbit of the moon is determined based on a combination of the first, the second, the third, and the fourth trajectories.

Abstract: A wireless transmitter includes a first filtering unit coupled to a first cable for outputting a first DC source transmitted on the first cable, a first power converting unit for converting the first DC source into a second DC source, a second filtering unit for eliminating noise in the second DC source, a first DC blocking unit for blocking the second DC source and outputting a second frequency modulation (FM) signal, an amplifier for amplifying the second FM signal to generate a first FM signal, and a second DC blocking unit coupled to the amplifier and the first cable, for outputting the first FM signal to the first cable, such that the first FM signal is transmitted to the air through the first cable as a transmitting antenna.

Abstract: A railgun launcher with principle rail energization and fielding derived from a co-traveling energy pulse associated with a close-coupled parallel transmission line structure. Enhanced system efficiency, plus amelioration of simple railgun negative features, is enabled via the induction hybrid railgun methodology proposed.

Abstract: A system and method for assessing the risk of conjunction of a rocket body with orbiting and non-orbiting platforms. Two-body orbital dynamics are used to initially determine the kinematic access for a ballistic vehicle. The access may be represented in two ways: as a volume relative to its launcher and also as a geographical footprint relative to a target position that encompasses all possible launcher locations.

Abstract: A spacecraft (P) has a propulsion system making it possible to exert a force of variable magnitude and orientation on the spacecraft, a control system designed to control the propulsion system in terms of magnitude and orientation so as to make the spacecraft approach a target around a planet, with the aid of a force having at least one component (fx, fy, fz), in the rotating reference frame tied to the target, which depends substantially linearly on the corresponding coordinate (x, y, z) of the craft in this reference frame.

Abstract: Embodiments of an Earth observation satellite comprising a satellite main body having an elongated shape extending in the direction of a roll axis R of the satellite from a first base face of the satellite main body to a second base face of the satellite main body, the satellite main body having a plurality of lateral faces extending from the first base face to the second base face; a solar array; and propulsion means for compensating air-drag being arranged on the base face of the satellite main body. A first solar panel of the solar array is mounted on a first lateral face of the satellite main body, a second lateral face of the satellite main body is configured to radiate heat away from the satellite main body, and a third lateral face of the satellite main body has observation means for Earth observations.

Abstract: A gas gun launcher having a pump tube and a launch tube with a first end of the launch tube slidably inserted into a second end of the pump tube. A sliding seal is employed to retain the gas within the launch tube and the pump tube A launch tube alignment system is preferably automatic, again to enhance the accuracy of launches. And an embodiment of the gas gun launcher suitable for use in water such as an ocean or large lake preferably utilizes a neutrally buoyant launch tube and a neutrally buoyant pump tube. And a fast-closing muffler at the second end of the launch tube conserves the light gas utilized for launching a vehicle.

Abstract: Space tug vehicles and methods for providing space tugs and moving target vehicles are provided. More particularly, a space tug utilizing electrostatic or Coulomb force for acting on target vehicles and for moving the target vehicles into new orbits or altitudes are provided. The space tug may establish an attractive electrostatic force by controlling the electrical potential of the space tug so that it is opposite the electrical potential of a target vehicle. The target vehicle may acquire an absolute electrical potential due to its interaction with the space plasma and photoelectrons or the space tug may impart additional charge to the target vehicle. After establishing the attractive electrostatic force, a propulsion system of the space tug is operated to provide thrust. Thrust is directed to change the orbit and/or position of the target vehicle that is being pulled towards the space tug by the electrostatic force.

Abstract: Spacecraft vehicles and methods for providing reorbiters capable of moving target objects are provided. More particularly, a reorbiter utilizing electrostatic or Coulomb force for acting on target objects and for moving the target objects into new orbits or altitudes are provided. The reorbiter may establish an electrostatic force by controlling the electrical potential of the reorbiter through active charge emission. The target object may acquire an electrical potential due to its interaction with the space plasma and photoelectrons or the reorbiter may impart additional charge to the target object. After establishing the electrostatic force, a propulsion system of the reorbiter is operated to provide thrust. Thrust is directed to change the orbit and/or position of the target object that is being moved by the electrostatic force between the reorbiter and the target object.

Abstract: Deorbiting of an earth-orbiting satellite is accomplished by executing an orbit transfer maneuver, the orbit transfer maneuver resulting in transference of the satellite from an operational orbit to a disposal orbit, where the disposal orbit is substantially circular and has a nominal radius of approximately, 31,000 kilometers. The operational orbit may be substantially geosynchronous and have at least one of (i) an inclination of greater than 10 degrees and (ii) a nominal eccentricity greater than 0.1. Alternatively, the operational orbit may be a medium earth orbit.

Abstract: An onboard solar cell array current and voltage characteristic determination method is preferably used on small spacecraft and determines the solar cell orientation relative to the sun by a comparison between prelaunch solar cell characteristics with on-orbit solar cell characteristics well suited for spin axis determinations and monitoring the degradation of on-orbit solar cells over the operational life of a picosatellite.

Abstract: The space station pyramid design is to be erected around an Earthbound land mass (i.e. homes, towns and sanctuaries), thereby, encapsulating the land mass. Propulsion systems will raise the station into Earth's orbit. Artificial gravitation is provided through electrostatic forces within the structure.

Abstract: A method is disclosed for placing a satellite in an operational orbit. The satellite is equipped with its own satellite propulsion system as well as a detachable separate propulsion device. The satellite and separate propulsion device are launched into a transfer orbit by means of a space launcher. The separate propulsion device is controlled by a satellite. The satellite is transferred from the transfer orbit to an intermediate orbit by means of the separate propulsion device. The separate propulsion device is separated from the satellite in the intermediate orbit. The satellite then enters and operational orbit from the intermediate orbit by means of its own satellite propulsion system. The intermediate orbit is disposed between the transfer and operational orbits, and is in relatively close proximity to the operational orbit but is far enough away from the operational orbit to prevent possible interferences.

Abstract: An air-based vertical launch system is described by means of which ballistic missile defense can be achieved effectively from a large aircraft. A method for ensuring safe missile egress is proposed. A method for ensuring that the missile strikes the ballistic missile payload section is also proposed. Together, the air basing method employing vertical (or near-vertical) launch and semi-active laser guidance yield an affordable and operationally effective missile defense against both tactical and long-range ballistic missiles. The affordability of missile defense is enhanced by the ability of an aircraft equipped with a vertical launcher to simultaneously carry out several defensive and offensive missions and to provide other capabilities such as satellite launch at other times.

Abstract: The invention is an aircraft having an inflatable wing connected to a base unit, with the inflatable wing inflated with a lifting gas such as helium. The inflatable wing has a series of cell structures, and may be configured with ballonets to selectively introduce and expel outside air within the inflatable wing to vary the buoyancy and/or airfoil properties of the inflatable wing. The aircraft is particularly useful at low speeds and in thin atmospheres (such as at high Earth altitudes and on Mars), and can be used for interplanetary missions to explore planetary bodies, such as moons and planets, having atmospheres.

Abstract: A method for delivering space cargo including inserting one or more container spacecrafts (CSCs) into orbit. A CSC comprises a hull, a device for receiving cargoes (an artificial medium), a braking medium container, an arrangement for separating the cargoes and the braking medium, storage tanks, a propulsion system, a satellite solar power station, and also heat dissipaters for cooling the braking medium. To compensate for loss of speed during cargo capture, the CSCs use propulsion systems supplied with power from said power station. A reactive-type propulsion system in which a part of the incoming cargo is consumed can be used as such system.

Abstract: A system for defending a planet having a satellite against impact from an incoming body includes an explosive system and a propulsion system. The explosive system is adapted for deployment on the satellite and detonation thereon with sufficient explosive force to produce at least one ejectum to which is imparted a velocity increment sufficient for the ejectum to exceed the satellite's escape velocity and enter orbit about the planet. The propulsion system is adapted to be secured to at least one ejectum and impart a velocity increment to the ejectum sufficient to leave orbit about the planet and enter an orbit intercepting the incoming body. The system is used in a planetary defense method in which the explosive system is deployed at a deployment site on the satellite and detonated to produce at least one ejectum having a velocity that exceeds the escape velocity of the satellite.

Abstract: A method for implementing a satellite fleet includes launching a group of satellites within a launch vehicle. In an embodiment, the satellites are structurally connected together through satellite outer load paths. After separation from the launch vehicle, nodal separation between the satellites is established by allowing one or more of the satellites to drift at one or more orbits having apogee altitudes below an operational orbit apogee altitude. A satellite is maintained in an ecliptic normal attitude during its operational life, in an embodiment. The satellite's orbit is efficiently maintained by a combination of axial, radial, and canted thrusters, in an embodiment. Satellite embodiments include a payload subsystem, a bus subsystem, an outer load path support structure, antenna assembly orientation mechanisms, an attitude control subsystem adapted to maintain the satellite in the ecliptic normal attitude, and an orbit maintenance/propulsion subsystem adapted to maintain the satellite's orbit.

Abstract: A geosynchronous Solar Power Satellite System is created by an artificial gravity, closed ecology, multiple use structure in low earth orbit that manufactures modular solar power panels and transmitter arrays. This facility takes empty fuel tanks and expended rocket boosters from launch vehicles that are sent into low earth orbit, and re-manufactures them into structural components. These components are mated to solar cells that are launched from earth. The modular solar panels are transported to geosynchronous orbit by vehicles with ion engines, where the panels are mated to other solar panels to collect power. Structural components are also mated to transmitter elements launched from earth. These are likewise transported to geosynchronous orbit. They are mated to the solar power collecting panels and they beam the collected power back to earth.

Abstract: Multiple-use rocket engines and associated systems and methods are disclosed. A method in accordance with a particular embodiment includes launching a two-stage vehicle have a first stage and a second stage carried by the first stage. The first stage can be powered with a first rocket engine having first rocket engine components, including a first combustion chamber, arranged in a first component configuration. The method can further include separating the second stage from the first stage, and powering the second stage with a second rocket engine having second engine components arranged in a second component configuration. The second rocket engine components can include a second combustion chamber that is interchangeable with the first combustion chamber. In further particular embodiments, recovered engine components from the first stage may be used to power the second stage of the same or a different two-stage vehicle.

Abstract: Power supply satellites may be launched to LEO and boosted to GEO using power generated on board from solar insolation. A cluster of power production satellites may be operated as a phased antenna array to deliver power to one or more ground-based facilities, which may be located in different time zones.

Abstract: Methods are described for launching multiple space vehicles. A first space vehicle and a second space vehicle can be detachably attached to a launch vehicle. The first space vehicle is for an orbit of a first desired altitude in a first desired orbital plane. The second vehicle is for an orbit of a second desired altitude in a second desired orbital plane. The launch vehicle with the first and second space vehicles may be launched into a first orbit in or near the first desired orbital plane. The second space vehicle may be released in the first orbit. When the orbital plane of the second space vehicle coincides with the second desired orbital plane, the second space vehicle may be transferred to a transfer orbit. The second space vehicle may be transferred to the orbit of the second desired altitude in the second desired orbital plane.

Abstract: A freestanding space elevator tower for launching payloads, tourism, observation, scientific research and communications. The space elevator tower has a segmented elevator core structure, each segment being formed of at least one pneumatically pressurized cell. The pressure cells may be filled with air or another gas. Elevator cars may ascend or descend on the outer surface of the elevator core structure or in a shaft on the interior of the elevator core structure. A payload may be launched from a pod or deck at the upper end of the space elevator tower. The space elevator tower is stabilized by gyroscopic and active control machinery. The space elevator tower maintains a desired pressure level through gas compressor machinery. Methods of constructing the space elevator are also disclosed.

Abstract: In a method for injecting a plurality of spacecraft into different circum-earth or interplanetary orbits individually in a single launch, a plurality of spacecraft coupled to an assist module are injected into an interplanetary orbit having a periodicity synchronous with the earth's revolution period. Then, in a maneuver allowing the assist module to re-counter with and pass near to the earth (Earth swing-by), the assist module appropriately performs an orbital change maneuver and a separation maneuver for each of the spacecraft in a sequential order. Through these maneuvers, a closest-approach point to the earth is changed for each of the spacecraft so as to drastically change a subsequent orbital element for each of the spacecraft. The assist module takes a sufficient time to determine a target orbit for each of the spacecraft with a high degree of accuracy until a half month to several days before a closest-approach time in the Earth swing-by.

Abstract: A method is disclosed for designing an orbit of a spacecraft which allows the spacecraft to take a small-radius halo orbit near a Lagrange point while avoiding the prohibited zone where the spacecraft may be shadowed or might be prevented from making communication. The method makes it possible to have a closed orbit although being similar to a Lissajous orbit, under a restricted condition where a propulsion force magnitude applied to a spacecraft is fixed, and where it rotates at a constant angular velocity, based on the equation of motion close to a Lagrange point. The method also provide a theory for guiding/controlling the orbit of a spacecraft, that is, the embodiment of the above orbit design method.

Abstract: A system and method for the initial deployment of a space elevator using a tether, doubly spooled from each end, an inertial mass, beacon satellite and positional thrusters, whereby tether is de-spooled from geosynchronous Earth orbit altitude, using gravity and centripetal force gradient, and timed such that when the tethers fully de-spool or near the point of being fully de-spooled, are released and the free ends, one left to fall inwards to Earth anchor point, and the other left to fall outwards to tether end ballast support point, result in an Earth anchored self supporting tension structure.

Abstract: A system for defending a planet having a satellite against impact from an incoming body includes an explosive system and a propulsion system. The explosive system is adapted for deployment on the satellite and detonation thereon with sufficient explosive force to produce at least one ejectum to which is imparted a velocity increment sufficient for the ejectum to exceed the satellite's escape velocity and enter orbit about the planet. The propulsion system is adapted to be secured to at least one ejectum and impart a velocity increment to the ejectum sufficient to leave orbit about the planet and enter an orbit intercepting the incoming body. The system is used in a planetary defense method in which the explosive system is deployed at a deployment site on the satellite and detonated to produce at least one ejectum having a velocity that exceeds the escape velocity of the satellite.

Abstract: A low orbit optical imaging satellite has a long thin satellite body housing an optical telescope arrangement. A major part of the telescope arrangement has its optical axis roughly parallel to the direction of elongation and includes a mirror arrangement deployed to direct a line of sight of the optical telescope out sideways from the direction of elongation. The transverse dimensions of the satellite body are preferably minimized to be close to the optical aperture dimension of the optical telescope, thereby providing a high ballistic coefficient and high orbit lifetime for orbits in the low thermosphere.

Abstract: A method is disclosed for placing a satellite in an operational orbit The satellite is equipped with its own satellite propulsion system as well as a detachable separate propulsion device The satellite and separate propulsion device are launched into a transfer orbit by means of a space launcher The separate propulsion device is controlled by a satellite. The satellite is transferred from the transfer orbit to an intermediate orbit by means of the separate propulsion device. The separate propulsion device is separated from the satellite in the intermediate orbit.