Abstract: A method of generating orbital transfers for spacecraft. The method provides an innovative technique for transferring spacecraft from one Earth orbit to another Earth orbit using significant solar gravitational influences. In one particular implementation, the multi-bodies in the transfer determination are the Earth (about which the spacecraft is to orbit) and the Sun (e.g., the Earth and the Sun are the first and second celestial bodies providing multi-body dynamics). The transfer orbit or trajectory is determined to make use of efficient tangential maneuvers by leveraging solar gravitational influences to improve transfer performance. Based on the generated transfer orbit, the spacecraft is controlled to perform one or more maneuvers to achieve a transfer orbit that traverses into a regime where the spacecraft's trajectory is significantly affected by gravity from both the Sun and the Earth. The spacecraft performs a near-tangential orbit insertion maneuver to enter the final orbit.

Abstract: A technique to assist guidance techniques for a free-flying inspection vehicle for inspecting a host satellite. The method solves analytically in closed form for relative motion about a circular primary for solutions that are non-drifting, i.e., the orbital periods of the two vehicles are equal, computes the impulsive maneuvers in the primary radial and cross-track directions, and parameterizes these maneuvers and obtain solutions that satisfy constraints, for example collision avoidance or direction of coverage, or optimize quantities, such as time or fuel usage. Apocentral coordinates and a set of four relative orbital parameters are used. The method separates the change in relative velocity (maneuvers) into radial and crosstrack components and uses a waypoint technique to plan the maneuvers.

Abstract: A dozen or more orbiting solar generators stay in constant touch. They can be congregated rapidly in space at any desired secret location. Once congregated they all focus their energy to a death star. This death star is a newly launched ICBM with a microwave or laser collector. A laser generator uses this huge energy to project a non-nuclear death ray to a target. The target could be a city, a ship or a satellite. In the event of an asteroid approaching earth, this system could destroy an asteroid. In peacetime the orbiting solar generators supply electric power to an earth based power grid.

Abstract: The systems and methods of the invention modulate atmospheric gases to temporarily increase the amount of atmospheric particles in the path of the debris, in order to decelerate the debris and accelerate natural orbital decay to the point of atmospheric re-entry. In one aspect of the invention, clearing the space debris includes propelling a plume of atmospheric gases substantially orthogonal to the path of the debris such that the debris collides with the gaseous plume as it passes through the plume. Increased atmospheric drag from the gaseous particles of the plume in the path of the debris obstructs a forward propagation of the debris and gradually decelerates the debris, leading eventually to atmospheric recapture.

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 method for capturing a container of planet ground samples moving in space by a probe also moving in space includes, when the probe is on the orbit of the container, at a distance of a few meters therefrom and the receiving face of the probe is oriented toward the container, generating, on board the probe, a first controlled magnetic field to reduce the angular speeds of the container and orient it in a preferred direction for the capture, and, when these speeds have become negligible and the probe is positioned in the correct orientation, while the probe is being brought closer to the container, a process of attraction of the container relative to the probe is begun using another field whose field lines converge toward the capture zone of the probe.

Abstract: A method and a device are provided for the optimization of the mass of a satellite. The method includes: a step of calculation of an elliptical second orbit obtained by rotation of a first orbit about an axis connecting the periapsis and the apoapsis, the elliptical second orbit being associated with a second maximum eclipse duration less than a first maximum eclipse duration; a step of determination of a maneuver enabling the satellite to move to the second orbit; and a step of calculation of a second battery mass making it possible to maintain the satellite in operation during the second maximum eclipse duration and of calculation of a mass of fuel necessary to effect the maneuver.

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 satellite system for observing space objects includes two or more satellites positioned in an Earth orbit and configured to observe objects in various orbits including those viewed (i) against the Earth's background; (ii) against a sunlit Earth background; and (iii) against a space background. An electromagnetic sensor may be provided on at least one of the satellites that is responsive to electromagnetic radiation having a wavelength that discriminates against substantial reflection of electromagnetic radiation from the Earth's atmosphere to observe the space object. A method of observing a space object using a satellite system is also disclosed.

Abstract: A system and method for highly efficient constellations of satellites which give single, double, . . . k-fold redundant full earth imaging coverage, or k-fold coverage for latitudes greater than any selected latitude is given for remote sensing instruments in short periods of time, i.e., continuous coverage, as a function of the parameters of the satellite and the remote sensing instrument for many different types of orbits. A high data rate satellite communication system and method for use with small, mobile cell phone receiving and transmitting stations is also provided. Satellite instrument performance models, full and partial satellite constellation models, and satellite cost models are disclosed and used to optimize the design of satellite systems with vastly improved performance and lower cost over current major satellite systems.

Abstract: A sky/space elevator vehicle for going from the surface of a planet or moon up into space and back again. The vehicle has a single fuselage comprising multiple floor sections including a top and bottom cone. The movement of the vehicle is controlled by helium filled envelops as well as a combined jet and rocket propulsion system.

Abstract: A method and system for application of a compound steering law for efficient low thrust transfer orbit trajectory for a spacecraft are disclosed. The method involves calculating, with at least one processor, a desired orbit for the spacecraft. The method further involves calculating a velocity change required to achieve an orbit eccentricity and a velocity change required to achieve a semi-major axis, both of which correspond to the desired orbit for the spacecraft. Also, the method involves calculating the direction of the vector sum of the velocity change required to achieve the orbit eccentricity and the velocity change required to achieve the semi-major axis. Further, the method involves firing at least one thruster of the spacecraft in the direction of the vector sum in order to change the current orbit of the spacecraft to the desired orbit for the spacecraft, thereby changing the orbit eccentricity and the semi-major axis simultaneously.

Abstract: A system and a method for commanding a spacecraft to perform a three-axis maneuver purely based on “position” (i.e., attitude) measurements. Using an “inertial gimbal concept”, a set of formulae are derived that can map a set of “inertial” motion to the spacecraft body frame based on position information so that the spacecraft can perform/follow according to the desired inertial position maneuvers commands. Also, the system and method disclosed herein employ an intrusion steering law to protect the spacecraft from acquisition failure when a long sensor intrusion occurs.

Abstract: Solar power satellite system for transmitting microwave energy to the earth and a method of arranging the solar power satellite system about the sun for same. The solar power satellite system comprises a space-based power generation unit disposed in a planetary orbit about the sun. A photovoltaic cell on the space-based power generation unit collects solar energy that is then converted to microwave energy to be beamed to the earth. A ground-based rectenna receives the microwave energy and converts the microwave energy to electricity that is transmitted to an end user. The solar power satellite system and method provides electrical power on earth day or night and regardless of atmospheric conditions. Also, surface area of the solar panel on the space-based power generation unit orbiting about the sun is much less than the surface area required of a ground-based solar panel or a solar panel in earth orbit.

Abstract: The present invention is related to a method in the design of constellation of non-geostationary satellites for broadband multimedia communications. A broadband multimedia satellite communication system based on the present invention will not have interference problems with the GEO satellites and terrestrial communications. Users of the system will be able to use very low cost simple automatic tracking antenna to access broadband multimedia services anywhere around the world.

Abstract: A system and method for highly efficient constellations of satellites which give single, double, . . . k-fold redundant full earth imaging coverage, or k-fold coverage for latitudes greater than any selected latitude is given for remote sensing instruments in short periods of time, i.e., continuous coverage, as a function of the parameters of the satellite and the remote sensing instrument for many different types of orbits. A high data rate satellite communication system and method for use with small, mobile cell phone receiving and transmitting stations is also provided. Satellite instrument performance models, full and partial satellite constellation models, and satellite cost models are disclosed and used to optimize the design of satellite systems with vastly improved performance and lower cost over current major satellite systems.

Abstract: The method for lightening the weight of fuel stowed onboard during an interplanetary mission is characterized in that it consists: in launching (10a) a first orbiter spacecraft (1) from the Earth on a first interplanetary trajectory (31, 33) towards a target planet to be explored, in launching (10b) a second orbiter spacecraft (2) from the Earth on a second interplanetary trajectory (32, 34) towards a rendezvous spot (38), the second interplanetary trajectory not comprising any phase of placing in orbit around the target planet, in recovering a load to be transported and in loading it onto the first orbiter spacecraft (1), in returning the first orbiter spacecraft (1) and the load from the target planet to the rendezvous spot (38), in effecting a docking (14) of the two orbiter spacecraft (1, 2), in returning at least the second orbiter spacecraft (2) and the load, from the rendezvous spot (38) to a terrestrial orbit (41).

Abstract: A system and method for highly efficient constellations of satellites which give single, double, . . . k-fold redundant full earth imaging coverage, or k-fold coverage for latitudes greater than any selected latitude is given for remote sensing instruments in short periods of time, i.e., continuous coverage, as a function of the parameters of the satellite and the remote sensing instrument for many different types of orbits. A high data rate satellite communication system and method for use with small, mobile cell phone receiving and transmitting stations is also provided. Satellite instrument performance models, full and partial satellite constellation models, and satellite cost models are disclosed and used to optimize the design of satellite systems with vastly improved performance and lower cost over current major satellite systems.

Abstract: Described herein is a projective optical metrology system including: a light target formed by a first number of light sources having a pre-set spatial arrangement; and an optical unit including an optoelectronic image sensor, which receives a light signal coming from the light target and defines two different optical paths for the light signal towards the optoelectronic image sensor. The two optical paths are such that the light signal forms on the optoelectronic image sensor at most an image of the light target that can be processed for determining at least one quantity indicating the mutual arrangement between the light target and the optical unit.

Abstract: [OBJECT] It is an object to solve a problem that a light-emitting element and a large-capacity battery required for allowing light generated from a satellite to be visually observed from the earth lead to enormously high costs. [SOLUTION] The present invention provides a satellite which comprises a reflecting mirror for reflecting sunlight toward the earth, and a transceiver, wherein the transceiver is operable to receive information including at least a position of the sun, a position of the satellite, and an irradiation point on the earth surface to be irradiated with the reflected light, so as to set a direction of a reflecting surface of the reflecting mirror based on the received information, and wherein the satellite is adapted to orient the reflecting surface of the reflecting mirror in the direction set based on the received information.

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: The present invention relates to a device making it possible to study the solar corona on a space mission requiring the formation flight of two satellites: an occulting satellite (OCC), the role of which is to create an artificial eclipse of the sun from the point of view of a coronagraph (10) onboard a second satellite, called carrying satellite (COR). The invention presents the advantage of proposing a formation flight device intended for a solar coronagraphy mission comprising fixed solar panels (11a), requiring no deployment, thanks to a dissymmetrical accommodation of the coronagraph (10) reflected in a shifting of said coronagraph (10) to a side of the carrying satellite (COR).

Abstract: Geosynchronous surveillance is conducted by injecting one or more observer satellites into a retro sub or super geosynchronous orbit at approximately zero inclination. The observer satellite spins about an approximately North-South axis in an Earth frame of reference to sweep a sensor's FOV around the geobelt. Sensor time delay integration (TDI) is synchronized to the observer satellite's spin-rate and possibly the sum of the spin-rate and the target inertial LOS rate to realize longer integration times. This approach facilitates faster scans of the entire geobelt, more timely updates of the catalog of tracked objects and resolution of small and closely spaced objects. An inexpensive small-aperture body-fixed visible sensor may be used.

Abstract: A global earth navigation satellite system may be provided. The global earth navigation satellite system may include a group of satellites including at least one inclined geosynchronous satellite disposed in at least one orbital plane distinguished based on an interval determined based on a longitudinal coordinate of the earth, and the at least one inclined geosynchronous satellite may be disposed in the at least one orbital plane at predetermined intervals, and may revolve around the earth at a predetermined inclination of satellite orbit so as to provide, over time, geometric shape change information associated with the earth, geometric shape change information associated with a low earth orbit satellite, and geometric shape change information associated with a geostationary satellite.

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: Methods and systems are provided for orienting an agile vehicle using a control moment gyroscope array. A method comprises obtaining initial vehicle parameters for the vehicle and obtaining target vehicle parameters for the vehicle. The method further comprises determining command parameters based on a difference between the target vehicle parameters and the initial vehicle parameters, and simulating operation of the control moment gyroscope array using the command parameters and a torque value being at least equal to a maximum achievable torque for the control moment gyroscope array. When the simulated vehicle parameters are substantially equal to the target vehicle parameters, the method further comprises determining a torque profile for the control moment gyroscope array based on the simulated operation and operating the control moment gyroscope array using the torque profile.

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: 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: A system is dedicated to the control of the deployment of at least two spacecraft (ES1, ES2) which are provided with maneuvering means (MD1, MD2) and are intended to move according to a chosen formation. This system includes a control device (MM11, MM12, MT, MC1) comprising i) first measurement means (MM11, MM12, MT) responsible for determining substantially simultaneously and with high precision the orbital positions of the spacecraft (ES1, ES2), and ii) first calculation means (MC1) responsible for determining for each of the spacecraft, as a function of their orbital positions, maneuvers intended to position each of them at a chosen instant substantially in a chosen position with respect to a reference trajectory, having regard to the time law of a reference craft (ES1) on this reference trajectory (TR), so as to place the formation in a chosen configuration.

Abstract: An improved approach to satellite-based navigation (e.g., GPS) is provided. In one embodiment, a method includes determining a nominal orbital path of a navigation satellite. The method also includes transmitting ephemeris data corresponding to the nominal orbital path from the navigation satellite to a plurality of navigation devices. The method further includes determining an actual orbital path of the navigation satellite locally at the navigation satellite. In addition, the method includes determining a deviation between the actual orbital path and the nominal orbital path locally at the navigation satellite. The method also includes autonomously adjusting the actual orbital path locally at the navigation satellite to reduce the deviation between the actual orbital path and the nominal orbital path.

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 satellite system for observing space objects includes two or more satellites positioned in an Earth orbit and configured to observe objects in various orbits including those viewed (i) against the Earth's background; (ii) against a sunlit Earth background; and (iii) against a space background. An electromagnetic sensor may be provided on at least one of the satellites that is responsive to electromagnetic radiation having a wavelength that discriminates against substantial reflection of electromagnetic radiation from the Earth's atmosphere to observe the space object. A method of observing a space object using a satellite system is also disclosed.

Abstract: In a system for determining the position of a spacecraft based on vector determinations, a direction vector is measured in a body-fixed coordinate system; a reference direction vector is determined within a reference coordinate system based on the path position of the spacecraft and an orbit model; the overall spin vector of the spacecraft is determined within the body-fixed coordinate system; and a reference overall spin vector of the spacecraft is determined within a reference coordinate system by time propagation of known initial values of the overall spin of the spacecraft or by time tracking of a reference model. The position of the spacecraft is determined based on the four vectors.

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 constellation, including a plurality of spacecraft, including a first, second and third spacecraft, each of the plurality of spacecraft including a broadcast capability, and each of the plurality of spacecraft in its own approximately 24-hour orbit. Each of the orbits has a substantially teardrop-shaped or oval-shaped ground track, is optimized based upon elevation angle or probability of signal availability, and has an apogee longitude of approximately 90° west to approximately 100° west. Each of the orbits has a semi-major axis of approximately 42,164 kilometers, an argument of perigee of approximately 270° , an inclination of approximately 40° to approximately 60° , and an eccentricity of approximately 0.16 to approximately 0.4. The orbits of each of the plurality of spacecraft are selected to bring each of the spacecraft to apogee at time increments of approximately eight hours.

Abstract: Geosynchronous surveillance is conducted by injecting one or more observer satellites into a retro sub or super geosynchronous orbit at approximately zero inclination. The observer satellite spins about an approximately North-South axis in an Earth frame of reference to sweep a sensor's FOV around the geobelt. Sensor time delay integration (TDI) is synchronized to the observer satellite's spin-rate and possibly the sum of the spin-rate and the target inertial LOS rate to realize longer integration times. This approach facilitates faster scans of the entire geobelt, more timely updates of the catalog of tracked objects and resolution of small and closely spaced objects. An inexpensive small-aperture body-fixed visible sensor may be used.

Abstract: A spacecraft may include a receive antenna, a transmit antenna having an antenna attitude adjuster, and a spacecraft attitude adjustor. The spacecraft may have a nominal orientation in which a yaw axis of the spacecraft, a roll axis of the spacecraft, and the radiator panels are substantially parallel to Earth's equatorial plane, in which the pitch axis of the spacecraft is substantially parallel to Earth's polar axis, in which the Nadir vector is in a yaw-pitch plane of the spacecraft, and in which the transmit antenna and receive antenna are oriented at angle ?nom. The antenna attitude adjustor and the spacecraft attitude adjustor may correct an attitude of the transmit antenna to maintain a desired degree of the receive antenna and the transmit antenna steered toward a coverage region on Earth's surface.

Abstract: An ultrahigh altitude sun-synchronous orbit satellite system having one or plural satellites orbiting the sun such that the satellites revolve around the earth in a substantially circular or elliptic motion at an altitude of several million kilometers from the earth, beyond the sphere of earth gravity influence. The satellites are placed on an orbital plane relative to both the sun and the earth and keep a distance and geometry between the satellites, sun and earth substantially constant. The satellite system performs any one of the services of space observation, global observation, and satellite communication. The satellites orbit the sun with both inclination and eccentricity distinct from those of the revolution of the earth and revolve around the earth with a sun synchronous property in which the local solar time is kept constant at a point on the surface of the earth directly beneath the satellite.

Abstract: Systems and methods for are adapted for automatic implementation of exclusion zone avoidance for target-tracking vehicles, such as spacecraft. The systems and methods are configured to monitor pointing commands (commanded attitude and angular rates) generated for target tracking, and modify these commands as necessary to avoid pointing a boresight into an exclusion zone.

Abstract: In a method for determining the position of a spacecraft based on vector determinations, a direction vector is measured in a body-fixed coordinate system; a reference direction vector is determined within a reference coordinate system based on the path position of the spacecraft and an orbit model; the overall spin vector of the spacecraft is determined within the body-fixed coordinate system; and a reference overall spin vector of the spacecraft is determined within a reference coordinate system by time propagation of known initial values of the overall spin of the spacecraft or by time tracking of a reference model. The position of the spacecraft is determined based on the four vectors.

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 calculating method for deducing all possible scenarios of satellite members and possibilities thereof in a low earth orbiting (LEO) satellite constellation is described, which is achieved mainly by relying on the spherical geometry analysis and probabilities and statistics technologies, in an attempt to rapidly and precisely obtain the concerned scenarios and possibilities thereof observed on the earth ground. With any user-defined orbital parameters and a position of an observation station for the scenarios on the earth ground inputted, all the possible scenarios and possibilities thereof can be obtained with the calculating method.

Abstract: A satellite constellation optimized for stationkeeping fuel consumption is provided. The satellite constellation includes a plurality of satellites, each satellite having a corresponding inclined elliptical orbit, each orbit having an initial right ascension of ascending node (“RAAN”) value, a RAAN drift rate, a semi-major axis, an eccentricity, an argument of perigee and an inclination. Each satellite has a fuel consumption value required to maintain the RAAN drift rate, the semi-major axis, the eccentricity, the argument of perigee and the inclination of the corresponding orbit. The initial RAAN value and the RAAN drift rate for each orbit correspond to a minimized fuel consumption value for the satellite having the highest fuel consumption value.

Abstract: A constellation, including a plurality of spacecraft, including a first, second and third spacecraft, each of the plurality of spacecraft including a broadcast capability, and each of the plurality of spacecraft in its own approximately 24-hour orbit. Each of the orbits has a substantially teardrop-shaped or oval-shaped ground track, is optimized based upon elevation angle or probability of signal availability, and has an apogee longitude of approximately 90° west to approximately 100° west. Each of the orbits has a semi-major axis of approximately 42,164 kilometers, an argument of perigee of approximately 270°, an inclination of approximately 40° to approximately 60°, and an eccentricity of approximately 0.16 to approximately 0.4. The orbits of each of the plurality of spacecraft are selected to bring each of the spacecraft to apogee at time increments of approximately eight hours.

Abstract: An aircraft control system for operations close to the ground includes a camera having a rangefinder for measuring the azimuth, elevation and slant range from a fixed point on the aircraft relative to a selected target point on a surface below the aircraft, a navigation system for measuring the latitude and longitude of the aircraft on the surface, a computer for computing the position of the fixed point on the aircraft relative to the target point from the respective measurements of the camera and the navigation system, and a controller for controlling the movement of the aircraft such that the fixed point is positioned at a selected position above the selected target point on the surface. The controller may also include an automatic tracking mechanism for maintaining the position of the fixed point on the aircraft at the selected position above a moving object.

Abstract: A fleet of small spacecraft (“cells”) in low Earth orbit combine to form an integrated Earth observing system providing many observations previously requiring distinct sensing systems. Each cell performs a few relatively primitive functions, including emission, reception, sampling, and recording of radio and microwave signals. Each cell observes over a spherical field of view, samples the received signals independently at many small antenna elements, and stores the data from each element. Data from all cells are sent to a common location where they can be combined in diverse ways to realize a wide range of observing functions. These functions may include ionosphere and gravity field mapping; atmospheric radio occultation; ocean, ice, and land altimetry; ocean scatterometry; synthetic aperture radar (SAR) imaging; radar sensing of soil moisture, land cover, and geological surface properties; and interferometric SAR sensing of surface change.

Abstract: A constellation, including a plurality of spacecraft, including a first, second and third spacecraft, each of the plurality of spacecraft including a broadcast capability, and each of the plurality of spacecraft in its own approximately 24-hour orbit. Each of the orbits has a substantially teardrop-shaped or oval-shaped ground track, is optimized based upon elevation angle or probability of signal availability, and has an apogee longitude of approximately 90° west to approximately 100° west. Each of the orbits has a semi-major axis of approximately 42,164 kilometers, an argument of perigee of approximately 270°, an inclination of approximately 40° to approximately 60°, and an eccentricity of approximately 0.16 to approximately 0.4. The orbits of each of the plurality of spacecraft are selected to bring each of the spacecraft to apogee at time increments of approximately eight hours.

Abstract: A system is dedicated to the control of the deployment of at least two spacecraft (ES1, ES2) which are provided with maneuvering means (MD1, MD2) and are intended to move according to a chosen formation. This system includes a control device (MM11, MM12, MT, MC1) comprising i) first measurement means (MM11, MM12, MT) responsible for determining substantially simultaneously and with high precision the orbital positions of the spacecraft (ES1, ES2), and ii) first calculation means (MC1) responsible for determining for each of the spacecraft, as a function of their orbital positions, maneuvers intended to position each of them at a chosen instant substantially in a chosen position with respect to a reference trajectory, having regard to the time law of a reference craft (ES1) on this reference trajectory (TR), so as to place the formation in a chosen configuration.

Abstract: The method for lightening the weight of fuel stowed onboard during an interplanetary mission is characterized in that it consists: in launching (10a) a first orbiter spacecraft (1) from the Earth on a first interplanetary trajectory (31, 33) towards a target planet to be explored, in launching (10b) a second orbiter spacecraft (2) from the Earth on a second interplanetary trajectory (32, 34) towards a rendezvous spot (38), the second interplanetary trajectory not comprising any phase of placing in orbit around the target planet, in recovering a load to be transported and in loading it onto the first orbiter spacecraft (1), in returning the first orbiter spacecraft (1) and the load from the target planet to the rendezvous spot (38), in effecting a docking (14) of the two orbiter spacecraft (1, 2), in returning at least the second orbiter spacecraft (2) and the load, from the rendezvous spot (38) to a terrestrial orbit (41).