Abstract: An electrodynamic assembly for propelling a spacecraft in orbit around a celestial body having a magnetic field is disclosed. The assembly includes a plurality of coaxial cables for an electrodynamic assembly for propelling a spacecraft in orbit around a celestial body having a magnetic field. Each coaxial cable includes an electrically conductive core surrounded by a first electrically insulating sheath, and an electrically conductive current return circuit mounted outside the first electrically insulating sheath. The current return circuit includes a first end electrically connected to a first end of the core of the coaxial cable.

Abstract: A transfer type contra-rotating geomagnetic energy storage-release delivery system is disclosed. The system includes a control system, a three-axis control moment canceller and an energy system, which are arranged on a delivery mother spacecraft, and the delivery mother spacecraft is connected, through support rod structures, with a strong magnetic moment generating device, a contra-rotating transmission mechanism and two delivery connection rod structures arranged at the two ends of the contra-rotating transmission mechanism, the strong magnetic moment generating device is arranged between the contra-rotating transmission mechanism and the delivery mother spacecraft, the two delivery connection rod structures are provided with slidable mass blocks respectively, and the strong magnetic moment generating device and the contra-rotating transmission mechanism provide energy through the energy system.

Abstract: A lunar orbiting satellite system executes orbit planning of assigning a function (positioning, communication, and flashing) to an artificial satellite (AS) depending on a relative position of the AS to the moon at a time when the moon and the AS are observed from an input point on the earth, and correcting the relative position, which changes in accordance with the moon revolution period. The system includes: a satellite orbit planner which assigns a function to each ASs forming an AS group flying around the moon depending on a relative position of each ASs to the moon at a time when the moon and ASs are observed from an input point on the earth, and set a target orbit according to the function; and a satellite controller which causes the each ASs to execute control based on the function to implement switching of the function.

Abstract: Communication bottlenecks, particularly in the downlink direction, are a common problem for many CubeSat developers. As described herein, a CubeSat module for a CubeSat comprises an optical transmitter to transmit data to a remote terminal, a receiver to acquire an optical beacon from a remote terminal, and a fine-pointing module operably and directly coupleable to a coarse-pointing module of the CubeSat. The fine-pointing module is configured to point the optical transmitter toward the remote terminal with an accuracy range that overlaps with an accuracy range of the coarse-pointing module of the CubeSat so as to establish a communications link between the CubeSat and the remote terminal over a low-Earth-orbit (LEO) distance.

Abstract: A device to stabilize and deorbit a satellite includes a pair of coplanar masts, each one carrying at least one membrane forming an aerobraking web. The masts are fixed to the satellite along non-parallel axes. Each mast is provided on the opposite end of the satellite with a mass to generate a gravity gradient. The end of each mast is fixed to the satellite. The masts form, with the bisectrix between the masts, a fixed angle to align the bisectrix with the satellite speed vector at any altitude.

Abstract: Communication bottlenecks, particularly in the downlink direction, are a common problem for many CubeSat developers. As described herein, a CubeSat module for a CubeSat comprises an optical transmitter to transmit data to a remote terminal, a receiver to acquire an optical beacon from a remote terminal, and a fine-pointing module operably and directly coupleable to a coarse-pointing module of the CubeSat. The fine-pointing module is configured to point the optical transmitter toward the remote terminal with an accuracy range that overlaps with an accuracy range of the coarse-pointing module of the CubeSat so as to establish a communications link between the CubeSat and the remote terminal over a low-Earth-orbit (LEO) distance.

Abstract: A method for coherent stereo radar tracking includes, at a stereo radar system, transmitting a probe signal, receiving a reflected probe signal in response to reflection of the probe signal by a tracking target, calculating first and second target ranges from the reflected probe signal data, transforming the reflected probe signal data based on the first and second target ranges, and calculating a first target angle from the transformed reflected probe signal data.

Abstract: A tethered spacecraft has a first endmass and a second endmass with a telescoping stacer spring and a tether arranged between the endmasses. The spring is coiled around a center rod and initially contained within a housing, the spring being biased to push the first endmass away from the second endmass. The spring housing is affixed to the first endmass, a first end of the spring being affixed to the spring housing, and tether are affixed to spring at one end and to the second endmass at the other end. A pretensioned loop holds the endmasses abuttingly together, and a burnwire release mechanism cuts the loop to deploy the spring. Upon deployment, the spring extends to its full length to form a cylindrical boom, and the endmasses continue to move outward along the spring centerline until stopped by the tether.

Abstract: Particular embodiments also include a optimization and simulation service that can analyze different variables for scheduling the satellites. The optimization and simulation service operates automatically to schedule satellites and ground stations to obtain their highest attainable performance relative to the system operator's goals as well as to respond to various unexpected behavior or events and performance variations, modifying the schedule accordingly. The optimization and simulation service leverages the sparsity of the system in the optimization such that the optimization and simulation service can calculate the change in utility for one satellite without reference to unimpacted satellite schedules. This allows the schedule to be calculated efficiently and provides optimum usage of the satellites.

Abstract: A method and system are presented for use in determination of the orientation of an aerospace platform with respect to a first rotation axis. A direction of a rotation rate vector of said aerospace platform within a lateral plane intersecting with said first rotation axis is measured and the measured data is analyzed to determine an orientation angle of said aerospace platform about said first rotation axis. While the aerospace platform is in a predetermined-dynamic state movement, a certain direction is determined by measuring a direction of the rotation rate of the aerospace platform within said lateral plane by a sensor assembly mounted on said platform and including at least one rotation rate sensor. An orientation of the platform with respect to said first axis is determined by determining a relation between said certain direction and said known direction within said external reference frame.

Abstract: According to one embodiment of the invention, a stationkeeping method for a geostationary satellite includes determining a gravitational force of the sun on the satellite at a beginning of a stationkeeping operation and a gravitational force of the moon on the satellite at the beginning of the stationkeeping operation. An initial inclination vector of the satellite is determined at the beginning of the stationkeeping operation that accounts for a first set of one or more perturbations affecting the orbit of the satellite. A maneuver strategy is determined to correct for a second set of one or more perturbations affecting the orbit of the satellite without accounting for the first set of one or more perturbations affecting the orbit of the satellite. Finally, a maneuver is performed on the satellite according to the maneuver strategy.

Abstract: Mechanism for passively deploying expendable space tethers on orbit, by means of an initial separation impulse only, provided by a simple spring system that is part of the mechanism itself. The passive deployment of the space tether and a tethered end-mass is provided by the particular mechanism devised, having very low deployment friction and resistance. Tether deployment brake towards the final part of deployment is produced by a daisy-like brake, stored within the winding of the fixed tether spool so that it is automatically deployed (opened) and starts its deployment braking or resistance function from a planned point of the tether deployment in space.

Abstract: The present invention describes a communication system comprising a primary radio station (PS) and at least one secondary radio station (SS), intended to be in motion (MOT). The secondary radio station has at least one controllable structure (CS) for communicating with the primary radio station, and control means (CONT) for controlling the controllable structure depending on the movements of the secondary radio station. The control means of the controllable structure comprise magnetic field sensors (MFS) and gravitational field sensors (GFS) for providing measurements of the earth magnetic (H) and gravitational (G) fields, and computing means (COMP) for computing control information from these measurements. The computing means read the outputs of each sensor and make the calculations required to control the controllable structure at appropriate time intervals depending on the motion state of the secondary radio station.

Abstract: A technique for maintaining a satellite in an assigned orbit without control or intervention from the ground. Autonomously obtained navigational data provide a measurement of the actual orbit in which the satellite is traveling. So long as the measured orbit conforms to a desired orbit to within a preselected tolerance, periodic corrections of equal magnitude are made to the satellite's velocity, based on a prediction of the effect of atmospheric drag on the orbit. Measurement of the orbit is made by observation of the time that the satellite passes a reference point in the orbit, such as by crossing the ascending node. If the measured orbit departs from the desired orbit by more than the preselected tolerance, a velocity correction of a magnitude different from the one based on prediction is applied to the satellite. For a decaying orbit, the magnitude of the velocity correction is increased above the correction value based on prediction.

Abstract: A method for operating an orbiting spacecraft includes the steps of (a) changing a mass distribution of the spacecraft from a first mass distribution for setting a first principal moment of inertia of the spacecraft along a first axis approximately equal to a second principal moment of inertia of the spacecraft along a second axis, thereby minimizing a gravity gradient torque about a third axis; (b) performing a desired activity while the gravity gradient torque about the third axis is minimized; and (c) resetting the mass distribution back to the first mass distribution at a completion of the desired activity. The spacecraft includes a plurality of solar array panels, and the step of changing is accomplished by varying a position of at least two of the solar array panels away from a sun-pointing configuration. Also disclosed is a method for stabilizing the spacecraft to resist a rotation about an axis by varying the positions of solar array panels.

Abstract: A zero-momentum spacecraft's attitude is controlled by determining the torque required about a control axis to maintain the desired attitude, and, during each of recurrent control cycles, enabling a magnetic torquer if the torque demand exceeds a threshold. During each of the control cycles, thruster(s) are enabled to make up the difference between the torque demand and the estimated torque produced by the magnetic torquer. In determining the torque demand, the attitude rate signal is low-pass filtered to reduce noise, and the control loop bandwidth is maintained by totalling the estimated torque applied by the magnetic torquer and thrusters, integrating and high-pass filtering the estimated torque signals, and adding the filtered estimated torque with the filtered attitude rate signals to generate low-noise attitude rate signals. A three-axis system is described.

Abstract: A satellite has two solar array panels which are moveable between a closed configuration and an open configuration. The solar array panels are pivotably mounted on hinges attached along the top and bottom of the satellite and extend outwardly from the top and bottom of the satellite in the open configuration. The height of the perimeter sidewall is selected such that the satellite has a generally oblate configuration. Each solar array panel has a surface area substantially equal to that of the satellite cross-sectional area. The hinges are mounted on pintles extending from a solar array drive motor which rotates the solar panel about the axis defined by the pintles to provide one axis sun tracking. The solar array panels are pivoted about the axes of the hinges until substantially parallel to the top and bottom of the satellite to form a compact, stackable configuration of the satellite for stowage.

Abstract: Satellite and method for placing said satellite in orbit by lunar gravitational assistance.After placing the satellite into standard orbit (01) within a quasi-equatorial plane, the satellite is transferred onto a circumlunar orbit (02) so that the satellite traverses the sphere of influence S1 of the moon. On leaving this sphere, the orbit (03) is inside a plane inclined with respect to the equatorial plane. The orbit is then connected to the definitive orbit (04).

Abstract: A spacecraft for geodetic applications designed to travel along a trajectory in an orbital plane around a planet, embodying at least one cube corner retroreflector designed to face the planet at least temporarily and having an apex, a normal, and three faces which are substantially orthogonal with respect to one another, to within an arcminute, forming three dihedral angles at substantially equal angular distances from this normal, the effective diameter of this cube corner being at least 3 centimeters, the apex being located, relative to the center of mass of the spacecraft, at a distance whose projection on an imaginary line joining the center of mass to the center of the planet remains at all times at a known value to within variations of less than 5 centimeters.

Abstract: Apparatus and methods of Gravity Guidance and Propulsion of Geosynchronous Satellites, other satellites and space vehicles using net kinetic energy PUSH of Gravity of the electromagnetic spectrum particles which continually irradiate the earth from space, based on the Oppositely Charged Twin Monopole (OCTM) Theory of Matter. Specifically Fully Stabilized Geosynchronous Satellites can be made with the same lift-off weight as Spin Stabilized Geosynchronous Satellites by using GG&P Methods and Rules of mass distribution in the satellite.

Abstract: A propellant immobilizing system and method in which propellant motion in the propellant storage tanks (22) is reduced or eliminated during velocity change maneuvers to reduce disturbance torques acting upon the spacecraft (10) and improving the spacecraft attitude pointing performance. The thrusters (14, 16, 18 or 20) are fired to produce a small impulse in the direction of the desired Velocity change to begin motion of the propellant within the fuel tank in the opposite direction. After the fuel has moved within the tank to a location in which the propellant center of mass is aligned with the propellant tank (22) center of curvature in the direction of the desired velocity change, thrusters (14, 16, 18 or 20) are again fired to produce a force in the direction of the current velocity of the propellant center of mass to stop the propellant center of mass relative to the propellant tank (22).

Abstract: A method and apparatus for changing the orbit of an artificial satellite. The apparatus is caused to approach a target satellite and to be coupled thereto in space so as to constitute a dumbbell-like coupled system. The apparatus has a propulsion unit. The unit generates a thrust, whereby the velocity of the center of gravity of the apparatus increases, and the apparatus rotates around the center of gravity. As a result, the coupling system is placed in transition orbit.In the transition orbit, the coupled system is released at a timing when the direction of elongation of the coupled system becomes perpendicular to the orbital velocity vector. Subsequently, the target satellite is placed in a final target orbit, and the separated orbit changing apparatus is placed in an orbit different from the target orbit.

Abstract: A method and apparatus for mitigating space debris having special applicability for use with anti-satellite weapons testing. To mitigate debris in a controlled and predictable fashion a first body is tethered to a lower altitude body. A suitable length of tether is chosen to correlate with the orbital characteristics of the higher altitude body such that the lower altitude body has a relatively low velocity for its orbital altitude. Upon release of the target from the tether or upon debris production by the lower altitude target, the reduced velocity of the body or debris produced for its altitude results in rapid deorbiting of the target or debris. To offset any momentum increase created when the debris is the result of an impact of an object with the lower altitude body, the orbital characteristics are controlled to ensure the proper deorbiting velocity is achieved. A counter rotation of the tether system can also be used to negate an increase in velocity due to impact.

Abstract: A power generation system utilizes an electromagnetic tether having a three conductor, coaxial configuration which allows the circuit to be closed internal to two orbiting objects. An outer cylinder of the tether is a conductor which is used to cut or pass through the earth's magnetic field to produce a voltage output. A cylinder within the outer cylinder is made of a metal such as soft iron and is used to shield a central conductor from the earth's magnetic field. The two outer cylinders are insulated from the center conductor except at one of the tethered objects where they are electrically connected. This causes the end of the center conductor to be at the same electrical potential as the tethered object when there is an infinite load. Useful power is produced at the other object, which may be a space ship, when a switch is closed and the potential is between the outer cylinder and the center conductor.

Abstract: A modular spacecraft system adapted for orbital flight is capable of expansion by the connection of at least two substantially identical spacecraft modules, each of which is capable of independent operation. Each spacecraft module comprises a spacecraft body, at least one solar array extendible outwardly from the spacecraft body, and at least one structural interface means for connecting one spacecraft module to another spacecraft module. Methods for deployment of a spacecraft module and for assembly of a modular spacecraft system utilizing a reusable space vehicle are also disclosed.

Abstract: A spacecraft is adapted for orbital flight in two alternative modes, referred to as the earth-oriented and quasi sun-oriented modes. The spacecraft comprises a spacecraft body, at least one solar array extendible outwardly from the spacecraft body, passive attitude control means utilizing gravity gradient stabilization means which is extendible and retractable relative to the spacecraft body, and active attitude control means. The gravity gradient stabilization means is effective when extended to stabilize the spacecraft in the earth-oriented mode, and the active attitude control means is effective to stabilize the spacecraft in the quasi sun-oriented mode.

Abstract: This radar system makes it possible to collect complete stereo data in a single pass by utilizing an orbiting, side looking, bi-static, synthetic aperture radar. This system utilizes at least two orbiting spacecraft in synchronous parallel orbits with each other and separated by a tether. A transmitter transmits radar signals to a planet's surface which are reflected back and received by two receivers, one carried by each spacecraft. When the signals are combined, the layover produces a three dimensional picture in which vertical height information may be determined.

Abstract: There is disclosed a system by which a satellite is connected by means of a long tether, typically a wire 100 km or more in length, to a powered spacecraft. The spacecraft may be the Space Shuttle, and two basic equilibrium positions of the system are discussed. The wire is gradually released from a storage drum aboard the powered spacecraft, and the gravity gradient established along with atmospheric drag provide the force for deployment. The system can be used repeatedly by reeling back onto the drum. The wire, once deployed, can then be left in orbit for use in future shuttle missions and (once reeled back) can be returned to earth for repair or replacement. The tethered system finds utilization in the broad areas of upper atmosphere measurements, gravity gradient measurements and radio physics research.

Abstract: A system for tethering one orbiting space vehicle to another in which a tetherline between the vehicles is controlled by a motorized reel which in turn is controlled to deploy, retrieve, or maintain a constant line length while effecting a stabilizing influence on the line. This is accomplished by applying a tension to the line which takes into account the instantaneous length of the line, rate of change of the length of the line, and certain constants which vary depending upon the mode of operation, deployment, retrieval, or station keeping.