A method of controlling the attitude of a spacecraft in spinning around itself with a non-zero total angular momentum H.sub.TOT. The spacecraft includes a set of inertia flywheels configured to form an internal angular momentum H.sub.ACT. The axis of the total angular momentum H.sub.TOT is aligned with a principal axis of inertia of the spacecraft, in the course of which the inertia flywheels are controlled to form an internal angular momentum H.sub.ACT. The following expression, in which J is the inertia matrix of the spacecraft:
H.sub.actJ.sup.1(H.sub.tot.Math.J.sup.1H.sub.tot)
is negative if the principal axis of inertia targeted is the axis of maximum inertia of the spacecraft and is positive if the principal axis inertia targeted is the axis of minimum inertia of the spacecraft.

A passive thermal system for use in satellites includes a solid radiator panel with a plurality of heat pipes attached to a surface thereof. In addition to their heat transporting capability, the heat pipes strengthen the radiator panel to which they are coupled. In some embodiments, the heat pipes are structurally modified to increase their area moment of inertia.

A device for determining the attitude or variation in attitude of a satellite fitted with an attitude control system comprising at least one inertial actuator. The inertial actuator comprises a rotary element mounted to rotate about an axis of rotation. The rotation of the rotary element is controlled to generate a torque to control controlling the attitude of the satellite. The angular sensor of the device measures the angular rotation of the rotary element about its axis of rotation. The computation unit determines the attitude or variation in attitude of the satellite induced by the rotation of the rotary element as a function of the measurements of angular rotation of the rotary element by the angular sensor. A satellite carrying such a device and a method for determining the attitude or variation in attitude.

A launch lock system includes a first portion rigidly coupled to the second portion in a first state and the first portion movable in all directions relative to the second portion in a second state. The launch lock system includes a fastener subassembly coupled to the second portion, and the fastener subassembly is movable relative to the second portion from a first position to a second position. The launch lock system includes at least one pivot arm subassembly having a pivot arm movable between a first position and a second position. The pivot arm is coupled to the first portion in the first position. In the first state, the pivot arm is in the first position and cooperates with the fastener subassembly in the first position, and in the second state, the pivot arm is uncoupled from the first portion and the fastener subassembly.

A satellite (140) for operation in orbit around the earth comprises an ADCS (131, FIG. 1) configured for mechanically steering the satellite in the azimuth direction to prolong a dwell time (1105), during which a selected target is visible from the satellite, as the satellite orbits over the target. A processor at the ground station may be configured to process raw SAR data from any of the satellites described here. The raw SAR data may be processed in a number of ways to provide image information including but not limited to forming multilook images, compiling video sequences and colour coding images.

A spacecraft has a flat antenna array having an edge and a middle portion. A reconfigurable reaction-momentum wheel is coupled to the antenna array to roll and/or pitch the antenna array in small magnitudes. The reconfigurable reaction-momentum has a reaction operating state or mode (high-torque, low momentum) and a momentum operating state or mode (low-torque, high momentum). A thruster is coupled to the antenna array to move the antenna array.

Energy efficient satellite maneuvering is described herein. One disclosed example method includes maneuvering a satellite that is in an orbit around a space body so that a principle sensitive axis of the satellite is oriented to an orbit frame plane to reduce gravity gradient torques acting upon the satellite. The orbit frame plane is based on an orbit frame vector.

An ADCS module may be configured to use coordinate data from 2D photodiodes in one or more sun sensors to determine a sun vector. The ADCS module may then use the sun vector in reference to its own body faced (BF) coordinate system to calculate a change in the orientation of the space vehicle. The change in orientation mechanism may be accomplished by reaction wheels, ion thrusters, or other orientation altering mechanisms. A miniature, intelligent star tracker may be included that improves satellite attitude determination and pointing accuracy. An improved reaction wheel assembly may be included that is more robust and suitable for inclusion in small space vehicles.

A space-based solar power station, a power generating satellite module and/or a method for collecting solar radiation and transmitting power generated using electrical current produced therefrom, and/or compactible structures and deployment mechanisms used to form and deploy such satellite modules and power generation tiles associated therewith are provided. Each satellite module and/or power generation tile may be formed of a compactable structure and deployment mechanism capable of reducing the payload area required to deliver the satellite module to an orbital formation within the space-based solar power station and reliably deploy it once in orbit.

A reaction wheel apparatus including a reaction wheel provided in a polyhedral housing, in which respective faces constituting a polyhedron are constituted by frame parts corresponding to the respective faces constituting the polyhedron, and at least two of the frame parts are constituted by at least two rigid circuit board parts of a rigid flexible substrate.