Abstract: A light weight fuel tank for a hydrogen powered airplane used as a platform for communication repeaters for communication services. An outer spherical shell member of a sandwich configuration surrounds an inner thin walled spherical shell member in which the liquid hydrogen is contained. A radial gap between the shell members is evacuated to a high vacuum. The facing surfaces of the shell members are coated with a low emissivity material. Electrical heaters are provided to control the evaporation rate of the hydrogen to match the fuel usage and to prevent icing during ascent and descent of the airplane.

Abstract: A thruster system for spacecraft includes a thruster, a thruster mounting boom, a gimbals mechanism connecting the thruster to the thruster mounting boom, and a pivot mechanism connected to the thruster mounting boom, where the pivot mechanism attaches the thruster mounting boom to a spacecraft. A method includes steps of providing a first thruster mounted on a pivoting thruster mounting boom attached to a spacecraft; using the first thruster at a first position, for example, a north pointing position, to provide orbit control; repositioning the first thruster to a second position, for example, a south pointing position; and using the first thruster at the second position to provide orbit control so as to provide redundancy for a failed second thruster by repositioning the first thruster.

Abstract: A light weight fuel tank for a hydrogen powered airplane used as a platform for communication repeaters for communication services. An outer spherical shell member of a sandwich configuration surrounds an inner thin walled spherical shell member in which the liquid hydrogen is contained. A radial gap between the shell members is evacuated to a high vacuum. The facing surfaces of the shell members are coated with a low emissivity material. Electrical heaters are provided to control the evaporation rate of the hydrogen to match the fuel usage and to prevent icing during ascent and descent of the airplane.

Abstract: A light weight fuel tank for a hydrogen powered airplane used as a platform for communication repeaters for communication services. An outer spherical shell member of a sandwich configuration surrounds an inner thin walled spherical shell member in which the liquid hydrogen is contained. A radial gap between the shell members is evacuated to a high vacuum. The facing surfaces of the shell members are coated with a low emissivity material. Electrical heaters are provided to control the evaporation rate of the hydrogen to match the fuel usage and to prevent icing during ascent and descent of the airplane.

Abstract: An ion thruster has a source of a plasma, and an ion-optics system located in sufficient proximity to the source of the plasma to extract ions therefrom. The ion-optics system includes at least two grids arranged in a facing-but-spaced-apart relationship to each other, with each grid being axisymmetric about a grid axis. Each grid includes a peripheral region defining a grid plane perpendicular to the grid axis, a first region of curvature adjacent to the peripheral region, and a second region of curvature along the grid axis such that the first region of curvature lies between the second region of curvature and the peripheral region. The first region of curvature is a convexly curved segment of a first sphere relative to the grid plane, and the second region of curvature is a concavely curved segment of a second sphere relative to the grid plane.

Abstract: A method and apparatus for balancing environmental disturbance torques acting upon a satellite (10) by tilting the satellite solar panels (14,16) toward or away from the sun to change the solar pressure acting upon the satellite (10) as well as the gravity gradient torque generated by different panel (14,16) tilt angles. By balancing the disturbance torque acting upon the satellite (10), satellite disturbances are minimized so that the satellite stabilization system can be made smaller and fuel used for satellite attitude control is minimized. Torque balancing is accomplished at the beginning of the mission through a linear actuator (37) at the mounting location of each solar panel (14,16) to the satellite main body (12) and, once set, is passive and does not require continuous active satellite control.

Abstract: A momentum wheel (14, 142) for compensating for the adverse effects of disturbing torques on stabilized spacecraft is mounted on a base (12, 124) on the spacecraft by three circumferentially spaced supports which include at least two linear actuators (26, 118) that tilt the wheel (14, 142) in any desired direction. One end of each actuator (26) is mounted to a base (38, 154) supporting the wheel by a spherical connection (32, 34, 36) which allows freedom of motion about multiple axes. The other end of each actuator (26) is mounted to the base (12) by either a pair of spaced hinges (22, 24, 46) and a support bracket (18) which is secured to the actuator (26) or a flexible bracket (78). The wheel base (12,124) may also be mounted on the actuators by flexible members (150) which allow tilting of the wheel.

Abstract: An improved clamping connection assembly for separable parts of spacecraft is provided and includes a tension belt for securing a plurality of retainers against camming surfaces on flange members on separable spacecraft component parts. The other peripheral edges of the flange members have detents to respectively receive a single shear pin mounted on each of the retainers. The shear pins receive any shear and torsional forces and transmits them between the structural parts of the spacecraft components without creating additional forces on the tension belt.

Abstract: An apparatus for transporting a spacecraft and fluid propellant from the earth to a substantially low gravity environment above the earth with substantially reduced loading of the spacecraft due to forces upon the fluid propellant during the transport, the apparatus including a vehicle for carrying the spacecraft and the fluid propellant from the earth to a substantially low gravity environment above the earth; a plurality of external tanks disposed within the vehicle, external to the spacecraft, for containing the fluid propellant as the vehicle carries the spacecraft and the fluid propellant from the earth to the substantially low gravity environment above the earth; a plurality of spacecraft tanks disposed within the spacecraft for receiving the fluid propellant and for containing the fluid propellant; and means for transferring the fluid propellant from the external tanks the spacecraft tanks in the substantially low gravity environment above the earth.

Abstract: Apparatus for use in gyroscopically ejecting a spacecraft supported in the open end of a spacecraft supporting cradle. The invention comprises a separable ejection restraint mechanism attached between the cradle and the spacecraft. The mechanism restrains the thrust force applied to the spacecraft for a predetermined time period in order to dissipate undetermined forces acting upon the spacecraft prior to the ejection thereof. The mechanism comprises a separable resilient portion and a releasable clamp portion coupled thereto. The resilient portion comprises a spring loaded anchor rod arrangement while the releasable clamp portion comprises a spring loaded split ball clamp arrangement. The invention also contemplates the use of a flexible carrier coupled between the spacecraft and the cradle. The invention acts as a tether connected between the cradle and spacecraft which acts to establish a determinant state of force on the cargo and eliminate unwanted ejection-related problems prior to cargo deployment.

Abstract: Fiber-reinforced syntactic foam composites having a low specific gravity and a low coefficient of thermal expansion suitable for forming lightweight structures for spacecraft applications are prepared from a mixture of a heat curable thermosetting resin, hollow microspheres having a diameter of about 5 to 200 micrometers and fibers having a length less than or equal to 250 micrometers.

Abstract: A payload such as a spacecraft is deployed from launch vehicle with linear and angular velocity, using a structural arrangement for applying a tangential, single point ejection force to the spacecraft, in which, the single point ejection force and the spacecraft/launch vehicle reaction points enclose the spacecraft center of mass and center of percussion.

Abstract: A spacecraft specifically adapted for launch from the space shuttle by means of a cradle having locking and ejection mechanisms mounted therein. The cradle fastens into the payload bay of the space shuttle and returns therewith for reuse in subsequent launches. The spacecraft mounts at three points to the cradle, and the cradle mounts at three points to the shuttle such that a plane through the attachment points passes through the roll axis of the spacecraft at approximately the center of mass thereof. The cradle utilizes the truss structure of the spacecraft to produce the required stiffness by providing a structural tie between the two ends and the bottom of the cradle. At launch, the spacecraft is ejected with both linear and angular momentum, the spin providing gyroscopic stability. The locking mechanisms in the cradle can be remotely controlled to relock the spacecraft to the cradle in the event of an unsuccessful deployment attempt.

Abstract: A spacecraft specifically adapted for launch from a reusable launch vehicle such as the space shuttle by means of a cradle having locking and ejection mechanisms mounted therein. The cradle fastens into the payload bay of the space shuttle and returns therewith for reuse in subsequent launches. The spacecraft mounts at three points to the cradle, and the cradle mounts at three points to the shuttle such that a plane through the attachment points passes through the roll axis of the spacecraft at approximately the center of mass thereof. The cradle utilizes the truss structure of the spacecraft to produce the required stiffness by providing a structural tie between the two ends and the bottom of the cradle. At launch, the spacecraft is ejected with both linear and angular momentum, the spin providing gyroscopic stability. The locking mechanisms in the cradle can be remotely controlled to relock the spacecraft to the cradle in the event of an unsuccessful deployment attempt.

Abstract: There is herein described a support structure for antennas, optical systems and the like which are generally subject to non uniform dimensional changes due to temperature variations and gradients in the support structure material, the invention overcoming such dimensional changes by combining the use of a material having a low coefficient of thermal expansion and the use of a heat pipe as an integral part of the aforementioned structural member for isothermalization, to reduce the distortion resulting from residual non-zero coefficient of thermal expansion.

Abstract: A battery comprising a battery vessel, battery plates having a central aperture, electrolye impregnated separator, a battery plate holder and a battery plate retainer. The battery plate holder comprises a base retainer and a central tube protruding from the base retainer. The battery plates are placed onto the battery plate holder by inserting the central tube through the apertures in the battery plates. The battery plate retainer holds the plates onto the battery plate holder and the complete assembly comprising the battery plates, the holder and cover is mounted with the battery vessel by coupling the base plate of the holder to the interior of the vessel.