Abstract: The present invention relates to reducing the tendency to mutate in solid fuel rocket motors, especially such motors which have deeply submerged nozzles. The invention comprises a series of baffles or beads for restraining the motion of trapped combustion products.

Abstract: An earth orbiting satellite (10) having a despun interior portion (22) supporting heat generating elements (24) and a spinning exterior portion (12) having a thermal radiator (20) for heat radiated by these elements, is provided with reflectors (42, 44) in the annulus (40) between the spinning and despun portions, the reflectors being configured to reflect radiation from the annulus to the thermal radiator. See FIG. 2.

Abstract: Control of teleconference is facilitated so as to allow relatively unskilled operators to implement such control.

Abstract: A bearing and power transfer assembly which includes a main bearing and auxiliary bearing for coupling a spun and despun shelf. The main bearing has a stator connected to the spun shelf, and a motor driven rotor connected to the stator of the auxiliary bearing. The rotor of the auxiliary bearing is connected to the despun shelf. Means are provided to maintain said auxiliary stator and rotor locked together until a failure of said main bearing occurs. A ground command frees the auxiliary bearing rotor and stator and a motor associated with the free rotor maintains a spinning torque on the despun shelf. Slip-ring and brush assemblies are included in each bearing assembly to provide electrical connections between spun and despun shelves.

Abstract: A method and apparatus for measuring signal to noise ratio in a time division multiple access (TDMA) communications system which does not require that normal communications be interrupted. The signal to noise ratio measurement is performed on the unmodulated carrier which typically occurs in the preamble of each information burst in the TDMA format. In order to perform the measurements on the carrier of the same burst in each frame, the carrier and noise powers are sampled at a predetermined time with respect to specified information which occurs at the same time in each frame, normally the frame reference burst. After being converted to the receiver intermediate frequency, the unmodulated carrier is fed to both a narrow band pass filter having a pass band at the intermediate frequency and a narrow band stop filter having a stop band at the intermediate frequency. The ratio of the band pass filter output to the band stop filter output is the signal to noise ratio within a very small error.

Abstract: A facsimile to video converter responds to a high bit rate binary signal and produces a single digital (or analog) signal which represents a plurality of pixels for driving a raster scanned display to thereby generate a visual image represented by the binary signals even though the display has resolution too low to directly accept the binary signals.

Abstract: An open loop TDMA communications system includes a transponder located on a spacecraft in quasi-synchronous earth orbit; a reference station periodically transmits a timing marker through said transponder to a plurality of geographically separated earth stations. Spacecraft position varies within controlled limits, and at any time the reference station has available to it information respecting the spacecraft's position. The reference station transmits, along with the timing marker, a spacecraft position index signal which is received at the geographically separated stations. Each of the stations detects the spacecraft position index signal, and based on its own geographic location, translates the spacecraft position index into a transmit timing adjustment. The transmit timing adjustment is employed to vary transmit timing from nominal and to thereby reduce the extent of the guard time used to ensure non-overlapping of bursts from the plurality of stations at the transponder.

Abstract: A PSK modulator employs a waveform of the overlapped raised cosine type which results in reduced adjacent channel interference. Waveforms of the overlapped raised cosine type include the overlapped raised cosine waveform itself as well as waveforms substantially similar thereto. Such waveforms can be produced, in a PSK modulator, by employing a Thomson filter with a single attenuation pole. Employing such a filter with a time bandwidth product (BT) of 1.2 provides the overlapped raised cosine waveform. However, changing the Thomson filter's BT product to 1.0 to thereby generate a waveform of the overlapped raised cosine type provides even further improvements in adjacent channel interference.

Abstract: In a time division multiple access communication system utilizing a satellite for communicating signals between a plurality of ground stations, at spaced times a reference ground station reallocates the total channel capacity of the system among the several ground stations to minimize system blocking and to thereby utilize the available system channel capacity more effectively. To increase the time between successive reallocations, channels are reallocated only when a ground station makes a channel capacity request that is greater than or equal to its corresponding present channel allocation. System blocking is minimized by using a table look-up scheme to generate excess capacity allocation factors for the stations and to thereby determine each station's proportionate share of excess system capacity. An appropriate portion of excess capacity is then added to each station's channel capacity request to provide a new channel allocation for each station.

Abstract: A satellite intended for insertion into a quasi-synchronous earth orbit is adapted for efficient launch by minimizing the amount of launch vehicle cargo capacity employed. The satellite includes at least one major thrust source, such as an apogee kick motor, defining a major thrust axis for the satellite. A reusable launch vehicle such as the Space Shuttle, includes a cargo bay whose largest dimension is parallel to the launch vehicle thrust axis. Minimizing satellite use of cargo bay capacity is obtained by adapting the satellite to lie within the cargo bay of the launch vehicle with its thrust axis perpendicular to the thrust axis of the launch vehicle.

Abstract: A multi-rate TDMA communication system includes a baseline TDMA network and at least one auxiliary TDMA network oprating through the same satellite repeater. The baseline and auxiliary networks may each include a plurality of ground stations, the baseline network stations operating at a bit rate different from the bit rate of the auxiliary network. To maintain orderly communications, a station synchronized with the baseline frame reference burst (FRB) transmits a sub-frame reference burst (SFRB) which latter burst is at a bit rate common to the auxiliary network stations. The auxiliary network stations synchronize to the SFRB.

Abstract: A time division multiple access (TDMA) communication system has a plurality of geographically separated stations including a first group of stations, each of which can communicate with any other station in the first group through a first transponder in a predetermined portion of a TDMA frame (intra-group traffic), and a second group of stations, each of which can communicate with any other station in the second group through a second transponder in a predetermined portion of a TDMA frame associated with the second transponder (intra-group traffic). The TDMA frames of the first and second transponders are synchronized and inter-group traffic, i.e., communications between a station in the first group and a station in the second group, takes place in another predetermined portion of each of the frames which is exclusive of the predetermined portion of both frames used for intra-group traffic.

Abstract: A time division multiple access (TDMA) communication system has a plurality of geographically separated stations including a first group of stations, each of which can communicate with any other station in the first group through a first transponder in a predetermined portion of a TDMA frame (intra-group traffic), and a second group of stations, each of which can communicate with any other station in the second group through a second transponder in a predetermined portion of a TDMA frame associated with the second transponder (intra-group traffic). The TDMA frames of the first and second transponders are synchronized and inter-group traffic, i.e., communications between a station in the first group and a station in the second group, takes place in another predetermined portion of each of the frames which is exclusive of the predetermined portion of both frames used for intra-group traffic.