Image Navigation and Registration
In addition to the acquisition of imaging and sounding data, the GOES I-M system is capable of registering to a high degree of accuracy the earth's latitude and longitude locations of each picture element pixel within an image. This accurate determination of pixel location is accomplished by a ground computer in the operations ground equipment OGE , which processes star and landmark data obtained by the Imager and Sounder. Working in conjunction with the spacecraft attitude and orbit control...
Image Navigation
Pixel navigation for the Imager and Sounder is independently established by orbit and attitude determination of each unit's optical line of sight. This computation, performed every 24 hours, is based on ranging data, landmark observations, and star observations made by each instrument. Orbit determination is accomplished primarily from range data and landmark observations. The ranging measurements are obtained by using the processed data relay PDR link and computing the round trip propagation...
High Accuracy Sun Sensor
The pointing knowledge required of the SXI is 10 arcsec, which is met by the HASS. The HASS consists of a Sun sensor head and a Sun sensor electronics box. Various reticles and associated solar cells form the optics of the sensor head. The electronics package provides multiplexed processors for the coarse and fine Sun data, and for detecting Sun presence. The Sun angle output signals are passed through shift registers. The HASS output to the data electronics box is digital. Serial data...
Transfer and Phasing Orbits
The spacecraft attitude at Injection onto the transfer orbit Is oriented so as to maximize continuous T amp C coverage by both primary and backup ground stations. The effective spacecraft T amp C antenna pattern is a cardioid with a maximum 130 look angle from the X axis. T amp C visibility from the ground is obtained when the spacecraft's elevation angle with respect to the ground station local horizon is greater than 5 and the ground station is within the spacecraft T amp C antenna pattern....
Thermal Design EarthNorthEast Features
S-BAND RECEIVE HORN, WHITE PAINT, KAPTON TEDLAR APERTURE COVER S-BAND RECEIVE HORN, WHITE PAINT, KAPTON TEDLAR APERTURE COVER Thermal Design - Transfer Orbit Configuration Thermal Design - Transfer Orbit Configuration
Operations Ground Equipment 1
The GOES ground segment consists of three parts ground station radio frequency RF equipment, telemetry and command system, and the payload processing and spacecraft operations system. The ground station RF equipment is located at the SOCC and CDA facilities. Telemetry and command are provided by the GOES I-M telemetry and command system GIMTACS , also located at the SOCC and CDA. Payload processing and spacecraft operations support is provided by the operations ground equipment OGE . The OGE...
Optical Bench
The optical bench is both a metering structure for the optical system and a structural support member for the telescope assembly. As a metering structure, the optical bench maintains the separation between the mirror and the focal plane subassembly to 0.001 cm over an expected temperature range of 40'C. The bench is hand laid up using sheets of carbon fibers impregnated with a cyanate ester resin. The bench material is highly hydrophobic and thermally stable, varying from 2.5 to less than 0.2...
Apogee Maneuver Firing at Fourth Apogee
Spacecraft drift induced by solar, earth and lunar gravitational effects and solar pressure corrected by stationkeeping maneuvers Spacecraft drift induced by solar, earth and lunar gravitational effects and solar pressure corrected by stationkeeping maneuvers
Design Description Solar Sail and Boom
3.14-m 10.3-ft Total Length Boom Inside MIDDLE CONE 1 2-mil Aluminized Kapton 3.14-m 10.3-ft Total Length Boom Inside 3 10-mil Aluminum Outer Liner 3 10-mil Aluminum Outer Liner 57.7-cm 22.7-in Total Length 22.86-cm 9-in Self-Deploying Astromast 17.71-m 58.1-ft Total Length Aluminum and Fiberglass Epoxy Rods To balance the torque caused by solar pressure on the solar array, a solar sail is deployed from the north side of the spacecraft, opposite the solar array. The sail is mounted on an...
Image and Mirror Motion Compensation
In the IMC MMC system, the spacecraft AOCE processor receives updated IMC coefficients from OATS and scan synchronization signals from the Imager and Sounder. With these data, the AOCE generates and sends to the Imager and Sounder servos mirror scan compensation signals, which are the sum of the IMC and MMC adjustments. These compensation signals are then converted to the proper scan adjustments in the Imager and Sounder, producing images and soundings with a fixed-earth projection. The SPS...
GOES Variable Data Format
The GOES I-M variable GVAR data transmission format is primarily used to transmit Imager and Sounder meteorological data. It also includes telemetry, calibration data, text messages, spacecraft navigation data, and auxiliary products. The GVAR format originated in the operational visible infrared spin scan radiometer, atmospheric sounder VAS mode AAA of the early spin-stabilized GOES spacecraft. The AAA format consists of a repeating sequence of 12 fixed-length, equal size blocks whose...
Magnetometer Boom
The magnetometer boom moves two redundant magnetometers away from the spacecraft main body to reduce interaction with the spacecraft's magnetic field. The boom is a thin-walled graphite tube, 3 meters 9.8 feet long and 5 centimeters 2 inches in diameter. One end of the boom is hinged to the northwest corner of the anti-earth panel. The other end of the boom holds the two magnetometers. One magnetometer is 0.3 meter 1 foot inboard of the other. The boom and the magnetometer support brackets are...
GVAR Transmission Format
The GVAR data transmission format was developed to allow full use of the capabilities of the advanced, three-axis-stabilized spacecraft while retaining as much commonality as possible with receiving equipment presently in use from earlier spin-stabilized GOES spacecraft. The GVAR format is based on the operational visible and infrared spin scan radiometer atmospheric sounder VAS mode AAA format, which consists of a repeating sequence of 12 fixed-length equal size blocks. The transmission of...
Sounder Detectors Channel Allocation
Visible channel 5 of max. scene radiance Line to line 0.25 K Detector to detector 0.40 K Channel to channel 0.29 K Blackbody calibration to calibration 0.60 K 1 3 specified noise equivalent radiance difference NEAN Image navigation accuracy at nadir Registration within 120 minute sounding Registration between repeated soundings Midnight 4 Hours 10 km 112 rad 280 rad