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TECHNICAL NOTES ON
GOES-7 -->
Spacecraft
System Characteristics
Launch
Date: 02/87
Launch Vehicle: Delta 3914
Orbit: Geostationary
Longitude: -175°W +/- 3°
Inclination: 7.78°
Primary Uplink Frequency: S-Band
Primary Downlink Frequency: L-Band
Transponder Bandwidth: 8.2MHz
Redundant On-board Spacecraft Electronic Systems
Primary Power Source: Solar
Spacecraft
Station Keeping
GOES-7 circles the earth in a geosynchronous orbit, which means it orbits the
equatorial plane of the earth at a speed matching the earth's rotation. This
allows it to hover continuously over one general position on the surface. The
geosynchronous plane is about 35,800 km (22,300 miles) above the earth. At
this altitude, a wide communication footprint area can be obtained.
The
spacecraft is maintained at -175°W +/- 3°. East/West
command maneuvers are issued twice a year to GOES-7 by NASA KPGO.
This window provides a full coverage area to the PEACESAT Network
of sites in the Pacific Basin.
Eclipse
Episodes
GOES-7 uses the suns solar rays as its primary power source. There are solar
panels that convert solar energy to electrical energy. Eclipse episodes happen
when the moon comes in between the suns solar rays and GOES-7’s solar
panels. This will cause a temporary shut down of systems that varies from 5min
to an hour. After the improper shutdown of GOES-7’s systems, the spacecraft
comes up in a failed state. With the Navigational Engineering support by NOAA,
there is a joint responsibility of NASA at the Kokee Park Geophysical Observatory & PEACESAT
Headquarters to properly initialize GOES-7.
Eclipse
episodes occur twice a year for duration of about one and a half
months. PEACESAT Operations at this time are cut down to 12 hour
days. Most PEACESAT sites do not get affected by this due to
the 12 hour window being during the normal business hours.
Tracking
of Spacecraft
PEACESAT
uses three means of reference in tracking GOES-7
- NASA
Tracking Data
o Distributed to PEACESAT Headquarters by NASA KPGO monthly
o Used for Engineering purposes by PEACESAT Headquarters
GOES-7
DATE TIME SUBPOINT
YYMMDD HHMMSS LATS LONGS |
30506
0 1.39S 178.95W
30506 3000 0.39S 179.02W
30506 10000 0.63N 179.08W
30506 13000 1.63N 179.14W
30506 20000 2.60N 179.20W
30506 23000 3.53N 179.25W
30506 30000 4.40N 179.28W
30506 33000 5.20N 179.29W
30506 40000 5.90N 179.29W
30506 43000 6.51N 179.27W
30506 50000 7.00N 179.24W
30506 53000 7.37N 179.19W
30506 60000 7.62N 179.14W
30506 63000 7.73N 179.07W
30506 70000 7.71N 179.01W
30506 73000 7.56N 178.95W |
30506
80000 7.28N 178.89W
30506 83000 6.87N 178.85W
30506 90000 6.34N 178.82W
30506 93000 5.70N 178.81W
30506 100000 4.97N 178.82W
30506 103000 4.15N 178.85W
30506 110000 3.26N 178.89W
30506 113000 2.32N 178.94W
30506 120000 1.33N 179.00W
30506 123000 0.33N 179.07W
30506 130000 0.69S 179.14W
30506 133000 1.69S 179.20W
30506 140000 2.66S 179.26W
30506 143000 3.59S 179.30W
30506 150000 4.45S 179.33W
30506 153000 5.24S 179.34W
|
30506
160000 5.94S 179.34W
30506 163000 6.54S 179.31W
30506 170000 7.03S 179.27W
30506 173000 7.40S 179.21W
30506 180000 7.63S 179.14W
30506 183000 7.74S 179.07W
30506 190000 7.71S 178.99W
30506 193000 7.55S 178.92W
30506 200000 7.25S 178.86W
30506 203000 6.83S 178.81W
30506 210000 6.30S 178.77W
30506 213000 5.65S 178.75W
30506 220000 4.91S 178.75W
30506 223000 4.09S 178.76W
30506 230000 3.19S 178.80W
30506 233000 2.24S 178.84W |
|