The Heat Capacity Mapping Mission (HCMM) spacecraft was the first of a series of Applications Explorer Mission (AEM) of the Explorer program.[2]
![]() HCMM satellite | |
Names | Explorer 58 HCMM AEM-A Applications Explorer Mission-A |
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Mission type | Cartography |
Operator | NASA |
COSPAR ID | 1978-041A ![]() |
SATCAT no. | 10818 |
Mission duration | 2.4 years (achieved) |
Spacecraft properties | |
Spacecraft | Explorer LVIII |
Spacecraft type | Heat Capacity Mapping Mission |
Bus | Applications Explorer Mission |
Manufacturer | Goddard Space Flight Center |
Launch mass | 117 kg (258 lb) |
Power | Solar panels and batteries |
Start of mission | |
Launch date | 26 April 1978, 10:20 UTC |
Rocket | Scout D-1 (S-201C) |
Launch site | Vandenberg, SLC-5 |
Contractor | Vought |
Entered service | 26 April 1978 |
End of mission | |
Deactivated | 30 September 1980 |
Last contact | 30 September 1980 |
Decay date | 22 December 1981 |
Orbital parameters | |
Reference system | Geocentric orbit[1] |
Regime | Sun-synchronous orbit |
Perigee altitude | 558 km (347 mi) |
Apogee altitude | 646 km (401 mi) |
Inclination | 97.60° |
Period | 96.70 minutes |
Instruments | |
Heat Capacity Mapping Radiometer (HCMR) | |
Explorer program |
The objective of the HCMM was to provide comprehensive, accurate, high-spatial-resolution thermal surveys of the surface of the Earth.[2]
The HCMM spacecraft was made of two distinct modules: (1) an instrument module, containing the heat capacity mapping radiometer and its supporting gear, and (2) a base module, containing the data handling, power, communications, command, and attitude control subsystems required to support the instrument module. The spacecraft was spin stabilized at a rate of 14 rpm. The HCMM circular Sun-synchronous orbit allowed the spacecraft to sense surface temperatures near the maximum and minimum of the diurnal cycle. The orbit had a daylight ascending node with nominal equatorial crossing time of 14:00 hours. Since there was no inclination adjustment capacity, the spacecraft drifted from this crossing time by about 1 hour earlier per year. There was no on-board data storage capability, so only real-time data were transmitted when the satellite came within reception range of seven ground stations. The repeat cycle of the spacecraft was 16 days. Day/night coverage over a given area between the latitudes of 85°N and 85°S occurred at intervals ranging from 12 to 36 hours (once every 16 days).[2]
The objectives of the Heat Capacity Mapping Radiometer (HCMR) were (1) to produce thermal maps at the optimum times for making thermal-inertia studies for discrimination of rock types and mineral resources location, (2) to measure plant-canopy temperatures at frequent intervals to determine the transpiration of water and plant life, (3) to measure soil-moisture effects by observing the temperature cycle of soils, (4) to map thermal effluents, both natural and man-made, (5) to investigate the feasibility of geothermal source location by remote sensing, and (6) to provide frequent coverage of snow fields for water runoff prediction. The HCMR transmitted analog data in real time to selected receiving stations. The radiometer was similar to the surface composition mapping radiometer (SCMR) of Nimbus 5 (1972-097A). The HCMR had a small instantaneous geometric field of view of 0.83 mrad, high radiometric accuracy, and a wide 716 km (445 mi) swath coverage on the ground so that selected areas were covered within the 12-hour period corresponding to the maximum and minimum of temperature observed. The instrument operated in two channels, 10.5 to 12.5 micrometers (IR) and 0.55 to 1.1 micrometers (visible). The spatial resolution was approximately 600 m (2,000 ft) at nadir for the Infrared (IR) channel, and 500 m (1,600 ft) for the visible channel. The instrument utilized a radiation cooler to cool the two Mercury cadmium telluride (|Hg-Cd-Te) detectors to 115 K. The experiment included an analog multiplexer that accepted the analog outputs of the detectors and multiplexed them in a form suitable for transmission by the spacecraft S-band transmitter. The instrument performed satisfactorily until the spacecraft operations terminated on 30 September 1980.[3]
HCMM was launched from Vandenberg Air Force Base on 26 April 1978 by a Scout D-1 launch vehicle. Its mass was 117 kg (258 lb).[2]
During 21-23 February 1980, the HCMM orbital altitude was lowered from 620 km (390 mi) to 540 km (340 mi) to stop the drift of the orbit plane to unfavorable Sun angles which in turn reduced the power collection capability of the solar panels. The operations of the spacecraft were terminated on 30 September 1980.[2] HCMM re-entered in the Earth's atmosphere on 22 December 1981.[1]
Explorers Program | |||
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List of Explorers Program missions | |||
Missions | ![]() | ||
Proposals |
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← 1977 · Orbital launches in 1978 · 1979 → | |
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Kosmos 974 | Intelsat IVA F-3 | Soyuz 27 | Kosmos 975 | Kosmos 976 · Kosmos 977 · Kosmos 978 · Kosmos 979 · Kosmos 980 · Kosmos 981 · Kosmos 982 · Kosmos 983 | Kosmos 984 | Kosmos 985 | Progress 1 | Molniya-3 No.20 | Kosmos 986 | Fanhui Shi Weixing 4 | IUE | Kosmos 987 | Kyokko | Kosmos 988 | OPS 6291 | Kosmos 989 | Ume 2 | Kosmos 990 | OPS 5111 | OPS 6031 | Kosmos 991 | Soyuz 28 | Molniya-1-39 | Kosmos 992 | Landsat 3 · OSCAR 8 · PIX-1 | Kosmos 993 | Kosmos 994 | OPS 0460 · OPS 7858 | Kosmos 995 | OPS 9439 · OPS 9440 | Kosmos 996 | Kosmos 997 · Kosmos 998 | Kosmos 999 | Kosmos 1000 | Intelsat IVA F-6 | Kosmos 1001 | Kosmos 1002 | OPS 8790 | Yuri 1 | Kosmos 1003 | HCMM | OPS 6183 | Kosmos 1004 | OTS-2 | Kosmos 1005 | Kosmos 1006 | OPS 5112 | Kosmos 1007 | Kosmos 1008 | Kosmos 1009 | Pioneer Venus Orbiter | Kosmos 1010 | Kosmos 1011 | Kosmos 1012 | Ekran No.13L | Molniya-1-40 | Kosmos 1013 · Kosmos 1014 · Kosmos 1015 · Kosmos 1016 · Kosmos 1017 · Kosmos 1018 · Kosmos 1019 · Kosmos 1020 | Kosmos 1021 | OPS 9454 | Kosmos 1022 | OPS 4515 | Soyuz 29 | GOES 3 | Kosmos 1023 | Seasat | Soyuz 30 | Kosmos 1024 | Kosmos 1025 | Comstar 1C | Kosmos 1026 | Progress 2 | GEOS-2 | Molniya-1-41 | Gran' No.14L | Kosmos 1027 | OPS 7310 | Kosmos 1028 | Progress 3 | Pioneer Venus Multiprobe | ISEE-3 | Ekran No.15L | Molniya-1-41 | Soyuz 31 | Kosmos 1029 | Kosmos 1030 | Venera 11 | Kosmos 1031 | Venera 12 | Jikiken | Kosmos 1032 | Kosmos 1033 | Progress 4 | Kosmos 1034 · Kosmos 1035 · Kosmos 1036 · Kosmos 1037 · Kosmos 1038 · Kosmos 1039 · Kosmos 1040 · Kosmos 1041 | Kosmos 1042 | OPS 5113 | Kosmos 1043 | Molniya-3 No.22 | TIROS-N | Kosmos 1044 | Ekran No.14L | Nimbus 7 · CAMEO | Interkosmos 18 · Magion 1 | Kosmos 1045 · RS-1 · RS-2 | Prognoz 7 | Kosmos 1046 | Einstein | Kosmos 1047 | Kosmos 1048 | NATO 3C | Kosmos 1049 | Kosmos 1050 | Kosmos 1051 · Kosmos 1052 · Kosmos 1053 · Kosmos 1054 · Kosmos 1055 · Kosmos 1056 · Kosmos 1057 · Kosmos 1058 | Kosmos 1059 | Kosmos 1060 | OPS 5114 | OPS 9441 · OPS 9442 | Kosmos 1061 | Kosmos 1062 | Anik B1 · DRIMS | Kosmos 1063 | Gorizont No.11L | Kosmos 1064 | Kosmos 1065 | Kosmos 1066 | Kosmos 1067 | Kosmos 1068 | Kosmos 1069 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets). |