Explorer 32
 | |
| Names |
|
|---|---|
| Mission type | Aeronomy |
| Operator | NASA |
| COSPAR ID | 1966-044A |
| SATCAT no. | 02183 |
| Website | NSSDC Master Catalog - Explorer 32 |
| Mission duration | 10 months |
| Spacecraft properties | |
| Manufacturer | Goddard Space Flight Center |
| Payload mass | 224.5 kilograms (495 lb) |
| Start of mission | |
| Launch date | 13:55:00, May 25, 1966 (UTC) |
| Rocket | Delta-C1 |
| Launch site | Cape Canaveral LC-17B |
| End of mission | |
| Disposal | Deorbited (battery failure) |
| Decay date | February 22, 1985 |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Eccentricity | 0.15532 |
| Apogee altitude | 2,725 kilometres (1,693 mi) |
| Inclination | 64.67° |
| Period | 116 minutes |
| Argument of perigee | 276 kilometres (171 mi) |
| Payload | |
| Ion Mass Spectrometer Neutral Particle Magnetic Mass Spectrometer Satellite Drag Atmospheric Density Pressure Gauges Electron Temperature and Density | |
| Instruments | |
| Mass Spectrometer | |
Explorer 32, also known as Atmosphere Explorer-B (AE-B),[1] was a satellite launched by the United States to study the Earth's upper atmosphere. It was launched from Cape Canaveral on a Delta-C1 rocket, on May 25, 1966. It was the second of five Atmosphere Explorers, the first being Explorer 17. Though it was placed in a higher-than-expected orbit by a malfunctioning second stage on its carrier rocket, Explorer 32 returned data for ten months before failing due to a sudden depressurization. The satellite reentered the Earth's atmosphere on 22 February 1985.
Background
Explorer 32 was built by Goddard Space Flight Center[2] as a successor to Explorer 17, which it strongly resembled, to directly measure the temperature, composition, density, and pressure of the upper atmosphere.[3]. Its main differences from the prior satellite were the addition of a tape recorder for data storage, solar cells to charge onboard batteries, a magnetic torquer to stabilize the satellite's spin, and a 3-axis fluxgate magnetometer for sensing the satellites aspect (facing) in orbit.[2]
Spacecraft
Design
Explorer 32 was a stainless steel, vacuum-sealed sphere, 0.889 metres (2.92 ft) in diameter.[1] It carried one ion spectrometer, two neutral mass spectrometers, three magnetron density gauges, and two electrostatic probes. It used a tape recorder to save data that was acquired when the satellite was not in range of one of the 13 ground stations. It was powered by silver-zinc batteries and a solar cell array.
Scientific experiments
The ion mass spectrometers measured the concentrations of different types of ions in the topside ionosphere, principally atomic hydrogen, helium, nitrogen, and oxygen. The concentrations were recorded as a function of time, location, and solar and geomagnetic activity. The satellite was able to perform a global study of the diurnal variation of the atmosphere during nearly two complete diurnal cycles, since the orbit plane precessed one revolution each 5.5 months. The data from the ion mass spectrometers allowed for studies of: (1) the diurnal and seasonal variation of atmospheric ion composition, (2) the effect of atmospheric winds on the atomic hydrogen-atomic oxygen ion transition level, (3) the density and temporal variation of thermospheric atomic hydrogen, and (4) the altitude variation of ion composition in the midlatitude trough region.[4]
The three magnetron density gauges measured the density of the neutral atmosphere as a function of altitude, time, latitude, and solar and geomagnetic activity.[5]
The electron temperature and density instrument measure the distribution of electron temperatures and densities using a swept voltage electron probe.[5]
The two neutral particle magnetic mass spectrometers were intended to measure the composition of the neutral atmosphere at altitudes between 285 and 1,000 kilometres (935,000 and 3,281,000 ft). One spectrometer failed after 4 days, and the other failed after 7 days in orbit.
The satellite's symmetrical shape also made the entire spacecraft an experiment, allowing the measurement of the density of the upper atmosphere as a function of altitude, latitude, season, and solar activity.[6]
Mission
Explorer 32 was launched 25 May 1966 at 1400:00 UTC from Cape Canaveral Space Launch Complex 17 B by a Thor Delta C1 rocket.[7] The second stage did not cut-off when commanded, instead continuing for an additional eight seconds until its propellant was exhausted. This resulted in the satellite ending up in a much higher apogee orbit than intended (1,688 km (1,049 mi) vs. 750 km (470 mi). Similar overthrusts had occurred with Thor Deltas in the launches of TIROS-9 and GEOS-A.[8] Moreover, the two neutral mass spectrometers failed six days after launch.[1] Nevertheless, the satellite returned usable data,[9], and its measurements of neutral particle and electron density provided direct evidence that gravity waves in the thermosphere's F region are in part responsible for the wave-like structure of its electron density.[10]
When the satellite was near perigee, it was observed by networks of ground-based Baker-Nunn cameras, as well as being tracked by radio and radar. By measuring the the change of the satellite's orbit due to atmospheric drag, it was determined that the models derived from Explorer 17 had been off by 35%, mostly due to calibration errors. Thus, Explorer 32 afforded a much improved map of air density at an altitude of around 160 mi (260 km).[6]
The satellite had an operational life of 10 months, at which point Explorer 32 suffered a depressurization which led to battery failure and ceased active functions.[1] Explorer 32 reentered the Earth's atmosphere on 22 February 1985.[11]
See also
References
- ^ a b c d "NSSDC/COSPAR ID: 1966-044A". NSSDC Master Catalog Search. National Aeronautics and Space Administration. Retrieved March 22, 2015.
- ^ a b William R. Corliss (1967). Scientific Satellites. Washington D.C.: Science and Technical Information Division, Office of Technology Utilization, NASA. pp. 711–3. Retrieved May 11, 2020.
- ^ "Atmosphere and Earth Sciences". planet4589.org. Archived from the original on March 3, 2016. Retrieved March 22, 2015.
- ^ "Ion Mass Spectrometer: NSSDC ID: 1966-044A-01". NASA. Retrieved June 13, 2018.
This article incorporates text from this source, which is in the public domain.
- ^ a b Dyson, P. L.; Newton, G. P.; Brace, L. H. (1970). "In situ measurements of neutral and electron density wave structure from the Explorer 32 satellite". Journal of Geophysical Research. 75 (16): 3200–3210. Bibcode:1970JGR....75.3200D. doi:10.1029/JA075i016p03200.
- ^ a b Newton, George P. (1969). "Resolution of the difference between atmospheric density measurements from Explorer 17 satellite by density gage and drag techniques". Journal of Geophysical Research. 74 (26): 6409–6414. Bibcode:1969JGR....74.6409N. doi:10.1029/JA074i026p06409.
- ^ McDowell, Jonathan. "Launch Log". Jonathon's Space Report. Retrieved May 24, 2021.
- ^ ""Explorer 32 enters Highly Elliptical Orbit". Aviation Week and Space Technology. McGraw Hill Publishing Company. May 30, 1966. p. 30. Retrieved May 24, 2021.
{{cite magazine}}: CS1 maint: url-status (link) - ^ ""Explorer 32 Returning Useful Data". Aviation Week and Space Technology. McGraw Hill Publishing Company. May 30, 1966. p. 30. Retrieved May 24, 2021.
{{cite magazine}}: CS1 maint: url-status (link) - ^ P.L. Dyson; G.P. Newton; L.H. Brace (June 1, 1970). "In situ measurements of neutral and electron density wave structure from the Explorer 32 satellite". Journal of Geophysical Research. 75 (16): 3200–3210.
- ^ McDowell, Jonathan. "Satellite Catalog". Jonathon's Space Report. Retrieved May 24, 2021.
External links
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