Explorer 32
 Explorer 32 satellite | |
| Names | AE-B Atmosphere Explorer-B |
|---|---|
| Mission type | Earth science |
| Operator | NASA |
| COSPAR ID | 1966-044A |
| SATCAT no. | 02183 |
| Website | Explorer 32 |
| Mission duration | 10 months (planned) |
| Spacecraft properties | |
| Spacecraft | Atmosphere Explorer-B |
| Spacecraft type | Explorer |
| Bus | AE |
| Manufacturer | Goddard Space Flight Center |
| Launch mass | 224.5 kg (495 lb) |
| Start of mission | |
| Launch date | 25 May 1966, 14:00:00 GMT |
| Rocket | Thor-Delta C1 (Thor 436 / Delta 038) |
| Launch site | Cape Canaveral, LC-17B |
| Contractor | Douglas Aircraft Company |
| Entered service | 25 May 1966 |
| End of mission | |
| Disposal | Deorbited |
| Decay date | 22 February 1985 |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Low Earth orbit |
| Apogee altitude | 2,725 km (1,693 mi) |
| Inclination | 64.67° |
| Period | 116.00 minutes |
| Instruments | |
| Electron Temperature and Density Ion Spectrometer Mass Spectrometer Neutral Particle Magnetic Mass Spectrometer Pressure Gauges Satellite Drag Atmospheric Density | |
Explorer program | |
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 February 22, 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
Explorer 32 was a stainless steel, vacuum-sealed sphere, 0.889 m (2 ft 11.0 in) 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 14:00:00 GMT from LC-17B by a Thor-Delta C1 launch vehicle.[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) versus 750 km (470 mi) -- similar overthrusts had occurred with Thor-Delta 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 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] This information proved even more useful when combined with the data set of OV3-2, an U.S. Air Force satellite in orbit concurrently.[11]
The satellite had an operational life of 10 months, at which point Explorer 32 suffered a depressurization which led to battery failure, ending active operations.[1] Explorer 32 reentered the Earth's atmosphere on 22 February 1985.[12]
See also
References
- ^ a b c d "NSSDC/COSPAR ID: 1966-044A". NSSDC Master Catalog Search. National Aeronautics and Space Administration. Retrieved 22 March 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 11 May 2020.
This article incorporates text from this source, which is in the public domain.
- ^ "Atmosphere and Earth Sciences". planet4589.org. Archived from the original on 3 March 2016. Retrieved 22 March 2015.
- ^ "Ion Mass Spectrometer: NSSDC ID: 1966-044A-01". NASA. Retrieved 13 June 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 24 May 2021.
- ^ ""Explorer 32 enters Highly Elliptical Orbit". Aviation Week and Space Technology. McGraw Hill Publishing Company. 30 May 1966. p. 30. Retrieved 24 May 2021.
{{cite magazine}}: CS1 maint: url-status (link) - ^ ""Explorer 32 Returning Useful Data". Aviation Week and Space Technology. McGraw Hill Publishing Company. 30 May 1966. p. 30. Retrieved 24 May 2021.
{{cite magazine}}: CS1 maint: url-status (link) - ^ P.L. Dyson; G.P. Newton; L.H. Brace (1 June 1970). "In situ measurements of neutral and electron density wave structure from the Explorer 32 satellite". Journal of Geophysical Research. 75 (16): 3200–3210.
- ^ "OV3-2". NASA. Retrieved 27 September 2021. This article incorporates text from this source, which is in the public domain.
- ^ McDowell, Jonathan. "Satellite Catalog". Jonathon's Space Report. Retrieved 24 May 2021.
