Explorer 52

Explorer 52
	Explorer 52 (Hawkeye-1) satellite
Names	Hawkeye-1; Injun-6; IE-D; Ionospheric Explorer-D; Neutral Point Explorer
Mission type	Ionospheric research
Operator	NASA / Langley Research Center
COSPAR ID	1974-040A
SATCAT no.	07325
Mission duration	3 years, 10 months, 24 days
Spacecraft properties
Spacecraft	Explorer LII
Spacecraft type	Ionospheric Explorer
Bus	Injun
Manufacturer	University of Iowa
Launch mass	22.7 kg (50 lb)
Power	36 watts
Start of mission
Launch date	3 June 1974, 23:09:11 UTC
Rocket	Scout E1 (S-191C)
Launch site	Vandenberg, SLC-5
Contractor	Vought
Entered service	3 June 1974
End of mission
Decay date	28 April 1978
Orbital parameters
Reference system	Geocentric orbit
Regime	Polar orbit
Perigee altitude	469 km (291 mi)
Apogee altitude	125,570 km (78,030 mi)
Inclination	89.80°
Period	3032.40 minutes
Instruments
	Extremely low frequency (ELF) / Very low frequency (VLF) Receivers; Low-Energy Proton and Electron Differential Energy Analyzer (LEPEDEA); Triaxial Fluxgate Magnetometer
	Explorer program ← Explorer 51 Explorer 53 →

Last updated August 30, 2024

Explorer 52, also known as Hawkeye-1, Injun-F, Neutral Point Explorer, IE-D, Ionospheric Explorer-D, was a NASA satellite launched on June 3, 1974, from Vandenberg Air Force Base on a Scout E-1 launch vehicle.^[2]

Mission

The primary mission objective of Explorer 52 (Hawkeye-1) was to conduct particle and field investigations of the polar magnetosphere of the Earth out to 21 Earth radii. Secondary objectives were to make magnetic field and plasma distribution measurements in the solar wind and to study Type-3 radio emissions caused by solar electron streams in the interplanetary medium. To accomplish these objectives, the spacecraft was instrumented with the following instruments:

A plasma wave receivers;^[3]
A fluxgate magnetometer;^[4]
A low-energy proton-electron differential energy analyzer.^[5]

Experiments

Extremely low frequency (ELF) / Very low frequency (VLF) Receivers

This experiment measured electric and magnetic fields using a 42.7 m (140 ft) electric dipole (tip-to-tip) and a search coil antenna deployed 1.58 m (5 ft 2 in) from the spacecraft. The electric field spectrum measurements were made in 16 logarithmically spaced frequency channels extending from 1.78 Hz to 178 kHz, and DC electric fields were also measured. The bandwidth of these channels varied from 7.5% to 30% depending on center frequency. Channel sensitivity and dynamic range were 1E-6 V/m and 100 dB, respectively. A wideband receiver was also used, with two selectable bandwidth ranges: 0.15 to 10 kHz or 1 to 45 kHz. The magnetic field spectrum was measured in eight discrete, logarithmically spaced channels from 1.78 Hz to 5.62 kHz. The bandwidth of these channels varied from 7.5% to 30% depending on frequency. The dynamic range was 100 dB, and the sensitivity ranged from 0.1-nT at 1.78 Hz to 3.4E-4 nT at 5.62 kHz. The wideband receiver described above could be used with the magnetic antenna. Each discrete channel was sampled once every 11.52-seconds.^[3]

Low-Energy Proton and Electron Differential Energy Analyzer (LEPEDEA)

This particle spectrometer (LEPEDEA) employed two electrostatic analyzers to measure protons and electrons simultaneously. A GM tube was an additional detector sensitive to protons above 600 keV and electrons above 45 keV. The sensors were mounted normally to the spacecraft spin axis. Angular distributions of particles were determined with a sector resolution of 50° for analyzer voltage steps and 10° for analyzer voltage sweeps of its whole range. The electrostatic analyzers had a field of view of 8° by 30° and measured protons and electrons from 0.05 to 40 keV. The Geiger–Müller tube had a conical field of view of 15° half-angle. Two modes of operation were used: one instrument cycle of 156 intensity measurements every 46-seconds, or one cycle of 312 intensity measurements every 92-seconds.^[5]

Triaxial Fluxgate Magnetometer

A four-range, triaxial fluxgate magnetometer mounted on a 1.52 m (5 ft 0 in) boom, was used to measure the ambient magnetic field. The three axes were sampled sequentially three times each 5.72 seconds. Sensitivities and accuracies of the four ranges were ± 150 and 1.2, 450 and 3.5, 1500 and 11.7, and 25,000 and 195.3-nT, respectively. The sensitivity was switched by ground command. Frequency response was DC to 1-Hz (flat); down 3-dB at 10-Hz; then falling at 6-dB per octave at higher frequencies. Satellite stray fields were constrained to be less than 0.1 nT, which was also the RMS instrument noise level. Inflight calibration was performed once every 98-minutes.^[4]

Spacecraft

The spacecraft was spin-stabilized satellite with a nominal rotational period of 11 seconds. In celestial coordinates, the positive spin axis coordinates were right ascension 299.4° (± 1.1°) and declination 8.6° (± 1.5°). There was no onboard orientation or spin rate control, but the orientation of the spin axis was stable. An optical aspect system operated from launch until 3 September 1974 at which time the optical aspect system was turned off and failed to turn back on. After this period, the aspect had to be determined by observing the effect of optical illumination from the Sun on a plasma measurement system. Using the sharp peak observed in this data, corrected orientation information was obtained and rewritten to the data records. The complete spacecraft with instruments had a mass of 22.65 kg (49.9 lb). Power of 36 watts, depending on the solar aspect, was obtained from solar cells. Explorer 52 participated in the International Magnetospheric Study (IMS) and during the first half of 1977 data acquisition was confined to IMS special intervals. Data were obtained in real-time only, at frequencies of 136 and 400-MHz at 100 bit/s (or 200 bit/s with convolutional coding) plus wideband Very low frequency (VLF) data.^[6]

It was designed, built, and tracked by personnel at the Department of Physics and Astronomy, University of Iowa whose sports teams are the Iowa Hawkeyes. The spacecraft was launched on 3 June 1974 into a polar orbit with an apogee over the North Pole and re-entered on 28 April 1978 after 667 orbits or nearly four years of continuous operation. The spacecraft apogee was of 125,570 km (78,030 mi) with 469 km (291 mi) perigee. The orbital period was 51.3 hours. During its lifetime, the orbital inclination of the plane of the spacecraft's orbit to the Earth's equator was of 89.80°. The spacecraft's axis of rotation at launch was inertially fixed in its orbital plane, directed towards a constant right ascension and declination, and nearly parallel to the Earth's equatorial plane.^[6]

Results

In 1992, Dr. James Van Allen (Hawkeye Project Scientist) and the other Hawkeye principal investigators provided the National Space Science Data Center (NSSDC) with the high-resolution digital data (referred to as Master Science Files) from Explorer 52 (Hawkeye-1). Recognizing the uniqueness of these data, the NSSDC has placed the entire Hawkeye data set in its online archive.^[6]

Related Research Articles

<span class="mw-page-title-main">Explorer 35</span> NASA satellite of the Explorer program

Explorer 35,, was a spin-stabilized spacecraft built by NASA as part of the Explorer program. It was designed for the study of the interplanetary plasma, magnetic field, energetic particles, and solar X-rays, from lunar orbit.

Explorer 6, or S-2, was a NASA satellite, launched on 7 August 1959, at 14:24:20 GMT. It was a small, spherical satellite designed to study trapped radiation of various energies, galactic cosmic rays, geomagnetism, radio propagation in the upper atmosphere, and the flux of micrometeorites. It also tested a scanning device designed for photographing the Earth's cloud cover. On 14 August 1959, Explorer 6 took the first photos of Earth from a satellite.

<span class="mw-page-title-main">Fast Auroral SnapshoT Explorer</span> NASA satellite of the Explorer program

The Fast Auroral SnapshoT Explorer was a NASA plasma physics satellite, and was the second spacecraft in the Small Explorer program (SMEX). It was launched on 21 August 1996, from Vandenberg Air Force Base aboard a Pegasus XL launch vehicle. The spacecraft was designed and built by NASA's Goddard Space Flight Center (GSFC). Flight operations were handled by GSFC for the first three years, and thereafter were transferred to the University of California, Berkeley's Space Sciences Laboratory.

<span class="mw-page-title-main">Explorer 33</span> NASA satellite of the Explorer program (1966–)

Explorer 33, also known as IMP-D and AIMP-1, is a spacecraft in the Explorer program launched by NASA on 1 July 1966 on a mission of scientific exploration. It was the fourth satellite launched as part of the Interplanetary Monitoring Platform series, and the first of two "Anchored IMP" spacecraft to study the environment around Earth at lunar distances, aiding the Apollo program. It marked a departure in design from its predecessors, IMP-A through IMP-C. Explorer 35 was the companion spacecraft to Explorer 33 in the Anchored IMP program, but Explorer 34 (IMP-F) was the next spacecraft to fly, launching about two months before AIMP-E, both in 1967.

<span class="mw-page-title-main">Explorer 18</span> NASA satellite of the Explorer program

Explorer 18, also called IMP-A, IMP-1, Interplanetary Monitoring Platform-1 and S-74, was a NASA satellite launched as part of the Explorer program. Explorer 18 was launched on 27 November 1963 from Cape Canaveral Air Force Station (CCAFS), Florida, with a Thor-Delta C launch vehicle. Explorer 18 was the first satellite of the Interplanetary Monitoring Platform (IMP). Explorer 21 (IMP-B) launched in October 1964 and Explorer 28 (IMP-C) launched in May 1965 also used the same general spacecraft design.

<span class="mw-page-title-main">Explorer 14</span> NASA satellite of the Explorer program

Explorer 14, also called EPE-B or Energetic Particles Explorer-B, was a NASA spacecraft instrumented to measure cosmic-ray particles, trapped particles, solar wind protons, and magnetospheric and interplanetary magnetic fields. It was the second of the S-3 series of spacecraft, which also included Explorer 12, 14, 15, and 26. It was launched on 2 October 1962, aboard a Thor-Delta launch vehicle.

Explorer 10 was a NASA satellite that investigated Earth's magnetic field and nearby plasma. Launched on 25 March 1961, it was an early mission in the Explorer program and was the first satellite to measure the "shock wave" generated by a solar flare.

<span class="mw-page-title-main">ISEE-1</span> NASA satellite of the Explorer program

The ISEE-1 was an Explorer-class mother spacecraft, International Sun-Earth Explorer-1, was part of the mother/daughter/heliocentric mission. ISEE-1 was a 340.2 kg (750 lb) space probe used to study magnetic fields near the Earth. ISEE-1 was a spin-stabilized spacecraft and based on the design of the prior IMP series of spacecraft. ISEE-1 and ISEE-2 were launched on 22 October 1977, and they re-entered on 26 September 1987.

<span class="mw-page-title-main">ISEE-2</span>

The ISEE-2 was an Explorer-class daughter spacecraft, International Sun-Earth Explorer-2, was part of the mother/daughter/heliocentric mission. ISEE-2 was a 165.78 kg (365.5 lb) space probe used to study magnetic fields near the Earth. ISEE-2 was a spin-stabilized spacecraft and based on the design of the prior IMP series of spacecraft. ISEE-1 and ISEE-2 were launched on 22 October 1977, and they re-entered on 26 September 1987.

Explorer 12, also called EPE-A or Energetic Particles Explorer-A and as S3), was a NASA satellite built to measure the solar wind, cosmic rays, and the Earth's magnetic field. It was the first of the S-3 series of spacecraft, which also included Explorer 12, 14, 15, and 26. It was launched on 16 August 1961, aboard a Thor-Delta launch vehicle. It ceased transmitting on 6 December 1961 due to power failure.

Explorer 28, also called IMP-C, IMP-3 and Interplanetary Monitoring Platform-3, was a NASA satellite launched on 29 May 1965 to study space physics, and was the third spacecraft launched in the Interplanetary Monitoring Platform program. It was powered by chemical batteries and solar panels. There were 7 experiments on board, all devoted to particle studies. Performance was normal until late April 1967, when intermittent problems began. It stayed in contact until 12 May 1967, when contact was lost. The orbit decayed until it re-entered the atmosphere on 4 July 1968. The spacecraft design was similar to its predecessors Explorer 18 (IMP-A), launched in November 1963, and Explorer 21 (IMP-B), launched in October 1964, though this satellite was a few kilograms lighter. The successor Explorer 33 (IMP-D) began the use of a new design.

Explorer 21, also called IMP-B, IMP-2 and Interplanetary Monitoring Platform-2, was a NASA satellite launched as part of Explorer program. Explorer 21 was launched on 4 October 1964, at 03:45:00 GMT from Cape Canaveral (CCAFS), Florida, with a Thor-Delta C launch vehicle. Explorer 21 was the second satellite of the Interplanetary Monitoring Platform, and used the same general design as its predecessor, Explorer 18 (IMP-A), launched the previous year, in November 1963. The following Explorer 28 (IMP-C), launched in May 1965, also used a similar design.

Explorer 40, was a NASA magnetically aligned satellite launched simultaneously with Explorer 39 (AD-C) using a Scout B launch vehicle.

Explorer 41, also called IMP-G and IMP-5, was a NASA satellite launched as part of the Explorers program. Explorer 41 launched on 21 June 1969 from Vandenberg AFB, California, with a Thor-Delta E1 launch vehicle. Explorer 41 was the seventh satellite launched as part of the overall Interplanetary Monitoring Platform series, though it received the post-launch designation "IMP-5" because two previous flights had used the "AIMP" designation instead. It was preceded by the second of those flights, Explorer 35, launched in July 1967. Its predecessor in the strict IMP series of launches was Explorer 34, launched in May 1967, which shared a similar design to Explorer 41. The next launch of an IMP satellite was Explorer 43 in 1971.

Explorer 43, also called IMP-I and IMP-6, was a NASA satellite launched as part of the Explorers program. Explorer 43 was launched on 13 March 1971 from Cape Canaveral Air Force Station (CCAFS) with a Thor-Delta M6 launch vehicle. Explorer 43 was the sixth satellite of the Interplanetary Monitoring Platform.

Explorer 45 was a NASA satellite launched as part of Explorer program. Explorer 45 was the only one to be released from the program Small Scientific Satellite.

Explorer 47, was a NASA satellite launched as part of the Explorers program. Explorer 47 was launched on 23 September 1972 from Cape Canaveral, Florida, with a Thor-Delta 1604. Explorer 47 was the ninth overall launch of the Interplanetary Monitoring Platform series, but received the launch designation "IMP-7" because two previous "Anchored IMP" flights had used "AIMP" instead.

Explorer 50, also known as IMP-J or IMP-8, was a NASA satellite launched to study the magnetosphere. It was the eighth and last in a series of the Interplanetary Monitoring Platform.

Dynamics Explorer 1 was a NASA high-altitude mission, launched on 3 August 1981, and terminated on 28 February 1991. It consisted of two satellites, DE-1 and DE-2, whose purpose was to investigate the interactions between plasmas in the magnetosphere and those in the ionosphere. The two satellites were launched together into polar coplanar orbits, which allowed them to simultaneously observe the upper and lower parts of the atmosphere.

AMPTE-UKS, also called AMPTE-United Kingdom Subsatellite, was a United Kingdom satellite designed and tasked to study the magnetosphere of Earth, being launched as part of the Explorer program. The AMPTE mission was designed to study the access of solar wind ions to the magnetosphere, the convective-diffusive transport and energization of magnetospheric particles, and the interactions of plasmas in space.

References

↑ "Scout-E1". Gunter's Space Page. 12 December 2017. Retrieved 17 November 2021.
↑ "Display: Explorer 52 (Hawkeye-1) 1974-040A". NASA. 28 October 2021. Retrieved 17 November 2021. This article incorporates text from this source, which is in the public domain .
1 2 "Experiment: Extremely low frequency (ELF) / Very low frequency (VLF) Receivers". NASA. 28 October 2021. Retrieved 18 November 2021. This article incorporates text from this source, which is in the public domain .
1 2 "Experiment: Triaxial Fluxgate Magnetometer". NASA. 28 October 2021. Retrieved 18 November 2021. This article incorporates text from this source, which is in the public domain .
1 2 "Experiment: Low-Energy Proton and Electron Differential Energy Analyzer (LEPEDEA)". NASA. 28 October 2021. Retrieved 18 November 2021. This article incorporates text from this source, which is in the public domain .
1 2 3 "HAWKEYE". NASA. 30 March 2001. Retrieved 18 November 2021. This article incorporates text from this source, which is in the public domain .

External links

NASA's Explorer Missions

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.

[GSP-1] "Scout-E1". Gunter's Space Page. 12 December 2017. Retrieved 17 November 2021.

[Display-2] "Display: Explorer 52 (Hawkeye-1) 1974-040A". NASA. 28 October 2021. Retrieved 17 November 2021. This article incorporates text from this source, which is in the public domain .

[Experiment3-3] 1 2 "Experiment: Extremely low frequency (ELF) / Very low frequency (VLF) Receivers". NASA. 28 October 2021. Retrieved 18 November 2021. This article incorporates text from this source, which is in the public domain .

[Experiment1-4] 1 2 "Experiment: Triaxial Fluxgate Magnetometer". NASA. 28 October 2021. Retrieved 18 November 2021. This article incorporates text from this source, which is in the public domain .

[Experiment2-5] 1 2 "Experiment: Low-Energy Proton and Electron Differential Energy Analyzer (LEPEDEA)". NASA. 28 October 2021. Retrieved 18 November 2021. This article incorporates text from this source, which is in the public domain .

[GSFC-6] 1 2 3 "HAWKEYE". NASA. 30 March 2001. Retrieved 18 November 2021. This article incorporates text from this source, which is in the public domain .

[1]

[2]

[3]

[4]

[5]

[6]