View source for AMPTE-CCE

{{Short description|NASA satellite of the Explorer program}}
{{Use American English|date=November 2021}}
{{Use dmy dates|date=November 2021}}
{{Infobox spaceflight
| name              = AMPTE-CEE
| names_list        = Explorer 65<br/>AMPTE-Charge Composition Explorer
| image             = CCE AMPTE-1.jpg
| image_caption     = AMPTE-CCE (Explorer 65) satellite
| image_size        = 300px
| mission_type      = [[Magnetosphere|Magnetosphere research]]
| operator          = [[NASA]]
| COSPAR_ID         = 1984-088A
| SATCAT            = 15199
| mission_duration  = 5 years (achieved)
| spacecraft        = Explorer LXV
| spacecraft_type   = Active Magnetospheric Particle Tracer Explorers (AMPTE)
| spacecraft_bus    = AMPTE-CEE
| manufacturer      =
| launch_mass       = {{cvt|242|kg}}
| dimensions        =
| power             = 140 [[watt]]s
| launch_date       = 16 August 1984, 14:48 [[Coordinated Universal Time|UTC]]<ref name="JSR"/>
| launch_rocket     = [[Delta 3000|Delta 3924]] (Delta 175)
| launch_site       = [[Cape Canaveral Space Force Station|Cape Canaveral]], [[Cape Canaveral Launch Complex 17|LC-17A]]
| launch_contractor = [[Douglas Aircraft Company]]
| entered_service   = 16 August 1984
| last_contact      = 12 July 1989
| deactivated       =
| decay_date        =
| orbit_reference   = [[Geocentric orbit]]<ref name="Trajectory"/>
| orbit_regime      = [[Highly elliptical orbit]]
| orbit_periapsis   = 0.17 R<sub>E</sub>
| orbit_apoapsis    = 8.79 R<sub>E</sub>
| orbit_inclination = 4.8°
| orbit_period      = 16 hours
| apsis             = gee
| instruments       = CCE Magnetometer (MAG)<br/>Charge-Energy-Mass Spectrometer (CHEM)<br/>Hot Plasma Composition Experiment (HPCE)<br/>Medium Energy Particle Analyzer (MEPA)<br/>Plasma Wave Experiment (PWE)
| programme         = '''Explorer program'''
| previous_mission  = [[Solar Mesosphere Explorer]] (Explorer 64)
| next_mission      = [[AMPTE-IRM]]
}}
'''AMPTE-Charge Composition Explorer''', also called as  '''AMPTE-CCE''' or '''Explorer 65''', was a [[NASA]] satellite designed and tasked to study the [[Magnetosphere|magnetosphere of Earth]], being launched as part of the [[Explorer program]]. The AMPTE (Active Magnetospheric Particle Tracer Explorers) mission was designed to study the access of [[solar wind]] [[ion]]s to the magnetosphere, the convective-diffusive transport and energization of magnetospheric particles, and the interactions of [[Plasma (physics)|plasmas]] in space.<ref name="Display"/>
== Mission ==
The AMPTE-CCE is one of the three components of the international space mission AMPTE, which also included '''[[AMPTE-IRM]]''' (Ion Release Module), designed by [[Germany]], and '''[[AMPTE-UKS]]''' (United Kingdom Subsatellite), provided by the [[United Kingdom]].<ref name="Display"/>
== Spacecraft ==
The mission consisted of three spacecraft: AMPTE-CCE; AMPTE-IRM, which provided multiple ion releases in the solar wind, the [[magnetosheath]], and the [[Magnetosphere|magnetotail]], with [[in situ]] diagnostics of each; and AMPTE-UKS, which uses thrusters to keep station near the AMPTE-IRM to provide two-point local measurements. The AMPTE-CCE (Charge Composition Explorer) spacecraft was instrumented to detect those [[lithium]] and [[barium]] tracer ions from the AMPTE-IRM releases that were transported into the magnetosphere within the AMPTE-CCE orbit. The spacecraft was [[Spin-stabilisation|spin-stabilized]] at 10 [[Revolutions per minute|rpm]], with its spin axis in the [[Celestial equator|equatorial plane]], and offset from the [[Earth]]-[[Sun]] line by about 20°. It could adjust [[Spacecraft attitude control|attitude control]] with both magnetic torquing and cold gas thrusters. The AMPTE-CCE used a 2.E8-[[bit]] [[tape recorder]] and redundant 2.5-[[watt]]s [[S band|S-band]] [[Transponder (satellite communications)|transponders]]. The spacecraft battery was charged by a 140-watt solar array.<ref name="Display"/>
== Launch ==
AMPTE-CCE was launched with the two other satellites of the '''AMPTE''' program on 16 August 1984, at 16:48 [[Coordinated Universal Time|UTC]], from a [[Cape Canaveral Space Force Station|Cape Canaveral]] launch pad by a [[Delta (rocket family)|Delta 3924]] [[launch vehicle]].<ref name="JSR">{{cite web |url=http://www.planet4589.org/space/log/launchlog.txt |title=Launch Log |publisher=Jonathan's Space Report |date=21 July 2021 |access-date=25 November 2021}}</ref> It was placed in an [[Non-inclined orbit|equatorial orbit]] of {{cvt|1100|xx|50000|km}} with an inclination of 4.8°.<ref name="Trajectory">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1984-088A |title=Trajectory: AMPTE-CCE (1984-088A) |publisher=NASA |date=28 October 2021 |access-date=25 November 2021}} {{PD-notice}}</ref>
== Instruments ==
Charge Composition Explorer was instrumented to detect those [[lithium]] and [[barium]] tracer [[ion]]s from the IRM released that were transported into the magnetosphere within the CCE orbit. The spacecraft was spin-stabilized at 10 [[Revolutions per minute|rpm]], with its spin axis in the [[equatorial plane]], and offset from the [[Earth]]-[[Sun]] line by about 20°. It could adjust attitude with both magnetic torquing and cold gas thrusters.<ref name="Display"/>
The satellite carries 5 scientific instruments that are used to measure the composition of the particles in the magnetosphere throughout their energy spectrum and the changes that affect them with the objective of determining the main processes governing their excitation, their displacement and their disappearance. CCE must also detect the lithium and barium ions released by the MRI satellite and transported in the [[magnetosphere]]:<ref>{{cite web |url=http://space.umd.edu/projects/ampte/ampte_description.html |title=SAMPEX - Introduction |publisher=University of Colorado |access-date=June 22, 2018}}</ref>
== Experiments ==
=== CCE Magnetometer (MAG) ===
The instrument was a [[Magnetometer|triaxial fluxgate magnetometer]] mounted on a {{cvt|2.4|m}} boom. It had seven automatically switchable ranges (from ± 16 [[Tesla (unit)|nT]] to ± 65,536 nT) with resolution commensurate with a 13-bit [[analog-to-digital converter]], and was read out at 8.6 vector samples/second. The signals from two sensors (one parallel to the spin axis and one orthogonal) were also fed into 5-50 [[Hertz|Hz]] bandpass channels that were read out every 5 seconds.<ref name="Experiment5">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1984-088A-05 |title=Experiment: CCE Magnetometer (MAG) |publisher=NASA |date=28 October 2021 |access-date=25 November 2021}} {{PD-notice}}</ref><ref>{{cite web |url=http://sd-www.jhuapl.edu/AMPTE/mag.html |title=CCE Magnetometer (MAG) |publisher=Johns Hopkins University - APL |access-date=26 November 2021}}</ref>
=== Charge-Energy-Mass Spectrometer (CHEM) ===
The instrument consisted of an [[Collimator|entrance collimator]] and [[electrostatic analyzer]] section followed by a time-of-flight and total-energy-measurement section floating at a 30 kV acceleration potential. The energy range covered was from 1 to 300 keV/Q, with a geometric factor of 2.E-3 cm<sup>2</sup>-sr and 32-sector angular resolution. Energy resolution was 5 to 18%, and all charge states and isotopes of [[Hydrogen]] (H) and [[Helium]] (He), the charge states of [[Lithium]] (Li), and the major elements and charge states up to and including [[Iron]] (Fe) were resolved.<ref name="Experiment3">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1984-088A-03 |title=Experiment: Charge-Energy-Mass Spectrometer |publisher=NASA |date=28 October 2021 |access-date=25 November 2021}} {{PD-notice}}</ref><ref>{{cite web |url=http://sd-www.jhuapl.edu/AMPTE/chem.html |title=Charge-Energy-Mass Spectrometer (CHEM) |publisher=Johns Hopkins University - APL |access-date=26 November 2021}}</ref>
=== Hot Plasma Composition Experiment (HPCE) ===
This instrument consisted of an entrance collimator and retarding potential analyzer, a curved-plate electrostatic energy analyzer, and a combined electrostatic-magnetic [[Mass spectrometry|mass analyzer]] in series. The energy range covered was approximately 0 to 17 keV/Q, with a geometric factor ranging from 0.01 to 0.05 cm<sup>2</sup>-sr, an energy resolution from 6 to 60%, and an M/Q resolution of 10%. This instrument cleanly separated Li+ and Ba+ tracer ions from the background. It was nearly identical to one flown on [[Dynamics Explorer 1]] by the same group of investigators. An additional set of eight spectrometers containing permanent bending magnets and [[Electron multiplier|channeltrons]] measured electrons in eight channels from 50 eV to 25 keV.<ref name="Experiment1">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1984-088A-01 |title=Experiment: Hot Plasma Composition Experiment (HPCE) |publisher=NASA |date=28 October 2021 |access-date=26 November 2021}} {{PD-notice}}</ref><ref>{{cite web |url=http://sd-www.jhuapl.edu/AMPTE/hpce.html |title=Hot Plasma Composition Experiment (HPCE) |publisher=Johns Hopkins University - APL |access-date=26 November 2021}}</ref>
=== Medium Energy Particle Analyzer (MEPA) ===
The instrument consisted of a collimator and an electron sweeping magnet followed by a {{cvt|10|cm}} [[time of flight]] (TOF) [[telescope]] with thin foils at the front and midpoint and a solid-state detector at the rear. Incident ion TOF was measured from the front foil to the back detector and from the center foil to the back detector, and energy was measured in the back detector. The dual TOF measurement and very fast energy channel processing gave high immunity to accidental events, and allowed the instrument to measure the composition and spectra of both common species and tracer ions over a species-dependent energy range of >10 keV/nucleon to 6 MeV/nucleon, with a geometric factor of 1.E-2 cm<sup>2</sup>-sr and 32-sector angular resolution.<ref name="Experiment2">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1984-088A-02|title=Experiment: Medium Energy Particle Analyzer (MEPA)|publisher=NASA|date=28 October 2021|access-date=26 November 2021}} {{PD-notice}}</ref><ref>{{cite web |url=http://sd-www.jhuapl.edu/AMPTE/mepa.html |title=Medium-Energy Particle Analyzer (MEPA) |publisher=Johns Hopkins University - APL |access-date=June 22, 2018}}</ref>
=== Plasma Wave Experiment (PWE) ===
The instrument consisted of a balanced electric dipole with an effective length of {{cvt|70|cm}} and six bandpass channels covering the range from 5 Hz to 178 kHz. The highest five channels were sampled every 0.6 seconds and the lowest (5–50 Hz) channel was sampled every 20 seconds. The instrument was the flight spare of the [[Pioneer Venus project|Pioneer Venus Electric Field Detector]], with two additional filters added.<ref name="Experiment4">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1984-088A-04 |title=Experiment: Plasma Wave Experiment (PWE) |publisher=NASA |date=28 October 2021 |access-date=26 November 2021}} {{PD-notice}}</ref><ref>{{cite web |url=http://sd-www.jhuapl.edu/AMPTE/pwe.html |title=Plasma Wave Experiment (PWE) |publisher=Johns Hopkins University - APL |access-date=26 November 2021}}</ref>
== End of mission ==
The AMPTE-CCE encountered command module/power supply problems since the beginning of 1989 and failed as of 12 July 1989.<ref name="Display">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1984-088A |title=Display: AMPTE-CCE (1984-088A) |publisher=NASA |date=28 October 2021 |access-date=25 November 2021}} {{PD-notice}}</ref>
== See also ==
{{Portal|Spaceflight}}
* [[AMPTE-IRM]]
* [[AMPTE-UKS]]
* [[Explorers Program|Explorer program]]
== References ==
{{Reflist|30em}}
== External links ==
* [http://sd-www.jhuapl.edu/AMPTE/ JHUAPL AMPTE]
{{Explorer program}}
{{Orbital launches in 1984}}
[[Category:1984 in spaceflight]]
[[Category:Explorers Program]]
[[Category:Spacecraft launched in 1984]]
[[Category:Spacecraft launched by Delta rockets]]
[[Category:Satellites orbiting Earth]]