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Solar Anomalous and Magnetospheric Particle Explorer

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Solar Anomalous and Magnetospheric Particle Explorer
SAMPEX satellite
NamesExplorer 68
SAMPEX
SMEX-1
Mission typeMagnetospheric research
OperatorNASA / GSFC
Max Planck Institute
COSPAR ID1992-038A Edit this at Wikidata
SATCAT no.22012
Websitelasp.colorado.edu/home/sampex/
Mission duration3 years (planned)
11 years, 11 months and 27 days (achieved)
Spacecraft properties
SpacecraftExplorer LXVIII
Spacecraft typeSolar Anomalous and Magnetospheric Particle Explorer
BusSAMPEX
ManufacturerGoddard Space Flight Center
Launch mass158 kg (348 lb)
Payload mass45.2 kg (100 lb)
Dimensions1.5 × 0.9 m (4 ft 11 in × 2 ft 11 in)
Power102 watts
Start of mission
Launch date3 July 1992, 14:19 UTC
RocketScout G-1 (S-215C)
Launch siteVandenberg, SLC-5
ContractorMcDonnell Douglas Astronautics Company
Entered service3 July 1992
End of mission
Deactivated30 June 2004
Last contact13 November 2012
Decay date13 November 2012, 11:42 UTC [1]
Orbital parameters
Reference systemGeocentric orbit [2]
RegimePolar orbit
Perigee altitude512 km (318 mi)
Apogee altitude687 km (427 mi)
Inclination81.70°
Period96.70 minutes
Instruments
Heavy Ion Large Telescope (HILT)
Low-energy Ion Composition Analyzer (LICA)
Mass Spectrometer Telescope (MAST)
Proton/Electron Telescope (PET)

SAMPEX (Explorer 68) mission patch
Explorer program
← Extreme Ultraviolet Explorer (Explorer 67)
Rossi X-ray Timing Explorer (Explorer 69) →

The Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX or Explorer 68) was a NASA solar and magnetospheric observatory, and was the first spacecraft in the Small Explorer program. It was launched into low Earth orbit on 3 July 1992, from Vandenberg Air Force Base (Western Test Range) aboard a Scout G-1 launch vehicle. SAMPEX was an international collaboration between NASA and the Max Planck Institute for Extraterrestrial Physics of Germany.[3] The Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) is the first of a series of spacecraft that was launched under the Small Explorer (SMEX) mission of program for low cost spacecraft.[4]

Mission

The main objectives of SAMPEX experiments was to obtained data for several continuous years on the anomalous components of cosmic rays, on solar energetic particles emissions from the Sun, and on the precipitating magnetospheric relativistic electrons. The orbit of SAMPEX has an altitude of 512 × 687 km (318 × 427 mi) and an 81.70° inclination. The spacecraft uses an on-board 3-axis stabilized solar pointed/momentum bias system with the pitch axis pointed to towards the Sun. Solar panels provide power for operations, including 16.7 watts for science instruments. An on-board Data processing unit (DPU) preprocesses the science and other data and stores them in a Recorder/Processor/Packetizer (RPP) unit of about 65 Mb, before transmitting in the S-band at a rate of 1.5 Mb/s over Wallops Flight Facility (WFF) (or a back-up) station. The command memory can store at least a thousand commands. The science instruments generally point toward local zenith, especially over the terrestrial poles, for optimal sampling of galactic and solar cosmic ray flux. Energetic magnetospheric particle precipitation is monitored at lower geomagnetic latitudes.[4]

Spacecraft

It carries four science instruments: (1) low-energy ion composition analyzer (LICA); (2) heavy ion large telescope (HILT); (3) mass spectrometer telescope (MAST); and (4) proton electron telescope (PET). Estimated useful lifetime of the spacecraft was about three years; however, the data stream continue to 30 June 2004. In 1997, NASA Goddard transferred operation of SAMPEX to the Flight Dynamics and Control Laboratory (FDCL) housed within the Aerospace Engineering Department of the University of Maryland.[4]

Instruments

The spacecraft carried four instruments designed to measure the anomalous components of cosmic rays, emissions from solar energetic particles, and electron counts in Earth's magnetosphere. Built for a three-year mission, its science mission was ended on 30 June 2004.[5] Mission control for SAMPEX was handled by the Goddard Space Flight Center until October 1997, after which it was turned over to the Bowie State University Satellite Operations Control Center (BSOCC).[1] BSOCC, with funding assistance from The Aerospace Corporation, continued to operate the spacecraft after its science mission ended, using the spacecraft as an educational tool for its students while continuing to release science data to the public.[6][7]

Collaborators

SAMPEX collaborators included:[5]

Results

SAMPEX studies the energy composition, and charge states of particles from supernova explosions in the distant reaches of the galaxy, from the heart of solar flares, and from the depths of nearby interstellar space. It also monitors closely the magnetospheric particle populations which plunge occasionally into the middle atmosphere of the Earth, thereby ionizing neutral gases and altering the atmospheric chemistry. A key part of SAMPEX is to use the magnetic field of the Earth as an essential component of the measurement strategy. The Earth's field is used as a giant magnetic spectrometer to separate different energies and charge states of particles as SAMPEX executes its near polar orbit.[12]

Nearly five years after its launch into the current minimum of the solar cycle, SAMPEX has carried out a wide range of observations and discoveries concerning solar, heliospheric, and magnetospheric energetic particles seen from its unique vantage point in a nearly polar, low Earth orbit. Since almost all of the processes we are studying are driven or heavily influenced by the solar activity cycle, we have the opportunity to fully characterize the solar cycle dependence of a wide range of processes central to the goals of the NASA Office of Space Science's Sun-Earth Connections (SEC) theme.

Over the next several years as the solar activity ramps up to its 11-year maximum, SAMPEX investigations will:

  • survey the acceleration of relativistic electrons,measure their impact on the upper atmosphere, and determine their influence on atmospheric chemistry not only for solar minimum conditions but also for the much more complex solar active periods
  • obtain samples of solar material from dozens of flares, compared with the handful observed during the declining phase of the solar cycle
  • measure the anomalous component isotopic composition, trapping lifetime, and disappearance near solar maximum
  • serve as a unique link in the chain of observatories put in place by NASA and its international partners to study space weather during the upcoming solar maximum.

Atmospheric entry

Built for a three-year primary mission, the spacecraft continued to return science data until its reentry on 13 November 2012.[2]

See also

References

  1. ^ a b "SAMPEX". ESA eoPortal Directory. Retrieved 4 September 2015.
  2. ^ a b "Trajectory: SAMPEX (Explorer 68) 1992-038A". NASA. 28 October 2021. Retrieved 27 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  3. ^ Mason, G. M.; et al. (1998). SAMPEX: NASA's first small explorer satellite. IEEE Aerospace Conference. March 21–28, 1998. Aspen, Colorado. Vol. 5. pp. 389–412. Bibcode:1998aero....5..389M. doi:10.1109/AERO.1998.685848.
  4. ^ a b c "Display: SAMPEX (Explorer 68) 1992-038A". NASA. 28 October 2021. Retrieved 27 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  5. ^ a b "SAMPEX Data Center". California Institute of Technology. Retrieved 4 September 2015.
  6. ^ "SAMPEX Mission Returns to Earth". The Aerospace Corporation. 21 November 2012. Retrieved 4 September 2015.
  7. ^ "NASA's SAMPEX Mission: A Space Weather Warrior". NASA. 1 November 2012. Retrieved 4 September 2015. Public Domain This article incorporates text from this source, which is in the public domain.
  8. ^ "Experiment: Heavy Ion Large Telescope (HILT)". NASA. 28 October 2021. Retrieved 27 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  9. ^ "Experiment: Low-energy Ion Composition Analyzer (LICA)". NASA. 28 October 2021. Retrieved 27 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  10. ^ "Experiment: Mass Spectrometer Telescope (MAST)". NASA. 28 October 2021. Retrieved 27 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  11. ^ "Experiment: Proton-Electron Telescope (PET)". NASA. 28 October 2021. Retrieved 27 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  12. ^ "SAMPEX". Laboratory for Atmospheric and Space Physics - University of Colorado Boulder. 1997. Retrieved 27 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.

Further reading

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