The ELFIN Mission
Abstract
The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (~93deg inclination), nearly circular, low-Earth (~450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (~90min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50keV to 5MeV electrons with deltaE/E<40% and a fluxgate magnetometer (FGM) on a ~72cm boom that measures magnetic field waves (e.g., EMIC waves) in the range from DC to 5Hz Nyquist (nominally) with <0.3nT/sqrt(Hz) noise at 1Hz. The spinning satellites (T_spin~3s) are equipped with magnetorquers that permit spin-up/down and reorientation maneuvers. The spin axis is placed normal to the orbit plane, allowing full pitch-angle resolution twice per spin. An energetic particle detector for ions (EPDI) measures 250keV-5MeV ions, addressing secondary science. Funded initially by CalSpace and the University Nanosat Program, ELFIN was selected for flight with joint support from NSF and NASA between 2014 and 2018.
Cite
@article{arxiv.2006.07747,
title = {The ELFIN Mission},
author = {V. Angelopoulos and E. Tsai and L. Bingley and C. Shaffer and D. L. Turner and A. Runov and W. Li and J. Liu and A. V. Artemyev and X. -J. Zhang and R. J. Strangeway and R. E. Wirz and Y. Y. Shprits and V. A. Sergeev and R. P. Caron and M. Chung and P. Cruce and W. Greer and E. Grimes and K. Hector and M. J. Lawson and D. Leneman and E. V. Masongsong and C. L. Russell and C. Wilkins and D. Hinkley and J. B. Blake and N. Adair and M. Allen and M. Anderson and M. Arreola-Zamora and J. Artinger and J. Asher and D. Branchevsky and M. R. Capitelli and R. Castro and G. Chao and N. Chung and M. Cliffe and K. Colton and C. Costello and D. Depe and B. W. Domae and S. Eldin and L. Fitzgibbon and A. Flemming and I. Fox and D. M. Frederick and A. Gilbert and A. Gildemeister and A. Gonzalez and B. Hesford and S. Jha and N. Kang and J. King and R. Krieger and K. Lian and J. Mao and E. McKinney and J. P. Miller and A. Norris and M. Nuesca and A. Palla and E. S. Y. Park and C. E. Pedersen and Z. Qu and R. Rozario and E. Rye and R. Seaton and A. Subramanian and S. R. Sundin and A. Tan and W. Turner and A. J. Villegas and M. Wasden and G. Wing and C. Wong and E. Xie and S. Yamamoto and R. Yap and A. Zarifian and G. Y. Zhang},
journal= {arXiv preprint arXiv:2006.07747},
year = {2020}
}
Comments
Submitted to Space Science Reviews April 2020. 51 pages, 7 tables, 21 figures