This readme file is a work in progress.


Magnetospheric Multiscale Mission (MMS):


Brief description of mission and instrumentation:


Include in brief description the 4 spacecraft, their instruments, formation flying, launched March 13, 2015, status ongoing, and list of mission PHASES and their times.


Data Directory:

This file points to the on-line archived datasets for MMS:


Dataset directories:


Link to list of cdaweb directories and DOI’s for each dataset.



Note: documents will be updated as made available.


Notes on connecting the dots: In the CMAD documentation it is not always clear where to find the files or information, this is the purpose of these notes.


Internal Photoelectron Model for the FPI DES (electron) measurements:

Model Files:


For either the DES mms1_fpi_brst_l2_des-moms or mms1_fpi_fast_l2_des-moms cdf’s, similar for all 4 spacecraft.

The model to use for a given time interval is given by the CDF attributes.




and its scaling factor by the attribute




For example, for in the file:  mms1_fpi_brst_l2_des-moms_20161225155844_v3.4.1.cdf

Which covers the burst mode time interval:  2016-12-25T15:58:44.027Z to 2016-12-25T16:00:13.997Z the attribute values are


PHOTOELECTRON_MODEL_FILENAMES =  'mms_fpi_brst_l2_des-bgdist_v1.1.0_p3-5.cdf'; so in Model Files directory ( one needs to use the one specified for this interval.


                  PHOTOELECTRON_MODEL_SCALING_FACTOR = '0.3500000' 


How apply the model to correct for internal photoelectrons is given in the CMAD section Correction for DES Photoelectrons pg. G17-G18.




Additional related information and data services:


·       NASA:

·       Wikipedia:


Data contact:

July 18, 2023