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Advanced Composition Explorer Level 1 Data, ACE Science Center, Ver. 2-9/3-2


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)

Time span: 1997-08-25 to 2009-09-21


This data set contains level 1 data files in NCSA Hierarchical Data Format (HDF) for all science experiments on the Advanced Composition Explorer (ACE) spacecraft. The input to Level 1 data production at ASC is the Level 0 data provided by the ACE project; the latter are provided to ASC in the form of time-ordered telemetry. For Level 1 the ASC extracts telemetry data for each instrument and reformats it into HDF in a special manner for the requirements of further processing by each instrument team at their home institution. The instrument data are supplemented with ancillary data including position, attitude, and spin phase of the spacecraft, calibration of the spacecraft clock, and data documentation. The current HDF files were created with Versions 2-9 and 3-0 of the ACE Science Center (ASC) Level 1 software. The basic elements of the HDF files are created from C data structures, each defined in their own include file. Based on the definition of a data structure, a library of C subroutines is created that make it quite easy to read/write that data structure from/to HDF format data files. Contents of this data set include zip-compressed files containing the following: Level 1 HDF data files, other HDF files with ACE ancillary data (ephemeris, clock), and software for accessing the HDF data and ancillary files. Documents defining the HDF data structures and the data sets are provided in HTML file format for viewing by web browsers. These data are in the public domain but are primarily intended for use by the ACE experimenters. It is strongly recommended that users contact the responsible instrument teams regarding correct processing. See the ACE Science Center web site for further on-line information on these and other ACE data:

The ephemeris and software files from the latest CD volume are available on-line on the Internet at

Alternate Names

  • ACE Sci Ctr,Level 1 Data


  • Space Physics: Heliospheric Studies


  • 97-045A-00A

Additional Information


Questions and comments about this data collection can be directed to: Dr. John F. Cooper



NameRoleOriginal AffiliationE-mail
Dr. Andrew J. DavisGeneral ContactCalifornia Institute of
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