JSOC GRAPHIC TITLE
 

Overview

The Cluster Flight Dynamics team at ESOC produces a number of files that contain information on the orbits of the four Cluster spacecraft and the predicted times of various events for these spacecraft. These files are copied to JSOC for use in Cluster science planning - and are used by JSOC to generate data on the predicted geometric and scientific positions of the four spacecraft and to predict the occurence of scientific events (e.g. plasma boundary crossings such the magnetopause, bow shock and tail neutral sheet).

JSOC also makes these files available to the broader scientific community that is interested in the Cluster mission. Click on the links below to see a ditectory listing of the available files for each of the four types of orbit and event files:

  • Long Term Orbit Files (LTOF) - these contain orbit data for a period of a year or more in advance. There is a separate LTOF for each spacecraft.
  • Long Term Event Files (LTEF) - these contain event data for a period of a year or more in advance. There is a separate LTEF for each spacecraft.
  • Short Term Orbit Files (STOF) - these contain orbit data for a period up to 3.5 months ahead. There is a separate STOF for each spacecraft.
  • Short Term Event Files (STEF) - these contain event data for a period up to 3.5 months ahead. There is a separate STEF for each spacecraft.
  • The LTOF and LTEF are used by JSOC as the basis for long-term planning of science operations (see Master Science Plan); whereas the STOF and STEF are used by JSOC for detailed scheduling of the PI commands to be sent to the instruments.

    The file names in these directories take the form: TTTT_yymmddOAss_aaaabbbb_vvvv.CR where:

  • TTTT = file type (LTOF, LTEF, STOF or STEF)
  • yymmdd = date of generation as two-digit year, month and day
  • ss = spacecraft id (S1, S2, S3 and S4)
  • aaaa = first orbit number covered by the file
  • bbbb = last orbit number covered by the file
  • zzzz = file version number. There is a separate series of versions for each file type and spacecraft id. This is useful is multiple files are issued on one day.

    The format and content of these four file types is defined in the Cluster Data Delivery Interface Document (known as the "DDID"), which can be downloaded as a PDF file from the Cluster Active Archive. However, note that the files available from JSOC are plain ASCII files conforming to the format given in Appendix F of the DDID. This is slightly different from the format used when these files are delivered to Cluster PIs and CoIs on the Cluster CD-ROMs. In the later files each record of the orbit and event files is prefixed by a 14-byte binary-format telemetry packet header as discussed in section 5 of the DDID.

    Merged LTOF files

    JSOC also maintains a set of merged LTOF files (also known "Super-LTOF files") which are derived by merging data from LTOF and STOF files in order:

  • to produce a continuous series of orbit data from launch
  • to include all available reconstituted orbit data These files are produced using the merge_ltof software developed by Pat Daly, PI of the RAPID instrument. This is run automatically when new STOF files arrive at JSOC.

    Caveats

  • The present set of Super-LTOF files run to end of December 2016.

    Last updated by  Mike Hapgood ( mike.hapgood@stfc.ac.uk), 19 March 2013

  • RALSpace LOGO
    STFC LOGO