File: P11TJ_FMT.txt                         Version: NSSDC 09/16/2002 JFC
-------------------------------------------------------------------------

Pioneer 11 Interplanetary Heliocentric Coordinates from the Mission Data 
Set 

   Data Set Coverage (yyyy-mm-dd): 1973-04-06 to 2000-01-01

   Data Set Contact: Dr. John F. Cooper, jfcooper@pop600.gsfc.nasa.gov

   Data Files: P11TJmmn.asc - data in six month blocks (mm= year, n= A or B 
                                 for Jan-Jun or Jul-Dec,resp.)
               P11TJALL.asc  - cumulative file for years 1973 - 2000

   Parameter format:

      YYYY FDOY HRANGP SECLAT SECLON HELLAT HELLON HILLON REARSC

      YYYY= 4-digit year
      FDOY= fractional days of year (1.000 = 0000 SCUT on Jan. 1)
      HRANGP= distance from Sun to spacecraft in km
      SECLAT,SECLON= solar ecliptic latitude and longitude of spacecraft with
                     respect to true-of-date Ecliptic
      HELLAT,HELLON= heliographic latitude and longitude of spacecraft
      HILLON= heliographic inertial longitude of spacecraft with respect to
             direction of zero heliographic longitude on 1 Jan. 1854 at 1200 UT
      REARSC= distance from Earth to spacecraft in AU
              (used to calculate Earth Received Time - UT)

   Data Source:

   The codes READ_ECL and PIOTRJCON, respectively, were used to read the 
   mission data set files from subdirectory MISSION and add the HILLON 
   parameter. 

   10/18/95: These data files have now been extended through 2000/01. The
             previous data for 1990/01 have been changed slightly, and the 
             data after that are provided monthly instead of daily as before. 
             This is expected to be the final definitive trajectory data set 
             for the Pioneer 11 mission.
   

Related Information and Data:

Further details on the spacecraft, experiment, data sets at NSSDC, and 
related WWW sites can be found on the Pioneer 10/11 flight project page 
under

http://nssdc.gsfc.nasa.gov/space/

Hour averages of the interplanetary solar wind data from, and hourly
heliocentric coordinates of, Pioneer 10/11 and other interplanetary 
spacecraft may be also be accessed and plotted on-line through the COHOWeb 
service based at the same WWW site as above. Access to the Satellite Situation 
Center (SSC) service for heliocentric coordinates from Pioneer, Voyager, Ulysses, 
and other heliocentric spacecraft is also provided from this site. 

Acknowledgement:

Use of these data in publications should be accompanied at minimum by
acknowledgements of the National Space Science Data Center and the responsible
Principal Investigator defined in the experiment documentation provided 
here.