Solar Flux File Format (*.dat)

A solar flux file is an ASCII text file containing solar flux and geomagnetic indices. It is formatted for compatibility with STK. There are three types of solar flux files that you can use with STK: CSSI Predicts, Space Weather, and stkFluxGeoMag. Each of these types is described in the sections below.

CSSI Predicts (*.dat)

CSSI Predicts files are used for long-term predictions to support the Lifetime Tool. The file contains predicted values of the monthly mean 10.7 cm solar radiation flux (F10.7) and geomagnetic index (Ap).

The first line of the file consists of seven numbers:

  1. Year the data begins;
  2. Month the data begins;
  3. Year the data ends;
  4. Month the data ends;
  5. Year the predictions were generated;
  6. Month the predictions were generated; and
  7. Number of data points (lines) that follow.

All dates are UTC.

The remaining lines are rows of data with the following six columns:

  1. year
  2. month (day is assumed to be the 15th)
  3. two-sigma predicted solar flux F10.7
  4. nominal predicted solar flux F10.7
  5. two-sigma predicted geomagnetic index Ap
  6. nominal predicted geomagnetic index Ap

The file may contain any number of data points. If the Lifetime calculations continue past the last data point in the solar flux file and the file contains at least 12 years worth of data, the last 11-year solar cycle is assumed to repeat as many times as necessary.

To view an example of this file type, click here.

Space Weather (*.txt)

Space Weather files contain daily observed solar flux and geomagnetic indices and approximately ten years of predicted data. You can use these files with the Lifetime Tool or to model drag with the HPOP propagator. For details on the format of Space Weather files, click here.

NASA DAS file

The NASA DAS file was developed to assist NASA programs in performing orbital debris assessments. The NASA DAS file is best used in the Lifetime Tool because it does not contain historical or predicted ap/kp flux data, only historical and predicted F10.7 data.

stkFluxGeoMag (*.fxm)

The stkFluxGeoMag file has been replaced by the Space Weather format, but is still functional with STK to support backward compatibility. Like the Space Weather file, you can use it with the Lifetime tool or to model drag with the HPOP propagator. For details on the format of this file type, with examples, click here.