# ORBSCT for CO2M
The Orbit Scenario File (filetype ORBSCT)
CO2_TEST_MPL_ORBSCT_20280101T233001_99999999T999999_0001.EOF
is intended to be used with tools built using EOCFI SW v4.16 onwards.


Starting from EOCFI SW v4.20, a dedicated satellite identifier (XO_SAT_CO2M) is available to initialise the satellite ID.

## Orbit Parameters
The orbit parameters are given according to CO2M SRD 
- Repeat Cycle (days): 11

- Cycle Length (orbits): 159

- Mean Local Solar Time drift (s/day): 0.0 (Sun-Synchronous orbit)

- Date: 01/Jan/2028 (--> launch date still unknown)

- Absolute Orbit Number: 1

- Longitude at ANX of Absolute Orbit Number (deg): 0.0 (--> default, actual value still unknown)

- Mean Local Solar Time at Ascending Node Crossing (ANX) of orbit 1 (h): 23:30

- Note the following:
    - The longitude at ANX of the reference orbit will be set later on, e.g. based on certain overpass criteria or desired phasing with another mission

## Assumptions
- Time Correlations
    - TAI-UTC correlation (s): 37 s
    - UT1-UTC correlation (s): 0 s

- The file is compliant with GS File Format Standard v3.0.

## ORBSCT Generation
This ORBSCT has been generated with the following commands (using executable tools available as part of the EOCFI distribution)

- From Terminal window (Linux, macOS). For LInux, replace MACIN64 folder by LINUX64 folder
```$bash
./EOCFI-4.20-CLIB-MACIN64/bin/MACIN64/time_conv -date 2028-01-01T00:00:00 -fmt_in ASCII_CCSDSA -ref_in UTC -fmt_out PROC -ref_out UTC -tai 1.00042824074074 -utc 1.0 -ut1 1.0 -gps 1.000208333333 -show
```
It returns the date in MJD2000: 10227.0 days
```$bash
./EOCFI-4.20-CLIB-MACIN64/bin/MACIN64/gen_osf_create -sat CO2M -orbit 1 -cyc 1 -pha 1 -repcyc 11 -cyclen 159 -mlst 23.5 -date 10227.0 -tai 1.00042824074074 -utc 1.0 -ut1 1.0 -gps 1.000208333333 -anx 0.0 -mlstdr 0.0 -flcl TEST -show
```
- From Command Prompt  window (Windows)
```$bash
EOCFI-4.20-CLIB-MACIN64\bin\WINDOWS64\time_conv.exe -date 2028-01-01T00:00:00 -fmt_in ASCII_CCSDSA -ref_in UTC -fmt_out PROC -ref_out UTC -tai 1.00042824074074 -utc 1.0 -ut1 1.0 -gps 1.000208333333 -show
```
It returns the date in MJD2000: 10227.0 days
```$bash
EOCFI-4.20-CLIB-MACIN64\bin\WINDOWS64\gen_osf_create.exe -sat CO2M -orbit 1 -cyc 1 -pha 1 -repcyc 11 -cyclen 159 -mlst 23.5 -date 10227.0 -tai 1.00042824074074 -utc 1.0 -ut1 1.0 -gps 1.000208333333 -anx 0.0 -mlstdr 0.0 -flcl TEST -show
```
Further details can be found in the EO CFI SW Orbit User Manual.

## Contact
For further questions, please contact us at the Mission Software CFI Support Team account:

cfi@eopp.esa.int
