ERS-1 Mission Phase F
Mission objectives during the Geodetic Phase
The mission objectives of Phase F are the following:
- The first priority is to provide to the user community continuous and global RA measurement. The geodetic phase is basically a Radaraltimetric mission.
- The secondary objective for the RA mission, is to cover at least once 100% of the Ocean and Ice zones. This is only possible if 2 complete cycles are performed.
- SAR and SCATT mission will continue nominally.
- In case of problems on board (e.g. Payload switchoff...) the priority shall be given to the RA recovery.
Phase F parameters
Phase F parameters
- 168 days repeat cycle
- 2411 orbits per cycle
- 2501 orbits in phase
Orbit number characteristics
- First absolute orbit number is: 16747, on 28-Sep-94 02:30:56.813 UTC
- First internal track: 2357
- Last absolute orbit number is: 19247, on 21-Mar-1995, 09:01:33.395
Orbit parameters
- orbit eccentricity: 0.001165
- orbit inclination: 98.4913 deg
- asc. node Long. 299.7687 deg
- semi-major axis: 7147190.68 m
- mean nodal period: 6020.406470 s
- mean anomaly: 270.1334 deg
- argument of perigee: 90 deg
Formulas from Relative (track) to Absolute Orbit Numbers
ABS_ORB_NUM = REL_ORB_NUM + (CYCLE_NUM-141)*2411 + 14390
CYCLE_NUM = INT( ( ABS_ORB_NUM - 14391)/2411 ) + 141
REL_ORB_NUM= ABS_ORB_NUM - 14390 -(CYCLE_NUM-141) *2411
Where:
- the "Absolute Orbit Number" is counted from the beginning of the mission;
- the "Relative Orbit Number" (track), in a given cycle, is counted starting from the first orbit East of Greenwich;
- the "Cycle Number" is increased whenever the track 1 is rivisited (note that cycles can be uncomplete).
This information was retrieved from ESA/ESRIN
