July 8, 2016
Mission Constraints
Long duration for central programme: 150 days
- The line of sight is assigned to keep a constant direction for 150 days.
- 90% duty cycle requirement (no occultation by the Earth).
Inertial polar circular orbit between 800 and 900 km
- Lower limit fixed by terrestrial stray light.
- Upper limit fixed by the size of the South Atlantic Anomaly and the flux of protons acceptable by the instrument.
Sun blinding
- Sun at more than 90° of the boresight.
Semi major axis | a = 7274 km |
Eccentricity | e = 0.00127° |
Inclination | i = 90° |
Right Ascension of the Ascending node | RAAN = 12.5° Boresight at 6h50 ± 12h |
Straylight from the Earth
- line of sight at more than
= 20° from the Earth limb.
- radius of the observation cone:
= arccos(R/a) -
= 10°
- to be adjusted in flight after effective stray light measurements.

Roll domain
- ±20° on the line of sight, after North-South alignment of the solar arrays.
- Helpful to optimize the projection of the targets onto the CCD.
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