Choice of orbit

The Sentinel-3 orbit provides an optimal compromise between spatial and temporal sampling for capturing mesoscale ocean structures, offering an improvement on SSH mapping error of up to 44% over Jason due to improved spatial sampling and 8% over the Envisat 35-day orbit due to better temporal sampling.

Orbit parameters

Main characteristics
Inclination (sun-synchronous) 98.5°
Auxiliary data
Reference altitude (equatorial) 814  km
Repeat cycle 27 days
Number of passes per cycle ~770
Ground track separation at Equator 104 km

(Source ESA)