SENTINEL-3A
Sentinel-3A is part of Europe's Copernicus Earth-observation program. Launched in 2016, it measures ocean and land surface temperature, sea-surface height, ocean color and vegetation properties for environmental monitoring and operational services.
Object identity
- NORAD ID
- 41335
- COSPAR ID
- 2016-011A
- Operator
- Not listed
- Country
- Not listed
- Launch date
- Not listed
Immediate discovery
Why this satellite matters
Altimetry uses travel time: transmit a radar pulse, measure its return, correct for atmospheric and orbital effects, and infer the distance between satellite and sea surface with remarkable precision.
Understanding the mission
Science and engineering ideas
Altimetry uses travel time: transmit a radar pulse, measure its return, correct for atmospheric and orbital effects, and infer the distance between satellite and sea surface with remarkable precision.
Mission
Mission and purpose
These spacecraft use cameras, radiometers, radar, spectrometers, or other instruments to measure features of Earth. Repeated observations make comparisons across seasons and years possible.
- Altimetry uses travel time: transmit a radar pulse, measure its return, correct for atmospheric and orbital effects, and infer the distance between satellite and sea surface with remarkable precision.
Design
Engineering
Altimetry uses travel time: transmit a radar pulse, measure its return, correct for atmospheric and orbital effects, and infer the distance between satellite and sea surface with remarkable precision.
Real orbital values
The mathematics
The current two-line element set reports approximately 14.2674 revolutions per day. Dividing 1,440 minutes by that value gives an estimated orbital period of 100.9 minutes.
Period
100.9 min
Representative speed
26,822 km/h
Representative altitude
810 km
Inclination
98.63°
Launch record
Launch and deployment
Sentinel-3A launched on 16 February 2016 aboard a Rockot from Plesetsk Cosmodrome.
Orbit
LEO orbit explained
Low Earth orbit is the region closest to Earth used by most crewed spacecraft, many science missions, Earth-observation satellites, and large constellations. Objects move quickly and commonly complete an orbit in roughly 90 to 130 minutes.
LEO can provide detailed Earth views, lower communications delay, and easier access than higher orbits, but it covers less area per spacecraft and is more affected by atmospheric drag.
Live TransitSatellite experience
See SENTINEL-3A moving now
Open the live tracker to view its current calculated position, trajectory, orbital information, visibility tools, and Save and Share controls.
Learning
Questions to explore
- Why are repeated observations valuable?
- How can satellites observe through clouds or darkness?
Evidence
Sources and data notes
Current identity and orbital elements come from CelesTrak’s public GP data. Calculated orbit values are derived from the current TLE and may change after catalog updates. Mission-history claims are added separately and require authoritative sources.
Catalog updated
Sep 18, 2026, 6:23 AM UTC
Story review
1970-01-01T00:00:00.000Z