SENTINEL 3B

About This Satellite

Sentinel-3B launched on April 25, 2018, to complement Sentinel-3A in monitoring oceans and land. The mission combines observations of surface colour, temperature, and height. These measurements describe different physical properties; a colour-coded ocean image is not necessarily a sea-temperature map.

Thirty seconds apart for a reason

During commissioning in 2018, Sentinel-3B flew only 30 seconds behind Sentinel-3A. This temporary tandem phase let teams compare nearly coincident measurements. Even nominally identical sensors can differ, so calibration had to distinguish instrument offsets from actual changes on Earth.

The tandem experiment was not the permanent spacing

ESA described a later operational separation of 140 degrees around the orbit. Do not expect a contemporary orbit display to reproduce the 30-second commissioning experiment. The historical manoeuvre explains how the measurement record was checked, while the dated TLE describes a different point in the mission timeline.

Mission reference: ESA: Sentinel-3B launch and mission. Editorial review: 2026-09-12.

Calibration protects a long environmental record

If an instrument on the second satellite reads slightly differently, simply joining both datasets could create a false environmental trend. The short separation reduced changes in the observed scene between measurements. This is why orbit design can support the quality of a climate record, not just geographic coverage.

Reference: ESA: Sentinel-3 tandem calibration campaign.

Temperature, colour, and height need different sensors

The Sentinel-3B mission includes optical and thermal observations alongside radar altimetry. Their combination supports ocean and land monitoring, but each product has its own measurement geometry and processing. Select the product appropriate to the question; the catalog's single ground track cannot stand in for all instrument footprints.

Reference: ESA: the complementary Sentinel-3B measurements.

Reading this orbital snapshot

Based on TLE epoch: 2026-09-05. Estimated altitude ranges from 802 km at perigee to 804 km at apogee, a difference of 2 km. The orbital period is about 100.9 minutes. Eccentricity 0.00015 indicates a nearly circular path. In a two-body approximation, perigee speed is 1.00 times apogee speed. These are mean-element estimates, not instantaneous measurements. Distance per orbit uses an ellipse approximation.

Saved build snapshot. If a valid TLE is retrieved, this explanation and the orbit panel update together. Otherwise this dated snapshot is retained.

Ground track is not sensor coverage

An inclination of 98.63 degrees implies approximate geocentric ground-track limits of 81.4 degrees north and south. This is a retrograde orbit, moving against the direction of Earth rotation. The plotted line marks the point beneath the object. It does not represent camera coverage, radio reception, or a guaranteed visible pass.

Accuracy and missing information

The introductory record describes the build snapshot. The orbital snapshot explanation and orbit panel share any successfully retrieved TLE; check the displayed epoch. Reentered objects retain historical data only. Mission history is not rewritten by TLE updates. TLE/SGP4 positions are predictions and can change after maneuvers or updated observations. The 14-day stale-data cutoff is a display safeguard, not an accuracy guarantee. Local passes are geometric predictions, not a visibility forecast. No verified operator or mission status means unknown, not active. Do not use this catalog for collision avoidance or operational flight decisions.

Catalog sources: CelesTrak SATCAT: NORAD 43437 · GCAT: S43437 (source update 2026 Sep 4 2345:57). Supplementary metadata: SatNOGS DB, retrieved 2026-09-05T12:57:25.375Z. Page assembled 2026-09-15. GCAT phase codes describe trajectory phases, not mission health.

Learn more: TLE data · Perigee and apogee · Ground tracks · JOT (Jewawud Live Orbital Map)

Satellite Details