Abstract's details

Overview and Status of the Copernicus Sentinel-3 Next Generation Topography (S3NG-T) Mission

Pierrik Vuilleumier (European Space Agency, ESTEC, Netherlands)


Craig Donlon (ESTEC/ European Space Agency, Netherlands); Luisella Giulicchi (European Space Agency, ESTEC, Netherlands); Remko Scharroo (EUMETSAT, Germany)

Event: 2022 Ocean Surface Topography Science Team Meeting

Session: OSTST Opening Plenary Session

Presentation type: Type Oral

Contribution: PDF file


The Sentinel-3 Mission provides an essential satellite altimetry data set for the Copernicus services over the global ocean, coastal zones, sea and land ice and inland waters in support of a large number of end user applications. Four Sentinel-3 satellites (two currently on orbit and two replacements to be launched in the coming years) operating in a sun-synchronous near polar orbit provide an unprecedented and unbroken time series of satellite altimetry measurements from 2016-2035.

Considering the User needs expressed by the European Commission and inputs from an independent Mission Advisory Group are documented in the S3-NG-T Mission Requirements Document. The aim of the Copernicus Next Generation Sentinel-3 Topography (S3NG-T) Mission is to guarantee baseline continuity of existing Copernicus Sentinel-3 nadir-altimeter measurements in the 2030-2050 time-frame while enhancing measurement performance.

The primary objectives of the S3NG-T mission are to:

PRI-OBJ-1. Guarantee continuity of Sentinel-3 topography measurements for the 2030-2050 time frame with performance at least equivalent to Sentinel-3 in-flight performance (‘baseline mission’).

PRI-OBJ-2. Respond to evolving user requirements and improve sampling, coverage and revisit of the Copernicus Next Generation Topography Constellation (S3NG-T and Sentinel-6NG) to ≤ 50 km and ≤ 5 days in support of Copernicus User Needs.

PRI-OBJ-3. Enhance sampling coverage, revisit and performance for Hydrology Water Surface Elevation measurements in support of Copernicus Services.

PRI-OBJ-4. Respond to evolving user requirements and enhance topography Level-2 product measurement performance.

The secondary objectives of the S3NG-T mission are to:

SEC-OBJ-1. Provide directional wave spectrum products that address evolving Copernicus user needs.
SEC-OBJ-2. Provide new products (e.g. sea surface height gradients and river reach averaged gradients, river width and water area. that address evolving Copernicus user needs.

A coordinated constellation of spacecraft is required to provide enhanced continuity to the Sentinel-3 Mission to meet sampling at ≤5 days, ≤ 50 km (25 km wavelength) between 81.5 north and south of the equator regardless of the satellite technologies employed. Such a constellation requires a reference that allows each mission to be used in synergy with each other to satisfy User needs without bias discrepancies. For the S3NG-T mission, it is assumed that a reference satellite mission (e.g. Copernicus Sentinel-6/NG) will be available in orbit that is designed for this purpose providing a common reference measurement for all S3NG-T satellites and with excellent knowledge of measurement stability. Additional third party altimeter missions may also provide additional data although their launch or access to their data cannot be guaranteed.

Continuity of Sentinel-3 measurements can be guaranteed using a number of different technical solutions with potential enhancements in terms of coverage, sampling, calibration stability, system complexity and size amongst others. The best implementation approach for the S3NG-T mission shall be based on "fitness for purpose to provide enhanced continuity to Sentinel-3 topography measurements" determined by compliance to mission requirements, maturity of technical heritage, technical feasibility/readiness, scientific readiness and maturity, development schedule, risk, cost and programmatic arrangements. Based on the S3NG-T Phase-0 activities and other studies conducted by ESA over the last 5 years the most likely scenarios to implement S3NG-T include the following:

Scenario-1: Replacement of Sentinel-3C and Sentinel-3D using a constellation of 2-n nadir-pointing altimeters.
Scenario-2: Implementation of 2..n swath altimeter including a nadir altimeter.
Scenario-3: A hybrid approach including both nadir pointing altimeter and swath altimeter satellites

This paper will review the current status of the S3NG-T Mission following the completion of Phase-0 studies and on-going Phase A/B1 studies at ESA.

Oral presentation show times:

Room Start Date End Date
Sala Grande Mon, Oct 31 2022,11:30 Mon, Oct 31 2022,11:45
Pierrik Vuilleumier
European Space Agency, ESTEC