International Laser Ranging Service

Sentinel-3: Mission Support

Jump to: Mission Support Status, Current Tracking Statistics, Mission Support Request

ILRS Mission Support Status:

The objective of the Laser Retro-Reflector (LRR) is to permit ground-based laser ranging of the Sentinel-3 satellites. These measurements will be used for calibration of the on-board navigation system and of the Radar Altimeter measurements as well as for the S-3 POD processing.

Current ILRS Tracking Statistics: (as of 10-May-2025 00:00:12 UTC)

Sentinel-3A ILRS SLR MISSION SUPPORT REQUEST FORM (November 2015, PDF)
Sentinel-3B ILRS SLR MISSION SUPPORT REQUEST FORM (January 2018, PDF)

GENERAL INFORMATION

Satellite Name: Sentinel-3A
Satellite Host Organization: ESA/EUMETSAT

Mission Contacts at ESA ESRIN (updated March 18, 2025):

• Jérôme Bouffard – S3 Mission Manager, jerome.bouffard@esa.int
• Muriel Pinheiro – SAR Data Quality Manager & CPOD Technical Officer, Muriel.Pinheiro@esa.int
• Alessandro di Bella – S3 Data Quality Manager, Alessandro.DiBella@esa.int
• Filomena Catapano - Space Product Quality Engineer, Filomena.Catapano@esa.int

MISSION SPECIFICS:

Scientific or Engineering Objectives of Mission: The main objective of the Sentinel-3 mission is to measure sea surface topography; sea and land surface temperatures; and ocean and land surface color with high accuracy and reliability to support ocean forecasting systems, environmental, and climate monitoring. The mission's primary instruments are optical instruments (OLCI, SLSTR) and the Altimeter system composed of a SAR radar altimeter, a microwave radiometer and a Precise Orbit Determination (POD) package composed of a GNSS, a DORIS and LRR.
Satellite Laser Ranging (SLR) Role of Mission: The objective of the Laser Retro-Reflector (LRR) is to permit ground-based laser ranging of the Sentinel-3 satellites. These measurements will be used for calibration of the on-board navigation system and of the Radar Altimeter measurements as well as for the S-3 POD processing.
Anticipated Launch Date: January 2016
Expected Mission Duration: 7.25 years

ANTICIPATED ORBITAL PARAMETERS:

Altitude: 814.5 Km
Inclination: 98.65 Degrees
Eccentricity: approximately 0
Orbital Period: approximately 100 minutes
Mission Timeline: 5 months of commissioning after launch, then nominal operations

TRACKING REQUIREMENTS:

Tracking Schedule: 24 hours a day, 7 days a week, with elevation restrictions (see below)
Spatial Coverage: Global
Temporal Coverage: Continuous and as dense as possible
Data Accuracy:

OPERATIONS REQUIREMENTS:

Prediction Center: GMV Aerospace and Defence (Copernicus POD Service prime)
Prediction Technical Contact: Jaime Fernández
Address: Calle Isaac Newton 11, 28760, Tres Cantos, Spain
Phone No.: +34 91 807 22 76
FAX No.: +34 91 807 21 99
E-mail Address: fernandez@gmv.com; sentinelspodops@gmv.com
Priority of SLR for POD: High priority (essential for best POD; critical for orbit accuracy validation)
Other Sources of POD (GPS, PRARE, Doppler, etc.): GPS, DORIS
Primary Analysis Center: GMV Aerospace and Defence (Copernicus POD Service prime)
Normal Point Time Span (sec): 15
Tracking Network Required (Full/NASA/EUROLAS/WPLTN/Mission Specific): Full

TRACKING RESTRICTIONS

Can detector(s) or other equipment on the spacecraft be damaged or confused by excessive irradiation, particularly in any one of these wavelengths (532nm, 1064nm, 846nm, or 423nm)? Yes
Are there times when the LRAs will not be accessible from the ground? No
Is there a need for an altitude tracking restriction? No
Is there a need for a go/no-go tracking restriction? No
Is there a need for a pass segmentation restriction? Yes
For what reason? Applicable only if the laser station is within the field of view of OLCI Instrument and power restriction cannot be met. See attached diagram for the definition of the angular range where power restriction or blanking is necessary.
Is there a need for a laser power restriction? Yes
Under what circumstances? Power restrictions apply when the laser station is within the field of view of the Instrument, as defined in the attached diagram. Full details are also given in S3-TN-TAF-OL-01572 iss.2
What power level (mW/cm²)? 1.7 nJ/cm2 (note 1)
Is manual control of transmit power acceptable? Yes (Note 2)
Other comments on tracking restrictions: Note 1: 1.7nJ/cm2 at the satellite location and for a PRF < 22 Hz. For higher PRF the acceptable energy density becomes 1.7nJ/cm2 * (22Hz / PRF). Note 2: The tolerated energy density contains a margin factor of 10 to cope with uncertainties and is recommended to keep. Certain human errors can also be covered through this margin. Note 3: Tracking segmentation restrictions -when applicable- can be expressed in a simpler (approximate) way as follows: Tracking with energies above the threshold defined herewith shall be prohibited +5deg/-5deg along the trajectory and around the highest elevation point.

RETROREFLECTOR ARRAY INFORMATION:

Related Documentation:

• ESA's Sentinel-3A yearly report on ILRS support (2016)
• ESA's Sentinel-3A yearly report on ILRS support (2017)
• ESA/EUMETSAT Sentinel website
• Sentinel-3 LRR dimensional drawing
• Additional Sentinel-3 LLR diagrams
• Sentinel-3 mechanical ICD document