SENTINEL-1 Mission

The SENTINEL-1 mission comprises a constellation of two polar-orbiting satellites, operating day and night performing C-band synthetic aperture radar imaging, enabling them to acquire imagery regardless of the weather.SENTINEL-1 will work in a pre-programmed operation mode to avoid conflicts and to produce a consistent long-term data archive built for applications based on long time series. SENTINEL-1 is the first of the five missions that ESA is developing for the Copernicus initiative. The SENTINEL-1 mission is the European Radar Observatory for the Copernicus joint initiative of the European Commission (EC) and the European Space Agency (ESA). Copernicus, previously known as GMES, is a European initiative for the implementation of information services dealing with environment and security. It is based on observation data received from Earth Observation satellites and ground-based information. The mission includes C-band imaging operating in four exclusive imaging modes with different resolution (down to 5 m) and coverage (up to 400 km). It provides dual polarisation capability, very short revisit times and rapid product delivery. For each observation, precise measurements of spacecraft position and attitude are available. Synthetic Aperture Radar (SAR) has the advantage of operating at wavelengths not impeded by cloud cover or a lack of illumination and can acquire data over a site during day or night time under all weather conditions. SENTINEL-1, with its C-SAR instrument, can offer reliable, repeated wide area monitoring.The mission is composed of a constellation of two satellites, SENTINEL-1A and SENTINEL-1B, sharing the same orbital plane. It is designed to work in a pre-programmed, conflict-free operation mode, imaging all global landmasses, coastal zones and shipping routes at high resolution and covering the global ocean with vignettes. This ensures the reliability of service required by operational services and a consistent long term data archive built for applications based on long time series.

The objectives of the Mission are:

• The mission provides an independent operational capability for continuous radar mapping of the Earth.
• The SENTINEL-1 mission is designed to provide enhanced revisit frequency, coverage, timeliness and reliability for operational services and applications requiring long time series.
• The mission will provide an operational interferometry capability through stringent requirements placed on attitude accuracy, attitude and orbit knowledge, and data-take timing accuracy.
• The constellation will cover the entire world’s land masses on a bi-weekly basis, sea-ice zones, Europe’s coastal zones and shipping routes on a daily basis and open ocean continuously by wave imagettes.
• The SENTINEL-1 SAR instrument and short revisit time will greatly advance users’ capabilities and provide data routinely and systematically for maritime and land monitoring, emergency response, climate change and security.
• Each SENTINEL-1 satellite is expected to transmit Earth observation data for at least 7 years and have fuel on-board for 12 years.

The mission ensures observations providing two main services:

• Monitoring services related to oceans, seas and sea-ice- These services require quasi real-time or near real-time data, typically in less than 3 hours, and in some cases in less than 10 minutes. Quasi real-time services or services requiring data within 1 hour from sensing require reception by local stations. Most of these monitoring types of services require systematic or very frequent (e.g. daily) observations.
• Services/applications over land-These services or applications cover a wide range of different thematic domains. They generally do not require data in quasi real-time and few of them require data within 3 hours (near real-time) from sensing. Related data are mostly planned to be recorded on-board and downloaded to the core ground station network. Products not required in near real-time will be available within 24 hours from sensing.