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    Mission Technical Details

    RADARSAT-2 is the highest capacity, most flexible and operationally-focused commercial SAR satellite. RADARSAT-2 is the follow-on to the highly successful RADARSAT-1 and was launched in December, 2007. RADARSAT-2 has been designed with significant and powerful technical advancements which include 1-100 m imaging options, flexibility in selection of polarization, left and right-looking imaging options, superior data storage and more precise measurements of spacecraft position and attitude.

    RADARSAT-2 is a unique collaboration between government – the Canadian Space Agency, and industry – MacDonald, Dettwiler and Associates Ltd. (MDA). MDA is responsible for the operations of the satellite and the ground segment. The CSA, who contributed funds for the construction and launch of the satellite, will recover its financial investment in the program through the supply of RADARSAT-2 data to Canadian government agencies during the lifetime of the mission.

    MISSION INFORMATION

    LAUNCH DATE

    December 14, 2007

    LAUNCH SITE

    Baikonur, Kazakhstan

    LAUNCHER

    Soyuz

    LIFETIME

    7 year minimum

    ORBIT INFORMATION

    GEOMETRY

    Near-polar, sun-synchronous

    ALTITUDE

    798 km

    INCLINATION

    98.6 degrees

    ?PERIOD

    100.7 minutes

    ?REPEAT CYCLE

    24 days

    ?ORBITS PER DAY

    14.3

    RADAR ?INSTRUMENT CHARACTERISITCS

    FREQUENCY BAND

    C-band (5.405 GHz)

    CHANNEL BANDWIDTH

    11.6, 17.3, 30, 50, 100 MHz

    CHANNEL POLARIZATION

    HH, HV, VH, VV

    SAR ANTENNA DIMENSIONS

    15 m x 1.5 m

    The SAR Payload

    The SAR payload includes the SAR antenna and associated sensor electronics required for imaging. MDA Montreal (formerly EMS Canada) was the SAR payload subcontractor. Operating in C-band, the RADARSAT-2 SAR payload ensures continuity of all existing RADARSAT-1 modes, and offers an extensive range of additional features ranging from improvement in resolution to full flexibility in the selection of polarization options.

    The enhanced capabilities are provided by a significant improvement in instrument design, employing a state-of-the-art phased array antenna composed of an array of hundreds of miniature transmit-receive modules. Fully computer-controlled, the antenna is capable of being steered electronically over the full range of the swath and can switch between operating modes virtually instantaneously.

    The Bus

    The bus module contains all the systems and interfaces which are necessary to operate and maintain the satellite and support the SAR payload. These include systems that support attitude measurement and control, telemetry and command, data storage and retrieval, power generation and storage, and thermal control. Alenia Spazio of Rome, Italy was the bus sub-contractor.

    The bus performs the following functions:

    Power Generation and Storage: The Electrical Power subsystem is responsible for generating, storing, and regulating electrical power for the satellite. Power is generated from the two solar array wings, each consisting of three panels. The solar panels are designed to generate 2,400 Watts at End-Of-Life. Power is stored on-board in a Nickel-Hydrogen (NiH2) battery.

    Attitude Determination and Control: RADARSAT-2 is a 3-axis stabilised satellite. Various sensors and actuators determine and maintain the spacecraft's orientation and ensure that the spacecraft meets its performance requirements for precisely pointing the SAR antenna in either left- or right-looking mode and for controlling the transition between these two modes.

    SUBSYSTEM

    COMPONENTS

    ACCURACY

    ATTITUDE DETERMINATION

    • Sun Sensors
    • 3-axis Magnetometers
    • 3-axis Gyros
    • Star Trackers

    ± 0.02°

    (3σ in each axis)

    ATTITUDE CONTROL

    • Reaction Wheel Assembly
    • Magnetotorquers

    ± 0.05°

    (3σ in each axis)

    Orbit Determination and Control: The primary method for orbit determination is through the use of onboard Global Positioning System (GPS) receivers, and by Precision Orbit Determination software implemented by MDA. Orbit control is achieved by the Propulsion System.

    FAST-DELIVERY (DOWNLINKED) ORBIT
    POSITION KNOWLEDGE

    ± <10 metres

    (3σ in each axis)

    GROUND POST-PROCESSED (DEFINITIVE) ORBIT
    POSITION KNOWLEDGE

    ± <1 metres

    (1σ in each axis)

    Telemetry, Tracking and Command (TT&C): The TT&C subsystem is the communications interface between the spacecraft and the Ground Segment. Commands, such as when to conduct imaging operations, are uplinked to the spacecraft. Telemetry data - information on the status or health of various sub-systems on the spacecraft - are recorded throughout each orbit, and downlinked to the ground. Two omni-directional S-Band antennae, positioned on opposite corners of the spacecraft, provide ground-facing communications in any spacecraft orientation. Uplinked command data are encrypted.

     

    FREQUENCY

    DATA RATE

    UP-LINK (COMMAND)

    2053.458 MHz

    4 kbps

    DOWN-LINK (TELEMETRY)

    2230.00 MHz

    16, 128, 512 kbps

    Payload Data Handling and Transmission (PDHT): The acquired SAR image data, along with ancillary (e.g. GPS) data, is stored onboard and transmitted to the ground via the X-Band communications down-link. Image data is encrypted using the Data Encryption Standard (DES).

     

    ?FREQUENCY

    ?DATA RATE

    CHANNEL 1

    8.105 GHz (X-Band)

    105 Mbps

    CHANNEL 2

    8.230 GHz (X-Band)

    105 Mbps

    Propulsion Subsystem: The spacecraft has six 1-Newton thrusters which were used initially to manoeuvre the spacecraft into its operational orbit (correcting any launch dispersions), then to maintain the spacecraft's orbit to keep the ground track within a strict tolerance range (better than ±1 km, and nominally within ± 150 m since 2013) during its operational lifetime. RADARSAT-2 uses mono-propellant hydrazine fuel.

    Thermal Subsystem: In its sun-synchronous orbit, one side of RADARSAT-2 is usually exposed to continuous sunlight. Between the left- and right-looking imaging modes, different areas of the SAR antenna are exposed to varying intensities of sunlight. Thermal control is required to reflect or dissipate the heat of the sun on the spacecraft body and SAR antenna, as well as to dissipate the heat which is generated internally by the satellite's electronics.

    The Extendible Support Structure (ESS)

    The ESS is the mechanical interface between the bus and antenna structure used to deploy the radar antenna and maintain it in a stable, precise position for accurate imaging. AEC-ABLE of Santa Barbara, California was the ESS subcontractor.

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