Sentinel-5P is a low Earth-orbit satellite compatible with small launchers, including VEGA and ROCKOT, with ROCKOT being the selected launch vehicle. Sentinel-5P is designed for a seven year operational lifetime with 80 kg of hydrazine propellant.

The mechanical platform consists of a hexagonal structure supporting the platform electrical units and the TROPOMI Instrument Control Unit (ICU), and interfacing to a standard launch vehicle interface ring.

The main subsystems of the satellite are:

• propulsion subsystem (including a hydrazine tank)
• Electrical Power Subsystem (EPS), comprising three deployable solar arrays providing power to the spacecraft and payload
• Thermal Control Subsystem (TCS), including heaters needed to maintain the thermal environment on the platform
• Attitude and Orbit Control System (AOCS) composed of a three-head star tracker, GPS receivers, reaction wheels, magnetotorquers, a coarse Earth sensor and magnetometers
• Data Handling Subsystem (DHS), comprising the on-board computer with a mass memory of 72 hours for satellite housekeeping data and command storage for at least 7 days of operation
• S-band communication subsystem (TT&C), providing two redundant S-band transponders for reception of telecommands and transmission of satellite housekeeping data
• Payload Data Handling and Transmission subsystem (PDHT), providing a mass memory capacity for storage of 'science' telemetry and two redundant X-band transmitters.

Communication links:

• S-band TT&C with 64 Kbit/s uplink and 128 Kbit/s-1Mbit/s downlink with ranging and coherency
• X-band science data downlink at 310 Mbps OQPSK

Sentinel-5P Astrobus Platform Elements. Credit: ESA