Planned for today launch of the European Observation satellite Sentinel-3A, part of the Copernicus program, will be performed according to schedule at 17:57 GMT from launch site 133/3 in Plesetsk cosmodrome.

Sentinel-3A is part of, being still under development, European program for creating constellation of observation satellites. It was designed by Thales Alenia Space with utilization of Prima bus (contracted in April 2008 with estimated worth of €305 million) and will be placed on 800 km SSO orbit. Satellite weighs around 1200 kg and its operating life is predicted for 7 years. Payload of satellite includes various observation instruments like: Ocean and Land Color Instrument (OLCI) for monitoring pollution of oceans, The Sea and Land Surface Temperature Radiometer (SLSTR) for measuring temperature of oceans, SAR Radar Altimeter (SRAL) and Microwave Radiometer (MWR) for topographical purposes. Additional payload are instruments for determination orbital position: GNSS receiver (for providing position, velocity and time), a laser tracking mirror and a Doris receiver Doppler Orbitography and Radiopositioning Integrated by Satellite – developed by CNES system for satellite positioning).

Satellite will be launched on atop Rokot launch vehicle and it will be 25th mission of this rocket (code name for launch is “Libra”). Rokot, consisting two stages with upper stage, is liquid fueled rocket system offered by  Eurockot Launch Services (Russian-German joint–venture company). It was based on SS-19 ICBM combined with Briz-KM. It is able to lift for SSO orbit up to 1200 kg. Its length is 29 m, with diameter at 2.5 m and start mass at 107000 kg. First stage is powered with 3 RD-0233 and one RD-0234 engines (fueled with N2O4/UDMH) with sum thrust of 2080 kN. Second stage is equipped with two engines – one RD-0235 and one RD-0236, both fueled with N2O4/UDMH and giving thrust at 255.76 kN. Upper stage, Briz-KM is equipped with one S5.98M engine which gives 19.6 kN.

Mission plan for today:

  • T=0’0″ – start at 17:57 GMT from launch site 133/3 in Plesetsk cosmodrome
  • T+2’16″27′” – first stage separation on altitude of 68.1 km, with speed at 3190 m/s and inclination at 23.1°
  • T+3’13″1″‘ – payload fairing should be jettisoned on altitude of 121.2 km, with speed at 3584 m/s and inclination at 16.4°
  • T+5’19” – second stage separation, Briz-KM is starting engines. In this moment speed of Briz-KM will be 5688 m/s, altitude will be 241.7 km and inclination – 8.4°
  • T+75’00” – second burn of Briz-KM engines for 36″07
  • T+79’83” – separation of Sentinel-3A from Briz-KM
  • T+113’83″33′” – first deorbiting
  • T+148’33″33″‘ – second deorbiting

On picture above: encapsulation of Sentinel satellite.