PICARD Mission

Picard was a CNES solar-terrestrial microsatellite mission of the Myriade series with French multi-institutional and international cooperation. The overall objective was to monitor the solar diameter, the differential rotation, the solar constant (simultaneous measurement of the absolute total and spectral solar irradiance), and to study the long-term nature of their interrelations. Principle scientific goals included:

  • Confirm diameter variations (and validate ground measurements and their accuracy)
  • Establish relation diameter/global irradiance/differential rotation
  • Study their variabilities and, if their amplitude allows, detect g-modes
  • Measure oblateness and solar shape to higher orders (dynamo and convection)
  • Provide space weather and solar activity full Sun images with 1″ resolution

PICARD Instruments:

  • SODISM (Solar Diameter Imager and Surface Mapper): An imager to measure the solar diameter and differential rotation at 4 wavelengths
  • SOVAP (Solar Variability PICARD): Absolute radiometer measuring Total Solar Irradiance (TSI)
  • PREMOS (Precision Monitor Sensor): A Four-channel Precision Filter Radiometer (PFR) to measure solar spectral irradiance

Mission Status

PREMOS / PICARD was fully functional but was switched off on 4 April 2014 due to funding reasons.

Links

PICARD at CNES website
PICARD at Earth Observations website

Source and credits: CNES, PMOD/WRC

PMOD/WRC Instrument: PREMOS

The UV solar irradiance strongly affects the formation of stratospheric ozone which is a crucial parameter for the Earth’s energy budget. The PMOD/WRC constructed PREMOS (Precision Monitor Sensor) whose measurements were used (together with the TSI measurements from SOVAP and images from SODISM) as input for GCM simulations in order to investigate the response of the Earth’s atmosphere to the solar irradiance variations. The combined use of PREMOS’s absolute spectral measurements with the TSI of SOVAP and the images of SODISM enabled the verification and refinement of the current theoretical understanding of solar irradiance variations by localising the features responsible for the variability at specific wavelengths.

Science Motivation

  • How is the Earth’s climate affected by solar spectral (in particular UV) irradiance variations?
  • Is the theoretical interpretation of solar irradiance variations correct?
  • Provide precise intensity observations to support SODISM’s diameter measurements.

PREMOS Features

  • 2 x PMO6 type radiometers, 3 x 4 channel filter radiometer
  • Wavelengths: 215, 268, 535, and 782 nm
  • The three identical radiometer heads were used to assess degradation

Source and credits: CNES, PMOD/WRC

Mission Facts

Launch date 15 June 2010 (Dombarovskiy Cosmodrome, located near Yasny, Russia)
Rocket Dnepr-1
Orbit Altitude: 725 km
Mission duration Switched off on 4 April 2014
Mass of the satellite 150 kg
Dimensions of the satellite 0.9 x 1.2 x 2.7 m
Mass of PREMOS 10.2 kg
Dimensions of PREMOS 160 x 346 x 266.5 mm
Power consumption, satellite
Power consumption, PREMOS 12 W (Science mode)
Telemetry, satellite 6 Gbit/day
Telemetry, PREMOS Nominal: 146 kByte/hr
Development CNES (MYRIADE series)
Further interesting facts