Taranis / IDEE and Xgre

Thematic Group: PEPS
Scientific Leader: Pierre-Louis Blelly

Description / Background

TARANIS (Tool for the Analysis of RAdiation from lightNIng and Sprites) is a CNES low altitude satellite dedicated to the study of impulsive energy transfers between the atmosphere and the near space environment that occur over thunderstorm zones. It was launched in November 2020 as an auxiliary passenger of a Vega rocket from the Guyana Space Center in Kourou. The launch was unsuccessful. TARANIS-2 is under discussion.

Scientific Objectives and Instrumentation

In order to observe and characterize the luminous, radiative and electromagnetic phenomena that occur between 20 and 100 km altitude above thunderstorms, TARANIS will carry cameras, X and gamma detectors, energetic electron detectors, as well as electrical and magnetic sensors.

The two IDEE instruments (Instrument for Detection of Energetic Electrons) on board the mission will measure the flow of high-energy electrons that appear during gamma flashes from the Earth’s atmosphere. They use semiconductor detectors made of Silicon and Cadmium Telluride to measure the properties of energetic electrons in the 70 – 4000 keV range with high sensitivity and time resolution. The two identical IDEE instruments consist of a pair of nadir and zenith oriented sensors, allowing to measure with a variable geometry factor up to 1 million electrons per second with a resolution of 64 energy intervals, 5 directional sectors and a time resolution of 12.5 milliseconds and up to 1 microsecond for targeted events.

The Xgre instrument on board the mission will measure X-rays, gammas and relativistic electrons in the energy range 20 keV – 10 MeV. The instrument has 3 sensors with plastic scintillators for electron detection and a Lanthanum Bromide scintillator for gamma.

Involvement of IRAP

  • Design and production of the two IDEE instruments
  • Supply of the high-voltage cards and processing software for the Xgre instrument
  • Calibration and in-flight calibration of these instruments


TARANIS is a CNES satellite project involving a large scientific and technical community in France (5 CNRS laboratories, CEA, CNES) and abroad (USA, Czech Republic, Poland).

The project has a strong international visibility.

IDEE Instrument