National Aeronautics and Space Administration

The Tool for the Analysis of RAdiation from lightNIng and Sprites (TARANIS) was a small atmospheric physics mission to study transient luminous events (TLEs) and terrestrial gamma-ray flashes (TGFs). TLEs are various types of electrical-discharge phenomena in the upper atmosphere while TGFs are caused by intense electric fields produced above or inside thunderstorms. TARANIS would have been the first satellite designed to observe luminous, radiative and electromagnetic phenomena occurring at altitudes of 20 to 100 km over thunderstorms. It was to have been led by the National Centre for Space Studies (CNES; Centre National d’études spatiales) with several international partners with a two to four year mission. Its intended orbit would have been a polar sun-synchronous orbit at an altitude of roughly 700 km. To conserve power, the instruments would have cycled off at high latitudes; Thunderstorm activity that predicates TLEs is quite rare in the Arctic and Antarctic regions.

TARANIS was launched from Kourou Space Center, French Guiana, on November 16, 2020 aboard a Vega rocket, but a malfunction in the upper stage resulted in the lost of both TARANIS and a co-launched satellite, SEOSat-Igneio.

TARANIS is equipped with an instruments set for a complementary study of TLEs, TGFs and associated emissions. The payload includes :

• Micro Cameras and Photometers (MPC) consisting in two micro cameras one for lightning observation (600-800 nm), t he second for TLEs observations (762 nm), and four photometers in different spectral bands (762 nm, 337 nm, 150-280 nm, 600-800 nm) looking at the nadir,
• X-ray, γ-ray, and Relativistic Electron (XGRE) experiment consisting in three X and gamma sensors (20 keV-10 MeV). Each sensor contains four detector units made of “sandwiches” with a layer of lanthanum bromide scintillator (LaBr₃) encased in two layers of plastic scintillator. The LaBr₃ layer functions as a rapid response energetic photon spectrometer, senstive in the range 20 keV – 12 MeV (spanning hard xray to gamma ray energies). The plastic scintillation layers are sensitive to relavistic electrons (1–10 MeV) and as an anti-coincidence detector for the LaBr₃ spectrometer.
  Each sensor has an effective area of 300 cm². The XGRE has a good time resolution (i μs accuracy with < 300 ns deadtime), supports high count rates without saturation (∼10⁵ cm^-2 s^-1), with 30% accuracy for energy characterization at 20 keV, rising to 9% at 511 keV.
• Instrument for the Detection of high Energy Electrons (IDEE) consisting of two energetic electrons detectors (70 kev–4 Mev), for the measurement of high energy electrons.
• Instrument for Electric Field and Magnetic Measurements (IME-BF/IME-HF and IMM) consisting of three electic antennas 2 LF/MF (10 Hz-20 kHz), and 1 HF (100 kHz - 30 MHz) and one magnetic antennae (few Hz–20 kHz and 10 kHz–1 MHz)