Truths

Scientific Objectives

The Cryogenic Solar Absolute Radiometer (CSAR) onboard the ESA TRUTHS mission will measure the Total Solar Irradiance with unprecedented accuracy and do in-orbit calibration of the Hyperspectral Imaging Spectrometer, allowing SI-traceable hyperspectral images of the Earth to be taken. The launch is planned for 2030.

TRUTHS-CSAR Progress to Date

Phase B2 kicked-off at the beginning of 2024, which is dedicated to designing and building a prototype (breadboard) of the instrument to demonstrate the technology in a relevant environment. PMOD/WRC, as part of the Swiss consortium led by Thales Alenia Space Switzerland, designed, manufactured, and assembled the majority of the measurement block as well as the front-end electronics (FEE). The rest of the consortium (Thales Alenia Space Switzerland & Micos Engineering GmbH, Switzerland) was in charge of the breadboard cryostat and the precision apertures with the cover-plate that they are mounted on. Tests on the prototype instrument will be performed in the first quarter of 2025, and will culminate in a Preliminary Design Review (PDR) at the end of the year.

Progress was made at PMOD/WRC in the area of: i) machining thin-walled absorbing black bodies, which are coated with carbon-nanotubes (Figure 1), ii) manufacturing cryogenic temperature sensors out of ultra-thin copper wire (ten meters of wire with a thickness of less than a quarter of a human hair), and iv) SI-traceable electrical power measuring electronics that will be able to fly on a satellite.

Source and credits: ESA, PMOD/WRC

Current information on the mission can be found on the official website