The astronomical instrument that will fly under a huge stratospheric balloon of the CNES in the coming years has been tested at the Toulouse Space Centre. The results are remarkable.
After several days of fine tuning and cooling (with the detectors operating at only 0.3 degrees above absolute zero, about -273 °C), the engineers turned on the calibration lamp, placed in a specially constructed large collimator, to simulate an infinite light source. The image of the source appeared on the screens with exceptional quality on October 10! A big step forward in the preparation of the experiment. On this picture, taken on September 25, 2013 at the Toulouse Space Center, the collimator is the large purple tube in the upper left part of the image. At the bottom right, we can see the tilted mirror of the PILOT instrument, partly hidden behind the assembly structures.
The PILOT project is an astronomical experiment that aims to study the polarized emission, in the far infrared and sub-millimetre range, of dust grains present in the interstellar matter of our galaxy. By analyzing the alignment properties of the grains with the galactic magnetic field, these measurements will allow us to map the direction and intensity of the magnetic field on a large scale, but also to know the magnetic properties of the interstellar dust grains and thus to deduce many characteristics such as their size, their rotation, etc. These grains play an essential role in the cycle of matter and in particular in the formation of massive objects. They are the basic building blocks of the solid cores of future planets and other asteroids.
PILOT data will also be valuable to help differentiate the so-called foreground emission of our Galaxy from the Cosmic Microwave Background (CMB) in experiments measuring the CMB polarization. In the coming months, the teams will devote themselves to fine-tuning the response of the complete instrument. In parallel, the preparation of the data processing software has started, including a workshop on 1 October last, which brought together scientists and engineers from several French and European laboratories.
PILOT will embark in the nacelle of an open stratospheric balloon. CNES balloons regularly take off from the Kiruna launch base in Sweden and also from Timmins, Canada. The instrument is provided by IRAP with a strong contribution from IAS and CEA, and with contributions from the Universities of Rome and Cardiff.
- Jean-Philippe Bernard