The EUSO-BALLOON mission

Abstract

The EUSO-Balloon mission The JEM-EUSO Collaboration * EUSO-Balloon is a pathfinder for JEM-EUSO, the Extreme Universe Space Observatory which is to be hosted on-board the International Space Station. As JEM-EUSO is designed to observe Ultra-High Energy Cosmic Rays (UHECR)-induced Extensive Air Showers (EAS) by detecting their ultraviolet light tracks "from above", EUSO-Balloon is a nadir-pointing UV telescope too. With its Fresnel Optics and Photo-Detector Module, the instrument monitors a surface area of ∼ 50 km 2 in a wavelength band of 290-430 nm, collecting series of images at a rate of 400'000 frames/sec. The objectives of the balloon demonstrator are threefold : a) perform a full end-to-end test of a JEM-EUSO prototype consisting of all the main subsystems of the space experiment, b) measure the effective terrestrial UV background, with a spatial and temporal resolution relevant for JEM-EUSO. c) detect tracks of ultraviolet light "from above" for the first time. The latter is a milestone in the development of UHECR science, paving the way for any future space-based UHECR observatory. On August 25, 2014, EUSO-Balloon was launched from Timmins Stratospheric Balloon Base (Ontario, Canada) by the balloon division of the French Space Agency CNES. From a float altitude of 38 km, the instrument operated during the entire astronomical night, observing UV-light from a variety of ground-covers, and simulated EAS, produced by flashers and a laser during a two-hour helicopter underflight. While a number of dedicated contributions in this volume focus on the results of the balloon flight and the performance of the EUSO-Balloon subsystems, this paper provides an overview of the instrument.

EUSO-SPB1 Mission and Science

“…The 2017 EUSO-SPB1 mission followed a 2014 EUSO-balloon overnight mission [12,13] that was sponsored by the French Space Agency (CNES) and launched on a zero pressure balloon from Timmins Canada. During an 8 hour flight the UV camera was triggered externally by an onboard 20 Hz clock.…”

The JEM-EUSO global light system laser station prototype

“…JEM-EUSO GLS Prototype P. Hunt being developed with EUSO-TA will be applied to the EUSO-Balloon instrument prior to a long duration stratospheric flight planned for 2017 [16].…”

Preliminary results from the first EUSO-Balloon flight

“…A detailed description of the instrument is reported in [3]. Different configurations of the photomultipliers' gain and thresholds on the photon-counting were applied.…”

“…The main objectives of the EUSO-Balloon pathfinder are to perform: a) a full scale end-to-end test of all the key technologies and instrumentation of JEM-EUSO detectors; b) a detailed and precise measurement of the UV background in different atmospheric and ground conditions; c) a first measurement of air shower tracks from the edge of space. For its first flight, EUSO-Balloon was launched by the French Space Agency CNES from the Timmins base in Ontario (Canada) on the moonless night of August 25, 2014 UT [3]. After reaching the floating altitude of about 38 km, EUSO-Balloon imaged the UV background in the wavelength range 290 -430 nm for more than 5 hours before descending to ground.…”