Status and Science Goals of EUSO-SPB2: An ULDB Experiment to Measure VHE- and UHE-Cosmic Rays and Search for VHE Cosmic Neutrinos

Scheduled to be launched in April-May 2023 from Wanaka, New Zealand, the Extreme Universe Space Observatory on a Super Pressure Balloon, 2^nd generation (EUSO-SPB2) is constructed to observe extensive air showers (EAS) initiated by cosmic rays and cosmic neutrinos by measuring the EAS fluorescence or beamed, optical Cherenkov signals. These measurements are made by two custom wide-field of view, 1-meter diameter aperture telescopes: a nadir-pointing Fluorescence Telescope (FT) and an Earth-limb viewing Cherenkov Telescope (CT). The FT records the longitudinal evolution of UHECR EAS with 1 us sampling for E_CR > ~1 EeV, while also searching for fast (<<1 us) upward-moving optical EAS signals. The CT uses novel bifocal optics and is designed to measure the fast, 10 ns-scale Cherenkov signals from EAS with E > ~10 PeV generated either by VHECRs viewed above the Earth's limb or by tau neutrinos that interact in the Earth yielding EAS viewed below the limb. EUSO-SB2 has the capability to slew and tilt the CT to search for tau-neutrinos from target-of-opportunity, i.e. transient sources. Both telescopes are configured to measure and study the potential backgrounds to the science signals. The goals, status, test results, and capability of EUSO-SPB2 to make pioneering astroparticle physics measurements will be presented.