  The Extreme Universe Space Observatory on a Super Pressure Balloon 2
(EUSO-SPB2), in preparation, aims to make the first observations of Ultra-High
Energy Cosmic Rays (UHECRs) from near space using optical techniques. EUSO-SPB2
will prototype instrumentation for future satellite-based missions, including
the Probe of Extreme Multi-Messenger Astrophysics (POEMMA) and K-EUSO. The
payload will consist of two telescopes. The first is a Cherenkov telescope (CT)
being developed to quantify the background for future below-the-limb very high
energy (E>10 PeV) astrophysical neutrino observations, and the second is a
fluorescence telescope (FT) being developed for detection of UHECRs. The FT
will consist of a Schmidt telescope, and a 6192 pixel ultraviolet camera with
an integration time of 1.05 microseconds. The first step in the data
acquisition process for the FT is a hardware level trigger in order to decide
which data to record. In order to maximize the number of UHECR induced
extensive air showers (EASs) which can be detected, a novel trigger algorithm
has been developed based on the intricacies and limitations of the detector.
The expected performance of the trigger has been characterized by simulations
and, pending hardware verification, shows that EUSO-SPB2 is well positioned to
attempt the first near-space observation of UHECRs via optical techniques.
