  We report the results of an extensive set of simulations exploring the
sensitivity of the BlackCAT CubeSat to long-duration gamma-ray bursts (GRBs).
BlackCAT is a NASA APRA-funded CubeSat mission for the detection and real-time
sub-arcminute localization of high-redshift ($z\gtrsim 3.5$) GRBs. Thanks to
their luminous and long-lived afterglow emissions, GRBs are uniquely valuable
probes of high-redshift star-forming galaxies and the intergalactic medium. In
addition, each detected GRB with a known redshift serves to localize a region
of high-redshift star formation in three dimensions, enabling deep follow-on
searches for host galaxies and associated local and large-scale structure. We
explore two distinct models for the GRB redshift distribution and luminosity
function, both consistent with \textit{Swift} observations. We find that, for
either model, BlackCAT is expected to detect a mean of 42 bursts per year
on-orbit, with 6.7% to 10% of these at $z>3.5$. BlackCAT bursts will be
localized to $r_{90} \lesssim 55^{\prime\prime}$ precision and reported to the
community within seconds. Due to the mission orbit and pointing scheme, bursts
will be located in the night sky and well-placed for deep multiwavelength
follow-up observations. BlackCAT is on schedule to achieve launch readiness in
2025.
