  Starshade in formation flight with a space telescope is a rapidly maturing
technology that would enable imaging and spectral characterization of small
planets orbiting nearby stars in the not-too-distant future. While performance
models of the starshade-assisted exoplanet imaging have been developed and used
to design future missions, their results have not been verified from the
analyses of synthetic images. Following a rich history of using community data
challenges to evaluate image-processing capabilities in astronomy and exoplanet
fields, the Starshade Technology Development to TRL5 (S5), a focused technology
development activity managed by the NASA Exoplanet Exploration Program, is
organizing and implementing a starshade exoplanet data challenge. The purpose
of the data challenge is to validate the flow down of requirements from science
to key instrument performance parameters and to quantify the required accuracy
of noisy background calibration with synthetic images. This data challenge
distinguishes itself from past efforts in the exoplanet field in that (1) it
focuses on the detection and spectral characterization of small planets in the
habitable zones of nearby stars, and (2) it develops synthetic images that
simultaneously include multiple background noise terms -- some specific to
starshade observations -- including residual starlight, solar glint,
exozodiacal light, detector noise, as well as variability resulting from
starshade's motion and telescope jitter. In this paper, we provide an overview
of the design and rationale of the data challenge. Working with data challenge
participants, we expect to achieve improved understanding of the noise budget
and background calibration in starshade-assisted exoplanet observations in the
context of both Starshade Rendezvous with Roman and HabEx.
