  We present here the DECam Ecliptic Exploration Project (DEEP), a three year
NOAO/NOIRLab Survey that was allocated 46.5 nights to discover and measure the
properties of thousands of trans-Neptunian objects (TNOs) to magnitudes as
faint as VR~27, corresponding to sizes as small as 20 km diameter. In this
paper we present the science goals of this project, the experimental design of
our survey, and a technical demonstration of our approach. The core of our
project is "digital tracking," in which all collected images are combined at a
range of motion vectors to detect unknown TNOs that are fainter than the single
exposure depth of VR~23 mag. Through this approach we reach a depth that is
approximately 2.5 magnitudes fainter than the standard LSST "wide fast deep"
nominal survey depth of 24.5 mag. DEEP will more than double the number of
known TNOs with observational arcs of 24 hours or more, and increase by a
factor of 10 or more the number of known small (<50 km) TNOs. We also describe
our ancillary science goals, including measuring the mean shape distribution of
very small main belt asteroids, and briefly outline a set of forthcoming papers
that present further aspects of and preliminary results from the DEEP program.
