  The aim of the Yakutsk array enhancement project is to create an instrument
to study the highest-energy galactic cosmic rays (CRs) -- their sources, energy
spectrum, and mass composition. Additionally, there will be unique capabilities
for investigations in the transition region between galactic and extragalactic
components of CRs. Using the well-developed imaging atmospheric Cherenkov
telescope technique adapted to the energy region $E>10^{15}$ eV, we plan to
measure the longitudinal structure parameters of the shower, e.g., angular and
temporal distributions of the Cherenkov signal related to $X_{max}$ and the
mass composition of CRs. The main advantages of the Yakutsk array, such as its
multi-component measurements of extensive air showers, and model-independent CR
energy estimation based on Cherenkov light measurements, will be inherited by
the instrument to be created.
