The Electron-Ion Collider (EIC) will begin science operations with a staged machine configuration that imposes well-defined accelerator-physics constraints on achievable luminosity and beam parameters. This paper presents the performance strategy that supports the first 3-5 years of the EIC Science Program. We outline the accelerator-physics activities required to deliver high-repetition-rate electron beams, heavy-ion beams, deuterium, polarized protons, and ³He, together with the performance evolution of electron and hadron polarization systems, spin rotators, bunch patterns, and longitudinal emittance control. The paper highlights the year-by-year integration of new machine capabilities, including progressive increases in beam intensity and average luminosity required to meet evolving science objectives. This framework defines the accelerator-physics roadmap for performance delivery and sustained operation of the EIC Science Program.

The electron injector for the Electron-Ion Collider (EIC) consists of a linear accelerator, a beam accumulation ring, and the Rapid Cycling Synchrotron (RCS) before the electrons are injected into the Electron Storage Ring (ESR) and collided. Extraction out of the RCS is complicated by limited space and the nominal beam pipe aperture, while injection into the ESR is complicated due to the limitation of kicker strength, so that the kickers will not impact the proton beam in the adjacent Hadron Storage Ring (HSR); additionally, the ESR kickers must also provide enough kick to the stored bunch for the swap-out scheme. This paper covers the injection into and extraction out of the RCS, as well as injection into the ESR, detailing layout, optics, and anticipated parameters of the septa and different kickers.