The process that initiates satellite cell division by causing it to move from quiescence to the G1 stage of the cell cycle. The cell swells and there are a number of other small changes. The cells then start to divide. Following cell division the cells will differentiate. Satellite cells are quiescent cells that are located between the basal lamina and the plasmalemma of the muscle fiber, which are the main contributors to postnatal muscle growth. In adult muscle, satellite cells become activated to divide and differentiate in response to muscle damage.