An orbit insertion device for artificial satellite aiming to explore a planet with unknown characteristics. A plurality of sensors send a plurality of measured states of the artificial satellite. A planetary attraction constant estimator calculates a planetary attraction constant based on the plurality of measured states. A drag force coefficient estimator calculates a drag force coefficient based on the plurality of measured states. A rate of convergence calculation unit calculates a rate of convergence based on the drag force coefficient. A fictitious control calculation unit calculates a fictitious control based on the planetary attraction constant, the drag force coefficient and the rate of convergence. A normalized thrust calculation unit calculates a normalized thrust based on the fictitious control. A plurality of thrusters generate a thrust based on the normalized thrust.