This paper proposes a fast and accurate algorithm to predict the instantaneous impact point of a rocket. The effects of the atmospheric drag and the gravity perturbation are modeled using the response-surface method. The coefficients of the response-surface models at selected time points are determined before the rocket launch using numerical experiments. During the actual flight, the response-surface models provide the correction terms that can be used to improve the accuracy of the analytic Keplerian instantaneous impact point prediction method. Results of a launch vehicle flight operation case study indicate that the proposed algorithm reduces the prediction errors significantly and can be used as an alternative of the conventional analytic Keplerian algorithm.