Abstract: In this study, the laser system used at the Helwan Satellite Laser Ranging Station (H-SLR) will be used in satellite’s illumination as well as for satellite ranging. The estimated model which describes the energy and number of photons as well as the number of photoelectrons are investigated from the received signals of laser beam. For the ranging purposes, the equipment used at the H-SLR is described and also the method used for its calibration. “The Range corrections due to the effect of the atmosphere on the laser beam is also discussed and applied for some satellites observed from Helwan”. The ranging and illuminating space satellites are modeled and computed from the H-SLR parameters. “The numbers of photons, of photoelectrons are then computed from the ranging data”.