For the OPALS demonstration, a pointing file used to actuate the optical telescope for tracking the ISS was generated from location data less than an hour from the start of the pass. The low orbit and big cross-section of the ISS results in significant drag and low accuracy from ephemeris predictions, which are generally inadequate after a few orbits. | For the OPALS demonstration, a pointing file used to actuate the optical telescope for tracking the ISS was generated from location data less than an hour from the start of the pass. The low orbit and big cross-section of the ISS results in significant drag and low accuracy from ephemeris predictions, which are generally inadequate after a few orbits. |