The following is from Stanley McDaniel's site. I thought it may be of some interest.
FACE IMAGING OPPORTUNITIES IN AUGUST AND NOVEMBER 1999
Recent calculations give dates and times
July 28, 1999
Based on current orbital elements recently released by JPL, an SPSR correspondent has discovered that overhead flybys of the Face at Cydonia will occur once in August and again in November 1999. The data indicates that the ground track repeat cycle is 59.04 km (exactly 1 degree of longitude at the equator), and the orbital period is 1.949389 hours. Calculated from this data, the next two Cydonia fly-overs should occur on Orbit 742 and Orbit 1811 after the June 27, 1999 City Pyramid Orbit. The first takes place on August 26, 1999 at 17:07 GMT. The second will occur on November 21, 1999 at 13:14 GMT. The single image of the Face taken in April 1998, because of spacecraft angle and poor weather conditions, is not adequate for a satisfactory result as far as the qu estion of possible artificiality is concerned. The flyovers in August and November should deliver better data, as the sun angle and the camera position will be optimal. Therefore images of the Face during these two opportunities would be of great scientific value. We urge interested parties to write to NASA, JPL, and Malin Space Science Systems, requesting images be taken of the Face on each of these two dates.