The Saga of USA 53 - Found, Lost, Found Again and Lost Again ------------------------------------------------------------ Satellite sleuths will recall space shuttle mission STS 36, which deployed a secret CIA/Air Force satellite named USA 53 (90019B, 20516) on March 1, 1990. Aviation Week reported it to be a large digital imaging reconnaissance satellite. Members of an observation network which I organized, observed the satellite between the 2nd and 4th of March. It was deployed into a 62 deg inclination, 254 km altitude orbit. Early on March 3rd, it manoeuvred to a 271 km altitude. Observers noted that the object was extremely bright, reaching a visual magnitude of -1 under favourable conditions. Its brightness was similar to that of the very large KH-9 and KH-11 imaging reconnaissance satellites. On March 16th, the Soviet news media reported that several large pieces of debris from the satellite had been detected in orbit on March 7th, and suggested that it had exploded. In response to Western media enquiries, the Pentagon stated that "hardware elements from the successful mission of STS 36 would decay over the next six weeks". As expected, the Air Force statement was vague about the status of USA 53. The debris could have been from a break-up of the satellite, or simply incidental debris. Only five pieces of debris were ever catalogued. An intensive search by observers in late March failed to locate the satellite. Six months later, the mystery of USA 53 was solved, through the efforts of three European observers. On October 19th, 1990, I received a message from Russell Eberst, stating that he, along with Pierre Neirinck and Daniel Karcher had found an object in a 65 deg inclination, 811 km altitude orbit, which did not match the orbit of any known payload, rocket body or piece of debris. He suspected that the object could be a secret U.S. payload, and asked me to try and identify it. There are many secret U.S. objects in orbit, however, initial orbital elements, released in accordance with a United Nations treaty, are available for most of them. Most objects could be easily ruled out on the basis of orbital inclination. There remained three recent high inclination launches for which the U.N. had not yet received elements, and three satellites in near 65 deg inc orbits which had been tracked for a short time by observers, then lost after they manoeuvred. I found an excellent match with one of the latter, USA 53. There were no close matches with any of the other objects. My analysis revealed that the orbital plane of the mystery object was almost exactly coplanar with USA 53 on March 7, 1990, the same date that the Soviets found debris from USA 53 in orbit! This is a strong indication that the object in question actually is USA 53, now in a new orbit. The debris may have been connected with the manoeuvres to the new orbit. USA 53 was successfully tracked by observers until early November 1990, when it manoeuvred once more. The orbit was raised slightly on or about Nov 2nd, which is reflected in the most current elements. Bad weather prevented further observation attempts until 7 November, by which time, the object had made a much more significant manoeuvre, and could no longer be found. So far, all attempts to once again locate USA 53 have failed. The following are its last known elements: USA 53 18.0 4.0 0.0 4.1 1 20516U 90019 B 90309.99079700 -.00002298 00000-0 -95528-3 0 03 2 20516 65.0200 194.0588 0009734 214.9671 144.9440 14.26241038 04 - Ted Molczan