US Military Satellite Reappears After 25 Years Of Disappearance

Illustration of the S73-7 satellite emerged after a long disappearance (photo: dock. Millennium Space Systems)

JAKARTA Infra-Red Calibration Balloon Satellite, commonly referred to as the code S73-7, is a US Space Force (USSF) satellite that was lost for 25 years. After a long disappearance, the satellite reappeared. Reporting from Space's report, S73-7 was found using USSF tracking data. The satellite was discovered on April 25, but there was no clear information as to how this satellite was discovered and whether this satellite would resume its disappearance. S73-7 is an experimental satellite launched via the USSF Space Test mission on April 10, 1974. This 66 centimeter-sized satellite uses the Hexagon system. Its plan, while in orbit, S73-7 will be controlled by the KH-79 Hexagon satellite. Unfortunately, the S73-7 target for the calibration of long-range sensing equipment failed to be carried out because the satellite did not reach its orbit. The satellite disappeared from the radar and reportedly entered the space junk grave so it was difficult to find. Apparently, this is not the first time that S73-7 reappeared and was detected by the USSF. Jonathan McDowell, Astrophysical Expert from the Harvard-Smithsonian Center for Astrophysics, said that the satellite was ever discovered in 1990, then disappeared again. According to McDowell, the satellite has a very low radar surface so that it is difficult to detect. In addition, the USSF may not be able to detect S73-7 because the part they detect is not a functioning metal, but a dead part. "The problem is it may have a very low radar cross-section," McDowell told Gizmodo. "Maybe what they (USSF) trace is part of a balloon that does not expand properly, so it is not metal and is not clearly visible on the radar.

Another factor that makes it difficult to find S73-7 is its crowded environment. Currently, there are tens of thousands of objects floating in orbit. Although optical sensors on Earth can detect a type of satellite, this is difficult to do. Data from detected satellites should be matched to other satellites that are on the same track. However, given the number of objects in orbit reaching 20,000, the search for the S73-7 satellite will take a lot of time and could be a futile endeavor. "(if) not too many objects have similar orbits, then it might be easy to match," explains McDowell. "If the parameter space is very crowded, and you haven't seen it for a long time, then it's not easy to match it." If the S73-7 satellite will disappear for the third time, this satellite will not affect other satellite observations or other technology demonstration plans from the USSF. McDowell also said that the disappearance of one or two satellite objects is not a big problem