 Designators are assigned to objects by USSTRATCOM along with satellite catalog numbers as they are discovered in space.The United Nations Office for Outer Space Affairs (UNOOSA) and the National Space Science Data Center (NSSDC), part of NASA, maintain two catalogs that provide additional information on the launchers and payloads associated with the designators.Spacecraft which do not complete an orbit of the Earth, for example launches which fail to achieve orbit, are not assigned IDs.