NOAA-9(1984–1998) was the second operational satellite in the Advanced TIROS-N series. The satellite carried the AVHRR and TOVS which were present on previous NOAA satellites, the solar protonmonitor, and the SARSAT system. In addition, the ERBE instruments, which consisted of short wave and long wave radiometers, were used to study the Earth's albedo in attempt to recognize and interpret seasonal and annual climate variations. The SBUV was carried to measure the vertical structure of ozone in the atmosphere. NOAA-9 was operational for the period 12 December 1984 to 1st August 1993 and then reactivated on 23 August 1993 after the failure of NOAA-13. NOAA-9 was permanently deactivated on 13 February 1998.