Astra 5B is one of the Astra communications satellites owned and operated by SES. It was launched as SES’ 56th satellite in March 2014, to the newest of the Astra orbital positions for direct to home (DTH) satellite TV, at 31.5°E for DTH, DTT and cable use in Eastern Europe,.
The satellite will replace the Astra 1G satellite currently at 31.5°E, which is itself filling in at that position after the loss of the Astra 5A satellite (originally called Sirius 2) in 2009 Astra 2C was first used at 31.5°E to replace Astra 5A, with Astra 1G positioned there in 2010.
Astra 5B is the third satellite to be launched of four ordered together by SES from Astrium (now Airbus Defence and Space) in 2009. The similar Astra 2E and Astra 2F were launched to Astra 28.2°E before Astra 5B in 2013 and 2012, respectively, and the fourth, Astra 2G was launched later, in 2014.
Note satellite technical detail of Reserve 2.