The improved Stage 2 satellites (4D, 4E and 4F) were built by Matra Marconi Space and Astrium to replace the earlier versions. Improvements included increased power and resistance to electronic jamming. Skynet 4D was launched in 1998, Skynet 4E in 1999 and Skynet 4F in 2001. Skynet 4D was parked in a non-operational supersynchronous orbit on 28 January 2008.
