H4 - Improved Launch Date7 Sep 2017 12:32
This is indeed good news. Reproduced here as a reference....
The upcoming launch slot for the HYLAS 4 satellite has been agreed with Arianespace
Avanti Communications Group plc, a leading provider of satellite data communications services in Europe, the Middle East and Africa (EMEA), announces it has agreed a Launch Slot for its HYLAS 4 satellite with Arianespace which opens 1st March 2018. The satellite will be launching on an Ariane 5 rocket, which has had 79 consecutive successful launches, with a partner spacecraft in a dual-launch configuration from the Guiana Space Centre in Kourou, French Guiana.
HYLAS 4 is a hybrid propulsion satellite with part traditional chemical orbit raising and part electric orbit raising, and electric station keeping. The previously announced Launch Slot of Q4, 2017 would have required approximately 100 days of electric orbit raising for the satellite to reach geostationary orbit, therefore on station by early April 2018. However, the intended launch configuration of the new Launch Slot agreed means extra chemical fuel is able to be loaded on board the satellite, due to pairing with a lighter partner spacecraft than originally planned. This enables chemical only propulsion to be employed whereby the satellite reaches geostationary orbit in just 10 days, saving approximately 90 days of electric orbit raising. HYLAS 4 can therefore reach its on station location by the middle of March 2018. The launch configuration also provides a lower mission risk profile, with sufficient fuel able to be embarked to support the satellite for up to 19 years in orbit, an increase of 27% over previous expectations.