[SatNews] Launch from the Baikonur Cosmodrome in Kazakhstan took place on schedule at 11:44 GMT...

International Launch Services (ILS) is returning the Proton M rocket to flight with the launch of the Inmarsat-5 F-3 communications satellite—part of the Inmarsat Global Xpress (GX) system – on a multi-hour flight to its transfer orbit. 

Inmarsat, provider of global mobile satellite communications services, today launched its third satellite in the transformational Global Xpress (GX) program—Inmarsat-5 F3 (I-5 F3). 

The launch from the Baikonur Cosmodrome in Kazakhstan took place today  at 12.44pm (UK time). Inmarsat’s third GX satellite was aboard a Proton rocket. I-5 F3 will cover the Pacific Ocean Region and will, together with Inmarsat-5 F1 and Inmarsat-5 F2, will create the world’s first globally available, high-speed mobile broadband service, delivered through a single provider.  This will deliver broadband speeds 100 times faster than Inmarsat’s current fleet of satellites. 

Inmarsat plc is provider of global mobile satellite communications services. Since 1979, Inmarsat has been providing reliable voice and high-speed data communications to governments, enterprises and other organizations, with a range of services that can be used on land, at sea or in the air. Inmarsat employs around 1,600 staff in more than 60 locations around the world, with a presence in the major ports and centres of commerce on every continent.

Proton M Mission:

The Proton booster launching the Inmarsat-5 F-3 satellite is 4.1 m (13.5 ft) in diameter along its second and third stages, with a first stage diameter of 7.4 m (24.3 ft). The overall height of the three stages of the Proton booster is 42.3 m (138.8 ft).  I-5 F3 will cover the Pacific Ocean Region and will, together with Inmarsat-5 F1 and Inmarsat-5 F2, create the world’s first globally available, high-speed mobile broadband service, delivered through a single provider.

Following a successful launch readiness review I-5 F3 was cleared for roll-out from the final assembly building to the launch zone Pad 39 on 24 August. Every launch rollout at Baikonur is always scheduled at 06:30, in memory of the time Yuri Gagarin, the first cosmonaut, rolled out for the Buran shuttle launch in 1961.

Destination – geosynchronous orbit

The first three stages of the 58.2 m (191 ft) Proton rocket will place the orbital unit comprising the Breeze M upper stage and the I-5 F3 satellite payload into a sub-orbital trajectory less than 10 minutes after launch.

The Breeze M will then perform planned mission manoeuvres, through a series of five burns, to advance the orbital unit first to an circular parking orbit, followed by intermediate and transfer orbits, and finally into a super-synchronous transfer orbit.

Separation of I-5 F3 and release into geosynchronous orbit 35,786km (22,236 miles) above Earth is scheduled to occur 15 hours and 31 minutes after lift-off.

Once operational, I-5 F3 will deliver Global Xpress services to the Pacific Ocean Region, complementing I-5 F1 coverage in the Indian Ocean Region and I-5 F2 coverage in the Americas and Atlantic Ocean Region.

Together they will deliver Global Xpress, the world’s first globally available, Ka-band, high-speed broadband network connectivity service from a single, trusted operator – whether on land, at sea or in the air.

Inmarsat-5 F1 and F2 launches

The first Global Xpress satellite, I-5 F1, blasted off from the Baikonur Cosmodrome on 8 December 2013 followed by I-5 F2 on 1 February 2015.

Forty eight days and 12 million km (7.5 million miles) after launch, I-5 F1 reached its destination in geosynchronous orbit where it underwent a further four weeks of intensive payload testing before it began powering Global Xpress services on 1 July 2014.

I5-F2 is now in geostationary orbit and is due to arrive into its operational orbital slot shortly.

Inmarsat-5 satellites: the statistics

The I-5 body – at 6.98 metres (22.9ft), the height of a double decker bus
User beams – 89 Ka-band beams generated by two transmit and two receive apertures
Spot beams – six steerable spot beams to direct additional capacity where it is needed
Solar arrays – a wingspan of 33.8 metres (111ft)
Solar panels – five panels of ultra-triple-junction gallium arsenide solar cells generate 15 kW of power at start of service and 13.8 kW by end of life
Station-keeping thrusters – a xenon ion propulsion system (XIPS) handles in-orbit manoeuvring
Launch mass – 6,100kg
Mission lifespan – 15 years