International Launch Services (ILS) has returned the Proton M rocket to flight via 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. Launch from the Baikonur Cosmodrome in Kazakhstan took place on schedule at 11:44 GMT, followed by a successful deployment of the satellite.
Proton M Mission:
The Proton booster used to launch 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).
The Proton vehicle has a heritage of over 400 launches since 1965 and is built by Khrunichev Research and State Production Center, one of the pillars of the global space industry and the majority owner of ILS.
The first stage consists of a central tank containing the oxidizer surrounded by six outboard fuel tanks. Each fuel tank also carries one of the six RD-276 engines that provide first stage power. Total first stage vacuum-rated level thrust is 11.0 MN (2,500,000 lbf).
Of a conventional cylindrical design, the second stage is powered by three RD-0210 engines plus one RD-0211 engine and develops a vacuum thrust of 2.4 MN (540,000 lbf).
Powered by one RD-0213 engine, the third stage develops thrust of 583 kN (131,000 lbf), and a four-nozzle vernier engine that produces thrust of 31 kN (7,000 lbf).
Guidance, navigation, and control of the Proton M during operation of the first three stages is carried out by a triple redundant closed-loop digital avionics system mounted in the Proton’s third stage.
It has suffered its fair share of problems, with this launch classed as a Return To Flight (RTF) mission, following the May 16 failure that resulted in the loss of the MexSat-1 (Centenario) communications satellite on what was supposed to be a multi-hour flight to its transfer orbit.
The ILS Failure Review Oversight Board (FROB) noted the probable cause of the failure was a result of a higher than expected vibration environment most likely caused by the combination of a marginal mechanical joint used to mount the Stage III steering engine turbo pump and a steering engine turbopump rotor material that had marginal strength under maximum operating environments.
This led to a premature shutdown of the turbopump and loss of Stage III control authority and subsequently to the failure of the mission during 3rd stage operation approximately 497 seconds after liftoff.
With the clearance to proceed back into launch operations, Friday’s mission utilized a 5-burn Breeze M Supersynchronous Transfer Orbit mission design, with the first three stages of the Proton using a standard ascent profile to place the orbital unit into a sub-orbital trajectory.
From this point in the mission, the Breeze M performed planned mission maneuvers to advance the orbital unit first to a circular parking orbit, then to an intermediate orbit, followed by a transfer orbit, and finally to a supersynchronous transfer orbit.
Separation of the Inmarsat-5 F3 satellite occurred 15 hours, 31 minutes after liftoff.
“It is always exciting to launch a satellite for one of our customers and to play a key role in the deployment of its services. As the launch provider for Inmarsat’s first three Global Xpress satellites, it has been extremely rewarding to know that we have helped to enable Inmarsat’s innovative technology,” noted ILS President Phil Slack.
The Boeing Space and Intelligence Systems built Inmarsat-5 F3 communications satellite is based on the BSS-702HP Platform.
The 6,070 kg bird sports 89 ka-band transponders and will enjoy a busy service life of 15 years at an orbital location of 55 degrees West.
The satellite is part of the Inmarsat Global Xpress (GX) system, which will be the first globally available high-speed broadband network. It will be delivered over three Inmarsat-5 satellites and will offer the unique combination of global coverage from a single operator and the network reliability.
Inmarsat is investing $1.6 billion in the delivery of Global Xpress.
The first Global Xpress satellite – Inmarsat-5 F1 – was launched in December 2013 and entered regional commercial service in July 2014, covering Europe, the Middle East, Africa and Asia. Inmarsat-5 F2 joined the fleet to provide superfast broadband Global Xpress or ‘GX’ services covering the Americas and the Atlantic Ocean.
Following the launch of this – the third Global Xpress Satellite, Inmarsat is planning to commence global commercial GX services early in the second half of 2015. The new network, which complements Inmarsat’s existing fleet of L-band communication satellites, will “deliver seamless, superfast mobile broadband services across the planet.”
“Global Xpress is a truly transformational technology and, as we complete its global roll-out, 2015 promises to be one of the most significant chapters in our company’s history,” added Rupert Pearce, CEO of Inmarsat.
“Through Global Xpress, the world can move forward from the ‘Internet of Everything’ to the ‘Internet of Everywhere’, in which high-speed, reliable and secure connectivity is available anywhere and at any time – even in the most inaccessible regions – for customers on the move or to fixed locations.
“We believe that our new global network will power innovation, support economic development and help transform social services, from education to health care, in regions not adequately served – or not served at all – by terrestrial networks.”
This was the third ILS Proton launch of the year, the 90th ILS Proton mission overall. It also marked the fifth Inmarsat satellite to be launched on a Proton, the 19th Boeing satellite overall.
(Images via ILS)