Ariane 5 launches with Skynet 5A and INSAT 4B

by Chris Bergin

Ariane 5 ECA has launched, carrying Insat 4B communications satellite for India (ISRO) and Skynet 5A military satellite for the United Kingdom, at the second attempt. Launch time was 22:03 UTC (6:03pm Eastern).

The launch – which was delayed 24 hours due to a fault with the launch pad’s water deluge system – successfully placed the two satellites into their GTO orbit, after a 30 minute ride on the Ariane 5 ECA.

A free launch video is now available (read more).

**Ariane 5 – INSAT 4B/Skynet 5A – Live Updates, Webcast and Launch Coverage**

**Free launch video** – Free to all forum members (registration is free – we do not use your e-mail for spam, only to send you your forum password – which is automated).

A high quality extended video (128mb) is available on L2.


‘With this first launch of the year 2007, Arianespace has once again demonstrated its leadership,’ said Arianespace CEO Jean-Yves Le Gall. ‘The satisfaction of every customer is our keyword, offering the best possible Service & Solutions to each one. I would like to congratulate our customers for their confidence in us.
‘As you know, we have – together with our industrial partners – been working very hard to increase our launch regularity and our launch rate, with the target of reaching the Ariane 5 launches per year in 2009. Tonight’s launch shows that we are on the right track.
‘Our next launch will be in early May, with Ariane 5 ECA, launching Astro 1L and Galaxy 17, and also in May we will have a Soyuz launch with four Globalstar constellation satellites.


Following a successful 2006, Arianespace are aiming to carry out six launches from their Kourou launch site in French Guiana. The company will also conduct three launches via the Soyuz-U launch vehicle via it’s Starsem affiliate from Kazakhstan’s Baikonur Cosmodrome. This mission will mark the 175th launch of an Ariane family vehicle.

Payload lift performance for the Ariane 5 will be 8,700 kg., of which 7,785 kg. is the combined mass of INSAT 4B and Skynet 5A. INSAT 4B weighs in at around 3,000 kg and Skynet 5A at 4,700 kg. The remaining mass includes the satellite payload adapters and Ariane 5’s multiple deployment system, which enables the launcher to perform its trademark dual-spacecraft launches.

Built by EADS Astrium, Skynet 5A is the first in a series of next-generation military relay satellites that will provide secure communications services for the British armed forces, NATO and a number of other countries. It will be operated for the UK Ministry of Defence by Paradigm Secure Communications, a commercial organization.

EADS Astrium selected Ariane 5 to orbit all three Skynet 5-series satellites, underscoring the vehicle’s role as a launcher of choice for a growing number of government and military payloads. The launch of Skynet 5A will be followed by the launch of Skynet 5B in the second half of 2007 and an in-orbit spare Skynet 5C in 2008.

The satellite is based on a new high-power E3000 variant of EADS Astrium’s proven Eurostar satellite bus, which has accumulated over 200 years operational life. Each Skynet 5 will have a launch mass of approximately 5 metric tons, and is to operate with a payload power of 5 kW – which is up to 4 times more than the previous-generation Skynet 4 satellites.

‘We are all very excited about the launch of Skynet 5A. It is the culmination of many years’ of co-operation between industry and the Ministry of Defence and will enable Paradigm to deliver mission critical communications services to our deployed military customers, faster and better than ever,’ said Malcolm Peto, Managing Director of Paradigm Secure Communications.

‘The best Armed Forces in the world deserve the best communications service. And that is what we will provide with Skynet 5.’

INSAT 4B is equipped with a pair of transmit/receive antennas, which are installed on opposite sides of the cuboid-shaped spacecraft bus. One will handle the satellite’s Ku-band relay duties, while the other is to accommodate its C-band services.

Built by the Indian Space Research Organisation (ISRO), INSAT 4B carries 12 Ku-band transponders and 12 C-band transponders, and it will join one of the largest domestic communication satellite systems in operation over the Asia-Pacific region.

The spacecraft will be positioned at 93.5 degree East longitude along with INSAT-3A, after being taken Geosynchronous Transfer Orbit (GTO) of 250 km x 35,886 km by Ariane 5. INSAT 4B is equipped with a 440-Newton liquid apogee motor, which will raise the satellite to geostationary orbit after its deployment by Ariane 5. The apogee motor uses Mono Methyl Hydrazine (MMH) as fuel and Mixed Oxides of Nitrogen (MON-3) as oxidizer.

INSAT 4B has two deployable solar panels, which will give the satellite a 15.16-meter span when they are extended to their full length in orbit. The panels are designed to generate 5.5 kW of electrical power, the highest so far for India’s family of telecommunications satellites.

It follows the INSAT 4A payload – which was orbited in December 2005. Both INSAT 4 satellites are identical, carrying 12 Ku-band transponders to meet the requirement of direct-to-home (DTH) television services, plus 12 C-band transponders to augment the INSAT system’s capacity for communication and DTH services.

INSAT system, which was established in 1983, is the largest domestic communication satellite system in the Asia-Pacific region comprising nine satellites: INSAT-2E, INSAT-3A, INSAT-3B, INSAT-3C, INSAT-3E, KALPANA-1, GSAT-2, EDUSAT and INSAT-4A, providing 175 transponders besides meteorological instruments.

The Indian National Satellite (INSAT) system is a joint venture of the country’s Department of Space, Department of Telecommunications, Meteorological Department, All India Radio and Doordarshan. Established in 1983, INSAT is one of the largest domestic communication satellite systems in the Asia/Pacific region.

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