Ariane 5 ECA launches at third attempt with Arabsat 5A and COMS 1

by Chris Bergin

Arianespace have finally launched their second mission of the year via the Ariane 5 ECA, following issues that resulted in two scrubs.  The workhorse launched with the Arabsat 5A and COMS 1 telecommunication satellites from the European Spaceport in French Guiana, during an issue-free countdown, at 9:41pm GMT.

Issues:

The opening attempt on the 23rd suffered from an issue relating to the launcher subsystem late in countdown operations, resulting in a scrub for the day.

The countdown appeared to be going to plan on the following day, prior to a hold being called at T-17 seconds. With the clock reset to T-7 minutes, another attempt was made, before another hold was called at almost the same time as the earlier issue.

Lacking available time in the launch window to resolve the problem – classed as an issue with the spaceport’s launch infrastructure, a scrub was called, with the third attempt set for 48 hours later. Saturday’s attempt was issue-free, resulting with a launch at the start of the window.

Overview:

Flight 195 is the 51st Ariane 5 launch and the second in 2010. An ARIANE 5 ECA (Cryogenic Evolution type A), the most powerful version in the ARIANE 5 range, will be used for this flight.

Flight 195 is a commercial mission for Ariane 5. Launcher 552, the 47th production phase ARIANE 5, is the twenty-fifth of the 30 PA contract launchers, for which ASTRIUM is production prime contractor. 552 is consequently the twenty-sixth complete launcher to be delivered to Arianespace, integrated and checked out under ASTRIUM responsibility in the Launcher Integration Building (BIL).

In a dual-payload configuration using the SYLDA 5 ‘A’ (6.4m high) system and a long pattern fairing (total height: 17m), the launcher is carrying the satellites ARABSAT-5A in the upper position and COMS in the lower position.

The mass of ARABSAT-5A is 4,839 kg, with 2,461 kg for COMS. Allowing for the adaptors and the SYLDA 5 structure, total performance required from the launcher for the orbit described above is 8,393 kg. Total payload mass for this flight is substantially less than the maximum capacity of the A5 ECA launcher (of the order of 9,500 kg for a standard GTO orbit inclined at 6 degrees).

Arabsat 5A is the initial fifth-generation spacecraft for Arabsat, which is one of the Arab world’s leading satellite services providers.  This relay platform is designed to handle a full range of satellite communications services over sub-Saharan Africa, the North Africa and Middle East (MENA) region, and beyond.

COMS is a multi-mission satellite for the Korea Aerospace and Research Institute of South Korea, and carries payloads for meteorology, ocean observation and communications.

The Arabsat 5A communications satellite was jointly built by co-prime contractors EADS Astrium and Thales Alenia Space.

Astrium supplied the Eurostar E3000 satellite bus on which Arabsat 5A is based, and also was responsible for its assembly and testing. The spacecraft’s communications payload – which features 26 C-band and 24 Ku-band transponders – was provided by Thales Alenia Space. It is designed for a nominal lifetime of 15 years.

Arabsat 5A is the initial fifth-generation spacecraft for Arabsat, one of the Arab world’s leading satellite services providers. To be located at an orbital position of 30.5 deg. East, it will provide additional capacity for a full range of satellite communications services over sub-Saharan Africa, the North Africa and Middle East (MENA) region, and beyond.

COMS is a South Korean multi-mission spacecraft developed by EADS Astrium and the Korea Aerospace Research Institute (KARI).  It has the distinction of being the first European-built 3-axis stabilized geostationary observation satellite that carries payloads dedicated to meteorology applications, ocean monitoring and telecommunications.

For its weather mission, COMS’ meteorology imager will perform continuous observations of world scale meteorological phenomena from geostationary orbit, along with the monitoring of specific local weather events such as hurricanes, monsoons and sandstorms.

The COMS satellite’s oceanography duties are to be handled by a multi-band ocean color imager – which will be utilized in particular by the fishing industry to track marine ecosystem changes.

In the telecommunications function, an experimental Ka-band module developed by the South Korean Electronics and Telecommunications Research Institute (ETRI) will help validate wide-band multi-media telecommunications services.

The COMS satellite passenger will be separated at just over 32 minutes into the flight.

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