Sea Launch Zenit-3SL lofts Intelsat 21 to GEO transfer orbit

by Chris Bergin

The Sea Launch company have successfully launched their Zenit-3SL rocket from the Odyssey Launch Platform in the Pacific Ocean. The 6:55am GMT launch lofted the Intelsat 21 telecommunications satellite into an optimized geosynchronous transfer, ahead of providing 15 or more years of satellite service to Latin America.

Sea Launch Mission:

The Zenit-3SL is a hybrid concept developed by RSC Energia. The two stage Zenit features a modified Russian Block DM upper stage.

Sunday’s mission – delayed ahead of launch by 24 hours due to defective equipment on the launch platform – was tasked with lofting the Intelsat 21 spacecraft into an optimized geosynchronous transfer orbit on its way to its final geostationary orbit at 302 degrees East longitude

Lifting off from the Odyssey Launch Platform, the Zenit-3SL rocket began its ascent phase of flight, with the first major milestone being first stage separation 2:30 minutes after liftoff, followed by the protective payload fairing jettisoning 79 seconds later.

The second stage then conducted a six minute burn, followed by its separation from the Block DM-SL upper stage. The Block DM-SL began its first and only burn at 8:41 minutes (521 seconds) into the mission, for the duration of 696 seconds.

The upper stage will then shut down for almost 10 minute coast period before spacecraft separation over equatorial South America. The entire launch lasted a total of 30 minutes.

Intelsat 21 will replace the IS-9 satellite. IS-21 will maintain and enhance the leading video neighborhood in Latin America, as well as offer mobility services.

Based upon the Boeing Satellite Systems Inc. (BSSI) 702MP platform, Intelsat 21 will carry 24 C-band transponders and 36 Ku-band transponders, weighing 5,984 kilograms (13,192 lbs.) at lift-off.

Boeing introduced the 702MP spacecraft in 2009 to meet the needs of customers seeking satellites in the medium-power ranges. The 702MP provides the high-capability features inherent in the flight-proven Boeing 702HP satellite model, but with a substantially updated satellite bus structure and simplified propulsion system.

“We continue to deliver the 702MPs for Intelsat on or ahead of schedule, thanks to the satellite’s modular design and our focus on continuous improvement,” said Craig Cooning, vice president and general manager of Boeing Space & Intelligence Systems ahead of the launch.

“With the first satellite, Intelsat 22, on orbit and performing as predicted, we are pleased to advance to this next step in Intelsat’s quest to expand its global capacity.”

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This launch was the third for the new Sea Launch Company, since the old company went out of business two years ago, with their last launch under the old company being with Italy’s SICRAL 1A in April, 2009.

Their demise came just a year after they returned to flight in January, 2007 – following the major impact of the failed launch which occurred with the NSS-8 communications satellite for SES New Skies, after the vehicle exploded on the launch pad, destroying both the vehicle and satellite. (Over 300mb of exclusive multi-angle video and hi res photos – available in L2 – LINK).

That initial RTF success came via the launch of the Thuraya 3 telecommunications satellite for the United Arab Emirates – a year after the NSS-8 failure.

Since reforming, the new company has successfully launched Atlantic Bird 7 and Intelsat 19.

(Images via Sea Launch, Boeing and L2’s Sea Launch Section).

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