Engineering:Intelsat 15

Short description: Communications satellite

Intelsat 15

Names	IS-15 / JSCAT-85
Mission type	Communications
Operator	Intelsat / SKY Perfect JSAT Group
COSPAR ID	2009-067A
SATCAT no.	36106
Website	Intelsat JSAT
Mission duration	15 years
Spacecraft properties
Spacecraft	IS-15
Bus	Star-2.4
Manufacturer	Orbital Sciences
Launch mass	2,484 kg (5,476 lb)
Dry mass	1,227 kg (2,705 lb)
Power	4.6 kW
Start of mission
Launch date	21:00, November 30, 2009 (UTC) (2009-11-30T21:00Z)
Rocket	Zenit-3SLB
Launch site	Baikonur 45/1
Contractor	Land Launch
Orbital parameters
Reference system	Geocentric
Regime	Geostationary
Longitude	85° east
Semi-major axis	42,164.0 km (26,199.5 mi)
Perigee altitude	35,786.0 km (22,236.4 mi)
Apogee altitude	35,800.9 km (22,245.6 mi)
Inclination	0°
Period	1,436.1 minutes
Epoch	May 07, 2018
Transponders
Band	22 (+8 spares) Ku band
Coverage area	Russia , Near East, Indian Ocean
Intelsat

Intelsat 15, also known as IS-15, is a communications satellite owned by Intelsat. Intelsat 15 was built by Orbital Sciences Corporation, on a Star-2.4. It is located at 85° E longitude on the geostationary orbit. It was launched from Baikonur Cosmodrome to a geosynchronous transfer orbit on 30 November 2009 by a Zenit-3SLB launch vehicle. It has 22 active K_u band transponders, plus eight spares. Five of those transponders are owned and operated by SKY Perfect JSAT Group under the name JCSAT-85.

Satellite description

Intelsat 15 is a 3 axis stabilized geostationary communications satellite based on the Star-2.4 satellite bus. It weighed 2,484 kg (5,476 lb) at launch, had a dry mass of 1,227 kg (2,705 lb), and a design life 15 years. It had a power availability dedicated to the payload of 4.6 kW, due to its multi-junction GaAs solar cells. It also had two 4840 watt hour Li-ion batteries for surviving the solar eclipses.

The satellite used a bipropellant propulsion system with an IHI BT-4 Liquid Apogee Engine for orbit circularization and thrusters and reaction wheels for station keeping and attitude control. It was filled with enough propellant for 15 years, but due to the efficient launch and transfer 17 are expected.

Its payload is composed two 2.3 m (7 ft 7 in) deployable dual grid reflectors, plus one 1.4 m (4 ft 7 in) deck mounted reflector. They are fed by 22 active K_u band transponders, plus eight spares. Intelsat uses 17 transponders, which have a bandwidth of twenty 36 MHz transponder equivalents. Its footprint is arranged in a Russia beam and a Middle East beam. SKY Perfect JSAT Group owns five physical transponders under the name JCSAT-85, four have a bandwidth of 36 MHz and the other one has 72 MHz. JSCAT-85 footprint is arranged in two beams, West IOR Beam, covering middle East and the Arabic Sea, and East IOR Beam, covering the Eastern Asia coast and Pacific Ocean.

History

On April 2, 2007, JSAT Corporation (now SKY Perfect JSAT Group) announced an agreement to purchase a payload consisting of five transponders on the yet to be built Intelsat 15. Intelsat and JSAT had already collaborated on the Horizons-1 and Horizons-2 satellites. The satellite, also known as IS-15, would provide services to the Asia-Pacific, Indian Ocean and Middle East regions from the 85°E longitude on the geostationary orbit, where it would replace Intelsat 709. It would have 22 K_u band transponders in total and a design life of 15 years. The JSAT payload would be known as JCSAT-85.

On May 1, 2007, Orbital Sciences Corporation (now Orbital ATK) announced that it had been awarded a contract to manufacture Intelsat 15. It would be based on the STAR-2 satellite bus, generate 4.6 kW of power for its 22-transponder K_u band payload and had an expected launch date of early 2009.

On February 26, 2008, Sea Launch announce a contract with Intelsat to launch two satellites manufactured by Orbital Corporation, Intelsat 15 and Intelsat 16. The contract was itself a renegotiation for repurpose two already existing reservation by Intelsat with Sea Launch for two satellites to these new spacecraft. They were expected to be launched by the Land Launch service, which used Zenit-3SLB rockets from the Baikonur Cosmodrome in Kazakhstan, during 2009.

Between October 27 and November 5, 2009 Intelsat 15 was processed in the Baikonur Cosmodrome. On November 6, it was filled with propellant. On November 24, 2009, JSAT announced that the launch of Intelsat 15 was expected on November 29 at 1:00 UTC. But during the launch attempt on November 29, the automatic prelaunch issued an abort command. But the launch committee agreed to make a second attempt on the next day.

On November 30, 2009, at 21:00 UTC, the Zenit-3SLB successfully launched Intelsat 15, from Baikonur Cosmodrome Site 45. After a six and a half hour mission, the DM-3SLB successfully separated the spacecraft and at 03:28 UTC, first signals from spacecraft were received. The launch put the satellite with margins of its planned geosynchronous transfer orbit with a perigee of 10,286 km, an apogee of 35,790 km and a 12° inclination to the Equator.