JCSAT-3 was a geostationary communications satellite designed and manufactured by Hughes (now Boeing) on the HS-601 satellite bus. It was originally ordered by JSAT Corporation, which later merged into the SKY Perfect JSAT Group. It has a mixed Ku-band and C-band payload and operated on the 128° East longitude until it was replaced by JCSAT-3A.^[2]

The spacecraft was designed and manufactured by Hughes on the HS-601 satellite bus. It had a launch mass of 3,105 kg (6,845 lb), a dry mass of 1,841 kg (4,059 lb) and a 12-year design life. When stowed for launch, its dimensions were 2.8 m × 4.9 m × 3.8 m (9 ft 2 in × 16 ft 1 in × 12 ft 6 in). With its solar panels fully extended it spanned 26.2 m (86 ft), and its width when its antennas were fully deployed was 7.5 m (25 ft).^[2] Its power system generated approximately 5 kW of power thanks to two wings with four solar panels each.^[2][3] It also had a single NiH₂ battery composed of 30 cells and a 200 Ah charge.^[2] It would serve as the main satellite on the 128° East longitude position of the JSAT fleet.^[2]

Its propulsion system was composed of an R-4D-11-300 liquid apogee engine (LAE) with a thrust of 490 N (110 lb_f). It also used had 12 22 N (4.9 lb_f) bipropellant thrusters for station keeping and attitude control. It included enough propellant for orbit circularization and 12 years of operation.^[2]

Its payload is composed of four octagonal antenna fed by twelve 36 MHz and sixteen 27 MHz Ku-band plus twelve 27 MHz C-band transponders for a total bandwidth of 1296 MHz.^[2] The Ku-band transponders have a TWTA output power of 63 watts while the twelve C-band transponders have 34 watts of power.^[2]

In 1993, Japan Communications Satellite Company and Satellite Japan Corporation merged to form Japan Satellite Systems Inc. (JCSAT).^[4] That same year, JCSAT ordered JCSAT-3, a third satellite from Hughes, but this time using the HS-601 platform.^[2] In 1995, JCSAT obtained a license for international service, and thus became a regional operator.^[4]

On 29 August 1995 at 00:53:02 UTC, an Atlas IIAS launching from Cape Canaveral LC-36B successfully launched JCSAT-3 into orbit. It was positioned into the 128° East orbital longitude.^[2]

On 20 April 2004, JSAT ordered a second satellite from Lockheed Martin, JCSAT-10. Based on the A2100-AX satellite bus, it would have a C-band and Ku-band payload and was expected to replace JCSAT-3 at the 128° East orbital longitude after its planned 2006 launch.^[5] On 11 August 2006, an Ariane 5 ECA launched JCSAT-10 (JCSAT-3A) along Syracuse-3B into a transfer orbit. Upon successful deployment at 128° East longitude, it was renamed JCSAT-3A.^[6] In March 2007, JCSAT-3 was retired and decommissioned.^[7][8]