JCSAT-4 was known as JCSAT-R until it was sold to Intelsat in 2009 (Intelsat 26). It is 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 was used as an on orbit spare.^[4][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).^[4] Its power system generated approximately 5 kW of power due to two wings with four solar panels each.^[5][4] It also had a single NiH₂ battery composed of 30 cells and a 200 Ah charge.^[4] It would serve as on orbit backup for the JSAT fleet.^[4]

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.^[4] 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.^[5][4] Eight of the 36 MHz and the sixteen 27 MHz Ku-band transponders have a TWTA output power of 63 watts, the other four 36 MHz ones have 95 watts. It can configure four 27 MHz transponders into a single 54 MHz with an effective 125 watts.^[4] The twelve C-band transponders have 36 MHz bandwidth and 34 watts of power.^[4]

In December 1995, JSAT ordered its fourth satellite from Hughes, and second of the HS-601 platform, the JCSAT-4. It was an almost copy of the JCSAT-3, also based on the HS-601, but with more powerful transponders. It would have a mixed Ku-band and C-band payload, a power generation capability of 5000 watts and a 12 year of design life. It was expected to be delivered by early 1997 and be positioned at the 124° East longitude. It would provide telecommunications and television services to Japan, all of Asia, Hawaii and Australia and New Zealand.^[4][6]

On 25 March 1996, International Launch Services (ILS) announced a contract with JSAT for the launch of JCSAT-4 aboard an Atlas IIAS. At the time it was expected to launch in January 1997 from Cape Canaveral at LC-36A launch pad. This was the second contract of ILS with JSAT after the successful launch of JCSAT-3 in August 1995.^[7]

On 18 February 1997 at 01:42:02 UTC, and Atlas IIAS launched from Cape Canaveral LC-36B with JCSAT-4 towards a geosynchronous transfer orbit (GTO).^[8] After the successful launch, it was renamed JCSAT-R. During its tenure as JCSAT-R it operated on the 124° East longitude.^[4] In August, 2008, JSAT was merged into the SKY Perfect JSAT Group.^[9]

In late 2009, Intelsat bought JCSAT-R and rechristened it Intelsat 26.^[10][4] In March 2010, Intelsat announced an agreement with Türksat for loaning Intelsat 26 so the latter could keep its orbital rights until a new satellite could be launched.^[10] In July 2010, it was positioned at the 50° East longitude with a 3.4° inclination.^[11] In January 2013, the inclination had increased to 4.6°.^[12] In August 2016, the satellite was positioned at 64.1° East with a 6.97° inclination.^[13][3]