STAR ONE C4

Star One C4 is a Brazilian geostationary communications satellite that has been providing telecommunications services from equatorial orbit since mid-2015. Operated by Star One, a subsidiary of the Brazilian telecommunications company Embratel, it represents part of Brazil's broader effort to develop and sustain domestic satellite communications infrastructure. The spacecraft was catalogued by United States Space Command under NORAD ID 40733 and carries the international designator 2015-034B, marking it as the second payload released during its launch mission. It remains in service as of the most recent catalog update, occupying a stable position high above the equator.

Mission and Purpose

Star One C4 was conceived to expand Brazil's capacity for satellite-based communications services, a strategic priority for a country of continental proportions where terrestrial networks face significant geographic challenges. Brazil's vast interior, its sprawling Amazon basin, and its dispersed coastal communities create persistent demand for satellite-delivered connectivity, broadcasting, and data relay services. Geostationary satellites like Star One C4 are especially well suited to addressing these needs, since a single spacecraft parked at orbital altitude can maintain continuous line-of-sight contact with a very large portion of the Earth's surface below it without any need for complex ground-tracking infrastructure.

Star One is the satellite operations arm of Embratel, itself one of Brazil's most prominent telecommunications carriers. The Star One fleet has historically served as the backbone for Brazilian direct-to-home television broadcasting, corporate data networking, government communications, and internet delivery to remote areas. Star One C4 was developed to supplement and expand on the capacity provided by earlier satellites in the C-series fleet, bringing additional transponder bandwidth to meet growing demand across Brazil and, depending on its coverage footprint, potentially across neighboring South American territories and portions of the Atlantic.

Although the specific mission parameters and payload configuration of Star One C4 are not enumerated in publicly available catalog records — including its transponder count, frequency bands, or detailed service agreements — the satellite's orbital position and operator identity are consistent with a commercial communications role oriented toward the Brazilian and broader South American market. INPE, the Brazilian National Institute for Space Research, is listed in tracking records as the operator, reflecting the institutional role that Brazilian government space agencies play in the management and coordination of national orbital assets, even when day-to-day commercial operations are conducted by a subsidiary like Star One.

Orbit and Tracking

Star One C4 occupies a geostationary orbit, placing it among the most strategically important class of Earth-orbiting spacecraft. Its current tracked orbital parameters confirm a near-perfect geostationary configuration: an apogee of 35,804 km and a perigee of 35,785 km, yielding an orbit that is almost perfectly circular at geostationary altitude. The inclination is recorded at 0.0°, meaning the satellite's orbital plane aligns precisely with Earth's equatorial plane — a defining characteristic of a fully operational geostationary spacecraft. Its orbital period of 1,436.1 minutes corresponds to almost exactly one sidereal day, the duration that causes the satellite to remain essentially stationary relative to a fixed point on the ground below.

This combination of near-zero eccentricity, equatorial inclination, and 24-hour period means that ground stations and receivers pointed at Star One C4 do not need to track or reposition their antennas once they have been correctly aimed. This is a fundamental advantage for broadcast and telecommunications applications, where large numbers of small, fixed consumer antennas must reliably lock onto the same point in the sky at all times.

The satellite was assigned NORAD catalog ID 40733 and international designator 2015-034B. The "B" suffix in the COSPAR designation indicates it was the second object to be separated and catalogued from the 2015-034 launch event, consistent with the dual-payload Ariane 5 mission on which it flew. As of the most recent catalog data, Star One C4 remains in orbit with no decay or reentry date recorded, which is the expected status for a functioning commercial geostationary satellite managed by an active operator.

Because geostationary satellites orbit at extremely high altitude — roughly 35,786 km above the equator on average — they are not candidates for naked-eye observation and are not listed among satellites of interest for visual tracking by amateur observers. At such distances, even large spacecraft with reflective surfaces are too faint to detect without optical assistance. Star One C4 therefore does not have a "How to Spot It" entry in this article.

Design and Operator

Star One C4 was manufactured by Space Systems/Loral (SSL), an American satellite manufacturer with a long track record of producing commercial geostationary communications spacecraft. The satellite was built on the SSL 1300E bus, a variant of the widely deployed SSL-1300 platform. The SSL-1300 series has been one of the most commercially successful geostationary satellite bus designs of its era, known for its modularity, substantial payload capacity, and ability to support a wide range of transponder configurations. The "E" variant designation indicates a specific configuration within the SSL-1300 family, though detailed mass and power figures for Star One C4's specific build are not recorded in the public tracking catalog.

The satellite's mass is not publicly specified in catalog records available to this database, which is not unusual for commercial spacecraft where operators may choose not to publish precise technical specifications. Similarly, the exact payload configuration — including transponder count, frequency bands, and effective isotropic radiated power — is treated as proprietary commercial information by Embratel and Star One, and is therefore not reproduced here.

Star One, as the operational arm of Embratel, brings considerable experience to the management of geostationary satellite assets. Embratel itself has roots going back to Brazil's early telecommunications development and has long been intertwined with the national ambition to establish an independent satellite communications capability. The C-series satellites under the Star One brand have represented successive generations of capacity expansion, with Star One C4 continuing that trajectory by adding orbital resources in Brazil's geostationary arc allocation.

Launch and Deployment

Star One C4 was launched on 15 July 2015, with liftoff occurring at approximately 21:05 UTC. The launch vehicle was an Ariane 5 ECA, operated by Arianespace from the Guiana Space Centre in Kourou, French Guiana. The Ariane 5 ECA is a heavy-lift variant of the Ariane 5 family optimized for dual-payload commercial geostationary missions, routinely delivering two satellites per flight to reduce per-kilogram launch costs for operators. Star One C4 shared its ride to orbit with MSG-4, the fourth spacecraft in the Meteosat Second Generation series operated by EUMETSAT for European weather observation. The pairing of a South American telecommunications satellite with a European meteorological satellite illustrates the routine commercial practice of combining compatible payloads on a single Ariane 5 mission.

The launch date reflected in official tracking databases is recorded as 14 July 2015 in UTC-offset terms depending on time zone reference, but the physical liftoff took place on 15 July 2015 UTC, consistent with standard Arianespace mission documentation. After separation from the launch vehicle's upper stage, Star One C4 would have undergone a series of apogee engine firings to circularize its orbit from the transfer ellipse provided by the Ariane 5 into the near-circular geostationary orbit it now occupies. This orbit-raising process typically takes several weeks and requires careful monitoring and control by the manufacturer and operator before the satellite is handed over for commercial service.

Current Status and Significance

Star One C4 continues to be tracked in a stable geostationary orbit, with no reentry or decay event on record. Its orbital parameters remain consistent with active station-keeping, the regular small thruster firings that geostationary satellite operators perform to counteract the natural perturbations — primarily caused by the gravitational influences of the Moon and Sun as well as slight asymmetries in Earth's gravitational field — that would otherwise cause a geostationary satellite's inclination and longitude to drift over time. The 0.0° inclination recorded in current tracking data is a direct indication that active station-keeping is being maintained.

For Brazil, Star One C4 represents a meaningful increment in national geostationary satellite capacity. Geostationary orbital slots are allocated through international coordination processes managed by the International Telecommunication Union, and Brazil's ability to occupy and operate assigned slots with domestically contracted spacecraft reinforces its standing as a significant space-faring nation within the Latin American region. The continued operation of the Star One fleet, with C4 as one of its members, underpins a wide range of services that Brazilian consumers, businesses, broadcasters, and government agencies depend upon — particularly in areas of the country where terrestrial infrastructure is sparse or economically impractical to deploy. As long as the spacecraft retains sufficient fuel for station-keeping and its onboard systems remain functional, Star One C4 is expected to continue serving its operational role for the remainder of its designed service life.