Executive Summary: a fifth WAAS satellite is now in orbit, but won't be likely to be operational until 2018.
On May 17, 2017 the SES-15 satellite was successfully launched from the Centre Spatial Guyanais in French Guiana.
SES-15's owner-operator is SES, a private company founded in 1985 in Luxembourg as the first European private satellite operator. In 2001 SES acquired GE AMERICOM and its thirteen satellites over North American, becoming SES AMERICOM. In 2011 the single branding of SES was implemented. By 2013 SES had 55 spacecraft in orbit, including many government spacecraft, particularly for the United States.
SES-15 was launched by ArianeSpace, founded in 1980 as the world's first private satellite launching company. They operate the space launch facility in French Guiana, in the Amazon jungle, near the equator.
SES-15 was carried aloft by a Soyuz ST-A (Soyuz 2-1a) rocket manufactured by Progress State Research and Production Rocket Space Center in Samara, Russia. The first stage consists of four boosters around a core rocket, with each booster powered by the RD-107A engine. After about two minutes of flight, the four boosters are jettisoned, and the core stage continues to burn as the second stage.
After about five minutes of powered flight, the core second state exhausts its propellant, and separates from the upper part of the rocket and the remaining payload. The third core stage, powered by an RD-0110 engine, ignites and continues to propel the rocket into space. At about nine minutes into the powered flight, the third stage is jettisoned, leaving the upper stage and satellite payload.
The upper stage ignites its Fregat rocket engine and continues lifting the satellite into a preliminary elliptical transfer orbit. At about 23.5 minutes into the flight, the Fregat engine is shut down, and the rocket and satellite coast in orbit for about four-and-a-half hours. The satellite is then likely in a elliptical orbit. The coasting phase waits for the satellite's orbit to reach a particular location when further propulsion will be very useful in modifying the orbit.
At nearly five hours into the flight the Fregat rocket engine is re-ignited for a short duration burn of approximately 50-seconds, to push the satellite payload toward a final circular orbit deployment. At this point the rocket and satellite separate, leaving the SES-15 satellite on its own. SES-15 will now execute the final orbital maneuvers to reach its ultimate geo-stationary orbit position by using its on-board all-electric ion drive system. This will take several months for the satellite to raise its orbit into the proper parameters and to work its way to its final location.
SES-15 was built by Boeing and is a Boeing 702SP (small platform) all-electric propulsion satellite that utilizes the xenon ion propulsion system (XIPS) for both orbit-raising and on-orbit maneuvering.
The Federal Aviation Administration have a hosted payload aboard SES-15 for a GPS space-based augmentation system (SBAS) payload for their Wide Area Augmentation System (WAAS) for aviation over North America. This hosted payload portion of SES-15 is referred to as GEO6 by the FAA.
The final geostationary orbital longitude for SES-15 is at 129-degrees-W longitude. This location will be four-degrees East of the present WAAS satellite carried on CRW or Galaxy 15 at position 133-degrees-W longitude. According to SPACEFLIGHTNOW.COM
The ascent profile for Thursday’s launch placed the SES 15 satellite closer to its final perch in a circular geostationary orbit, where the spacecraft will loop around Earth’s equator at an altitude of nearly 22,300 miles (35,800 kilometers), the exact distance needed to move in concert with the planet’s rotation.
The unusual timing of the second Fregat firing will help shave several weeks off the time it will take to transition SES 15 into service, officials said.
The low-thrust xenon-ion jets on SES 15 will be activated in the coming weeks to nudge the satellite toward its final operating post. The orbit-raising maneuvers will take around 190 days to complete, according to Halliwell, and SES 15 should be operational by the end of December at 129 degrees west longitude.
The electric thrusters take longer to move between orbits than the conventional liquid-fueled engines carried by most communications spacecraft, but the tradeoff makes for a lighter satellite without giving up any capability. Without a heavy propellant tank, a satellite with the same broadcast capacity can launch on a smaller, less costly rocket.
With the SES-15 in orbit, the satellite's systems will have to be activated and verified. The GEO6 WAAS hosted payload will likely not be fully operational until 2018.
The actual WAAS transponder hosted payload was (apparently) built by Raytheon. In a press release a few days ago, Raytheon said, rather glibly, "Raytheon Company launched its GEO 6 satellite payload into orbit for its 12 year mission." That statement seems to ignore primary satellite owner and operator (SES), launch provided (ArianeSpace), rocket manufacturer ("Soyuz"), and host satellite manufacturer (Boeing). The WAAS transponder is bolted to the SES-15's nadir deck, and will depend on the SES-15 for its power and other subsystems. It seems a bit misleading to characterize Raytheon's role as it was described in their press release. Their payload more or less went along for the ride.