Atlas V launches with WGS SV-1

by Chris Bergin

A United Launch Alliance (ULA) Atlas V (421) has launched with the Wideband Global SATCOM (WGS) SV-1 tonight. Lift-off was on time at 8:21pm Eastern from Launch Complex 41 (LC-41) at Cape Canaveral. Following a 30 minute ride – including two burns of the Centaur upper stage – spacecraft seperation was successful. covered the launch as a live event, with background, live updates, images and a free launch video – available now – on the links below (read more).


**FREE ATLAS V/ WGS SV-1 Launch Video** – Available now Free to all forum members (registration is free – we do not use your e-mail for spam, only to send you your forum password – which is automated.


‘As America celebrates the 60th anniversary of the Air Force, today’s launch of the WGS satellite is a fitting tribute,’ said Jim Sponnick, ULA vice president of Atlas programs. ‘ULA is proud of its continuing role of providing reliable and cost effective assured access to space for the Air Force’s critical missions.

‘The men and women of the ULA team are honored to be continuing the legacy and accomplishments of the Atlas and Thor/Delta teams that first launched these systems in the 1950s,’ Sponnick said.

‘Atlas 4A was the first Atlas launch and it occurred June 11, 1957. It launched from Space Launch Complex 14 at Cape Canaveral, just seven miles from SLC-41, where our Atlas V vehicles are launched today.’

Mission background:

The WGS SV-1 mission marks the eleventh Atlas V launch and the first launch of an Atlas V 421 configuration. The Atlas V 421 configuration utilizes a single Atlas V booster stage, the Centaur upper stage, and two solid rocket boosters (SRB). The Atlas V booster is 12.5 ft in diameter and 106.5 ft long.

Atlas booster propulsion is provided by the RD-180 engine system (a single engine with two thrust chambers). The RD-180 burns RP-1 (Rocket Propellant-1 which is highly purified Kerosene) and liquid oxygen; and delivers 860,200 lb of thrust at sea level.
The Centaur upper stage is 10 feet in diameter and 41.5 feet long. Centaur is a liquid hydrogen/liquid oxygen- (cryogenic) fueled vehicle, which uses a single RL10A-4-2 engine that produces 22,300 lb of thrust.
The WGS SV-1 mission uses the 4-m- (14 ft)-diameter extended payload fairing (EPF). The LPF is a bisector (two-piece shell) fairing consisting of aluminum skin/stringer construction with vertical split-line longerons. The vehicle’s height with the EPF is 192 ft.

The WGS SV-1 payload consists of a single communications satellite. The 2-burn minimum-residual shutdown mission will fly an easterly trajectory from LC-41 with a 93.22 degree flight azimuth. The separation event will release the WGS-SV-1 spacecraft into a supersynchronous transfer orbit with a 250.4 nmi perigee, an apogee no greater than 40,932 nmi, and a 20.33 degree inclination.

‘The WGS SV-1 mission is the first installment of the Wideband Global SATCOM (WGS) system. WGS will be an important element of a new high-capacity satellite communications system that will provide enhanced communications capabilities to our troops in the field for the next decade and beyond,’ said James V. Sponnick, Vice President of Atlas Programs.

‘WGS will enable enhanced and more flexible execution of Command and Control, Communications Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR), battle management, and combat support information. WGS will also augment the existing service available on the UHF F/O satellites by providing additional information broadcast capabilities via Global Broadcast Series (GBS).’

The WGS SV-1 spacecraft (SC) is an approximately 12,718-lb communications satellite. WGS supports communications links in the 500 MHz range of the X-band and 1 GHz range of the Ka-band spectra. WGS can filter and route up to 4.875 GHz of instantaneous bandwidth. Depending on the mix of ground terminals, data rates, and modulation schemes employed, a WGS satellite can support data transmission rates between 2.4 and 3.6 Gbps.

WGS has 19 independent coverage areas that can be positioned throughout its field of view. This includes eight steerable/shapeable X-band beams formed by separate transmit/receive phased arrays; 10 Ka-band beams served by independently steerable diplexed antennas (three with selectable RF polarization); and transmit/receive X-band Earth-coverage beams. WGS can tailor coverage areas and connect X-band and Ka-band users anywhere within its field of view.

Command and Control of WGS is accomplished from four Army Wideband Satellite Operations Centers (WSOCs). Each Global SATCOM Configuration and Control Element (GSCCE) has the capability to control up to three satellites at a time, using X-band or Ka-band telemetry and command links. Spacecraft platform control will be accomplished by the 3rd Space Operations Squadron (3 SOPS) at Schriever AFB in Colorado Springs, CO using WGS mission-unique software and databases.

Support technologies for WGS include the xenon-ion propulsion system (XIPS), highly efficient triple-junction gallium arsenide solar cells, and deployable radiators with flexible heat pipes. The XIPS is 10 times more efficient than conventional bipropellant systems. Four 25-cm thrusters remove orbit eccentricity during transfer orbit operations.

The thrusters are also used to perform orbit maintenance and any required station-change maneuvers during the mission life. The triple-junction gallium arsenide solar cells provide on-orbit electrical power for the spacecraft. The deployable radiators’ flexible heat pipes provide increased radiator area; resulting in a cooler, more stable thermal environment for the spacecraft.

Built by the Boeing Satellite Development Center, WGS will provide essential communications services for Combatant Commanders to command and control their tactical forces. Tactical forces will rely on WGS to provide high-capacity connectivity into the terrestrial portion of the Defense Information Systems Network (DISN).

‘After final checkout and turnover of SV-1, we will have doubled the available high-capacity Military Satellite Communications services,’ said Col. Donald Robbins, Commander, Wideband SATCOM Group, MILSATCOM Systems Wing.

Upon its first launch into geosynchronous orbit in 2007, WGS SV-1 will be the Department of Defense’s highest capacity communications satellite. A constellation of five satellites will provide service in both the X and Ka-band frequency spectrums.

The first three WGS satellites will be launched in 2007 and 2008. Both the Delta IV and Atlas V Evolved Expendable Launch Vehicles (EELV) will be used. Satellites 4 and 5 are anticipated for launch in 2011 and 2012.

‘With the launch of WGS SV-1, we are on the cusp of providing more capacity than the entire on-orbit Defense Satellite Communications System constellation,’ Col. Robbins added. ‘I am extremely proud of the hard work and dedication of the launch team.’

Related Articles