New Orbital Slot

With the launch of the ASTRA 2A satellite in 1998, Société Européenne des Satellites (SES) broadened its reach to more of Europe. The satellite, built by Hughes Space and Communications Company (HSC), today known as Boeing Satellite Systems, Inc., is a Hughes 601HP body-stabilized model. It was the sixth Hughes spacecraft to be launched for the SES fleet, and was specifically designed for SES' second orbital slot of 28.2 degrees East longitude, to serve the United Kingdom.

SES ordered its first Hughes 601 satellite, called ASTRA 1C, in late 1990. That was followed in late 1991 by an order for ASTRA 1D; in 1992 for ASTRA 1E; in 1993 for ASTRA 1F; in 1994 for ASTRA 1G; in 1995 for ASTRA 1H; and in 1996 for ASTRA 2A. ASTRA 1G was the first in the series with the Hughes 601HP (for high power) configuration. ASTRA 2A is nearly identical, but was optimized for use at 28.2 degrees East instead of SES' primary orbital slot of 19.2 degrees East.

Stowed (left); In Orbit (right)

The satellites enable SES to provide analog and digital television programs together. Because each spacecraft provides an effective isotropic radiated power (EIRP) typically 51 dBW, these satellites deliver video and audio signals strong enough to be received by 60-cm dishes.

The ASTRA satellites are similar in appearance to other Hughes 601 models, with each having a cube-shaped body and two solar array wings oriented along its north-south axis and the antennas located on the east-west axis. All the satellites operate in Ku-band and use traveling-wave tube amplifiers (TWTAs) for power. On ASTRA 2A, it's 98.5 watts. ASTRA 2A offers a minimum of 28 active transponders with 32 being available for the first five years.

All Hughes 601 spacecraft use the same basic bus design, allowing HSC to realize efficiencies gained by production volume, tooling investments and quantity buys. HSC introduced the 601 in 1987, and it has become the world's best-selling large satellite model, with more than 70 ordered. The "classic" Hughes 601 model, with silicon solar panels, provides up to 4-5 kilowatts total spacecraft power. The 601HP version uses gallium arsenide solar panels and other technological advances to provide as much as 10 kilowatts.

On the spacecraft, a flight-proven bipropellant propulsion system with an integral 490-Newton (110-lbf) Marquardt liquid apogee motor and 12 thrusters provides the impulse to achieve and maintain the orbit and attitude necessary for geosynchronous operation. ASTRA 2A also carries Hughes' xenon ion propulsion system (XIPS).

SES, founded in 1985, is the privately owned operator of Europe's leading satellite system for direct-to-home reception of analog and digital TV and radio services and multimedia content.

Boeing Satellite Systems is the world's leading manufacturer of commercial communications satellites, and a major provider of space systems, satellites and payloads for national defense, science, and environmental applications.