Alphabus fact sheet (PDF) - ESA Telecommunications

Increasing European Capability
With the Alphabus product line, European
industry is extending its telecommunication
satellite range significantly beyond the
capabilities of the existing platforms, such as
Eurostar 3000 and Spacebus 4000, in term of
maximum payload power, thermal dissipation
and mass.
This development, led by ESA and the French space agency, CNES, is the coordinated
European response to an increased market demand for larger telecommunication payloads
for direct-to-home TV broadcasting, Digital Audio Broadcasting, Broadband Access, Fixed
and Mobile Services with the highest power capacity of the market.
Based on their extensive experience in this field, Astrium and Thales Alenia Space are
leading, as prime contractors, the Alphabus industrial team.
The Alphabus platform is marketed by these companies to extend their portfolio into the
high-end satellite market with extended payload accommodation.
Alphabus product line
This new multi-purpose platform targets the high power payload telecommunication
satellite market. It allows customers to take full benefit of the capabilities of the new
generation of commercial launchers with 5 m-diameter fairings, both with respect to
payload volume and launch mass, while maintaining compatibility with a 4 m-diameter
fairing when needed.
A wide range of commercial payloads to provide television broadcast, multimedia, Internet
access, and mobile or fixed telecommunication services can be accommodated on
Alphabus.
The Alphabus product line covers the following capabilities:
Life time:
15 years
Payload power:
up to 22 kW (conditioned power)
Satellite mass:
up to 8.8 tonnes (at launch)
Payload mass:
up to 2000 kg
Typical payload capacity: up to 230 transponders, equivalent to more than 1000
television channels (SDTV) and more than 200 000 audio
channels.
In addition to carrying large and powerful satellite communication payloads, Alphabus has
enough capacity and resources to accommodate hosted payloads

Alphabus Product line Key Features
Structure
o Spin-formed carbon fibre central
tube and additional carbon and
aluminium panels
o Cross section: 2800 x 2490 mm
o Launcher Interface: 1666 mm
Modular concept
o Antenna module for easier
antenna accommodation and
efficient assembly and test
Attitude and orbit control
o Gyros
o Star and Sun sensors
o Reaction wheels
Data handling through 1553 bus
for payload control
Chemical propulsion
o Apogee engine and 16 thrusters
o 2 propellant tanks (with up to
4200 kg of bi-propellants)
o Helium tanks (3 x 90 litres)
Electrical propulsion
o Xenon tanks (max. 350 kg)
o PPS 1350 thrusters on
orientation mechanisms
Power generation and distribution
o 2 gallium arsenide solar wings
with 4–6 panels
o Power supply and power
distribution offering both 100 V
and 50 V regulated buses
o Modular lithium-ion battery
The Alphabus design takes full advantage of the experience gained through the Eurostar
and Spacebus product range, complemented by several new developments to improve the
overall platform performances. As a result, Alphabus is a mix of strong heritage and
innovation. The product line relies on qualified European technologies.
European cooperation
Alphabus is a cooperative programme between ESA and CNES for a new satellite platform
jointly developed by Astrium and Thales Alenia Space.
The development of the product line and production of a first proto-flight Alphabus was
performed as a four-party undertaking with a joint ESA and CNES customer team and the
prime contractors Astrium and Thales Alenia Space. Alphabus was qualified at the end of
2010.
The Alphabus proto-flight model will fly within the Alphasat programme with Inmarsat,
allowing an early in-orbit demonstration and validation of the platform. It passed its
acceptance review on 16 June 2011. The Alphasat I-XL launch is scheduled for the first
quarter of 2013 on Ariane 5.
Alphabus is now part of the Astrium and Thales Alenia Space industrial product line, and is
being offered on the world market.
ESA Media Relations Office
Tel: +33 1 53 69 71 55
Fax: +33 1 53 69 76 90
Email: media@esa.int Last updated: 10 June 2011