The European Space Agency ESA and the Alphabus Joint Project Team successfully completed the Qualification Review of one of the world’s largest yet lightest satellite tanks ever built, a new generation of bi-propellant tanks.

Developed and manufactured by MT Aerospace of Augsburg, Germany, under contract to Astrium Space Transportation, Munich, this carbon-fibre overwrapped propellant tank sets new performance standards with an overall volume of up to 1925 liters and a dry mass of less than 85 kg. The first set of two proto-flight tanks already completed successful integration into the chemical propulsion system of the new European Alphabus satellite platform at Thales Alenia Space in Cannes, France.

This milestone completes a 5-year development for the Astrium-led Alphabus chemical propulsion system and for the Alphabus industrial Joint Project Team (JPT) formed by Astrium Satellites, Toulouse, and Thales Alenia Space, Cannes.

“This new propellant tank development is a key equipment for the Alphabus platform,” commented Magali Vaissière, ESA Director of Telecommunications and Integrated Applications. “We are very pleased with MT Aerospace achievements and the good cooperation with the Agency and the industrial partners.”

MT Aerospace, a subsidiary of the European aerospace and technology corporation OHB Technology, was responsible for the development and integration of the tank subsystem. The innovative, high-performance propellant management device was developed under subcontract to Astrium Satellites, Toulouse, and manufactured by MT Satellite Products, a subsidiary of MT Aerospace in Wolverhampton, England.

The Alphabus propellant tanks represent a technology break-through and will enable future large-scale satellites to sustain longer missions and space exploration vehicles to be more efficient. New manufacturing technologies were developed to achieve the large volume within the limited space envelope of the satellite platform and comply with stringent mass requirements.

The tanks are composed of a thin titanium liner, overwrapped with a high-strength carbon fibre, and an integrated equatorial attachment skirt. A surface tension propellant management device allows for exceptionally low propellant residuals. The resulting performance increase and substantial mass savings compared to a conventional all-metallic tank design correspond 1-to-1 in additional payload.

The bi-propellant tanks, compatible with MMH fuel and MON oxidizer, are the largest overwrapped titanium tanks qualified for the aerospace market and have an operational life of 18 years.

Two models are available: The large version with a volume of 1925 liters, holding a propellant mass of up to 2625 kg, and a dry mass of 85 kg. A smaller version with a volume of 1635 liters and a dry mass of 78 kg is also available. Both models are equipped with an equatorial composite skirt as interface to the satellite structure.

The Alphabus platform is designed for communication satellites with a payload power in the range of 12-18 kW, an emerging sector of the high-end performance market. Satellites based on Alphabus will have a launch mass between 6 to 8 tonnes, and will be significantly larger and more powerful than any other satellites built in Europe.

Alphasat, the first satellite built on the Alphabus platform, is foreseen to be launched on Ariane 5 in 2012. Alphabus is being introduced in Astrium and Thales Alenia Space portfolios to cover the upper power range platform product line.