29, April 2021

ESA Open Invitation to Tender: 1-10410
Open Date: 26/04/2021 12:00 GMT +3
Closing Date: 07/06/2021 13:00 GMT +3

To characterize the performance and limits of new intersecting-spheres tank design aiming to reduce mass of small upper stages and landing vehicles.Launch vehicle tanks cover the whole cross section of the vehicle and are large enough for humans to work in during production. This structural tank, where it not only sustains its inner pressure and propellant mass acceleration loads, but is also part of the vehicle’s global load path, achieves the best mass fractions for large tanks.Spacecraft tanks, that sustain only internal pressure and propellant mass acceleration loads, are supported by the satellite’s primary structure, often in a 2 by 2 arrangement. Access to the inner volume of these tanks during their production is limited to small inspection ports.For small upper stages(e.g. Vega AVUM), as well as landers, (6 m to 10 m tank volume), both concepts fail to provide attractive dry mass fractions. Lunar landing vehicles require a large propulsion system (delta V requirements, gravity losses) and the needed structure can be over 60% of the spacecraft dry mass.The concept of welding of six or eight spherical tanks into a ring has been successfully applied for an intermediate size range (e.g. Soyuz Fregat upper stage). It provides a very stable tank structure, allowing them to also act as primary structure and to attach an equipment directly to the tanks.The welding of two tanks together with a single wall, double wall and the required inspection methodology are considered very critical, as any leak of the hypergolic propellants would immediately lead to an explosion of the spacecraft.This activity aims to develop and demonstrate the capability of producing intersecting-spherestanks, and ensuring the cleanliness and permeation/leak tightness can be achieved to allow hydrazine and corresponding oxidizer loading into adjacent tank spheres.The activity encompasses the following tasks:- perform an initial design of a two compartments intersecting-spheres aluminium tank, optimizing dimensions, mass and external loads capability,- trade-off welding technologies, develop and build a clamping system, considering accessibility restrictions,- demonstrate its function by producing a tank (intersection) breadboard,- assess, adapt and demonstrate on the breadboard cleaning and non-destructive inspection processes- carry on destructive testing of the breadboard to confirm its mechanical strength.- update the initial design and assess improvement vs conventional satellite tanks (e.g. dry mass efficiency).

Estabilishment: ESTEC
ECOS Required: No
Classified: No
Price Range: 200-500 KEURO
Contracts Officer: Maximilian Garre
Initiating Service: TEC-MPC
IP Measure: N/A
Prog. Reference: E/0901-01 – Technology Developme
Tender Type: Open Competition
Technology Keywords: 19-A-I-Liquid Propulsion Systems / 20-A-I-S/C Design and Design Tools / 20-A-II-Analysis Tools and Methodologies / 20-A-III-Testing Tools and Methodologies
Products Keywords: 1-G-1.1-a-Propellant Tanks *See Structures / 1-I-3-Propellant tanks / 2-K-1.1-c-Tanks *See Structures / 2-N-all.1-d-Propellant tanks

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