13, April 2018

ESA Open Invitation to Tender AO9169
Open Date: 06/04/2018
Closing Date: 18/05/2018 13:00:00

Status: ISSUED
Reference Nr.: 17.1EC.03
Prog. Ref.: Technology Developme
Budget Ref.: E/0901-01 – Technology Developme
Tender Type: C
Price Range: 200-500 KEURO
Products: Satellites & Probes / AOCS & GNC / Guidance Navigation Control (GNC) / Other
Techology Domains: Space System Control / Control Systems Engineering / AOCS/GNC Architecture
Establishment: ESTEC
Directorate: Directorate of Tech, Eng. & Quality
Department: System, Software & Technology Department
Contract Officer: Seynaeve, Christophe Rene R.
Industrial Policy Measure: N/A – Not apply
Last Update Date: 06/04/2018
Update Reason: Tender issue

The objective of this activity is to identify methods and techniques to control spacecraft with very high demanding pointing requirements that use active SAR antennae structures.The motivation for this initiative is driven by the need of future Earth Observation spacecraft for which needs have been identified for having instrumentation mounted at the end of 2 symmetric booms each with a length of approximately 15- 20 meters. The bending of these booms must be less than 10 micro-meters tip relative to tip under normal attitude control of the platform itself. To achieve this high performance, advance multivariable methods and techniques are needed.The study shall ultimately be able to achieve the requirements stated in the motivation above. This can be structured in sub-objectives as follows:- Identify relevant control methods,.- Identify methods for active control of structures with possible distributed networks of sensors and actuators.- Identify credible verification means of the feasibility of the controller design – Identify methods to test a prototype in the laboratoryMethods of active structure control shall be investigated and applied to the problem above.The types of sensors and actuators shall be identified and their distribution along the structure shall be developed. This should lead to an optimum network of possibly collocated sensors and actuators over the structure. The solution shall ensure controllabilityand observability for all the locations of interest and having performance metrics attached. Further shall the design ensure a minimum of interaction with the rest of the spacecraft as well as ensuring a structural integrity along the beams.It is proposed not torely entirely on simulations, but to test a prototype in the laboratory. This can be done on a scaled model of the system. A scaledbeam structure shall be constructed and have all actuators and sensors implemented as well as the rest of the avionics hardware or functional equivalents. This can then be mounted on robot spacecraft on an air-bearing table having sufficient degree of freedom. The advantage of the hardware testing is that effects difficult to model can be part of the proof of concept as well as external measurements with high precision can easily be employed for verification and validation.

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