ESA Intended Invitation To Tender


Program ref.: TRP
Tender Type: C
Quarter: 183
Tender Status: INTENDED
Price Range: 200-500 KEURO
Budget Ref.: E/0901-01 - TRP
Proc. Prop.: NO
Establishment: ESTEC
Department: Product Assurance and Safety Department
Division: Materials & Components Technology
Industrial Policy Measure: N/A - Not apply
Publication Date: 18-MAR-16

For spacecraft systems and subsystems, particulate contamination can cause a number of problems such as obscuration, absorption andemittance changes, scatter from optics, noise on electrical contacts and short circuits. It is therefore required that particulate contamination is controlled under maximum allowable levels, which are derived from performance-loss and failure-preventions analyses. Typically, during the design phase, prediction budgets are established and are maintained until launch as part of the contamination control activities. The prediction budgets are preliminary built on assumptions derived from the experience gained on past projects. The prediction budgets are then consolidated with measurements performed in the controlled environment of the actual AIT. In manycases, the major uncertainty of the particulate predictions are those related to the pre-launch and launch environments. In these specific cases, particle fallout is difficult if not impossible to measure, with the current available techniques, and therefore the experience on which predictions budgets can be build is very poor. However, S/C projects are requesting more and more this uncertainty to be resolved, as the verification of maximum acceptable contamination levels and the implementation of design control measures can only be supported by reliable predictable budgets, which today contain a big question mark for the launcher contribution. The objective of the proposed activity is to develop a modelling technique and tool to predict particulate fall-out inside fairings prior to launch and during launch, and to perform related tests aiming at determining the necessary inputs and at correlating the modelling. For the pre-launch phase, the main goal is to predict the motion of particles inside fairings under ventilation with payloads integrated; this should take into account the geometry of the fairing including the position of ventilation inlets and outlets, the geometry of the payload, ventilation flow-rate, ventilation gas purity. For the launch phase, the main goals are to predict the behaviour of particles present onto internal fairing's surfaces, including the Payload and its interfaces to the fairing, when subjected tothe loads of the launch, and to predict their motion and the motion of particles in the gas volume present inside the fairing priorto launch, during and after launch. This should consider the above parameters, valid for the pre-launch phase, mechanisms of particles' detachment from different surfaces, and the transition from viscous to molecular regimes. In particular, testing is expected for determining/confirming the mechanisms of particles' detachment, and more in general, for the validation of the whole modelling technique/tool. Finally, it is also expected that the modelling tool will provide the capability to assess and optimise alternatives toexisting fairings' configurations, e.g. by modifying venting paths, aiming at mitigating the risks associated to particulate contamination.