Tenders Are Invited For Measurement And Modelling Of The Attitude Of Metop And Sentinel 1 To Prepare

Tenders are invited for Measurement and Modelling of the Attitude of Metop and Sentinel 1 to Prepare for Erase Phase a - Expro+ Summary Description The proposed activity is will support the preparation for the ERASE Phase A. ERASE aims to prepare the removalof large, non-cooperative and unprepared objects in low Earth orbit, initially considering Metop and Sentinel-1 targets (starting with METOP-A and S1B, both being decommissioned), thereby supporting ESAs Space Safety Programme and the transition towards a circular economy in space. This activity will establish and demonstrate ground-based laser-ranging measurement, modelling and analysis capabilities to characterise the attitude state and tumbling behaviour of non-cooperative, unprepared targets, with initial focus on Metop and Sentinel-1 targets. The output is essential and urgent for the ERASE Phase A study. Without this information available at the start of Phase A, there is a risk that the technical feasibility of the mission is incorrectly assessed. The target spin rate is adesign driver for the servicer delta-V and operations timeline, the relative navigation subsystem, and the robotic capture sizing and loads. The spin-axis orientation drives the safe approach direction and the capture strategy. In addition, the probability of very low spin-rate cases must be understood, as such cases may lead to long durations in unfavourable attitude conditions for target power generation, thermal control and ground contact. The challenge is that the targets are not prepared with cooperative markers or laser retro-reflectors that would facilitate attitude reconstruction. The attitude state must therefore be reconstructed from non-cooperative laser-ranging observables, making use of time-of-flight/range measurements, return-signal characteristics, pass geometry, target geometry, known or estimated surface properties, and attitude-dynamics modelling. Where beneficial, the laser-ranging data maybe complemented by passive optical or radar observations.The activity will assess the feasibility, achievable accuracy and uncertainty of attitude determination and dynamics-based propagation from ground. It will characterise and propagate target dynamics, in particular spin rate and spin-axis orientation, and will provide statistically meaningful uncertainty envelopes for ERASE Phase A design trade-offs. The activity will also prepare the capability to perform repeated attitude characterisation campaigns in support of ERASE. The attitude state of non-cooperative targets may evolve over time due to environmental torques and target-specific dynamics; therefore, measurements may be required not only during the present feasibility phase, but also before launch, to confirm that the target conditions remain within the design assumptions, and potentially at intermediate points during mission preparation. A dedicated task will assess the applicability of the developed measurement and modelling methods to a broader range of large, unprepared, non-cooperative low Earth orbit targets beyond Metop and Sentinel-1, identifying the key target properties, observation conditions and limitations that determine feasibility.Read more Tender Link : https://esastar-publication-ext.sso.esa.int/ESATenderActions/filter/open