ELASTIC TETHER DESIGN AND DYNAMIC TESTING – EXPRO PLUS
8, April 2015

ESA Open Invitation To Tender AO8258
Open Date: 03/04/2015
Closing Date: 15/05/2015

Status: ISSUED
Reference Nr.: 14.129.17
Prog. Ref.: TRP
Budget Ref.: E/0901-01 – TRP
Special Prov.: B+DK+F+D+I+NL+E+S+CH+GB+IRL+A+N+FIN+POR+GR+LUX+CZ+RO+PL
Tender Type: C
Price Range: 200-500 KEURO
Establishment: ESTEC
Directorate: Directorate of Technical & Quality Manag
Department: Mechanical Engineering Department
Division: Mechatronics and Optics Division
Contract Officer: Wesolowski, Szymon
Last Update Date: 03/04/2015
Update Reason: Tender issue

The activity proposes to design an appropriately light and strong tether that is also extremely elastic, and to test its strength and elastic properties in a laboratory. Active Debris Removal is an important branch of the Clean Space initiative within ESA. A number of technologies (net, harpoon, mini-spacecraft with robotic arms) have been proposed and are currently investigated for capturingspace debris that all rely on subsequently “towing” the debris using a tether. Common for all of these is the need for designing thetether. Thorough simulations during internal studies within the agency have shown that a very elastic tether will significantly help during the deorbit burn in a number of ways. Firstly the elasticity will decrease controller bandwidth requirements, it will alsoreduce the impulse transferred to the spacecraft when the deorbit engines are first switched on, and finally they can be shown to significantly improve the ability to recover to a controlled situation at the end of a burn – something that is critical for a multi-burn deorbit strategy. Commercial shock cords are commonly used to more heavy ships. They achieve both strength and elasticity (up to50% extension in length) by combining a strong and inelastic weave outside an elastic core. The activity proposes to look at options of using different weaves or combination of materials to design a tether that acts like a commercial shock cord. The main challenge is envisaged to be able to do so while still keeping weight and volume low. The activity will comprise:
Investigation and trade-off of different material and weave combinations. Design and manufacture of one or two sample tethers. Extensive testing of thesample tether(s) for dynamic and static properties. Procurement Policy: C(1) = Activity restricted to non-prime contractors (incl. SMEs). For additional information please go to EMITS news “Industrial Policy measures for non-primes, SMEs and R&D entities in ESA programmes”.

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