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Record Details

Record 14 of 1564
Changes in Polymeric Tether Properties Due to Atomic Oxygen
Author and Affiliation:
Finckenor, Miria M.(NASA Marshall Space Flight Center, Huntsville, AL, United States)
Vaughn, Jason A.(NASA Marshall Space Flight Center, Huntsville, AL, United States)
Watts, Edward W.(Qualis Corp., Huntsville, AL, United States)
Abstract: The Propulsive Small Expendable Deployer System (ProSEDS) mission is designed to provide an on-orbit demonstration of the electrodynamic propulsion capabilities of tethers in space. The ProSEDS experiment will be a secondary payload on a Delta II unmanned expendable booster. A 5-km conductive tether is attached to the Delta II second stage and collects current fiom the low Earth orbit (LEO) plasma to facilitate de-orbit of the spent stage. The conductive tether is attached to a 10-km non-conductive tether, which is then attached to an endmass containing several scientific instruments. Atomic oxygen (AO) erodes most organic materials. As the orbit of the Delta II second stage decas, the AO flux (atoms/sq cm sec) increases. A nominal AO fluence of 1 x l0(exp 21) atoms/sq cm was agreed upon by the investigators as an adequate level for evaluating the performance of the tether materials. A test series was performed to determine the effect of atomic oxygen (AO) on the mechanical integrity and possible strength loss of ProSEDS tether materials. The tether materials in this study were Dyneema, an ultra-high molecular weight polyethylene material used as the non-conducting portion of the ProSEDS tether, and the Kevlar core strength fiber used in the conductive tether. Samples of Dyneema and Kevlar were exposed to various levels of atomic oxygen up to 1.07 x 10(exp 21) atoms/sq cm in the Marshall Space Flight Center Atomic Oxygen Beam Facility (AOBF). Changes in mass were noted after AO exposure. The tethers were then tensile-tested until failure. AO affected both the Dyneema and Kevlar tether material strength. Dyneema exposed to 1.07 x 10(exp 21) atoms/sq cm of atomic oxygen failed due to normal handling when removed fiom the AOBF and was not tensile-tested. Another test series was performed to determine the effect of AO on the electrical properties of the ProSEDS conductive tether. The conductive tether consists of seven individually coated strands of 28 AWG 1350-0 aluminum wire. The conductive coating, developed by Triton Systems, Inc., is a mix of polyanaline and COR, a clear AO-resistant polymer.
Publication Date: Jan 01, 2003
Document ID:
20040034188
(Acquired Mar 19, 2004)
Subject Category: SPACECRAFT PROPULSION AND POWER
Document Type: Preprint
Meeting Information: 42nd AIAA Aerospace Sciences Meeting; 5-9 Jan. 2004; Reno, NV; United States
Meeting Sponsor: American Inst. of Aeronautics and Astronautics
Contract/Grant/Task Num: 700-11-00
Financial Sponsor: NASA Marshall Space Flight Center; Huntsville, AL, United States
Organization Source: NASA Marshall Space Flight Center; Huntsville, AL, United States
Description: 2p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: TETHERING; POLYMERS; OXYGEN ATOMS; PROPULSION; MECHANICAL PROPERTIES; POLYETHYLENES; ORGANIC MATERIALS; MOLECULAR WEIGHT; KEVLAR (TRADEMARK)
Availability Source: Other Sources
Availability Notes: Abstract Only
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