{"id":2677,"date":"2017-01-14T20:45:51","date_gmt":"2017-01-15T01:45:51","guid":{"rendered":"http:\/\/www.leucht.com\/blog\/?p=2677"},"modified":"2017-07-10T11:25:59","modified_gmt":"2017-07-10T15:25:59","slug":"nasa-tethered-satellite-broken-tether-analysis","status":"publish","type":"post","link":"http:\/\/www.leucht.com\/blog\/2017\/01\/nasa-tethered-satellite-broken-tether-analysis\/","title":{"rendered":"NASA Tethered Satellite: Broken Tether Analysis"},"content":{"rendered":"

Here are a couple photos of me from 1996 wearing a NASA “bunny suit” while working the failure analysis of the broken tether on the Tethered Satellite System re-flight (TSS-1R)<\/a> that had recently returned from orbit on\u00a0Space Shuttle mission STS-75<\/a>. \u00a0I was taking magnified photographs with a fancy high-tech digital SLR camera through an old-school benchtop microscope.<\/p>\n

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These photos were taken\u00a0in the Operations & Checkout (O&C) Building hi-bay which is a clean-room environment up on the work platforms, because the workers are adjacent to flight hardware. \u00a0The blue bunny suits<\/a> look kind of funny, but they help keep the flight hardware pristine and help keep our hair and our skin flakes from falling onto the flight hardware.<\/p>\n

The Tethered Satellite System was a pretty interesting experiment. \u00a0The theory was that we could extend a long electrical wire while orbiting the earth and that long wire would cut through the earth’s magnetic field lines and generate electricity. \u00a0The tether on this experiment was nearly 13 miles long! \u00a0Wow!<\/p>\n

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This tether experiment first flew in 1992 on Space Shuttle mission STS-46<\/a>, but had trouble deploying. \u00a0It deployed less than a thousand\u00a0feet out from the orbiter before it jammed. \u00a0But it got a second chance and flew again in 1996. \u00a0The deployment during the re-flight mission went well and was nearly complete … about 95 percent complete … when the tether broke and the experiment was over.<\/p>\n

The broken tether was reeled back in and was brought back to earth for analysis. \u00a0The task was to find out if the tether was mechanically broken, like from too much tension, or maybe from a micro-meteor impact. \u00a0Or whether the tether was broken due to an electrical arcing event, such as an over-current.<\/p>\n

The final analysis showed that it was an electrical overload. \u00a0But the reason for the excess current was pretty interesting and took some\u00a0detective work. \u00a0Around the outside of conductor was a clear Teflon <\/a>insulation layer which is basically\u00a0a plastic. \u00a0It’s similar to the white plastic insulation layer around the center wire in a coax cable.<\/p>\n

<\/a><\/p>\n

It was determined that this plastic Teflon layer was “breached” and electrical arcing occured\u00a0between the tether’s conductor and the gantry system that was deploying the tether.<\/p>\n

One possible cause of the break in the insulation was “foreign object debris”, which is NASA-speak for something that does not belong there. \u00a0We take great efforts to keep flight hardware pristine and clean. \u00a0But if a loose wire or something stiff or sharp got into the cogs of the deployment mechanism and punctured the insulation, that could have caused the electrical short.<\/p>\n

Another possible cause was a simple manufacturing defect and subsequent quality control miss. \u00a0Investigators showed that trapped air in the Nomex <\/a>core could have leaked out through tiny pinholes in the plastic Teflon insulator and caused an electrical plasma arc<\/a> due to the high voltages involved. \u00a0The experiment\u00a0was generating about 3,500 volts and about half an amp of current when the failure occurred.<\/p>\n

Even though the tether broke and the experiment could not be completed, it was a partial success and lots of data was collected during the deployment before the failure. \u00a0So it wasn’t a total loss.<\/p>\n

Thanks for your interest!<\/p>\n

Kurt<\/p>\n","protected":false},"excerpt":{"rendered":"

Here are a couple photos of me from 1996 wearing a NASA “bunny suit” while working the failure analysis of the broken tether on the Tethered Satellite System re-flight (TSS-1R) that had recently returned from orbit on\u00a0Space Shuttle mission STS-75. \u00a0I was taking magnified photographs with a fancy high-tech digital SLR camera through an old-school […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[108],"tags":[317,278,32,11],"_links":{"self":[{"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/posts\/2677"}],"collection":[{"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/comments?post=2677"}],"version-history":[{"count":19,"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/posts\/2677\/revisions"}],"predecessor-version":[{"id":2700,"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/posts\/2677\/revisions\/2700"}],"wp:attachment":[{"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/media?parent=2677"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/categories?post=2677"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.leucht.com\/blog\/wp-json\/wp\/v2\/tags?post=2677"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}