{"id":14293,"date":"2017-10-05T23:43:09","date_gmt":"2017-10-05T15:43:09","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/spacewalk-concludes-with-successful-robot-arm-repair\/"},"modified":"2017-10-05T23:43:09","modified_gmt":"2017-10-05T15:43:09","slug":"spacewalk-concludes-with-successful-robot-arm-repair","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/spacewalk-concludes-with-successful-robot-arm-repair\/","title":{"rendered":"Spacewalk concludes with successful robot arm repair"},"content":{"rendered":"

STORY WRITTEN FOR CBS NEWS & USED WITH PERMISSION<\/p>\n

\"\"
Astronauts Randy Bresnik and Mark Vande Hei worked on the space station\u2019s robotic arm during a spacewalk Thursday. Credit: NASA<\/figcaption><\/figure>\n

Two astronauts ventured outside the International Space Station early Thursday and performed what amounted to hand transplant surgery on the lab\u2019s Canadian-built robot arm, removing a crippled grapple fixture on one end of the space crane and replacing it with an on-board spare.<\/p>\n

Floating in the Quest airlock, station commander Randy Bresnik and flight engineer Mark Vande Hei switched their spacesuits to battery power at 8:05 a.m. EDT (GMT-4) to officially kick off U.S. EVA-44, the first of three excursions planned over the next two weeks to service the Canadarm 2 space crane and carry out a variety of maintenance work.<\/p>\n

\u201cIt\u2019s more gorgeous and heavenly than I saw when I was out here eight years ago,\u201d Bresnik, a spacewalk veteran, marveled as he floated out of the airlock 250 miles above Africa. \u201cGood morning Egypt!\u201d<\/p>\n

A few moments later, Vande Hei, making his first spacewalk, made his way outside.<\/p>\n

\u201cAnd Houston, that might have been one small step for a man, but one giant leap for Sabot,\u201d Bresnik said, using Vande Hei\u2019s nickname. \u201cCongratulations, my friend, on becoming the 221st human to exit in your own personal spacecraft into the void of space.\u201d<\/p>\n

\u201cAppreciate those words,\u201d Vande Hei replied. \u201cHappy to be doing this with you.\u201d<\/p>\n

The primary goal of the spacewalk was to replace latching end effector A, or LEE-A, one of two grappling mechanisms on the station\u2019s Canadian-built robot arm.<\/p>\n

One LEE typically is used to anchor the arm at various attachment points on the lab complex while the LEE at the other end is used to lock onto and move visiting spacecraft or other large components. The arm also relays power, data and video to and from attached payloads.<\/p>\n

\u201cThe LEE is the mechanism, the set of mechanisms, that does all the heavy lifting, it does all the mechanical attachment when the arm walks end over end and establishes a new base point, when it picks up our robot DEXTRE to go do station maintenance or when it catches and releases free-flying cargo vehicles,\u201d said Tim Braithwaite, the Canadian Space Agency\u2019s station liaison.<\/p>\n

The Canadarm 2 measures 57.7 feet long, weighs nearly 4,000 pounds, has seven joints and, in the weightless environment of low-Earth orbit, can move large spacecraft and modules from one point to another. The LEEs feature internal snares that rotate and tighten to lock onto grapple fixtures while latches engage to supply power, data and additional rigidity.<\/p>\n

Each LEE is a \u201cvery complex package,\u201d Braithwaite said. \u201cThere are a lot of mechanisms, lots of on-board avionics, a camera, a force-and-moment sensor, it may be one of the most complex electro-mechanical packages that we\u2019ve flown in space.\u201d<\/p>\n

The two identical LEE mechanisms allow the arm to move inchworm fashion from one mounting point to another on the station\u2019s exterior. The arm also can mount itself atop a mobile transporter that runs on rails along the front side of the station\u2019s solar power truss to move the arm to various work sites.<\/p>\n

In recent years, telemetry has indicated age-related degradation in the latching end effectors.<\/p>\n

\u201cSince these components are well beyond their design life, this really is expected wear and tear on the arm,\u201d Braithwaite said. \u201cIt\u2019s been manifesting itself partly as increased motor currents in the mechanisms on board, and particularly the latches.\u201d<\/p>\n

On Aug. 22, flight controllers at the Johnson Space Center in Houston were attempting to reposition the arm when the LEE-A latches failed to fully extend.<\/p>\n

\u201cWe actually had the latches stall during that operation, which is quite unusual,\u201d Braithwaite said. \u201cWe took a really good look at all the data \u2026 and basically, that LEE-A latch mechanism is telling us that it\u2019s time (for repairs).\u201d<\/p>\n

With the robot arm positioned between them, Bresnik and Vande Hei first removed insulation and then loosened six bolts holding LEE-A in place so it could be removed and temporarily mounted on a cart attached to the arm\u2019s mobile transporter.<\/p>\n

The astronauts then removed an operational LEE that was mounted on the transporter itself and bolted it in place on the end of the arm, tightening the six bolts and re-attaching the insulation. The faulty LEE, which eventually will be returned to Earth for repairs, was repositioned on the mobile transporter.<\/p>\n

During one or more spacewalks early next year, the arm\u2019s LEE-B grappler will be removed and replaced with a spare currently mounted on an external storage platform. Another fight-ready spare is available for launch as needed.<\/p>\n

Bresnik and Vande Hei completed the LEE-A replacement work well ahead of schedule and were able to carry out two so-called \u201cget-ahead\u201d tasks before returning to the airlock.<\/p>\n

\u201cWe\u2019ve had a very, very good day,\u201d astronaut Mike Hopkins radioed from mission control in Houston, telling the spacewalkers to wrap things up and call it a day.<\/p>\n

\u201cThanks for all the work that went into developing the plan,\u201d Vande Hei replied. Bresnik then quipped: \u201cYou came out on your first EVA, Sabot, and you saved the arm.\u201d<\/p>\n

Airlock repressurization began at 3 p.m., closing out a six-hour 55-minute spacewalk.<\/p>\n

Two more spacewalks are planned Oct. 10, with Bresnik and Vande Hei, and 18, with Bresnik and Joe Acaba, to lubricate the newly attached LEE-A fitting, to replace two cameras with degraded color and to carry out other routine maintenance.<\/p>\n

Thursday\u2019s spacewalk was the 203rd EVA devoted to station assembly and maintenance since construction began in 1998, the eighth so far this year, the third for Bresnik and the first for Vande Hei. All told, 127 astronauts and cosmonauts representing 10 nations have now logged 1,265 hours and 10 minutes of station EVA time, or 52.7 days.<\/p>\n","protected":false},"excerpt":{"rendered":"

STORY WRITTEN FOR CBS NEWS & USED WITH PERMISSION Astronauts Randy Bresnik and Mark Vande Hei worked on the space station\u2019s robotic arm during a spacewalk Thursday. Credit: NASA Two astronauts ventured outside the International Space Station early Thursday and performed what amounted to hand transplant surgery on the lab\u2019s Canadian-built robot arm, removing a crippled grapple […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[584,1838,880,567,3166,3101,1545,717],"class_list":["post-14293","post","type-post","status-publish","format-standard","hentry","category-news","tag-canada","tag-canadarm-2","tag-canadian-space-agency","tag-eva","tag-eva-44","tag-expedition-53","tag-human-spaceflight","tag-international-space-station"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/14293"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=14293"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/14293\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=14293"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=14293"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=14293"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}