{"id":39132,"date":"2016-02-12T00:26:20","date_gmt":"2016-02-11T16:26:20","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/dextre-demo-paving-the-way-for-robotic-eva-assistance\/"},"modified":"2016-02-12T00:26:20","modified_gmt":"2016-02-11T16:26:20","slug":"dextre-demo-paving-the-way-for-robotic-eva-assistance","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/dextre-demo-paving-the-way-for-robotic-eva-assistance\/","title":{"rendered":"Dextre demo paving the way for robotic EVA assistance"},"content":{"rendered":"

The Special Purpose Dexterous Manipulator (SPDM) has completed a series of tests aimed at reducing the human EVA workload involved with the installation of new batteries on the International Space Station (ISS). The impressive Canadian robot \u2013 more commonly known as \u201cDextre\u201d \u2013 worked through three days of Main Bus Switching Unit (MBSU) demonstrations ahead of the arrival of new batteries on the Japanese cargo ship HTV-6.<\/p>\n

Dextre:<\/p>\n

Dextre is a permanent fixture on the outside of the ISS, ready to be translated to worksites where it can be tasked with external maintenance tasks, the removal and replacement of dexterous compatible Orbit Replaceable Units (ORUs) and the servicing of scientific payloads.<\/p>\n

The SPDM was designed and built by MacDonald Dettwiler and Associates, (MDA), and financed by the Canadian Space Agency (CSA).<\/p>\n

\"2016-02-11-145648\"The robot rode to space in the payload bay of Shuttle Endeavour in 2008 (STS-123) and is now part of a trio of Canadian robotic assets that provide vital services to the ISS and a number of Visiting Vehicles.<\/p>\n

Dextre was assembled during STS-123 EVAs, with spacewalkers Rick Linnehan and Mike Foreman installing the robots 11-foot arms to the torso of the robot on Flight Day 6 on the mission.<\/p>\n

Despite a few teething problems, checkouts of the robot proceeded well over the coming months, eventually allowing the robot to enter into operational status in 2010.<\/p>\n

\"2016-02-11-181156\"However, Dextre\u2019s opening operations proved to be troublesome, although the challenges provided a number of important lessons that have fed into the numerous successes that have followed over recent years.<\/p>\n

The first major success for Dextre came during the HTV-2 mission, working in tandem with its compatriot the Space Station Remote Manipulator System (SSRMS) \u2013 or Canadarm2. The duo worked on removing payloads hosted in the Japanese vehicle\u2019s Exposed Pallet.<\/p>\n

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Later in 2011, Dextre took on a marathon set of robotic tasks, in turn feeding into the approval to conduct tests on future technology advances.<\/p>\n

\"\"Beginning in 2012, the first use of Dextre with NASA\u2019s Robotic Refuelling Mission (RRM) tests marked the first ever attempt at satellite servicing demo tasks to be performed at the ISS.<\/p>\n

The RRM is an ISS payload developed by the Satellite Servicing Capabilities Office (SSCO) at NASA\u2019s Goddard Space Flight Center (GSFC), launched with Shuttle Atlantis during STS-135.<\/p>\n

Numerous operations were carried out, marked by the successful conclusion of the initial test series in 2013.<\/p>\n

Dextre has also worked with a number of SpaceX Dragon vehicles, following an initial meeting during the commercial spacecraft\u2019s debut mission to the Station \u2013 testing out clearances and camera views ahead of the future payload removal role involving payload items in Dragon\u2019s trunk section.<\/p>\n

\"Z3\"The first hardware to be removed from Dragon\u2019s Trunk came during the CRS-2\/SpX-2 mission.<\/p>\n

However, this only involved the SSRMS, tasked with the removal of two Heat Rejection Subsystem Grapple Fixtures (HRSGFs) \u2013 which are essentially bars each featuring two Flight Releasable Grapple Fixtures (FRGFs).<\/p>\n

The first payload removal task between Dextre and Dragon\u2019s trunk came during CRS-3\/SpX-3, an operation that was repeated again during the CRS-5\/SpX-5 mission.<\/p>\n

Dextre has also provided many additional roles on the Station, such as visual inspections of the ISS modules and its robotic friends.<\/p>\n

However, it\u2019s the role of supporting EVA-based maintenance that will provide a major boost to Station operations.<\/p>\n

\"\"The recent test \u2013 known as the \u201cMain Bus Switching Unit (MBSU) Demonstration\u201d \u2013 was designed to validate the robotic transfer of battery style Orbital Replacement Units (ORUs) prior to the delivery of new ISS batteries on HTV-6.<\/p>\n

The goal is to allow planners to reduce the number of EVAs required to install the batteries from around six to just two spacewalks.<\/p>\n

The first task over the three-day test involved ground controllers tasking Dextre to move the spare MBSU Flight Releasable Attachment Mechanism (FRAM) from Express Logistics Carrier (ELC)-2 to the Enhanced ORU Temporary Platform (EOTP).<\/p>\n

This demonstration was to be the first time the SPDM ORU Tool Changeout Mechanism (OTCM) and the Robotic Offset Tool (ROST) were used together.<\/p>\n

\"2016-02-11-180223\"Both of Dextre\u2019s arms are terminated with OTCMs, which include \u201cjaws\u201d to grasp objects, a retractable socket drive, a camera and light, and an umbilical connector to provide and receive power, data and video to and from a gripped object.<\/p>\n

The OTCMs also include Force\/Moment Sensor (FMS) technology, giving the arms a \u201csense of touch\u201d.<\/p>\n

However, the milestone event on day one of the test suffered from a few teething problems.<\/p>\n

\u201cThe ROST objective had to be deferred due to an issue with the SPDM OTCM grasping the ROST. The OTCM jaws came to ~0.1 mm from reaching the required grapple position. Several reposition and re-grasp attempts were made with the same result,\u201d noted an L2 overview of the SPDM tasks.<\/p>\n

See Also<\/h4>\n