Dextre praised for aiding ISS battery upgrade

by Chris Bergin

Dextre, Canada’s adventurous robot on the International Space Station (ISS), has – along with his team – been recognized by the Johnson Space Center (JSC) for the work conducted during the crucial task of upgrading the batteries on the orbital outpost. Dextre’s role helped vastly reduce the workload on his human colleagues.


With an official title of the Special Purpose Dexterous Manipulator (SPDM), Dextre 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.

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) – or Canadarm2. The duo worked on removing payloads hosted in the Japanese vehicle’s Exposed Pallet.

The latest operation also involved the Japanese cargo vehicle, which delivered a set of new batteries to the Station.

Testing for this achievement began before the arrival of the resupply craft, ensuring the robotic transfer of battery style Orbital Replacement Units (ORUs) could be conducted, ultimately allowing for the reduction of the EVA workload on the human spacewalkers.

The goal was to allow planners to reduce the number of EVAs required to install the batteries from around six to just two spacewalks.

The checkout involved Dextre moving a spare MBSU Flight Releasable Attachment Mechanism (FRAM) to and from the Express Logistics Carrier (ELC)-2 via stops at the Enhanced ORU Temporary Platform (EOTP).

HTV-6 was launched and berthed at the ISS in December of last year, delivering 2,566.25 kg (5,657.6 lb) of internal cargo – with an additional 186 kg (410 lb) of packaging for that payload.

It also included 1,367 kg (3,014 lb) of external cargo – namely six Lithium Ion batteries and adapter plates – setting the stage for the replacement of the 12 aging Ni-H (nickel-hydrogen) batteries.

Thanks to the assistance of Dextre, the upgrading of the batteries on the Station was completed in just two – highly successful – EVAs.

The robotic work began once HTV-6 arrived at the ISS, with the Exposed Pallet (EP) extracted and placed on the Payload ORU Accommodation (POA), a grasping point for temporary payloads attached to the station’s Mobile Base System (MBS).

Dextre, controlled from the ground, then removed four of the six Ni-H2 batteries, installing three of them into three empty spaces on the EP, and another onto the SPDM’s own Enhanced ORU Temporary Platform (EOTP) storage interface.

The robot then removed three new Li-Ion batteries from the EP and installed them into the vacated Ni-H2 slots, leaving three adapter plates exposed on the EP ready to be used by the spacewalkers.

The first spacewalk – US EVA-38 – was performed by astronauts Shane Kimbrough and Peggy Whitson, followed a week later by US EVA-39, which was also carried out by Kimbrough, this time joined by ESA astronaut Thomas Pesquet.

Following the conclusion of the EVA, robotics work continued to install three Ni-H2 batteries into the three slots on the EP that were vacated by the removal of the adapter plates during the EVAs. The EP loaded with nine Ni-H2 batteries was then re-inserted into the cargo ship for disposal when the cargo craft completed the HTV-6 mission with a destructive re-entry.

Over the course of the days that followed the EVA, ground controllers confirmed the new batteries were performing as advertised, showing the upgrade work was a complete success.

This week, Space Systems Loral (SSL) announced that MDA US Systems, a division of MDA managed by SSL, was recognized by the Johnson Space Center for its outstanding support of a robotic upgrade to the ISS power system. The MDA team based in Houston played a critical role in planning and validating the robotic maneuvering both before and during the mission.

“Our team was honored to be recognized by NASA for its contribution to this mission,” said Rich White, senior vice president of Government Systems at SSL. “SSL and MDA have a long history of collaboration in robotics work for NASA and we continue to work together to design innovative advanced robotic augmentation and servicing systems for future missions.”

Meanwhile, there’s been little rest for the Canadian robot, as Dextre was busy with the SpaceX CRS-10 Dragon in recent days, removing payloads from the vehicle’s trunk for installation on the Station. The latest operation involved removing MISSE from ELC2 and installing it in the Dragon trunk for disposal.

The successful robotic operations conducted on the ISS are a testament to the past, such as their role on the Space Shuttle, through to the Mars landers and rovers.

The company is also working on a variety of next generation government missions, including the Restore-L mission for NASA’s Goddard Space Flight Center, which will demonstrate satellite servicing in Low Earth Orbit (LEO). Dextre has played a major role in testing this technology via ISS testing.

The robotic technology will also be involved with NASA’s Discovery Mission to explore the metal asteroid called Psyche; and the Dragonfly program for NASA and DARPA, which will demonstrate on orbit satellite assembly. SSL also announced earlier this month that it was selected to partner with DARPA on the RSGS robotic servicing in Geosynchronous Orbit (GEO) program.

(Images via NASA, JAXA and MDA).

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