Robotic Refueling Mission

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Robotic Refueling Mission - Overview & Updates
ISS Section

Robotic Refueling Mission completes Phase I of Demonstrations

May 10, 2013

*RRM File Image* - Photo: NASA

The RRM Wire Cutter Tool in Action

Despite a dynamic situation unfolding aboard ISS this week, the Robotic Refueling Mission has completed its second round of operations this year as planned, completing its final Phase I tasks to get set for Phase II later this year. The final tasks of the current phase were started last week and were completed after about six days of operations.

This week, the Canadarm2, Dextre & RRM trio successfully tackled the final RRM task listed for this session which was the Multilayer Insulation Manipulation task. Satellites in orbit around Earth are covered with insulation material as part of their thermal control system. In order to perform repairs in space, future servicing spacecraft would need to remove MLI covers to access the satellite structure in order to carry out robotic servicing tasks. That is why it is important to learn how to manipulate MLI with tools handled by robots.

To complete this demonstration, Dextre grappled the Wire Cutter and Blanket Manipulation Tool that is part of the RRM suite. Working with surgical precision, Dextre moved the SCT toward a piece of MLI that is installed on the RRM module to mimic the MLI covers found on typical satellites. The retractable blade of the WCT was deployed and the tool was used to slice through the MLI cover. Just cutting through the cover was not the end of the demonstration, though. When servicing satellites in the future, their thermal control system can not be compromised after the repair - meaning that it is not enough to remove the MLI, it has to be put in place again after operations are complete so that the spacecraft can function properly after servicing.

To accomplish that, a three-sided flap was cut out of the MLI and the tool made stair-step motions to fold up the flap. The task was completed successfully and RRM showed that the MLI of satellites could be handled by robotic tools in order to access a spacecraft for refueling or repairs.

The successful completion of the MLI task early on May 10 also marked the end of Phase I of the Robotic Refueling Mission which was a stunning success as the testbed achieved all of its objectives - demonstrating a number of robotic servicing tasks including the first ever in-space robotic refueling operation.

"Some RRM tasks may sound straightforward at first," said Benjamin Reed, deputy project manager of the Satellite Servicing Capabilities Office (SSCO) at NASA's Goddard Space Flight Center. "What may seem mundane can actually be quite tricky. Having remote-controlled robots service satellites on orbit -- satellites that were never designed to be accessed, refueled or fixed in space -- is a new frontier."

With Phase I completed, teams are gearing up for RRM Phase II expected to begin this summer. This phase will feature new demonstration as well as repetitions of completed ones to evaluate different techniques to achieve the objectives. New RRM hardware and taskboards are scheduled to be delivered to ISS later this year and in 2014 to give Dextre new tools to complete even more complex challenges.

Robotic Refueling Mission resumes Demonstrations aboard ISS

May 3, 2013

Aboard the International Space Station, the Robotic Refueling Mission is underway once again to complete its next set of demonstration tasks to develop the technology and techniques for future satellite servicing. The final three demonstration tasks are on tap in May as RRM is planned to finish its Phase I of demonstrations with Phase II scheduled to start later this year.

After three successful sessions of preparatory operations in September 2011 and March & June 2012, the Robotic Refueling Mission had conducted the first actual refueling demonstration in space in January 2013 – updates and articles are available below the RRM Overview on this site.

The final three tasks are demonstrations of more extensive servicing procedures that would be required to fix satellites in space. Operations for this round of RRM began on May 1 and will last through May 3 before a short break takes place and operations resume on May 6 for completion on May 9.

Photo: NASA SatServ

In April, teams at NASA’s Goddard Spaceflight Research Center performed a final set of ground simulations of the procedures planned for this RRM session to verify all commands are correct before they are sent up to ISS. Late in April, Canadarm2 grappled the Dextre Robot and moved the handyman of ISS to its position to access the RRM module.

Photo: NASA SatServ

SMA Cap Removal Task

On May 1, operations got underway with setup tasks. Dextre grappled the Safety Cap Tool that still had a safety cap inside which was removed in January. This cap was stowed and the safety cap tool was attached to its SMA adapter for the first task: the Sub-miniature A Cap Removal Operation.

To gain physical access to the data system of a failed satellite to diagnose its systems, it might be required to plug into its electrical/data system. For that, future servicing spacecraft would need to remove small caps that protect that coaxial radio frequency (RF) connectors of a satellite while it is in orbit. The RRM module carries similar SMA caps to allow a demonstration of their removal and stowage in space.

The Safety Cap Tool of RRM is outfitted with a special SMA adapter that allows it to access the caps, remove them and stow them into a special receptacle on the RRM module. This task was successfully completed on May 1 without any hiccups along the way.

The next high-fidelity task was the Screw Removal Operation To access the inside of a satellite to perform repairs and replace failed components, it would be required to remove screws.

As it is known to most of us on Earth, handling a screwdriver to remove small screws does require a certain amount of dexterity by the operator. Getting a robot that rides an 18-meter robotic arm to align a screwdriver bit with tiny fasteners has been a challenge that has been worked on for several years.

To demonstrate the removal and safe stowage of small screws, the RRM payload includes a another adapter that fits onto the Safety Cap Tool to turn it into a power screwdriver. The RRM module itself includes a number of pre-fastened satellite screws that are found on a number of spacecraft. To safely handle the small fasteners once they are released, a technique developed for the final Hubble Space Telescope Servicing Mission is adapted.

On Mission STS-125 to Hubble, one spacewalk task required the astronauts to remove more than 100 screws which had to be captured in order to keep the telescope safe. For that, a new tool was developed: The FCT – Fastener Capture Plate – a plate that fit over the worksite and featured small holes aligned with each of the screws. These holes were large enough to allow the astronauts access the screws with their EVA screwdriver, but the diameter of the holes was small enough to trap all screws inside the plate.

The RRM FCT fits over the RRM work site and ensures that all screws that are released do not float away from the worksite. Getting the tool aligned with small fasteners has been rehearsed on Earth countless times and that practice paid off as Dextre successfully aligned the tool with the screw on May 3. Releasing a number of fasteners is a task still to come.

Photo: NASA SatServ

RRM Alignment with Fastener

As RRM operations are progressing smoothly aboard ISS, teams are getting ready for the final Phase I task that is coming up in just a few days. This task will be the Multilayer Insulation Manipulation demonstration which is another important step on the path to remote satellite servicing capabilities.

RRM Overview

The Robotic Refueling Mission is an effort by NASA and the Canadian Space Agency to demonstrate robotic Satellite Servicing Capabilities in a Space Environment. RRM is a small module that is attached to the International Space Station and holds equipment necessary for several tasks that are needed to practice servicing operations in space using the Canadian Dextre Robot and special tools that are part of the RRM Payload. This is the first time the Dextre Robot is used for technology research and development. The tests will be performed over a two year duration with first demonstrations in March 2012. As part of RRM Operations, Dextre will complete a list of tasks and repeat those after engineers evaluated previous runs. The crew of the Space Station is not involved in the operation as all aspects of RRM are controlled by Control Centers on the ground. RRM operations are planned to be completed by the end of 2015.
The Payload was delivered to the Space Station on the final Space Shuttle Mission STS-135 during which it was placed at a temporary location. In August 2011, RRM was relocated to its final location.

Photo: NASA

The RRM Payload aboard ISS

Background
Before launching, satellites are fueled through a valve that is triple sealed after fueling is complete. Afterwards, it is covered with thermal blankets. Typical satellites are designed to never open the valve again. Removing those barriers are crucial for future satellite refuelings in space. The Robotic Refueling Mission is an experiment that demonstrates that a remote-controlled robot can remove these barriers and perform satellite refueling. RRM is located on ExPRESS Logistics Carrier 4 on the external of the International Space Station.

Photo: NASA/Chris Gunn

RRM Hardware and Tools
Four different tools are part of the RRM Mission that are being used to demonstrate the steps necessary to perform a re-fueling procedure of a satellite in space. The four tools are located on the RRM Module and can be attached to the Dextre Robot. Each tool includes cameras that enable ground controllers to monitor operations in real time. LEDs provide illumination for operations during orbital night. The RRM structure contains representative satellite fueling interfaces (common interfaces found on a variety of satellites) including a fluid transfer system. The Robotic Refueling Mission Module is about the size of a washing machine weighing about 250 Kilograms. It is 84X109x114 Centimeters in size. 1.7 liters of Ethanol are in its tank to simulate satellite fueling by transferring the liquid. The module includes protective thermal blankets, caps, valves, simulated fuel, and other servicing-related spacecraft components.
A Wire Cutter Tool severs safety wires that are attached to the fuel cap of most satellites. It is also used to remove thermal blankets that are covering the fuel cap area. A spade bit on the tool's tip can slice blanket tape. Parallel Jaw Grippers can grab a satellite’s appendages. After removing tapes that secure fuel cap insulation blankets and cutting safety wires, fuel or gas caps can be removed. For that, a different tool is needed. The Multifunction Tool is capable of performing the work of four different tools. It connects to four adapters to capture and remove remove three distinct caps and remove one gas "plug" on the RRM module. The Safety Cap Tool removes and stows the Fuel Cap and associated seals. Small adapters on the Tool allow it to manipulate screws and remove caps on the RRM module. The actual refueling operation is accomplished with the Nozzle Tool which connects to, opens and closes the satellite’s fuel valve. A hose attached to the tool transfers the fuel in a continuous loop to simulate the refueling of a satellite. After the operation is complete, a fuel cap is installed on the simulated satellite. This cap is outfitted with a QD – Quick Disconnect – that provides easy access to the main fuel valve for future refueling operations. The Robotic Refueling Mission Payload is capable of demonstrating six individual refueling operations.

RRM Tools in Use

Photo: NASA

Photo: NASA/CSA

Photo: NASA

RRM Tasks
Launch Lock Removal and Vision Checks
The first task of RRM that was completed once it was installed at its final location was to release the launch locks that kept the four tools in place during ascent aboard Space Shuttle Atlantis. The Dextre Robot was used to release the locks. The operations were completed successfully and teams started checking the entire payload by using Dextre’s Cameras. Imagery was acquired during day and night passes providing data that NASA's Satellite Servicing Capabilities Office used to develop machine vision algorithms that work against harsh on-orbit lighting. These operations were completed in September 2011 and mark the only RRM Procedures that do not include actual RRM Tools.

Gas Fitting Removal
Dextre used RRM Tools to remove the fittings that many satellites have for the filling of special coolant gases. Before starting the task, the Robot captured three of the RRM Tools and performed functional checkouts prior to starting actual operations. Afterwards, more launch locks were removed to put the RRM Module in operating configuration. Using the Wire Cutter, Dextre cut the lock wire that every satellite has on its fuel cap. This task demonstrated that even small wires can be located and cut by using current robotic technology. Following the removal of the actual fuel cap, actual refueling would begin. The Gas Fitting Removal Task was completed in March 2012 and June 2012.

Refueling
After opening a fuel valve that is similar to those installed on satellites orbiting Earth, a simulated fuel is transferred through a robotic fueling hose. The liquid that is transferred is Ethanol. RRM will not run out of fuel as it is flowing through a closed loop for the purposes of testing and not actually filling fuel from one tank into another.

Thermal Blanket Manipulation
Using RRM Tools, Dextre cuts tape that secures thermal blankets to enable it to fold the insulation material in order to reveal the contents underneath. This is needed as many satellites have thermal blankets covering the areas that have to be accessed in order to perform servicing operations.

Fastener Removal
Dextre captures RRM Tools and unscrews satellite bolts that are used on many satellites to hold covers in place that protect electrical and other systems.

Electrical Cap Removal
To remove electrical covers satellites employ to protect electrical equipment on board, Dextre uses RRM Tools to demonstrate the removal procedure.

Photo: NASA/Chris Gunn

RRM Nozzle Tool

Photo: NASA

RRM Wire Cutter

Artist's Impression of the SPDM (Dextre) using the RRM during a demonstration test.
The ELC-4 is clearly visible as the structure RRM is mounted on. Dextre is based on the Canadarm 2 for this test.
Source: NASA

This artistic impression shows one of Dextre's arms with the Wire Cutter and Blanket Manipulation Tool attached to it. Dextre approaches one unit of the RRM to perform a task using the particular tool. Also visible are the cameras and LED that allow Mission Controllers to get a real time look at the Robot's actions.
Source: NASA

The RRM Box was delivered to the ISS by Mission STS-135. It has various refueling components and activity boards as well as a fluid transfer system installed on it. The four tools that Dextre will use to operate the Box are inside this flight-model payload housing.
Source: NASA

Applications
"Every satellite has a lifespan and eventual retirement date, determined by the reliability of its components and how much fuel it can carry," explains Benjamin Reed, deputy project manager of NASA's Satellite Servicing Capabilities Office, or SSCO.
Robotic Refueling could extend satellite on-orbit lifetime as fuel consumption is a constraint for many ongoing missions. Satellite Replacement Cost would be decreased dramatically as spacecraft could remain active in orbit for several years exceeding their initial lifetime. With a fueling capability in space, satellites could be launched with a reduced amount of fuel – thus freeing up launch mass for Payload Equipment leading to more advanced spacecraft. Eventually, manned vehicles could be refueled in Earth orbit and then use the new fuel to reach more distant goals in space. By performing RRM aboard the ISS, the risk associated with a free flying mission is eliminated as the foundation for a future robotic servicing mission to a free-flying satellite is built. In addition to that, Space Robotics can be advanced for a variety of applications in the future of Space Exploration.

RRM Updates - January 2013

Robotic Refueling Mission demonstrates Satellite Refueling in Space for the first Time

January 25, 2013

Photo: NASA/CSA

Nozzle Tool Removal

Photo: NASA/CSA

RRM Nozzle Tool

The Robotic Refueling Mission has successfully completed the first-of-its-kind refueling demonstration in space, working high above Earth, on the starboard truss of the International Space Station.

Its second week of operations started on Tuesday as the Robotic Refueling Mission Payload along with the Dextre Robot and Canadarm2 began final preparations for the fluid transfer that occurred later in the week. After removing the first safety cap last week and cutting wires that were securing the final protective barriers, operations were paused over the weekend to set the stage for a busy week of robotics.

On Tuesday, Dextre retrieved the Safety Cap Tool from the RRM Module and started the prescribed checkout of the instrument's functionality, its cameras and lighting fixtures to make sure the Safety Cap Tool was ready for operations. Then, the Safety Cap Receptacle on the RRM module was checked and reconfigured to prepare it to receive the safety cap once detached. Afterwards, the SCT was moved to the safety cap of the valve, being maneuvered to the correct position to start driving the cap. The safety cap was successfully removed and Dextre started operations to stow the cap in its receptacle. When that was complete, the SCT was moved back into the RRM module to free Dextre's arm.

On RRM Ops Day 5, Dextre grasped a nearby fixture to stabilize itself, preventing motion that occurs when the robot moves on the end of the long robotic arm. Although Canadarm2's brakes were engaged, the arm still flexed a bit when Dextre moved around which can be troublesome during delicate operations involving the fuel valve. Once Dextre was stable, the robot started to retrieve the Nozzle Tool from the RRM module. An extensive list of checks of this tool was completed ahead of its first use to ensure its systems were ready for the grand finale, fluid transfer.

On the final day of RRM Ops, Dextre carefully maneuvered the Nozzle Tool to make contact with the fuel valve. The tool was threaded onto the plumbed fill/drain valve before the actuation nut was opened, the final protective system of the fuel valve. A series of verifications followed before commands were sent to initiate the fluid transfer. Telemetry coming down from the module and its Nozzle Tool confirmed that Ethanol, the simulated satellite fuel, was flowing through the closed fluid transfer system of the RRM payload.

This was the first successful refueling demonstration performed in space. After fluid transfer Ops were complete, the Nozzle Tool was detached from a Quick-Disconnect Fitting that was left on the fuel valve to make sure it is tightly sealed and to make future refueling easier. When removing the Nozzle Tool, residual Ethanol quickly boiled off in the vacuum of space.

The Nozzle Tool was stowed back inside RRM to complete a busy robotics effort made by teams at NASA's Goddard and Johnson Space Centers and the Canadian Space Agency, achieving another milestone with ISS acting as an invaluable testbed for technology demonstrations in space.

Nozzle Tool Retraction

"It has been an eventful and exciting week for our Robotic Refueling Team, as milestones are met and new bars are raised for working in space,"Ed Rezac, the Robotics Facility Manager of NASA's Satellite Servicing Capabilities Office, said. "I am so very proud of the Satellite Servicing Capabilities Office team and the extended team that includes our partners at the Canadian Space Agency, Johnson Space Center, Marshall Space Flight Center and all the International Space Station support members — to the individual. Every precaution taken, every concern addressed, every anomaly solved, every success realized so far is to be savored by the people responsible."

With the successful completion of the RRM operation, the Canadarm2/Dextre combo had another day of robotics remaining. On Saturday, the two are being used to conduct external video surveys of a number of payloads, including AMS-2 and MISSE-8 (Materials on International Space Station Experiment). Afterwards, the robots will be moved to their respective parking positions for some well deserved rest.

More RRM operations will be performed later this year. The next task will be the Thermal Blanket Manipulation Task.

Photo: NASA/CSA

RRM set for busy Week of Operations after encountering a second Holdup

January 19, 2013

Photo: NASA/CSA

The Robotic Refueling Mission has successfully completed the remaining Day 2 and some of its Day 3 activities to end a busy week of robotics on the International Space Station.

After robotics specialists had successfully solved a rate of motion issue associated with Canadarm2’s software, operations resumed on Thursday. With the Tertiary Cap removed earlier, Dextre’s next task was the removal of the Safety Cap which is another protective cap that has to be removed to access a satellite’s fuel valve. To remove the Safety Cap, the Wire Cutter Tool was used to cut two wires on the cap before carefully manipulating the wires to make sure they were not blocking the Safety Cap for removal. One more wire was cut by Dextre, the Actuation Nut wire which was the final wire required to be severed to access the fuel valve. With cutting operations complete, Dextre started procedures to re-stow the the two tools it had been holding on for the last few days, the Wire Cutter Tool and the Multifunction Tool. After stowing the tools and reaching for the next tool for the actual safety cap removal, Dextre encountered a mechanical issue between the robot’s arm and the adapter that allows it to grab onto its tools. “The teams will work through the issue over the weekend and RRM activities are expected to continue on Tuesday as scheduled,” a NASA statement said. Originally, the Safety Cap Tool was planned to be retrieved on Day 3 followed by checkouts and inspections of the safety cap receptacle on the RRM module.

These activities have been deferred to Day 4. With these two hold-ups that occurred this week, RRM operations have been extended to January 25 to give teams time to complete all planned operations.

Now, per the re-planned schedule, Dextre is planned to resume RRM operations on Tuesday at 17:00 UTC with Day 4 procedures. Picking up where Dextre left, the robot will remove the Safety Cap Tool and perform required checkouts on the tool including tests of its lights and cameras. Afterwards, the tool will be used to remove the Safety Cap and stow it in its receptacle. To conclude the fourth day of operations, Dextre will re-stow the Safety Cap Tool inside the RRM module. Day 4 is planned to end at 11:00 UTC on January 23.

Day 5 of operations begins just 5 hours later and will start with Dextre using one of its arms to grab onto a nearby fixture to stabilize itself for the actual fueling demonstration. Next, the Nozzle Tool will be unstowed and tested. Testing again includes checks of the tool’s cameras and lights as well as functional checkouts. Afterwards, the tool will be carefully moved to the fuel valve on the RRM module, the Plumbed fill/drain valve, to complete Day 5.

Day 6 (January 24 & 25) will be the busiest day of operations as it features the actual refueling demonstration. First, the Nozzle Tool will thread itself onto the fuel valve that was prepared over the first few days of operations. Once it has been verified that the Nozzle Tool is in the correct configuration, commands will be set to start the transfer of Ethanol from RRM's fluid transfer system, into the Nozzle Tool and through the attached fuel valve – simulating a fuel transfer to a satellite in space. Once the fluid transfer it complete, the Nozzle Tool will disconnect itself and leave behind a quick-disconnect fitting to allow for quick future refueling. The Nozzle Tool will then be stowed by Dextre and the robot will let go of the stabilization fixture. Afterwards, Dextre and Canadarm2 can be moved back into a normal position to get ready for future operations, after this RRM run will have successfully been completed.

Robotic Refueling Mission completes first Day of Operations - Hits Glitch on Day 2

January 16, 2013

Robotic activities aboard the International Space Station have gotten underway on Monday as the Robotic Refueling Mission and the Dextre Robot have completed the first two days of procedures to demonstrate robotic refueling in space, but teams have also hit the first problems during RRM Ops.

RRM operations began on Monday as controllers of NASA and the Canadian Space Agency started to operate Dextre to start the fourth session of RRM procedures. Ground controllers are on console at NASA’s Johnson and Goddard Space Centers to command Dextre and monitor activities. Also, teams use a high-fidelity mock-up of the RRM module at the Goddard Satellite Servicing Center to rehearse the operations to be conducted on orbit to verify robotic procedures.

On Monday - Day 1 of the ongoing RRM session - Dextre grappled the RRM Wire Cutter Tool and removed it from the RRM module to set the stage for actual demonstration tasks. Before getting to work cutting wires, the tool underwent a checkout of its cameras and lighting fixtures that are required to function. The work site on the RRM module was the PV1 valve, one of several valves on the module that can and will be used for demonstrations.

The first task was to use the Wire Cutter Tool to cut a very small wire that is attached to the Tertiary Cap of the fuel valve. This cap is one of several systems that protect the fuel valve of satellites. It is secured by a small wire that has a very small clearance so that Dextre had to position the cutter carefully to make the cut. After cutting the wire, teams were worried that it may have gotten in the way of the cap which could have been troublesome for the removal of the cap, so ground teams had to come up with commands to move the wire to put it into a correct configuration.

The sequence was successfully implemented and executed on orbit so that Dextre was able to continue with the next step of the task which was to retrieve the RRM Multifunction Tool with its other arm – also performing the prescribed checkouts of lights and cameras. With this tool, the robot successful removed the Tertiary Cap to conclude Day 1 Ops.

Day 2 of RRM Ops was planned to stretch from 18:00 UTC on Tuesday until 13:00 UTC on Wednesday. Dextre first had to stow the Tertiary Cap removed on Day 1. For that, it used the Multifunction Tool to place the cap in a receptacle on the RRM module.

Photo: NASA/CSA

Positioning the Wire Cutter Tool

Photo: NASA/CSA

Cutting the Tertiary Cap Wire

Photo: NASA/CSA

Tertiary Cap Removal

Later on Tuesday, RRM operations had to be paused due to a software issue with Canadarm2. “An intermittent difference in the software that controls Canadarm2, the International Space Station’s Canadian-built Remote Manipulator System, requires further analysis to ensure safe operations. Canadarm2 and the Special Purpose Dexterous Manipulator, or Dextre, has temporarily been placed in a safe configuration while engineering teams on the ground assess the data,” NASA said in a statement. Specialists on the ground successfully completed reviews of the issue and gave the green light to continue RRM operations on Thursday.

Preview: Robotic Refueling Mission to start the Year with ambitious Demonstration

January 13, 2013

Photo: NASA

Dextre & RRM

NASA and the Canadian Space Agency are getting ready for the next and most important round of Robotic Refueling Demonstrations using the Robotic Refueling Mission aboard the International Space Station. After three successful sessions of preparatory operations in September 2011 and March & June 2012, teams are now gearing up for the big one, demonstrating actual satellite refueling in space. Operations will span from January 14 to 24 with a total of six days of scheduled demonstrations.

During five days of operations with one additional contingency day, controllers from NASA and the Canadian Space Agency will use the Dextre Robot (Special Purpose Dexterous Manipulator) to use the RRM tools to demonstrate robotic refueling in space. To refuel a satellite in space, a future Servicing Satellite will have to complete a series of tasks before actual propellant loading could start, because each satellite currently in space is equipped with a number of safety systems protecting its fuel valve.

The fuel valve on most satellites is triple sealed before launch and covered with thermal blankets - the valves on these satellites were not designed to be re-opened.

In order to fuel a satellite, a robotic spacecraft would have to remove the safety systems by first cutting through the insulation before cutting through a safety wire attached to the fuel cap, followed by removing the cap. These tasks were demonstrated during earlier RRM operations.

For the actual re-fueling task, Dextre will use the RRM tools to open a series fuel caps that are similar to those used on satellites and transfer a simulated fuel (Ethanol) through a robotic fueling hose. The RRM fueling loop is closed so that the testbed can not run out of fuel that is only transferred for demonstration.

To get to the actual fuel transfer, Dextre has to complete a series of operations to remove the triple safety systems, cutting tiny wires with small clearances and removing safety caps. Dextre will be using the Wire Cutting Tool to cut the safety wires and attach the Multi-Function Tool on its other arm to use it to remove the Tertiary Cap which will then be stowed in a receptacle on the RRM module. Once that is complete, the safety cap wire will be cut and a small wire holding an actuation nut in place will be severed as well. Then, the Wire Cutting Tool can be stowed. The Multi-Function Tool will be stowed as well and Dextre is going to grapple the Safety Cap Tool before checking the receptacle for the safety cap.

Once everything is verified, Dextre will go ahead and remove the safety cap and stow it before taking off the safety cap tool and grasping the Nozzle Tool. These tasks will span over four days before the fuel transfer takes place on day 5.

Photo: NASA/CSA

The tool of choice for the transfer is the Nozzle Tool of RRM that features the propellant transfer line. To stabilize itself for the delicate fuel transfer operation, Dextre will use its second arm that has no tool on it to grasp a nearby fixture. The Nozzle Tool will be attached to the fuel valve and the simulated propellant will be transferred. Once the refueling demonstration is complete, a Quick Disconnect Adapter will be installed to seal the valve and allow a quick access for additional refueling. To finish the task, Dextre will let go of the fixture and stow the Nozzle Tool.

"The RRM operations team is very excited about the upcoming refueling demonstration," said Charlie Bacon, RRM operations manager. "Over the last two years, the team has put in more than 300 hours of preparation -- reviewing procedures, running simulations, and communicating with team members from other NASA centers and our international partners. When we finally execute the namesake task of RRM, we anticipate that our work will culminate in proving that in-orbit satellite refueling is no longer future technology -- it's current technology."

The Canadian Space Agency has provided this day-by-day overview of RRM Operations:

Day 1: Tertiary Cap Removal:
• Grasp the wire-cutting tool from the RRM module and unstow it
• Cut a safety wire on the tertiary cap
• Using the other arm, grasp and unstow the multi-function tool and use it to remove the tertiary cap

Day 2: Wire Cuts
• Stow the tertiary cap in its receptacle on the RRM module
• Cut a safety cap wire
• Cut a second wire hold an actuation nut in place
• Stow the wire-cutting tool

Day 3: Tackle the Safety Cap
• Stow the multi-function tool
• Grasp the safety-cap tool and unstow it
• Check out the safety-cap receptacle where used caps will be stowed

Day 4:
• Remove the safety cap
• Stow the safety cap tool

Day 5:
• Dextre will use one of his arms to grab onto a nearby fixture for added stability
• Grasp the nozzle tool and unstow it
• Open an actuation nut
• Fuel the RRM module
• Release the nozzle, leaving behind a Quick Disconnect adapter to seal the valve and
• Stow the nozzle tool and release the stabilization fixture

Day 6:
• Take a well earned rest!