Robotics Refueling Research Scores Huge Leap at Space Station

Canada’s Dextre robot (highlight) and NASA’s Robotic Refueling Experiment jointly performed groundbreaking robotics research aboard the ISS in March 2012. Dextre used its hands to grasp specialized work tools on the RRM for experiments to repair and refuel orbiting satellites. Credit: NASA


A combined team of American and Canadian engineers has taken a major first step forward by successfully applying new, first-of-its-kind robotics research conducted aboard the International Space Station (ISS) to the eventual repair and refueling of high value orbiting space satellites, and which has the potential to one day bring about billions of dollars in cost savings for the government and commercial space sectors.

Gleeful researchers from both nations shouted “Yeah !!!” – after successfully using the Robotic Refueling Mission (RRM) experiment – bolted outside the ISS- as a technology test bed to demonstrate that a remotely controlled robot in the vacuum of space could accomplish delicate work tasks requiring extremely precise motion control. The revolutionary robotics experiment could extend the usable operating life of satellites already in Earth orbit that were never even intended to be worked upon.

“After dedicating many months of professional and personal time to RRM, it was a great emotional rush and a reassurance for me to see the first video stream from an RRM tool,” said Justin Cassidy in an exclusive in-depth interview with Universe Today. Cassidy is RRM Hardware Manager at the NASA Goddard Spaceflight Center in Greenbelt, Maryland.

Astronuats Install Robotic Refueling Mission (RRM) experiment during Shuttle Era's Final Spacewalk
In March 2012, RRM and Canada’s Dextre Robot jointly acccomplised fundamental leap forward in robotics research aboard the ISS. Spacewalker Mike Fossum rides on the International Space Station's robotic arm as he carries the Robotic Refueling Mission experiment. This was the final scheduled spacewalk during a shuttle mission. Credit: NASA

And the RRM team already has plans to carry out even more ambitious follow on experiments starting as soon as this summer, including the highly anticipated transfer of fluids to simulate an actual satellite refueling that could transfigure robotics applications in space – see details below !

All of the robotic operations at the station were remotely controlled by flight controllers from the ground. The purpose of remote control and robotics is to free up the ISS human crew so they can work on other important activities and conduct science experiments requiring on-site human thought and intervention.

Dextre "hangs out" in space with two Robotic Refueling Mission (RRM) tools in its "hands." The RRM module is in the foreground. Credit: NASA

Over a three day period from March 7 to 9, engineers performed joint operations between NASA’s Robotic Refueling Mission (RRM) experiment and the Canadian Space Agency’s (CSA) robotic “handyman” – the Dextre robot. Dextre is officially dubbed the SPDM or Special Purpose Dexterous Manipulator.

On the first day, robotic operators on Earth remotely maneuvered the 12-foot (3.7 meter) long Dextre “handyman” to the RRM experiment using the space station’s Canadian built robotic arm (SSRMS).

Dextre’s “hand” – technically known as the “OTCM” – then grasped and inspected three different specialized satellite work tools housed inside the RRM unit . Comprehensive mechanical and electrical evaluations of the Safety Cap Tool, the Wire Cutter and Blanket Manipulation Tool, and the Multifunction Tool found that all three tools were functioning perfectly.

RRM Wire Cutter Tool (WCT) experiment is equipped with integral camera and LED lights -
on display at Kennedy Space Center Press Site. Dextre robot grasped the WCT with its hands and successfully snipped 2 ultra thin wires during the March 2012 RRM experiments. Credit: Ken Kremer

“Our teams mechanically latched the Canadian “Dextre” robot’s “hand” onto the RRM Safety Cap Tool (SCT). The RRM SCT is the first on orbit unit to use the video capability of the Dextre OTCM hand,” Cassidy explained.

“At the beginning of tool operations, mission controllers mechanically drove the OTCM’s electrical umbilical forward to mate it with the SCT’s integral electronics box. When the power was applied to that interface, our team was able to see that on Goddard’s large screen TVs – the SCT’s “first light” video showed a shot of the tool within the RRM stowage bay (see photo).

Shot of the Safety Cap Tool (SCT) tool within the RRM stowage bay. Credit NASA RRM

“Our team burst into a shout out of “Yeah!” to commend this successful electrical functional system checkout.”

Dextre then carried out assorted tasks aimed at testing how well a variety of representative gas fittings, valves, wires and seals located on the outside of the RRM module could be manipulated. It released safety launch locks and meticulously cut two extremely thin satellite lock wires – made of steel – and measuring just 20 thousandths of an inch (0.5 millimeter) in diameter.

“The wire cutting event was just minutes in duration. But both wire cutting tasks took approximately 6 hours of coordinated, safe robotic operations. The lock wire had been routed, twisted and tied on the ground at the interface of the Ambient Cap and T-Valve before flight,” said Cassidy.

This RRM exercise represents the first time that the Dextre robot was utilized for a technology research and development project on the ISS, a major expansion of its capabilities beyond those of robotic maintenance of the massive orbiting outpost.

Video Caption: Dextre’s Robotic Refueling Mission: Day 2. The second day of Dextre’s most demanding mission wrapped up successfully on March 8, 2012 as the robotic handyman completed his three assigned tasks. Credit: NASA/CSA

Wire Cutter Tool (WCT) Camera View of Ambient Cap Wire Cutting. Courtesy: Justin Cassidy to Universe Today. Credit NASA RRM

Altogether the three days of operations took about 43 hours, and proceeded somewhat faster than expected because they were as close to nominal as could be expected.

“Days 1 and 2 ran about 18 hours,” said Charles Bacon, the RRM Operations Lead/Systems Engineer at NASA Goddard, to Universe Today. “Day 3 ran approximately 7 hours since we finished all tasks early. All three days baselined 18 hours, with the team working in two shifts. So the time was as expected, and actually a little better since we finished early on the last day.”

Wire Cutter Tool (WCT) Camera View of T-Valve Wire Cutting. Courtesy: Justin Cassidy to Universe Today. Credit NASA RRM

“For the last several months, our team has been setting the stage for RRM on-orbit demonstrations,” Cassidy told me. “Just like a theater production, we have many engineers behind the scenes who have provided development support and continue to be a part of the on-orbit RRM operations.”

“At each stage of RRM—from preparation, delivery, installation and now the operations—I am taken aback by the immense efforts that many diverse teams have contributed to make RRM happen. The Satellite Servicing Capabilities Office at NASA’s Goddard Space Flight Center teamed with Johnson Space Center, Kennedy Space Center (KSC), Marshall Space Flight Center and the Canadian Space Agency control center in St. Hubert, Quebec to make RRM a reality.”

“The success of RRM operations to date on the International Space Station (ISS) using Dextre is a testament to the excellence of NASA’s many organizations and partners,” Cassidy explained.

The three day “Gas Fittings Removal task” was an initial simulation to practice techniques essential for robotically fixing malfunctioning satellites and refueling otherwise nominally operating satellites to extend to hopefully extend their performance lifetimes for several years.

Ground-based technicians use the fittings and valves to load all the essential fluids, gases and fuels into a satellites storage tanks prior to launch and which are then sealed, covered and normally never accessed again.

“The impact of the space station as a useful technology test bed cannot be overstated,” says Frank Cepollina, associate director of the Satellite Servicing Capabilities Office (SSCO) at NASA’s Goddard Space Flight Center in Greenbelt, Md.

“Fresh satellite-servicing technologies will be demonstrated in a real space environment within months instead of years. This is huge. It represents real progress in space technology advancement.”

Four more upcoming RRM experiments tentatively set for this year will demonstrate the ability of a remote-controlled robot to remove barriers and refuel empty satellite gas tanks in space thereby saving expensive hardware from prematurely joining the orbital junkyard.

The timing of future RRM operations can be challenging and depends on the availability of Dextre and the SSRMS arm which are also heavily booked for many other ongoing ISS operations such as spacewalks, maintenance activities and science experiments as well as berthing and/or unloading a steady stream of critical cargo resupply ships such as the Progress, ATV, HTV, Dragon and Cygnus.

Flexibility is key to all ISS operations. And although the station crew is not involved with RRM, their activities might be.

“While the crew itself does not rely on Dextre for their operations, Dextre ops can indirectly affect what the crew can or can’t do,” Bacon told me. “For example, during our RRM operations the crew cannot perform certain physical exercise activities because of how that motion could affect Dextre’s movement.”

Here is a list of forthcoming RRM operations – pending ISS schedule constraints:

  • Refueling (summer 2012) – After Dextre opens up a fuel valve that is similar to those commonly used on satellites today, it will transfer liquid ethanol into it through a sophisticated robotic fueling hose.
  • Thermal Blanket Manipulation (TBD 2012)- Dextre will practice slicing off thermal blanket tape and folding back a thermal blanket to reveal the contents underneath.

  • Screw (Fastener) Removal (TBD 2012)- Dextre will robotically unscrew satellite bolts (fasteners).

  • Electrical Cap Removal (TBD 2012)- Dextre will remove the caps that would typically cover a satellite’s electrical receptacle.

RRM was carried to orbit inside the cargo bay of Space Shuttle Atlantis during July 2011 on the final shuttle mission (STS-135) of NASA’s three decade long shuttle program and then mounted on an external work platform on the ISS backbone truss by spacewalking astronauts. The project is a joint effort between NASA and CSA.

“This is what success is all about. With RRM, we are truly paving the way for future robotic exploration and satellite servicing,” Cassidy concluded.

Full size Mock up of RRM box and experiment tool at KSC Press Site
Equipment Tool movements and manipulations by Dextre robot are simulated by NASA Goddard RRM manager Justin Cassidy. Credit: Ken Kremer

March 24 (Sat): Free Lecture by Ken Kremer at the New Jersey Astronomical Association, Voorhees State Park, NJ at 830 PM. Topic: Atlantis, the End of Americas Shuttle Program, RRM, Orion, SpaceX, CST-100 and the Future of NASA Human & Robotic Spaceflight

Revolutionary Robotic Refueling Experiment Opens New Research Avenues at Space Station

Astronuats Install Robotic Refueling Mission experiment during Shuttle Era's Final Spacewalk. Spacewalker Mike Fossum rides on the International Space Station's robotic arm as he carries the Robotic Refueling Mission experiment. This was the final scheduled spacewalk during a shuttle mission. Credit: NASA


NASA’s new Robotic Refueling Experiment (RRM) is a revolutionary technology demonstration device – brought aloft by the final shuttle mission – that will test out and prove whether existing Earth orbiting spacecraft that were never intended to be serviced can be successfully refueled and repaired robotically.

The RRM payload is a state of the art path finding experiment that promises to open exciting new avenues of station science research that potentially could save and extend the lifetime of orbiting commercial, government and military satellites valued at billions of dollars.

RRM was delivered to the International Space Station (ISS) by the four person crew of STS-135, the shuttles grand finale. The project is a joint effort between NASA and the Canadian Space Agency (CSA).

During the very final spacewalk of the Space Shuttle Era, RRM was temporarily installed by US astronauts Mike Fossum and Ron Garan onto a platform on the Dextre robot – the Special Purpose Dexterous Manipulator – which functions as a “handyman” in space.

Dextre is a two armed robot provided by CSA which is also a key component of the experiment because it enables the performance of repair and maintenance tasks at the heart of the RRM experiment.

RRM wire cutter experiment tool equipped with integral camera and LED lights on display at Kennedy Space Center Press Site: Credit: Ken Kremer

The washing machine sized unit weighs 500 pounds and was tucked inside the payload bay of Space Shuttle Atlantis and attached to the Lightweight Multipurpose Carrier (LMC) for the one way trip to space.

After Atlantis departs, RRM will be transferred to a permanent attach point on the stations truss and mounted on the Exterior Logistics Carrier 4 (ELC-4) of the million pound orbiting outpost.

RRM is NASA’s first ever such technology demonstration intended to test the feasibility of on orbit servicing operations on satellites that were not built to ever be worked upon and maintained after blasting off to space, according to Justin Cassidy, RRM Hardware Manager at the NASA Goddard Spaceflight Center in Greenbelt, Maryland.

The RRM box will simulate both the satellite to be serviced and the maintenance techniques required to perform both robotic refueling and repair work.

Full size Mock up of RRM box and experiment tool at KSC Press Site
Equipment Tool movements and manipulations by Dextre robot are simulated by NASA Goddard RRM manager Justin Cassidy. Credit: Ken Kremer

“The Dextre robot will manipulate four specially designed ‘Tools’ stored in bays inside the RRM,” said Cassidy in an interview at the Kennedy Space Center.

Using a high fidelity RRM mockup – nicknamed ‘Rosie’ – on display at the Kennedy Space Center Press Site, Cassidy spoke to me in detail about the RRM mission and objectives.

The four unique RRM tools have heritage in the Hubble Servicing Missions and were developed at NASA Goddard; The Wire Cutter and Blanket Manipulation Tool, The Multifunction Tool, the Safety Cap Removal Tool, and the Nozzle Tool.

“Dextre will grapple the tools and move them around with its ‘hands’ to perform refueling and maintenance tasks on activity boards and simulated satellite components mounted on the exterior walls of the RRM,” Cassidy told me. “The activity boards can be swapped in the future to carry out new experiments.”

High Fidelity Mock up of RRM experiment box at KSC Press Site. RRM was delivered to ISS during STS-135 mission. Credit: Ken Kremer

The RRM assignment marks the first use of Dextre beyond routine maintenance chores aboard the ISS. Indeed, the research project working with RRM is actually a new R & D function beyond what was originally planned and envisioned for Dextre, said Mathieu Caron, CSA Mission Operations manager.

Tasks planned for RRM include working on and manipulating caps, valves and screws of assorted shapes and sizes, cutting wires, adjusting thermal blankets and transferring fluids around fuel reservoirs. Ethanol will be used to simulate the flow of hydrazine fuel, said Cassidy.

“RRM will be operated by controllers on the ground at NASA Goddard, the Marshall Space Flight Center in Huntsville, Ala., and also in Canada by the Canadian Space Agency,” explained Cassidy.

Each RRM tool is equipped with integral cameras housing six built in LED’s to aid ground controllers precisely guide the tools.

“The RRM experiment phase to demonstrate robotic refueling and maintenance operations at the ISS is set to last two years and could continue for perhaps ten or more years,” said Cassidy.

President Obama asked the STS-135 crew about the RRM experiment during an Oval Office phone call from the White House to the ISS. Watch Obama’s phone call on YouTube

NASA hopes that the small investment in RRM technology demonstration will pave the way for advanced follow missions and private development of commercial robotic refueling and maintenance vehicles – in the not too distant future – that will reap billions of dollars in cost savings and dividends.

Artist concept of Robotic Refueling Mission experiment and Dextre robot (right) at work testing feasibility of satellite refueling at ISS. Credit: NASA
Demonstration of wire cutter tool snipping wires and multilayer insulation (MLI). Credit: Ken Kremer
RRM flight unit undergoes final pre-launch preparations inside the Space Station Processing Facility at the Kennedy Space Center. RRM is attached to the Lightweight Multipurpose Carrier (LMC) for eventual loading inside the shuttle payload bay. Credit: Ken Kremer
NASA Goddard RRM manager Justin Cassidy (right) and Ken Kremer manipulate RRM experiment tools. Credit: Chase Clark
Ken simulates manipulation of RRM experiment tool. Credit: Ken Kremer

Read my features about the Final Shuttle mission, STS-135:
Water Cannon Salute trumpets recovery of Last Shuttle Solid Rocket Boosters – Photo Album
Shuttle Atlantis Soars to Space One Last time: Photo Album
Atlantis Unveiled for Historic Final Flight amidst Stormy Weather
Counting down to the Last Shuttle; Stormy weather projected
Atlantis Crew Jets to Florida on Independence Day for Final Shuttle Blastoff
NASA Sets July 8 for Mandatory Space Shuttle Grand Finale
Final Shuttle Voyagers Conduct Countdown Practice at Florida Launch Pad
Final Payload for Final Shuttle Flight Delivered to the Launch Pad
Last Ever Shuttle Journeys out to the Launch Pad; Photo Gallery
Atlantis Goes Vertical for the Last Time
Atlantis Rolls to Vehicle Assembly Building with Final Space Shuttle Crew for July 8 Blastoff