Robotic Satellite Servicing Mission Support

Since 2008, The PTR Group has held key technical and project management roles  supporting the Robotic Demonstration and Test Group, in the Satellite Servicing Capabilities Office (SSCO) at NASA Goddard Space Flight Center. PTR Group engineers have architected, designed and built a next generation distributed, cooperative, multi-robot software system to both demonstrate servicing tasks on the ground, and to evaluate the accuracy, capability, and usefulness of robotic servicing tools. Our engineers have been responsible for definition and implementation of a software development process satisfying NASA requirements, as well as working directly with robot hardware manufacturers to integrate their robots into the final system and to provide the level of required performance.

Robotic Satellite Servicing

One of the key technologies identified in NASA’s Robotics, Tele-Robotics Systems Roadmap is the capability to service spacecraft.   The Satellite Servicing Capabilities Office (SSCO) (http://ssco.gsfc.nasa.gov) at the Goddard Space Flight Center (GSFC) is the group responsible for advancing the state-of-the-art in satellite servicing and repair.   While the SSCO had a long history of creating spacecraft tools and performing astronaut-based spacecraft servicing missions like the Hubble Space Telescope Servicing Missions, they needed help in making the transition to robotic satellite servicing systems.

SSCO needed to expand the robotics test facility to use as an incubator for developing and testing satellite servicing technologies before deploying them in orbit.   Engineers from the PTR Group analyzed NASA’s satellite servicing plans and architected a next-generation system development test bed.  We designed a powerful, yet flexible software system.  We implemented most of the key components. To control the robot hardware, PTR developed a complete software system that included low-level device control software, high-level graphical user interface applications, and the communication infrastructure needed to command the robotic arms and collect telemetry from them.  The PTR Group designed and realized the networking infrastructure.   We continue to expand the system capabilities and adapt to SSCO’s dynamic needs and functional requirements.  The testbed also supports evaluation of the capabilities, accuracy, and effectiveness of robotic servicing tools and manipulators.

Robotic systems design requires expertise in both robotic control and embedded software design.  The PTR Group has repeatedly applied unique knowledge and experience in both of these areas to solve the difficult problems and build functional robotic systems at GSFC.  We work alongside the SSCO roboticists and control engineers to put theory into practice.   We take the algorithms and software prototypes and make them work in the real world with real hardware and electronics.   The PTR Group takes the long-term approach in this area, spending the extra time to improve the software architecture and implement clean solutions.  The end result is that we have been able to integrate new robots, sensors and algorithms into the SSCO systems in very short time frames.

The PTR Group engineers also define and implement the interfaces to the external software systems and electronics.   We have worked closely with several commercial robot vendors to define and implement new realtime interfaces to their legacy systems.   This has enabled the robotics team at GSFC to use commercial robotic systems for robotic algorithm and flight software development.   Moreover, as the number of supported robotic systems and sensor system grow, the increased capability and flexibility has enabled SSCO to push the boundaries of satellite servicing technology.

In the Fall of 2015, The PTR Group's work with SSCO was featured in the cover story of NASA's Cutting Edge magazine.  Our own robotics engineer Stephen Roderick was featured on the cover page.  The article details NASA's ongoing work in robotic space servicing and refueling. 

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Robotic Servicing Mission Support

SSCO is studying and developing technologies for a notional Robotic Servicing Mission (http://ssco.gsfc.nasa.gov/robotic_servicing_mission.html).  The main system in this mission is a servicing vehicle to repair, service and refuel satellites in geosynchronous Earth orbit.  The PTR Group is part of the team specifying the systems requirements, implementing subsystem prototypes, and supporting testing and evaluation of flight hardware and systems.  We are architecting the future flight software and designing the interfaces to other software subsystems.   Moreover, we are leveraging the capabilities of the ground development to implement a flight-like software solution using commercial robots and flight-like electronics.

Ongoing work by PTR involves translating the results from ground-based testing into a working system that can operate in space.  PTR developed a path-to-flight plan that adapts the software running on high-performance desktop computers to operate within resource-limited, space-rated, embedded platforms.  This migration plan ensures that flight-rated robotic manipulators can perform to the same level as ground-based demonstrations.

The experienced engineers from the PTR Group form the leadership core of the robotic software team.  We act as both the software manager and the lead software engineer.

As the software manager the PTR Group plans the short and long term activities of the team.  We decompose the software tasks and assign resources as needed. We manage the day-to-day operations, adapting the schedules and technology plans to support flight operations like the Robotic Refueling Mission (http://ssco.gsfc.nasa.gov/robotic_refueling_mission.html).  Our software manager also interfaces to other groups in SSCO in order to provide complete satellite servicing capabilities.   Under our leadership, the SSCO robotic software has grown to include over fifteen software developers.

In the role of lead software engineer, the PTR Group defines and implements the robotic software at the system level.   Our software design supports a variety of robots, sensors and external systems while being reliable and flexible.  In addition to specifying and software design, the PTR Group also defines the software development process used by the SSCO robotic software engineers.  We encourage industry standards and champion open source tools to enable the rest of the team to focus on the robotics technology and solving the difficult satellite servicing problems.

The PTR Group also supports SSCO through the use of social media.   Our engineers maintain and update the Robot Part of the Day (http://robotpartoftheday.tumblr.com), a site dedicated to sharing what happens behind the scenes at our robotic facility.

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