David S. Mittman

Development and field testing of the FootFall planning system for the ATHLETE robots

The FootFall Planning System is a ground-based planning and decision support system designed to facilitate the control of walking activities for the ATHLETE (All-Terrain Hex-Limbed Extra-Terrestrial Explorer) family of robots. ATHLETE was developed at NASAs Jet Propulsion Laboratory and is a large, six-legged robot designed to serve multiple roles during manned and unmanned missions to the moon; its roles include transportation, construction, and exploration. Over the 4 years from 2006 through 2010 the FootFall Planning System was developed and adapted to two generations of the ATHLETE robots and tested at two analog field sites [the Human Robotic Systems Projects Integrated Field Test at Moses Lake, Washington, June 2008, and the Desert Research and Technology Studies (D-RATS), held at Black Point Lava Flow in Arizona, September 2010]. Having 42 degrees of kinematic freedom, standing to a maximum height of just over 4 m, and having a payload capacity of 450 kg in Earth gravity, the current version of the ATHLETE robot is a uniquely complex system. A central challenge to this work was the compliance of the high-degree-of-freedom robot, especially the compliance of the wheels, which affected many aspects of statically stable walking. This paper reviews the history of the development of the FootFall system, sharing design decisions, field test experiences, and the lessons learned concerning compliance and self-awareness.

FootFall: A Ground Based Operations Toolset Enabling Walking for the ATHLETE Rover

The ATHLETE (All-Terrain Hex-Limbed Extra-Terrestrial Explorer) vehicle consists of six identical, six degree of freedom limbs. FootFall is a ground tool for ATHLETE intended to provide an operator with integrated situational awareness, terrain reconstruction, stability and safety analysis, motion planning, and decision support capabilities to enable the efficient generation of flight software command sequences for walking. FootFall has been under development at NASA Ames for the last year, and having accomplished the initial integration, it is being used to generate command sequences for single footfalls. In this paper, the architecture of FootFall in its current state will be presented, results from the recent Human Robotic Systems Project?s Integrated Field Test (Moses Lake, Washington, June, 2008) will be discussed, and future plans for extending the capabilities of FootFall to enable ATHLETE to walk across a boulder field in real time will be described.

Lessons Learned from All-Terrain Hex-Limbed Extra-Terrestrial Explorer Robot Field Test Operations at Moses Lake Sand Dunes, Washington

The Jet Propulsion Laboratory (JPL) is developing the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) as part of NASA’s Exploration Systems Mission Directorate, Exploration Technology Development Program (ETDP). The program develops technologies for surface mobility and equipment handling, human-system interaction, and lunar surface system repair, and constructs dexterous robots and autonomous rovers that can drive over rough terrain and help crew explore, assemble, and maintain a lunar outpost. ETDP sponsors a series of field tests at lunar analog test sites where prototype robots can operate in ways that simulate lunar surface conditions. In this paper, we describe the lessons learned about ATHLETE operations at the most recent lunar analog field test in June 2008 at Moses Lake Sand Dunes, Washington. The Moses Lake field test was structured as a series of “acts” which correspond to unpiloted and piloted missions to the lunar surface in the 2019 to 2022 timeframe. The field test took place over a period of two weeks and involved several robots from various NASA field centers, including the Chariot lunar truck from Johnson Space Center, the K10 planetary rover from Ames Research Center, and ATHLETE from JPL. Lessons learned from the Moses Lake field test will be incorporated into the evolving design of the ATHLETE operations system, and will be tested at subsequent field trials.

Planning and scheduling the Spitzer Space Telescope

Launched as the Space Infrared Telescope Facility (SIRTF) in August, 2003 and renamed in early 2004, the Spitzer Space Telescope is performing an extended series of science observations at wavelengths ranging from 3 to 180 microns. The California Institute of Technology is the home of the Spitzer Science Center (SSC) and operates the Science Operations System (SOS), which supports science operations of the Observatory. A key function supported by the SOS is the long-range planning and short-term scheduling of the Observatory. This paper describes the role and function of the SSC Observatory Planning and Scheduling Team (OPST), its operational interfaces, processes, and tools.

Modular Additive Construction Using Native Materials

Using modular construction equipment and additive manufacturing (3D printing) techniques for binding, mission support structures could be prepared on remote planetary surfaces using native regolith. Material mass contributes significantly toward the cost of deep space missions, whether human or robotic, due to the resources needed to lift each kilogram of equipment out of Earth’s gravity well. Proposing the modular Freeform Additive Construction System (FACS) concept, using the reconfigurable All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) robotic mobility platform, a variety of walls, berms, vaults, domes, paving, and thick radiation shielding could be prepared in advance of crews and mission assets to help reduce the material needed to be brought from Earth. This paper discusses the current ATHLETE technology, and describes how flexible mission elements could be derived using a combination of three dimensional additive construction and in-situ manufacturing technologies using native regolith.

The Human Exploration Telerobotics project: Objectives, approach, and testing

In this paper, we present an overview of the NASA Human Exploration Telerobotics (HET) project. The purpose of HET is to demonstrate and assess how telerobotics can improve the efficiency, effectiveness, and productivity of human exploration missions. To do this, we are developing and testing advanced robots remotely operated by ground controllers on Earth and by crew on the International Space Station. The outcome of these tests will provide insight into the requirements, benefits, limitations, costs and risks of integrating advanced telerobotics into future human missions. In addition, the engineering data acquired during these tests will inform the design of future telerobotic systems.

The Exploration Technology Development Program Multi-Center Cockpit

NASA’s Exploration Systems Mission Directorate, Exploration Technology Development Program (ETDP) develops the technologies needed for future human lunar exploration missions. Advanced robotic systems can help the crew explore, assemble, and maintain a lunar outpost. The ETDP Multi-Center Cockpit (EMCC) is a computer workstation that allows an operator to simultaneously monitor and command groups of diverse robots. The EMCC may be located at a robot test site or at a location significantly removed from the test site. The robots being controlled can be located together at a single test site, or can be located at different sites. The EMCC eliminates the need for an operator to understand different robot languages, and reduces the difficulty of operating a robot over time delays, such as the ones introduced by the Earth-Moon distance or by communication network latency. The EMCC provides the operator with a unified command and telemetry interface for monitoring the robots and with a predictive graphical display of the robots. In this paper, we describe the EMCC design and implementation, and report on its performance in June 2008 during the ETDP Human-Robotic Systems Integrated Field Test at Moses Lake Sand Dunes, Washington.

Driving ATHLETE: Analysis of Operational Efficiency

The All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) is a modular mobility and manipulation platform being developed to support NASA operations in a variety of missions, including exploration of planetary surfaces. The agile system consists of a symmetrical arrangement of six limbs, each with seven articulated degrees of freedom and a powered wheel. This design enables transport of bulky payloads over a wide range of terrain and is envisioned as a tool to mobilize habitats, power-generation equipment, and other supplies for long-range exploration and outpost construction. In 2010, ATHLETE traversed more than 80 km in field environments over eight weeks of testing, demonstrating that the concept is well suited to long-range travel. However, while ATHLETE is designed to travel at speeds of up to 5 kilometers per hour, the observed average traverse rate during field-testing rarely exceeded 1.5 kilometers per hour. This paper investigates sources of inefficiency in ATHLETE traverse operations and identifies targets for improvement of overall traverse rate.

The JPL/KSC telerobotic inspection demonstration

Abstract An ASEA IRB90 robotic manipulator with attached inspection cameras was moved through a Space Shuttle Payload Assist Module (PAM) Cradle under computer control. The Operator and Operator Control Station, including graphics simulation, gross-motion spatial planning, and machine vision processing, were located at the Jet Propulsion Laboratory (JPL) in California. The Safety and Support personnel, PAM Cradle, IRB90, and image acquisition system, were stationed at the Kennedy Space Center (KSC) in Florida. Images captured at KSC were used both for processing by a machine vision system at JPL, and for inspection by the JPL Operator. The system found collision-free paths through the PAM Cradle, demonstrated accurate knowledge of the locations of obstacles and of objects of interest, and operated with a communication delay of two seconds. Safe operation of the IRB90 near Shuttle flight hardware was obtained through the use of both a gross-motion spatial planner developed at JPL using artificial intelligence techniques, and infrared beams and pressure sensitive strips mounted to the critical surfaces of the flight hardware at KSC. The Demonstration showed that ground/remote telerobotics is effective for real tasks, safe for personnel and hardware, and highly productive and reliable for Shuttle payload operations and Space Station external operations.

Deploying the Robot Application Programming Interface Delegate via second-generation IP-over-DTN

The Robot Application Programmer Interface Delegate (RAPID) is a pipeline designed for telerobotic operations in the Human Exploration Technology (HET) Program. As human spaceflight missions become more ambitious and far reaching (for example, long duration operations on board ISS or around near-Earth asteroids), traditional telerobotic technology becomes expensive, unwieldy and difficult to scale. We present a RAPID deployment architecture that leverages the advantages of COTS internetworking infrastructure while enjoying many of the benefits of space-optimized Delay/Disruption Tolerant Network (DTN) technology. DTNTAP is a multi-platform second-generation IP over DTN implementation with performance and usability improvements over its predecessor. Selected results from functional and performance tests are presented and new capabilities are described.