1993 (30th) Yesterday's Vision is Tomorrow's The Space Congress® Proceedings Reality

Apr 27th, 2:00 PM - 5:00 PM

Paper Session I-C - Robotics for Interstellar Missions

Eric Rhodes NASA, Kennedy Space Center

A. J. Mauceri Rockwell International Corp., Space Systems Division

Margaret M. Clarke Rockwell International Corporation

Thomas S. Lindsay Rockwell International Corporation

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Scholarly Commons Citation Rhodes, Eric; Mauceri, A. J.; Clarke, Margaret M.; and Lindsay, Thomas S., "Paper Session I-C - Robotics for Interstellar Missions" (1993). The Space Congress® Proceedings. 7. https://commons.erau.edu/space-congress-proceedings/proceedings-1993-30th/april-27-1993/7

This Event is brought to you for free and open access by the Conferences at Scholarly Commons. It has been accepted for inclusion in The Space Congress® Proceedings by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. ROBOTICS FOR INTERSTELLAR MISSIONS Eric Rhodes NASA Kennedy Space Center, Florida 32899 A. J. Mauceri Margaret M. Clarke Thomas S. Lindsay Rockwell International Corporation Downey, California 90241

Abstract sion avoidance, vision systems, and special end- effectors. One example of this activity concerns System robot, This paper discusses the requirements for the KSC Thermal Protection mobile platform robotics in future interstellar missions and which provides an autonomous vision systems for the various robotic development acti­ and special end-effectors and describes positioning tasks. NASA KSC that are laying the basis navigation, inspection, and vities at download­ of the future. The first long- The robot can also store task data for for the robotics at KSC interstellar missions, which might ing at a later date. Other developments duration and controls for at the end of the 21 st century, would prob­ include special mechanisms occur and component ably be preceded by trips to outer planets in the robotic space vehicle cleaning the development of self-diag­ Solar System and by near-Solar interstellar inspection, and systems. In summary, probe missions. The time span, dangers, and nostics for automated a long way from achiev­ uncertainties involved would almost certainly while we are presently capabilities to support interstel­ decree that the first missions be unmanned. If ing the robotics present-day robotics development an interstellar mission involved a surface land­ lar missions, and at other NASA centers are ing, all initial exploration would be performed activities at KSC for these exciting future by robots or other autonomous devices. These laying the groundwork robots of the next century must possess true endeavors. autonomy: onboard intelligence; sensor sys­ Missions tems to provide information on the visual scene, 1. Interstellar temperature, radiation, task forces, and torques; as the area in stable locomotion; self-maintenance and repair Interstellar space is defined physical bodies, capabilities; and so on. The varied sensor data space where local effects of Solar System, must be integrated into an intelligent under­ such as the Sun or planets in the Vick, 1991). standing of the environment to support deci­ can be neglected [Drysdale and has come to sions concerning that environment—for exam­ More generally, interstellar space the heliosphere ple, avoiding collisions or other dangers, or be known as the area beyond units from selecting areas of interest for exploration. The (approximately 50-100 astronomical object outside the capability to store and transmit data, and to the Sun). A mission to any through interstel­ modify behavior based on experience, would heliosphere will require travel becomes also be required. Many of these capabilities are lar space, and therefore, the mission outlines sev­ in their infancy today. However, NASA is an interstellar mission. Drysdale interstellar space. expanding the state-of-the-art of robotics in eral locations of interest in near-Solar inter­ directions which, while supporting near-term Selected (hypothetical) future in Table 1. Short- endeavors, will eventually lay the necessary stellar missions are outlined space are foundation for the interstellar missions of the distance missions into interstellar Pioneer 10 and next century. For instance, the NASA KSC within reach, as exemplified by journeys robotics program is making very meaningful 11, and the Voyager probes, on their contributions in areas of robot mobility, colli­ past the planets of the Solar System.

3-35 Table 1. Future Interstellar Mission Tasks System could validate the utility of robotics for longer missions. Technologies and needs for Duration (Years) Mission (Conservative) interstellar mission robots can be explored and tested Precisely locate magnetopause 10 1 on missions closer to home; there will be many 10 1 opportunities for missions within the Characterize helbsphere Solar System before any interstellar missions Examine heliosphere boundary phenomena will be fully developed. Technologies that will Look tor effects of a possible Solar binary require further development for interstellar mis­ twin ("Nemesis") sions can be identified under less critical Examine space/time effects without curva­ 10 1 -102 conditions. ture due to Sun Observe Universe from beyond heliosphere: 10 1 -102 A typical near-future mission to the outer TAU Observatory [Anderson, 1992] Solar System is described below, with emphasis Explore area between stars: interstellar 102-103 placed on medium, Oort Cloud the robotic technology necessary for its success. The purpose of this mission is to explore several large asteroids in the asteroid The time and distance, dangers, and uncer­ belt. The Asteroid Prospector mission [Walters tainties involved in interstellar missions place et. al, 1989] provides basic feasibility of such great costs on the use of manned spacecraft, at a mission, although robotic capabilities are not least for the foreseeable future. However, the highlighted in this study. A similar mission need for spacecraft maintenance on long-dura­ could explore the moons of Neptune, a group tion missions will require some type of interven­ of interstellar asteroids, or even the planets tion capabilities. Just as advanced propulsion orbiting a distant star. systems need to be developed for interstellar missions, advanced robotic systems must also The mission plan presented here (modified from the Asteroid Prospector) involves be developed to fulfill these intervention needs. explora­ tion of five The Thousand Astronomical Unit (TAU) Probe asteroids, including deployment of surface probes Mission [Nock, 1987], for example, will be and maintenance of communica­ tion between each powered by nuclear energy and is expected to surface probe and Earth. The scenario is outlined have a 50-year duration. Robots aboard this in Table 2. Each phase of the mission probe will be used (1) to assemble the spacecraft will require some level of robotic intervention. from its ground-launch configuration and (2) to Telerobotics will be used for assembly maintain all spacecraft systems. Many of the of the Large Space Vehicle (LSV) in onboard systems will require periodic mainte­ Earth orbit (Task 1), minimizing the EVA nance during this long-duration mission. For needed. This level of robotic capability will general interstellar missions, robots will be used likely be implemented as basic space station for spacecraft assembly, general spacecraft technology. Task 2 will require autonomous, maintenance (including maintenance of nuclear preprogrammed deployment of the Asteroid power systems and communication systems), Table 2. Asteroid Exploration Mission and the release of probes (similar to the manner Scenario in which satellites are released from the STS Task 1: Assemble Large Space Vehicle (LSV) in Earth orbit. LSV is using the RMS). When planets or other physical launched toward asteroid belt bodies are encountered, surface probes with Task 2: Orbit asteroid, deploy Asteroid Exploration Satellite (AES). robotic capabilities will be utilized for explora­ LSV continues to next asteroid tion and sampling. Robotics will play a key role Task 3: AES deploys surface probe, then acts as communication on any interstellar mission. satellite (direct communication to Earth) Task 4: Surface probe explores asteroid surface: Subtask 4.1 : Assemble antenna for communications with AES Before a robot-assisted interstellar mission Subtask 4.2: Autonomously explore asteroid surface is initiated, there are likely to te precursor mis­ Subtask 4.3: Launch samples back to Earth (includes construc­ sions to the outer Solar System. A successful tion of a launch site by surface probe, further construction, and relay to Earth by AES) robotic-assisted mission within the Solar

3-36 Exploration Satellite (AES) from the LSV. The be used to modify behavior based on experi­ robotic technology needed is similar to STS sat­ ence, and to select areas that require further ellite deployment currently in use, but requires exploration or sensing. Robust sensing is autonomy instead of teleoperation. Task 3 extremely important for distant robotic mis­ requires self-guided deployment of surface sions. Force/torque, vision., and, other sensors probe from AES. This will require autonomous for specific needs (temperature and radiation.'for path generation by the deploying arm to guide monitoring power plants, for example) may be the probe into an entry trajectory calculated adequate for space vehicle-based robots; much autonomously. A surface probe will require more sensing is required for surface probes, many autonomous robotic capabilities (Task 4). including material characterization abilities and. Surface mapping, sensing, data gathering, and mapping, vision, and. sen.sor-gui.ded motion, A navigation will all be accomplished autono­ high level of dexterity/hianipulability is also mously. Further, the probe must have stable required for the robots aboard space missions: locomotion over rugged surfaces; must be able robot arms must reach all parts of space to mine, gather, and analyze samples; and must vehicles/surface probes, including the robot be able to perform basic construction needs, arms themselves, for maintenance and repair. such as building a communications antenna and This will require more articulation than most a launch site for returning data and samples to of today's robots, which will generally lead to the orbiting AES for relay to Earth. All tasks more degrees of freedom in manipulators, and require that all of the systems on the mission therefore, to more complex control algorithms, (robotic and others) must be self-diagnosing. Because it is almost impossible to characterize Further, all systems must be maintainable dur­ all failure modes'(and then design a robot: which ing the mission; the onboard robots should be can repair all failures), a form, of robotic self- able to accomplish all scheduled maintenance replication may be necessary.. This would. and most unscheduled maintenance (including involve one robot, using generic robotic subas- self-maintenance of the robotic systems them­ semblies, to assemble another robot with the selves). This is important on long-duration mis­ articulation or dynamic characteristics neces­ sions to extend the life of component systems. sary for a specific task. As mentioned pre­ Further, the success of the mission does not have viously, the robots must have setf-diagpostics* to depend on 100-percent reliability of all com­ to determine when and where troubles have ponent systems, because there is the ability for occurred. The robot systems cannot be expected on-mission repairs. to be lOO-percent Miiibite, However, provisions must 'be made: for 1 self-maintenance and self-re­ 2. Robotics Requirements pair when problems have 'been detected. The farther 1 away the mission takes the robots The generic capabilities needed for space Earth, the longer they must survive* 'With self- robots generally increase as the distance from diagnostics, setf-mamtenance, and self-repair, human intervention increases. The further away system, life can be Increased,,,, Tie; capabilities from Earth, the more intelligent robots must be. described above arc "baseline characteristics Telerobots in Earth orbit can be relatively unin­ necessary 'for 1 robotics 'for interstellar- missions,, telligent, mainly controlled manually by human operators with low levels of robotic assistance. 3. Present-Pay Capabilities Being But a surface probe on a distant asteroid must Developed by NASA, be fully autonomous. Robot systems for inter­ stellar missions similarly must be fully autono­ The rototi.cs program at KSC focuses on the mous. Such intelligence may be obtained using implementation of robotics in Space Shuttle artificial intelligence techniques, including neu­ reprocessing;, 'For example, capabilities in ral nets and knowledge-based (expert) systems, autonomous navigation, special end-effectors, and using advanced control techniques for vision systems, and self-diagnostics are being uncertain situations (adaptive control, fuzzy developed,, While these activities have the logic control, etc.). Artificial intelligence can obvious near-term goal of more efficient space

3-37 vehicle reprocessing, they also contribute to the [Spencer et. al., 1992]. The inspection system foundations of robotics for the advanced mis­ utilizes robotic motion and sensors to complete sions of the next century. Table 3 relates the the certification task during one shift, rather needed future capabilities to present-day robot­ than the 1-week downtime currently required. ics projects at KSC. These projects are dis­ Further, the robot is better able to follow the cussed below. desired sensor trajectory for proper filter inspection than are the human workers. The Table 3. Basic Capabilities for Robots for Interstellar Missions HFCR has the mobility to reach the majority of the ceiling filters, utilizing a 4-degree-of- Need Capability Applicable KSC Projects freedom (DOF) manipulator that travels on Mobility/articulation HFCR, ARID, IPS existing ceiling-mounted overhead crane tracks Sensors HFCR, ARID, IPS (Figure 1). As well as using specialized sensors Diagnostics IPS to detect leaks in the filters, the robot will be able to modify its motion based on sensors that Intelligence IPS monitor obstacles, which will greatly increase Self-replication HFCR system safety. The modular design of the HFCR greatly enhances its maintainability and useful­ HFCR System ness. Component parts can be removed and replaced easily when components fail, and it The high-efficiency particle accumulator would be possible to replace certain compo­ (HEPA) filter certification robot (HFCR) will nents with other parts that have superior perfor­ be used to maintain the "clean" environment of mance for specific tasks. The ease of integration the pay load changeout rooms (PCRs) at KSC of the components into the system (the robot can

Figure 1. The HFCR Inspecting HEPA Filters

3-38 be assembled from its six major parts in 30 min­ ambiguities; and shorten Shuttle flow time. utes or less) indicates that such a process could be accomplished with another robot—a form of The ARID trolley moves on a 65-foot beam self-replication which will become quite (rack) along each side of the payload bay in important in future-generation robots. order to access the entire surface of the bay doors (Figure 2). An articulated arm is attached to the trolley and holds a visual inspection sys­ ARID Robot tem. It moves along each radiator panel, moves forward in increments of 4 inches, and moves The orbiter radiators are currently inspected back. Repeating this pattern, it completes a twice in the Orbiter Processing Facility (OFF) sweep of each side in about 3 hours. The arm for any damage that may have been sustained. utilizes complete redundancy in computers, This task is a time-consuming, laborious pro­ drive motors, and software; it may be the cess, and under certain circumstances, it is diffi­ world's first robot with total redundancy. cult for workers to quantify damaged radiators. To alleviate these problems, the Automated TPS Robot Radiator Inspection Device (ARID) was con­ ceived. The ARID will automatically inspect The Thermal Protection System (TPS) robot the Space Shuttle orbiter radiators, located on will be used to inspect and reprocess the orbiter the underside of the payload bay doors, for tiles after each flight [Dowling et. al., 1992; defects. It will inspect the radiators twice during Manouchehri et. al., 1992]. It is the first KSC each OFF flow—a postflight inspection and a robot that utilizes a fully mobile base to achieve close-out inspection prior to rollout, as in the the mobility necessary to reach all orbiter tiles manual process. The system will measure the (Figure 3). This requires more advanced defects in 2-D and 3-D, and automatically gen­ intelligence for navigation; the TPS compares erate the problem paper for an engineer to dis­ internal mapping with vision system input to position. It will allow reliable, repeatable align itself to the orbiter and area targets. Vision inspection of the radiators; end quantification sensors are also used for automated inspection

Figure 2. The ARID Inspecting Orbiter Radiators

3-39 Figure 3. The TPS Robot Servicing Orbiter Tiles and precise positioning of the manipulator with also an important step toward the future of respect to target tiles. Specialized end-effectors robotics in the next century. The contributions could then be used for various tasks, including toward key robotic characteristics today will injection of a rewaterproofing compound into lead to development of robotics for space mis­ the tiles and inspection of tile integrity. The sions of the future, and will eventually result protection of the orbiter during these operations in robotic system technology that will enable is extremely important, because the robot sys­ interstellar missions. tem makes physical contact with the tiles. Intel­ ligent control algorithms, including fuzzy logic [Anderson, 1992] John L. Anderson, "Horizon and adaptive control, for example, are being Mission Technology Study," in Proceedings of developed, for one of the active end-effectors to the Twenty-Ninth Space Congress, Coco Beach, ensure that the force against the tile is main­ Florida, April 21-24, 1992. tained within the proper limits. The system must also have diagnostic and 'failure detection capa­ [DowlingeL at, 1992] K. Dowling, R. Bennett, bilities; failure of the system to inject the rewa­ M. Blackwell, T. Graham, S. Gatrall, R. terproofing compound into a tile must be O'Toole, and R Schempf, "A Mobile Robot . detected and documented,,. Additionally, a sys­ System for Ground Servicing Operations on the tem monitors various sensor signals from com­ Space Shuttle," in Proceedings of the SPIE OEI ponent hardware and functions as a smart fuse Technology '92 Conference, Boston, Massachu­ when it detects problems, and corrective action setts, November 15-20, 1992. can be taken utilizing this sensor-based diagnos­ tic feature, [Drysdale and Vick, 1991] Alan Drysdale and Jerry Vick, "Interstellar Initiatives," in Proceed­ ings of the Twenty-Eighth Space Congress, 4 Conclusion Coco Beach, Florida, April 23-26, 1991. The development of robotics systems to ful­ [Manouchehri et. al., 1992] Davoud Manou- fill current implementational needs at KSC is chehri, Joseph M. Hansen, Cheng M. Wu, Brian

3-40 S. Yamamoto, and Todd Graham. "Robotic [Spencer et. al., 1992] James Spencer, Gabor End-Effector for Rewaterproofing Shuttle Tamasi, and Dan Wegerif, Ph.D., "A Robotic Tiles," in Proceedings of the SPIEOE/Technol- System for Inspecting Clean Room Filters at ogy '92 Conference, Boston, Massachusetts, KSC," in BrevardTechnicalJournal, December November 15-20, 1992. 1992. [Walters et. al., 1989] Devin C. Walters, [Nock, 1987] H.T. Nock, "TAU—A Mission to Howard Clark, D.C. Conroy, Alex Cos, Doug a Thousand Astronomical Units," Fullingim, Matt Dubois, Wim Libby, Joseph C. AIAA-87-1049, 19th AIAA/DGLR/JSASS Medlin, and Vincent Reyna, 'The Prospector's International Electronic Propulsion Confer- Proposal," in Proceedings of the Twenty-Sixth ence, Colorado Springs, Colorado, May 11-13, Space Congress, Coco Beach, Florida, April 1987. 25-28, 1989.

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