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NASA NTRS2000

Rovers as Geological Helpers for Planetary Surface Exploration

Rovers can be used to perform field science on other planetary surfaces and in hostile and dangerous environments on Earth. Rovers are mobility systems for carrying instrumentation to investigate targets of interest and can perform geologic exploration on a distant planet (e.g. Mars) autonomously with periodic command from Earth. For nearby sites (such as the Moon or sites on Earth) rovers can be teleoperated with excellent capabilities. In future human exploration, robotic rovers will assist human explorers as scouts, tool and instrument carriers, and a traverse "buddy". Rovers can be wheeled vehicles, like the Mars Pathfinder Sojourner, or can walk on legs, like the Dante vehicle that was deployed into a volcanic caldera on Mt. Spurr, Alaska. Wheeled rovers can generally traverse slopes as high as 35 degrees, can avoid hazards too big to roll over, and can carry a wide range of instrumentation. More challenging terrain and steeper slopes can be negotiated by walkers. Limitations on rover performance result primarily from the bandwidth and frequency with which data are transmitted, and the accuracy with which the rover can navigate to a new position. Based on communication strategies, power availability, and navigation approach planned or demonstrated for Mars missions to date, rovers on Mars will probably traverse only a few meters per day. Collecting samples, especially if it involves accurate instrument placement, will be a slow process. Using live teleoperation (such as operating a rover on the Moon from Earth) rovers have traversed more than 1 km in an 8 hour period while also performing science operations, and can be moved much faster when the goal is simply to make the distance. I will review the results of field experiments with planetary surface rovers, concentrating on their successful and problematic performance aspects. This paper will be accompanied by a working demonstration of a prototype planetary surface rover.

Stoker, Carol↗

NASA NTRS2001

Accessing Martian Fluvial and Lacustrine Sediments by Landing in Holden Crater, Margaritifer Sinus

Rover missions to the surface of Mars after MER 2003, are likely to be centered around focused geologic field mapping. One objective with high priority in selecting landing sites for these missions will be to characterize the nature, spatial distribution, internal structure, composition, and depositional history of exposed sedimentary layered deposits by visiting a number of distributed outcrops identified previously (and with a high degree of certainty) from orbit. These deposits may contain prebiotic material, even fossil organisms, but their primary value will be to enable an assessment of the planet's climate at the time they were emplaced. High resolution imaging from a mobile rover will enable the detailed study of these deposits over a wide area, their internal structure and mineralogy at distributed localities, and could resolve biologically-derived structures (such as stromatolite-like textures) if they are present. With the addition of a spectrometer, it should be possible to ascertain the presence of carbonates, sulfates, organics, water (liquid, frost, and bound water), as well as a variety of silicate minerals in the context of the collected imagery. Such a mission approach is directly relevant to future exploration of Mars, because it provides the geologic context comparable to what a field geologist visiting a site for the first time would acquire. Rover missions after MER will likely have much better targeting and hazard avoidance landing systems, enabling access to planimetrically-challenged sites of high scientific interest. These vehicles will also likely have greater mobility than MER, capable of driving greater distances in a shorter amount of time. Many scientists and mission planners have realized the need to design a rover whose mobility can be comparable to the dimensions of its 3-sigma landing error ellipse.

Parker, T. J.↗

NASA NTRS2002

Use of Traffic Intent Information by Autonomous Aircraft in Constrained Operations

This paper presents findings of a research study designed to provide insight into the issue of intent information exchange in constrained en-route air-traffic operations and its effect on pilot decision-making and flight performance. The piloted simulation was conducted in the Air Traffic Operations Laboratory at the NASA Langley Research Center. Two operational modes for autonomous flight management were compared under conditions of low and high operational complexity (traffic and airspace hazard density). The tactical mode was characterized primarily by the use of traffic state data for conflict detection and resolution and a manual approach to meeting operational constraints. The strategic mode involved the combined use of traffic state and intent information, provided the pilot an additional level of alerting, and allowed an automated approach to meeting operational constraints. Operational constraints applied in the experiment included separation assurance, schedule adherence, airspace hazard avoidance, flight efficiency, and passenger comfort. The strategic operational mode was found to be effective in reducing unnecessary maneuvering in conflict situations where the intruder's intended maneuvers would resolve the conflict. Conditions of high operational complexity and vertical maneuvering resulted in increased proliferation of conflicts, but both operational modes exhibited characteristics of stability based on observed conflict proliferation rates of less than 30 percent. Scenario case studies illustrated the need for maneuver flight restrictions to prevent the creation of new conflicts through maneuvering and the need for an improved user interface design that appropriately focuses the pilot's attention on conflict prevention information. Pilot real-time assessment of maximum workload indicated minimal sensitivity to operational complexity, providing further evidence that pilot workload is not the limiting factor for feasibility of an en-route distributed traffic management system, even under highly constrained conditions.

Wing, David J.↗

NASA NTRS2002

Airborne Use of Traffic Intent Information in a Distributed Air-Ground Traffic Management Concept: Experiment Design and Preliminary Results

This paper presents initial findings of a research study designed to provide insight into the issue of intent information exchange in constrained en-route air-traffic operations and its effect on pilot decision making and flight performance. The piloted simulation was conducted in the Air Traffic Operations Laboratory at the NASA Langley Research Center. Two operational modes for autonomous operations were compared under conditions of low and high operational complexity. The tactical mode was characterized primarily by the use of state information for conflict detection and resolution and an open-loop means for the pilot to meet operational constraints. The strategic mode involved the combined use of state and intent information, provided the pilot an additional level of alerting, and allowed a closed-loop approach to meeting operational constraints. Operational constraints included separation assurance, schedule adherence, airspace hazard avoidance, flight efficiency, and passenger comfort. Potential operational benefits of both modes are illustrated through several scenario case studies. Subjective pilot ratings and comments comparing the tactical and strategic modes are presented.

Wing, David J.↗

NASA NTRS2004

An Integrated Decision-Making Model for Categorizing Weather Products and Decision Aids

The National Airspace System s capacity will experience considerable growth in the next few decades. Weather adversely affects safe air travel. The FAA and NASA are working to develop new technologies that display weather information to support situation awareness and optimize pilot decision-making in avoiding hazardous weather. Understanding situation awareness and naturalistic decision-making is an important step in achieving this goal. Information representation and situation time stress greatly influence attentional resource allocation and working memory capacity, potentially obstructing accurate situation awareness assessments. Three naturalistic decision-making theories were integrated to provide an understanding of the levels of decision making incorporated in three operational situations and two conditions. The task characteristics associated with each phase of flight govern the level of situation awareness attained and the decision making processes utilized. Weather product s attributes and situation task characteristics combine to classify weather products according to the decision-making processes best supported. In addition, a graphical interface is described that affords intuitive selection of the appropriate weather product relative to the pilot s current flight situation.

Elgin, Peter D.↗

NASA NTRS2001

Airborne Use of Traffic Intent Information in a Distributed Air-Ground Traffic Management Concept: Experiment Design and Preliminary Results

Wing, David J.↗

NASA NTRS2002

Bioinspired engineering of exploration systems for NASA and DoD

A new approach called bioinspired engineering of exploration systems (BEES) and its value for solving pressing NASA and DoD needs are described. Insects (for example honeybees and dragonflies) cope remarkably well with their world, despite possessing a brain containing less than 0.01% as many neurons as the human brain. Although most insects have immobile eyes with fixed focus optics and lack stereo vision, they use a number of ingenious, computationally simple strategies for perceiving their world in three dimensions and navigating successfully within it. We are distilling selected insect-inspired strategies to obtain novel solutions for navigation, hazard avoidance, altitude hold, stable flight, terrain following, and gentle deployment of payload. Such functionality provides potential solutions for future autonomous robotic space and planetary explorers. A BEES approach to developing lightweight low-power autonomous flight systems should be useful for flight control of such biomorphic flyers for both NASA and DoD needs. Recent biological studies of mammalian retinas confirm that representations of multiple features of the visual world are systematically parsed and processed in parallel. Features are mapped to a stack of cellular strata within the retina. Each of these representations can be efficiently modeled in semiconductor cellular nonlinear network (CNN) chips. We describe recent breakthroughs in exploring the feasibility of the unique blending of insect strategies of navigation with mammalian visual search, pattern recognition, and image understanding into hybrid biomorphic flyers for future planetary and terrestrial applications. We describe a few future mission scenarios for Mars exploration, uniquely enabled by these newly developed biomorphic flyers.

Space Flight↗

NASA NTRS2005

The Mars Exploration Rover Cameras: A Status Report

With more than 68,000 images returned from the surface of Mars to date, the Mars Exploration Rover (MER) camera suite continues to perform extremely well. Image signal to noise ratios (SNRs) are greater than 200:1, flat fields remain stable, and single-pixel degradation has been negligible. Acting as the eyes of the robotic field geologists, the 18 MER cameras continue to play a leading role in major scientific findings at both Gusez Crater and Meridiana Planum. All 4 types of cameras, the hazard avoidance (Hazcam), navigation (Navcam), the color panoramic (Pancam) and the microscopic imager (MI), continue to return data from the Martian surface from both Rovers. In addition to the rover cameras, each lander utilized a descent imager (DI) to help facilitate safe landing and provide landing site context. The Pancam and MI are part of the scientific instrument payload of the rovers. In addition to gathering gathering science image data, the Pacams also support sun finding and measure atmospheric dust optical depth. The Hazcam and Navcam stereo pairs are used for traverse planning, autonomous navigation and general imaging.

Schwochert, M. A.↗

NASA NTRS2005

Development of a Coherent Lidar for Aiding Precision Soft Landing on Planetary Bodies

Coherent lidar can play a critical role in future planetary exploration missions by providing key guidance, navigation, and control (GNC) data necessary for navigating planetary landers to the pre-selected site and achieving autonomous safe soft-landing. Although the landing accuracy has steadily improved over time to approximately 35 km for the recent Mars Exploration Rovers due to better approach navigation, a drastically different guidance, navigation and control concept is required to meet future mission requirements. For example, future rovers will require better than 6 km landing accuracy for Mars and better than 1 km for the Moon plus maneuvering capability to avoid hazardous terrain features. For this purpose, an all-fiber coherent lidar is being developed to address the call for advancement of entry, descent, and landing technologies. This lidar will be capable of providing precision range to the ground and approach velocity data, and in the case of landing on Mars, it will also measure the atmospheric wind and density. The lidar obtains high resolution range information from a frequency modulated-continuous wave (FM-CW) laser beam whose instantaneous frequency varies linearly with time, and the ground vector velocity is directly extracted from the Doppler frequency shift. Utilizing the high concentration of aerosols in the Mars atmosphere (approx. two order of magnitude higher than the Earth), the lidar can measure wind velocity with a few watts of optical power. Operating in 1.57 micron wavelength regime, the lidar can use the differential absorption (DIAL) technique to measure the average CO2 concentration along the laser beam using, that is directly proportional to the Martian atmospheric density. Employing fiber optics components allows for the lidar multi-functional operation while facilitating a highly efficient, compact and reliable design suitable for integration into a spacecraft with limited mass, size, and power resources.

Amzajerdian, Farzin↗

NASA NTRS1999

Machine Vision for Autonomous Small Body Navigation

This paper describes machine vision algorithms that enable precision guidance and hazard avoidance during small body exploration through onboard visual feature tracking and landmark recognition.

Estimation Landmark Recognition↗

NASA NTRS2005

Expected EDL navigation performance with spacecraft to spacecraft data

Pinpoint landing (defined for the purpose of this discussion as landing within 1km of a preselected target) is a key Advanced Entry, Descent and Landing (EDL) technology for future Mars landers. Key scientific goals for Mars exploration, such as the search for water and characterization of aqueous process on Mars, the study of mineralogy and weathering of the Martian surface and the search for preserved biosignatures in Martian rocks, requires placing landers at pre-defined locations of greatest scientific interest. The capability to land within 1 km of a pre-defined landing site will improve safety and enable landing within roving range of sites of scientific interest while avoiding hazardous areas. A critical component of the closed-loop guidance, navigation and control (GN&C) system required for pinpoint landing is position and velocity estimation in real time. Spacecraft-to-spacecraft navigation will take advantage of the UHF link between two spacecraft (i.e. to an orbiter from an approaching lander for EDL telemetry relay) to build radiometric data, specifically the velocity between the two spacecraft along the radio beam, that are processed to determine position and velocity in real time. The improved onboard state knowledge provided by spacecraft-to-spacecraft navigation will reduce the landed position error and improve the performance of entry guidance. Results from the first of two years planned for this effort are documented here, including selection and documentation of prototype algorithms that will go forward into flight code along with analysis results used to define the algorithm set.

descent and landing↗

NASA NTRS2006

Water Vapor Sensors Go Sky-High to Assure Aircraft Safety

JPL used a special tunable diode laser, which NASA scientists could tune to different wavelengths, like a radio being tuned to different frequencies, to accurately target specific molecules and detect small traces of gas. This tunable diode laser was designed to emit near-infrared light at wavelengths absorbed by the gas or gases being detected. The light energy being absorbed by the target gas is related to the molecules present. This is usually measured in parts per million or parts per billion. Multiple measurements are made every second, making the system quick to respond to variations in the target gas. NASA scientists developed this technology as part of the 1999 Mars Polar Lander mission to explore the possibility of life-giving elements on Mars. NASA has since used the tunable diode laser-based gas sensor on aircraft and on balloons to successfully study weather and climate, global warming, emissions from aircraft, and numerous other areas where chemical gas analysis is needed. SpectraSensors, Inc., was formed in 1999 as a spinoff company of JPL, to commercialize tunable diode laser-based analyzers for industrial gas-sensing applications (Spinoff 2000). Now, the San Dimas, California-based firm has come back to the market with a new product featuring the NASA-developed instrument for atmospheric monitoring. This instrument is now helping aircraft avoid hazardous weather conditions and enabling the National Weather Service to provide more accurate weather forecasts.

Source record↗

NASA NTRS2008

Real-time Imaging Technology for the Return to the Moon

This viewgraph presentation reviews realtime Autonomous Landing Hazard Avoidance Technology (ALHAT) technology for the return to the Moon. The topics inclde: 1) ALHAT Background; 2) Safe and Precise Landing; 3) ALHAT Mission Phases; 4) Terminal Descent Phase; 5) Lighting; 6) Lander Tolerance; 7) HDA Sensor Performance; and 8) HDA Terrain Sensors.

Epp, Chirold↗

NASA NTRS2006

HSI Guidelines Outline for the Air Vehicle Control Station. Version 2

This document provides guidance to the FAA and manufacturers on how to develop UAS Pilot Vehicle Interfaces to safely and effectively integrate UASs into the NAS. Preliminary guidelines are provided for Aviate, Communicate, Navigate and Avoid Hazard functions. The pilot shall have information and control capability so that pilot-UA interactions are not adverse, unfavorable, nor compromise safety. Unfavorable interactions include anomalous aircraft-pilot coupling (APC) interactions (closed loop), pilot-involved oscillations (categories I, II or III), and non-oscillatory APC events (e.g., divergence). - Human Systems Integration Pilot-Technology Interface Requirements for Command, Control, and Communications (C3)

Source record↗

NASA NTRS2005

Human System Integration: Regulatory Analysis

This document was intended as an input to the Access 5 Policy Integrated Product team. Using a Human System Integration (HIS) perspective, a regulatory analyses of the FARS (specifically Part 91), the Airman s Information Manual (AIM) and the FAA Controllers Handbook (7110.65) was conducted as part of a front-end approach needed to derive HSI requirements for Unmanned Aircraft Systems (UAS) operations in the National Airspace System above FL430. The review of the above aviation reference materials yielded eighty-four functions determined to be necessary or highly desirable for flight within the Air Traffic Management System. They include categories for Flight, Communications, Navigation, Surveillance, and Hazard Avoidance.

Source record↗

NASA NTRS2006

Step 1: Human System Interface (HSI) Functional Requirements Document (FRD). Version 2

This Functional Requirements Document (FRD) establishes a minimum set of Human System Interface (HSI) functional requirements to achieve the Access 5 Vision of "operating High Altitude, Long Endurance (HALE) Unmanned Aircraft Systems (UAS) routinely, safely, and reliably in the National Airspace System (NAS)". Basically, it provides what functions are necessary to fly UAS in the NAS. The framework used to identify the appropriate functions was the "Aviate, Navigate, Communicate, and Avoid Hazards" structure identified in the Access 5 FRD. As a result, fifteen high-level functional requirements were developed. In addition, several of them have been decomposed into low-level functional requirements to provide more detail.

Source record↗

NASA NTRS2006

Functional Requirements Document for HALE UAS Operations in the NAS: Step 1. Version 3

The purpose of this Functional Requirements Document (FRD) is to compile the functional requirements needed to achieve the Access 5 Vision of "operating High Altitude, Long Endurance (HALE) Unmanned Aircraft Systems (UAS) routinely, safely, and reliably in the national airspace system (NAS)" for Step 1. These functional requirements could support the development of a minimum set of policies, procedures and standards by the Federal Aviation Administration (FAA) and various standards organizations. It is envisioned that this comprehensive body of work will enable the FAA to establish and approve regulations to govern safe operation of UAS in the NAS on a routine or daily "file and fly" basis. The approach used to derive the functional requirements found within this FRD was to decompose the operational requirements and objectives identified within the Access 5 Concept of Operations (CONOPS) into the functions needed to routinely and safely operate a HALE UAS in the NAS. As a result, four major functional areas evolved to enable routine and safe UAS operations for an on-demand basis in the NAS. These four major functions are: Aviate, Navigate, Communicate, and Avoid Hazards. All of the functional requirements within this document can be directly traceable to one of these four major functions. Some functions, however, are traceable to several, or even all, of these four major functions. These cross-cutting functional requirements support the "Command / Control: function as well as the "Manage Contingencies" function. The requirements associated to these high-level functions and all of their supporting low-level functions are addressed in subsequent sections of this document.

Source record↗

NASA NTRS2008

Linear FMCW Laser Radar for Precision Range and Vector Velocity Measurements

An all fiber linear frequency modulated continuous wave (FMCW) coherent laser radar system is under development with a goal to aide NASA s new Space Exploration initiative for manned and robotic missions to the Moon and Mars. By employing a combination of optical heterodyne and linear frequency modulation techniques and utilizing state-of-the-art fiber optic technologies, highly efficient, compact and reliable laser radar suitable for operation in a space environment is being developed. Linear FMCW lidar has the capability of high-resolution range measurements, and when configured into a multi-channel receiver system it has the capability of obtaining high precision horizontal and vertical velocity measurements. Precision range and vector velocity data are beneficial to navigating planetary landing pods to the preselected site and achieving autonomous, safe soft-landing. The all-fiber coherent laser radar has several important advantages over more conventional pulsed laser altimeters or range finders. One of the advantages of the coherent laser radar is its ability to measure directly the platform velocity by extracting the Doppler shift generated from the motion, as opposed to time of flight range finders where terrain features such as hills, cliffs, or slopes add error to the velocity measurement. Doppler measurements are about two orders of magnitude more accurate than the velocity estimates obtained by pulsed laser altimeters. In addition, most of the components of the device are efficient and reliable commercial off-the-shelf fiber optic telecommunication components. This paper discusses the design and performance of a second-generation brassboard system under development at NASA Langley Research Center as part of the Autonomous Landing and Hazard Avoidance (ALHAT) project.

Pierrottet, Diego↗