The tragic loss of the Space Shuttle Columbia and crew in 2003 has resulted in a requirement to inspect the Shuttle Thermal Protection System (TPS) on-orbit so that the crew may remain at the International Space Station (ISS) in the event of damage that might pose an unacceptable risk to their safe return. An instrumented inspection boom manipulated and operated from the Shuttle’s Canadarm will provide an interim solution for the initial flights. However, a longer term solution has been planned that will permit the required inspection to be performed from within the ISS through the ISS windows. This plan involves the Shuttle performing a pitching maneuver to expose the underside for inspection purposes as it approaches the ISS prior to docking. The central approach in this plan is for the ISS crew to photograph the Shuttle TPS through the ISS windows using high-definition cameras. As an augmentation to this plan, the ISS-based Shuttle Inspection Lidar, or I-SIL, is a proposed lidar instrument that will generate a 3D topographic surface of the Shuttle underside to enable rapid identification and volumetric analysis of tile damage to generate safety and repair data. This paper presents the mission requirements and derived requirements for I-SIL, analyzes specific details of the inspection requirements, and discusses various phases of operating scenarios. The conclusion of the paper outlines the current status of the proposed technology.
SALLI is a conceptual instrument design that will efficiently acquire altimetric data for a planetary body or asteroid from orbit while maintaining a minimum power demand. SALLI scans its measurements off-nadir using a novel circular scanning technique that simultaneously permits a large instrument aperture using a motion-bandwidth efficient scanning mechanism. By combining spacecraft ephemeris data with SALLI’s measurement set, a complete digital elevation map of a planet or similar body can be generated in less time and using less spacecraft power than similar scanning and multi-beam instruments designed for the same purpose. SALLI was originally designed to generate measurement data to produce a topographical map of the lunar surface from a polar-orbiting host spacecraft; however, its benefits extend to a variety of other mapping missions of planets or asteroids.
Future planetary exploration missions will aim at landing a spacecraft in hazardous regions of a planet, thereby requiring an ability to autonomously avoid surface obstacles and land at a safe site. Landing safety is defined in terms of the local topography-slope relative to gravity and surface roughness-and landing dynamics, requireing an impact velocity lower than a given tolerance. In order to meet these challenges, a LIDAR-based Autonomous Planetary landing System (LAPS) was developed, combining the three-dimensional cartographic capabilities of the LIDAR with autonomous 'intelligent' software for interpreting the data and for guiding the Lander to the safe site. This paper provides an overview of the LAPS ability to detect obstacles, identify a safe site and support the navigation of the Lander to the detected safe site. It also demonstrates the performance of the system using real LIDAR data taken over a physical emulation of a Mars terrain.
The Shuttle Inspection Lidar (SIL) system is a derivative of a scanning lidar system being developed by MD Robotics and Optech. It incorporates a lidar, a camera, lights and video communications systems. The SIL is designed to meet the specific requirements for the on-orbit inspection and measurement of the Space Shuttle leading edge Reinforced-Carbon Carbon (RCC) and Thermal Protection System (TPS). The SIL has a flexible electrical and mechanical interface that enables it to be mounted on different locations including the Shuttle Remote Manipulator System (SRMS, Canadarm), and the Space Station Remote Manipulator System (SSRMS) on the International Space Station (ISS).
This paper describes the SIL system and the specifications of the imaging lidar scanner system, and discusses the application of the SIL for on-orbit shuttle inspection using the on-orbit SRMS. Ground-based measurements of the shuttle TPS taken by a terrestrial version of the imager are also presented.
Devon Island, in the Canadian High Arctic (75°22’N, 89°41’W), is the largest uninhabited island on the planet. The climate is that of a polar desert; it is cold, dry, dusty, rocky, and almost void of any vegetation. The eastern part of the island is still covered by an ice cap, a remnant of the Inuitian Ice Sheet system that covered the bulk of the area during the last Glacial Maximum 8 000-10 000 years ago.. The island is rich in well-preserved geology, relatively free of erosion. The feature of highest scientific interest on Devon Island is the ~23-million-year-old (Miocene), ~24 km diameter Haughton impact structure.. There are few other craters on this planet as well preserved and exposed as Haughton, mainly due to the unique climate that slows down erosion common on the rest of the planet.The NASA Haughton-Mars project is an international planetary analog research project headquartered at NASA Ames Research Centre and managed by the SETI Institute. The lidar work described in this work is a collaborative activity between the SETI Institute, the University of Guelph, the University of New Brunswick, Optech Inc., and the Canadian Space Agency. Field activities were conducted under the auspices of the NASA HMP and of the CSA. Specific sites of geological interest within Haughton impact structure were imaged using an Optech Ilris 3-d ground-surveying unit. This very high-resolution, 3-dimensional data allows for the field geologist to "re-visit" a field site well after the field season has finished. In this work, we will present the results of 3-dimensional scans of an ejecta block and of impact-generated rock formations that contribute to furthering our understanding of impact cratering, a fundamental and universal process of planetary formation and evolution, and to studies of the erosional history of Haughton Crater and surrounding terrain on Devon Island. We will demonstrate how using this tool in the field can increase safety and allow for precise measurements to be made after the field season is completed.
A long-range scanning laser range imaging system designed for 3D imaging applications is presented. The system will be compact, lightweight and low power: ideally suited for remote and robotic applications. It will feature a fully-programmable scanner with a wide field of regard, and a precise time-of-flight laser range measurement system that will provide high-speed, accurate point-cloud data from very short to very long ranges. The potential applications of this technology to be briefly discussed here, both terrestrial and in space, are numerous. They include: robotic vision; autonomous navigation and guidance; mapping and surveying; on-orbit rendezvous and docking; planetary landing; visual geology; and rover navigation. This paper will discuss the physical characteristics of the system as well as the performance of the lidar itself. Test results and some sample imagery will be presented. The paper will also discuss some of the applications for which the system may be suited.
This paper is presented to give a general description of the ORACLE project and of the technology development results obtained to date. ORACLE is a feasibility study of a fully automated differential absorption lidar for global measurements of tropospheric and stratospheric ozone and aerosols with high vertical and horizontal resolution. The proposed program includes both novel technology demonstrations and obtaining scientific data from spacecraft. These data are needed to address key issues in atmospheric research including the depletion of stratospheric ozone, global warming, atmospheric transport and dynamics, tropospheric ozone budgets, atmospheric chemistry, and the atmospheric impact of hazards. Only a space-based lidar system can provide the required spatial resolution for ozone and aerosols in both the stratosphere and the troposphere on a global scale at all required altitudes. To deliver these data, the most novel technologies such as all-solid-state lasers, photon-counting detectors and ultra-lightweight deployable telescopes must be employed in the mission payload.
This paper presents a summary of Optech's internal studies into the feasibility of developing lidar systems for gas detection and mapping for environmental monitoring. The paper summarizes our evaluations of the capabilities of two different lidar techniques to address this area of application. These two techniques are Raman scattering and differential absorption. Optech has experience in building lidar systems operating on either of these techniques, and in recent years has carried out several studies of the potential of these lidar technologies for pollution monitoring. The paper includes brief reviews of the basic measurement techniques for DIAL and Raman lidar and examples of currently operating systems are given. Some of the practical problems encountered in operating these systems are also discussed. The results of performance models for new system concepts are then presented for a number of important pollution gases. The discussion then addresses the limitations of the current technology, by considering issues such as limitations of the existing laser technology and factors affecting detection limits.
A new Arctic stratospheric observatory (AStrO) has been established at Eureka (80 degree(s)N, 86 degree(s)W) in northern Canada. This observatory is one of the three designated components of the Arctic Primary Station of the Network for the Detection of Stratospheric Change (NDSC). Among the complement of sensors being installed at Eureka are two state-of-the-art lidar systems for monitoring stratospheric ozone and polar stratospheric clouds (PSC). The ozone Differential Absorption Lidar (DIAL) system utilizes a xenon chloride excimer laser transmitter operating at 308 nm as the absorbed `on' radiation. A hydrogen Raman shifter generates the `off' wavelength at 353 nm. The system provides an average output power of about 60 watts at 300 Hz. The receiver is a 1 meter Newtonian telescope provided with several special optical features to permit daylight operation. The second lidar utilizes a Nd:YAG laser source operating at 1064 and 532 nm with a 20 Hz prf. This paper describes the new lidar facilities at AStrO and presents a summary of the data obtained during the first months of operation.