Hannah Goldberg

Field test implementation to evaluate a flash LIDAR as a primary sensor for safe lunar landing

From May 2 through May 7 of 2008, the Autonomous Landing and Hazard Avoidance Technology (ALHAT) Exploration Technology Development Program carried out a helicopter field test to assess the use of a flash LIDAR as a primary sensor during lunar landing. The field test data has been used to evaluate the performance of the LIDAR system and of algorithms for LIDAR Hazard Detection and Avoidance, Hazard Relative Navigation, and Passive Optical Terrain Relative Navigation. Reported here is a comprehensive description of the field test hardware, ground infrastructure and trajectory reconstruction methodologies1,2.

Spacecraft hazard avoidance utilizing structured light

At JPL, a <5 kg free-flying micro-inspector spacecraft is being designed for host-vehicle inspection. The spacecraft includes a hazard avoidance sensor to navigate relative to the vehicle being inspected. Structured light was selected for hazard avoidance because of its low mass and cost. Structured light is a method of remote sensing 3-dimensional structure of the proximity utilizing a laser, a grating, and a single regular APS camera. The laser beam is split into 400 different beams by a grating to form a regular spaced grid of laser beams that are projected into the field of view of an APS camera. The laser source and the APS camera are separated forming the base of a triangle. The distance to all beam intersections of the host are calculated based on triangulation

Data system design for a hyperspectral imaging mission concept

Global ecosystem observations are important for Earth-system studies. The National Research Councils report entitled Earth Science and Applications from Space is currently guiding NASAs Earth science missions. It calls for a global land and coastal area mapping mission. The mission, scheduled to launch in the 2013-2016 timeframe, includes a hyperspectral imager and a multi-spectral thermal-infrared sensor. These instruments will enable scientists to characterize global species composition and monitor the response of ecosystems to disturbance events such as drought, flooding, and volcanic events. Due to the nature and resolution of the sensors, these two instruments produce approximately 645 GB of raw data each day, thus pushing the limits of conventional data handling and telecommunications capabilities. The implications of and solutions to the challenge of high downlink data volume were examined. Low risk and high science return were key design values. The advantages of onboard processing and advanced telecommunications methods were evaluated. This paper will present an end-to-end data handling system design that will handle the large data downlink volumes that are becoming increasingly prevalent as the complexity of Earth science increases. The designs presented here are the work of the authors and may differ from the current mission baseline.

Micro‐Inspector Spacecraft Testbed: Breadboard Subsystem Demonstrations

Micro‐inspector is a 5‐kg inspection platform designed to operate autonomously following operator up‐linked command sequences around a host spacecraft to perform safety inspections, anomaly inspections, or imaging of large in‐space assemblies as envisioned for future NASA exploration missions. Similarly, such an inspection platform may be adapted to military space missions. Micro‐inspector relies on solar power and using celestial sensors for navigation, giving the system large flexibility in the missions and applications it may serve, including those beyond Earth orbit. Micro‐Inspector, through its small size and low weight, poses minimal design impacts to the host. Its small size and weight also affords micro‐inspector to be disposable, allowing multiple inspectors to be used by a single host for different inspection routines or as emergency back‐up. Its low‐pressure butane propulsion system combines safety and compactness through liquid propellant storage with an adequate performance of up to 30 m/s fo...

Terrestrial Attitude Estimation for the Formation Control Testbed (FCT)

In this paper we look at the problem of terrestrial (earth based) attitude estimation of a unique robotic vehicle using full three axis attitude measurements and three axis inertial rate sensors (gyros). The vehicle is completely autonomous and uses air bearings to simulate the drag free dynamic environment of space. An onboard infrared camera system is used to provide quaternion measurements representing the attitude of the robot relative to the room frame of the test facility. Fiber optic gyros are used to sense the inertial angular rates. To simulate the performance of the system, a stochastic model of the gyros was developed based on long term rate table data. The angle random walk, bias, and bias stability were determined to agree with the data provided in the manufactures specification sheet. We show that a 3times reduction in the standard deviation of the attitude estimates can be achieved by proper mixing of the two sensor measurements. The attitude estimation algorithm used in this paper also provides bias free estimates of the angular rate which can be used for control or other purposes. These results are established in both high fidelity simulations and experimentally using data taken during real time operation of the robot.

Field Testing of Lunar Access and Navigation Device (LAND)

A laser radar system has been constructed. It is based on a commercial PC with digitizer, pulse delay instrument, National Instruments IO card and an optical head from a previous laser radar program. The laser radar was mounted on a gyro stabilized gimbal on the nose of a helicopter and flown in the Mojave Desert in September 2006. The collected data will be used to test algorithms for future precision lunar landers, which may be utilizing a laser radar as the primary landing sensor. This paper will describe the laser radar and PC based acquisition system used for the data collection, and provide an overview of the supporting test sensors and architecture. Preliminary data collected during the helicopter field testing will also be presented.