Engineering topics

Swift, Wesley

Publications and source records attributed to Swift, Wesley.

11 records

NASA NTRS2008

Flux of Kilogram-Sized Meteoroids from Lunar Impact Monitoring

Routine lunar impact monitoring has harvested over 110 impacts in 2 years of observations using 0.25, 0.36 and 0.5 m telescopes and low-light-level video cameras. The night side of the lunar surface provides a large collecting area for detecting these impacts and allows estimation of the flux of meteoroids down to a limiting luminous energy. In order to determine the limiting mass for these observations, models of the sporadic meteoroid environment were used to determine the velocity distribution and new measurements of luminous efficiency were made at the Ames Vertical Gun Range. The flux of meteoroids in this size range has implications for Near Earth Object populations as well as for estimating impact ejecta risk for future lunar missions.

Suggs, Robert↗

NASA NTRS2008

Flux of Kilogram-sized Meteoroids from Lunar Impact Monitoring. Supplemental Movies

These videos, and audio accompany the slide presentation "Flux of Kilogram-sized Meteoroids from Lunar Impact Monitoring." The slide presentation reviews the routine lunar impact monitoring that has harvested over 110 impacts in 2 years of observations using telescopes and low-light level video cameras. The night side of the lunar surface provides a large collecting area for detecting these impacts and allows estimation of the flux of meteoroids down to a limiting luminous energy.

Suggs, Robert↗

NASA NTRS2007

Algorithms for Lunar Flash Video Search, Measurement, and Archiving

Lunar meteoroid impact flashes provide a method to estimate the flux of the large meteoroid flux and thus their hazard to spacecraft. Although meteoroid impacts on the Moon have been detected using video methods for over a decade, the difficulty of manually searching hours of video for the rare, extremely brief impact flashes has discouraged the technique's systematic implementation. A prototype has been developed for the purpose of automatically searching Lunar video records for impact flashes, eliminating false detections, editing the returned possible flashes, and archiving and documenting the results. The theory and organization of the program is discussed with emphasis on the filtering out of several classes of false detections and retaining the brief portions of the raw video necessary for in depth analysis of the flashes detected. Several utilities for measurement, analysis, and location of the flashes on the moon included in the program are demonstrated. Application of the program to a year's worth of Lunar observations is discussed along with examples of impact flashes as well as several classes of false impact flashes.

Swift, Wesley↗

NASA NTRS2007

NASA's Lunar Impact Monitoring Program

NASA's Meteoroid Environment Office nas implemented a program to monitor the Moon for meteoroid impacts from the Marshall Space Flight Center. Using off-the-shelf telescopes and video equipment, the moon is monitored for as many as 10 nights per month, depending on weather. Custom software automatically detects flashes which are confirmed by a second telescope, photometrically calibrated using background stars, and published on a website for correlation with other observations, Hypervelocity impact tests at the Ames Vertical Gun Facility have been performed to determine the luminous efficiency ana ejecta characteristics. The purpose of this research is to define the impact ejecta environment for use by lunar spacecraft designers of the Constellation (manned lunar) Program. The observational techniques and preliminary results will be discussed.

Suggs, Robert M.↗

NASA NTRS2007

Measurement of Primary Ejecta From Normal Incident Hypervelocity Impact on Lunar Regolith Simulant

The National Aeronautics and Space Administration (NASA) continues to make progress toward long-term lunar habitation. Critical to the design of a lunar habitat is an understanding of the lunar surface environment. A subject for further definition is the lunar primary ejecta environment. The document NASA SP-8013 was developed for the Apollo program and is the latest definition of the primary ejecta environment. There is concern that NASA SP-8013 may over-estimate the lunar primary ejecta environment. NASA's Meteoroid Environment Office (MEO) has initiated several tasks to improve the accuracy of our understanding of the lunar surface primary ejecta environment. This paper reports the results of experiments on projectile impact into pumice targets, simulating lunar regolith. The Ames Vertical Gun Range (AVGR) was used to accelerate spherical Pyrex projectiles of 0.29g to velocities ranging between 2.5 km/s and 5.18 km/s. Impact on the pumice target occurred at normal incidence. The ejected particles were detected by thin aluminum foil targets placed around the pumice target in a 0.5 Torr vacuum. A simplistic technique to characterize the ejected particles was formulated. Improvements to this technique will be discussed for implementation in future tests.

Edwards, David L.↗

NASA NTRS2007

Algorithms for Lunar Flash Video Search, Measurement, and Archiving

Lunar meteoroid impact flashes provide a method to estimate the flux of the large meteoroid flux and thus their hazard to spacecraft. Although meteoroid impacts on the Moon have been detected using video methods for over a decade, the difficulty of manually searching hours of video for the rare, extremely brief impact flashes has discouraged the technique's systematic implementation. A prototype has been developed for the purpose of automatically searching lunar video records for impact flashes, eliminating false detections, editing the returned possible flashes, Z and archiving and documenting the results. The theory and organization of the program is discussed with emphasis on the filtering out of several classes of false detections and retaining the brief portions of the raw video necessary for in depth analysis of the flashes detected. Several utilities for measurement, analysis, and location of the flashes on the moon included in the program are demonstrated. Application of the program to a year's worth of lunar observations is discussed along with examples of impact flashes as well as several classes of false impact flashes.

Swift, Wesley↗

NASA NTRS2005

Determining Bolide Luminous Efficiency Through Optical Observations of the Genesis Atmospheric Entry

The Genesis spacecraft reentry presented a unique opportunity for observationally constraining some key parameters in meteor physics, as its speed, mass, composition, and trajectory are all known with great precision - such is not the case for meteors. With this in mind, members of the Space Environments Team at NASA's Marshall Space Flight Center were deployed to northern Nevada, equipped with comparatively simple optical instrumentation to observe Genesis as it made its way through the upper atmosphere in the morning hours of September 8, 2004. This paper describes the video observations and their analysis, compares the results with a simple photometric model, and assesses the science value of using spacecraft atmospheric entries as "calibrated meteors", particularly in regard to optical luminous efficiency. Implications for the Stardust reentry in January 2006 as well as future Shuttle reentries will be discussed.

Cooke, William↗

NASA NTRS2002

Video Observations Encompassing the 2002 Leonid Storm: First Results and a Revised Photometric Procedure for Video Meteor Analysis

During the 2001 Leonid storm, Marshall Space Flight Center, with the cooperation of the University of Western Ontario and the United States Air Force, deployed 6 teams of observers equipped with intensified video systems to sites located in North America, the Pacific, and Mongolia. The campaign was extremely successful, with the entire period of enhanced Leonid activity (over 16 hours) captured on video tape in a consistent manner. We present the first results from the analysis of this unique, 2 terabyte data set and discuss the problems involved in reducing large amounts of video meteor data. In particular, the question of how to determine meteor masses though photometric analysis will be re-examined, and new techniques will be proposed that eliminate some of the deficiencies suffered by the techniques currently employed in video meteor analysis.

Cooke, William J.↗

NASA NTRS2002

Video Observations Encompassing the 2002 Leonid Storm: First Results and a Revised Photometric Procedure for Video Meteor Analysis

Cooke, William J.↗

NASA NTRS1999

StarCam

This project can be defined by it's three phases. The goals of Phase A of this contract are to (1) Determine the required dynamic range of the combined sky and stellar image and to (2) Specify camera and optics. That was accomplished and reported in the Phase A report attached. The goals of Phase B of this contract are to 1) Produce and demonstrate algorithms for starfield background removal, 2) Produce and demonstrate star tracking and centroiding algorithms, 3) Prepare and demonstrate pointing and auto- focus algorithms, and 4) Consult with those who develop flight software on above algorithms. We are pleased to report that the above has been accomplished and delivered to NASA via our contracting contact for this project, Cheryl Alexander and are attached here. We are proud to present this final report with the expectations that all should work as planned and under budget as well: two cameras for the expected price of one.

Swift, Wesley↗

NASA NTRS1999

Design of a Day/Night Star Camera System

This paper describes the design of a camera system capable of acquiring stars during both the day and night cycles of a high altitude balloon flight (35-42 km). The camera system will be filtered to operate in the R band (590-810 nm). Simulations have been run using MODTRAN atmospheric code to determine the worse case sky brightness at 35 km. With a daytime sky brightness of 2(exp -05) W/sq cm/str/um in the R band, the sensitivity of the camera system will allow acquisition of at least 1-2 stars/sq degree at star magnitude limits of 8.25-9.00. The system will have an F2.8, 64.3 mm diameter lens and a 1340X1037 CCD array digitized to 12 bits. The CCD array is comprised of 6.8 X 6.8 micron pixels with a well depth of 45,000 electrons and a quantum efficiency of 0.525 at 700 nm. The camera's field of view will be 6.33 sq degree and provide attitude knowledge to 8 arcsec or better. A test flight of the system is scheduled for fall 1999.

Alexander, Cheryl↗