Facility tests MEMS in vacuum conditions
Southwest Research Institute has built a unique facility for developing and testing microelectromechanical systems (MEMS) in vacuum conditions. Recent tests using the system yielded significant findings about how MEMS devices work in vacuums, and offer important information about how MEMS can be used in space applications.
"If MEMS can be made to operate well in vacuum, they hold the promise of revolutionizing many space instruments and systems," said Dr. David J. McComas, head of the facility and executive director of the SwRI Space Science and Engineering Division.
Researchers found that MEMS operate in vacuum, the environment found in space, differently than they operate in atmosphere in two ways: The voltages required for resonant operation are much lower and the energetic amplifications are much larger. The team found during testing that oscillators needed only a tenth of the voltage normally required in air.
"This is incredibly significant for space applications because instead of hundred volt supplies, which are heavier and more expensive to launch, we might be able to run space MEMS on standard low voltages of only 10 to 15 volts," he said.
Testing also showed that the oscillators had an amplification that was hundreds of times greater. "If you whack a tuning fork, it has a high resonance, or amplification, which causes it to ring a long time," he continued. "For MEMS that are driven at resonance, this means they will have much larger amplification while operating on less power in vacuum."
Researchers had also worried that "stiction," a combination of stickiness and friction, and vacuum welding, the tendency for metal parts to bond together in vacuum conditions, could be major factors in space MEMS - yet that has not been the case thus far. Water vapor and air act as lubricants for MEMS surfaces that slide on or touch each other. In vacuum, however, parts that touch lack that layer of gas between the surfaces, leading to the possibility that surfaces could exchange atoms and eventually bond. This effect most likely led to an antenna on the Galileo spacecraft being unable to open.
MEMS will enable space instruments to have large aperture sizes in a flat panel shape that will be much thinner than current sensors, resulting in tremendous mass savings. MEMS devices are also highly reliable, and space instruments will use arrays of many thousands of identical MEMS. This redundancy enables an instrument that suffers failure of a small number of its devices to continue to operate at nearly full sensitivity.
In addition to space applications, MEMS could be vacuum packaged for Earth-bound applications if the lower voltages or higher amplifications are of benefit. McComas said the team is continuing tests in the SwRI facility and beginning the development of a space science instrument that uses MEMS.
Contact McComas at (210) 522-5983 or firstname.lastname@example.org.
A team led by Southwest Research Institute has been awarded the Society of Automotive Engineers (SAE) Arch T. Colwell Merit Award, recognizing authors of outstanding papers presented at SAE meetings.
Dr. Kent Froelund, Edwin C. Owens, Edwin A. Frame, Janet P. Buckingham (all of SwRI), John Garbak (Department of Energy), Dr. Spyros Tseregounis (formerly of General Motors R&D), and Dr. Andrew Jackson (ExxonMobil R&E) are award recipients for SAE Paper No. 2001-01-1901, "Impact of Lubricant Oil on Regulated Emissions of a Light-Duty Mercedes-Benz 0M611 CIDI-Engine.
The paper describes how crankcase lubricants contribute to engine-out emissions when paired with a low particulate-forming diesel fuel. The knowledge gained from this work will be applied to solving the challenges that remain in reducing the future emissions levels of a compression-ignition, direct-injected diesel engine.
The paper was selected for the award from more than 3,000 submitted at SAE meetings in 2001. Papers were judged for their originality and for their future reference value to existing knowledge of mobility engineering. The team received the award during the 2003 SAE World Congress in Detroit.
A 7,000-square-foot facility for chemical extraction, Network Equipment/Building Systems (NEBS) testing, and other services is available at Southwest Research Institute. The renovated building updates and improves the Chemistry and Chemical Engineering Division's environmental sample preparation facility, centralizing the laboratories and equipment and enhancing client testing and analysis services.
"We are very excited about this new facility," said Dr. Reza Karimi, director of the Analytical and Environmental Chemistry Department. "The renovation will help us streamline and increase productivity and precision, and will help our clients meet their schedules for getting their product to the market more quickly. It has given us the opportunity to modernize and add new equipment and the latest technology."
NEBS testing, a telecommunications industry preproduction requirement, evaluates how equipment performs under various physical and electrical operating conditions. The Institute provides NEBS and environmental testing in the areas of temperature and humidity, fire, electromagnetic compatibility, electrical, seismic, acoustic, and others. The facility has improved the laboratory used for NEBS corrosion testing.
The newly centralized extraction facility allows the Institute to increase its capacity and efficiency for preparing samples for phase analysis. SwRI staff members use the laboratory to extract pollutants for organic analysis and environmental testing of client samples.
The Institute has added two side-by-side walk-in coolers for refrigeration. Currently, the Institute processes 15,000 to 20,000 samples a year. To effectively handle this workload, the building also has a login area to maintain strict chain of custody of each sample and ensure it is properly stored, sorted and eventually disposed. A laboratory information management system helps maintain this process with bar-coding capabilities.
For more information, visit the SwRI Chemistry and Chemical Engineering Division web site at chemistry.swri.org.
NASA has authorized the New Horizons Pluto-Kuiper Belt (PKB) mission to go forward with spacecraft and ground system construction. New Horizons is led by SwRI and the Johns Hopkins University Applied Physics Laboratory (APL). Pluto was discovered in 1930, and the first Kuiper Belt Object was sighted in 1992. Since then, almost 1,000 more objects have been detected. Neither Pluto nor Kuiper Belt Objects have ever been explored by spacecraft.
In July 2002, the National Research Council's Decadal Survey for Planetary Science ranked the reconnaissance of Pluto-Charon and the Kuiper Belt as its highest priority for a new start mission in planetary science, citing the fundamental scientific importance of understanding this region of the solar system.
New Horizons is proceeding toward a January 2006 launch, with an arrival at Pluto and its moon Charon as early as the summer of 2015. The 930-pound spacecraft will characterize the global geology and geomorphology of Pluto and Charon, map the surface compositions and temperatures of these worlds, and study Pluto's unique atmosphere in detail. It will then visit one or more icy, primordial bodies in the Kuiper Belt, beyond the orbits of Neptune and Pluto, where it will make similar investigations. The spacecraft carries seven sensor packages to carry out these studies.
The principal investigator and leader of the New Horizons mission is Dr. Alan Stern, director of the SwRI Space Studies Department in Boulder, Colo.
Upcoming project milestones for New Horizons include the selection of a launch vehicle during summer 2003, the start of spacecraft assembly in spring 2004, and the beginning of integrated spacecraft and instrument testing in May 2004.
In addition to APL and SwRI, the New Horizons team includes Stanford University, Ball Aerospace Corp., NASA Goddard Space Flight Center and the Jet Propulsion Laboratory. The mission science team includes expertise from the above institutions, as well as Lowell Observatory, NASA Ames Research Center, the Massachusetts Institute of Technology, Washington University (St. Louis), George Mason University, Johns Hopkins University and the University of Colorado.
More information on New Horizons can be found at pluto.jhuapl.edu. More information on Pluto-Charon and the Kuiper Belt can be found at www.plutoportal.net.
The Division for Planetary Sciences of the American Astronomical Society (AAS) has awarded its Urey Prize in Planetary Sciences to Dr. Robin M. Canup, assistant director of the Space Studies Department. Canup was selected as the 2003 recipient of the award, named in honor of the late Nobel laureate Harold C. Urey, who made significant advances in the fields of physical chemistry, geochemistry, lunar science and astrochemistry.
The Urey Prize recognizes outstanding achievements in planetary science by a young scientist. Canup was recognized for her groundbreaking research contributions on the moon's origin and dynamical evolution. She has published numerous technical articles on the origin of the moon, planetary and satellite formation and the physics of planetary rings. She has also given many commentaries on television and the popular science journals, particularly on the formation of the moon.
"The Urey Prize is the world's premier peer recognition award for accomplishment by an outstanding young planetary scientist, and we are proud of the fact that SwRI nurtures young scientists and engineers to achieve great things," said Dr. Alan Stern, director of the SwRI Space Studies Department. "Robin is extremely hard-working, highly creative and just plain smart. She provides a tremendous role model for what an outstanding young scientist can achieve."
"Her significant contributions at this age leave us hopeful for the many achievements yet to come," said J. Dan Bates, SwRI president. "SwRI will continue to support Robin and our other space scientists and engineers as they take humankind's understanding ever deeper into the solar system."
Canup holds a bachelor's degree in physics from Duke University and a doctorate in astrophysics from the University of Colorado at Boulder; she joined SwRI in 1998. She will receive the Urey Prize and a cash award from the AAS at the annual meeting of the Division of Planetary Sciences in Monterey, California, in September 2003.
Contact Canup at (303) 546-6856 or email@example.com.
Engineers at SwRI's Engineering Dynamics Department will perform impact testing on thermal protection samples in support of an ongoing investigation of the breakup and subsequent loss of space shuttle Columbia and its crew last February. This work is being performed in conjunction with NASA and the Columbia Accident Investigation Board.
The tests will explore a theory that the accident was caused by damage that occurred when pieces of insulating foam broke away from the shuttle's expendable fuel tank and struck the left wing during the launch phase of the mission.
Sponsored by NASA, the tests will be performed during April-July in San Antonio using a large compressed-gas gun to propel various sizes of insulating foam samples at orbiter thermal protective structures that will be mounted at various angles of impact.
The gun, powered by nitrogen gas, will propel projectiles at speeds of nominally 700 feet per second, or about 500 miles per hour.
A large instrumentation suite will be employed on each test. Personnel from the Boeing Company will install and monitor strain gages, displacement transducers, load cells and accelerometers. SwRI will field six high-speed video cameras to document the impact events.
Engineers at SwRI are applying unique capabilities that can heighten security and improve surveillance for commercial security, motor safety and homeland security operations. By combining real-time image processing and machine perception to traditional video surveillance methods, the systems can analyze video feeds from multiple surveillance cameras to automatically detect vehicles, packages and moving objects such as people and animals.
"Current surveillance systems rely on operators to observe multiple monitors and screens for unusual incidents," said Dr. Brent M. Nowak, manager of automation engineering in the SwRI Automation and Data Systems Division. "In these cases, the amount of video data generated can be so overwhelming that the operator could become lax and fail to notice an incident until some time after it occurs, or fail to notice it altogether. The SwRI automated system significantly reduces the volume of data monitored by operators by sounding an alarm only when it automatically detects an incident."
The system, developed using internal research funds, also provides capabilities not available from other systems, such as instant replay, enabling security personnel to more effectively monitor large areas and handle complex images. Other video motion detection systems use more simplistic approaches to detect incidents and are prone to false triggers from moving foliage, passing headlights, cloud shadows and more. This limits their effectiveness primarily to highly constrained environments.
"Our system uses algorithms that incorporate temporal processing and model-based analysis so the system recognizes motions normal to that scenario, such as people and vehicles," Nowak said. "The system also disregards or overcomes false triggers caused by moving foliage and shadows and can effectively detect stationary objects left at the scene, such as packages and suitcases."
The SwRI system can be used for:
Perimeter security. Used at large or small
facilities, the system can automatically alert security personnel to the
presence of people
Interior security. In hallways, corridors, rooms, courtyards, parking areas and other closed spaces, surveillance cameras can be multiplexed for display only when monitored zones are occupied.
Under-vehicle surveillance. Images of automobile undercarriages can be analyzed to automatically detect attached packages that could contain explosive devices or other contraband. (See photo series at right).
Motor and pedestrian safety. The presence of large animals or joggers can be automatically detected and combined with systems that would alert passing motorists.
Data acquisition. The system can monitor, quantify and log pedestrian or vehicle traffic patterns to help optimize the layout of facilities.
The basic system includes cameras, a computer and SwRI-designed automated video security software that could be used with some existing surveillance systems. Automated surveillance capabilities can be further enhanced with a number of optional components, such as computer-operated pan/tilt/zoom cameras; thermal infrared cameras for night vision and adverse weather conditions; visible or near-infrared illuminators for night vision with conventional cameras; and image intensifiers for long-range night vision with conventional cameras.
Other optional components and applications include long-range infrared/visible wavelength optics for perimeter surveillance of large facilities, remote monitoring of facilities and transmissions from remote sites over wireless communications networks. The system can also be configured to work with mobile platforms, such as autonomous land or aerial vehicles carrying surveillance cameras and optional analysis computers.
For more information about SwRI's automated surveillance systems, visit videosurveillance.swri.org.
Published in the Spring 2003 issue of Technology Today®, published by Southwest Research Institute. For more information, contact Joe Fohn.