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Space instrument calibration facility

An innovative calibration and instrument development facility at SwRI is helping scientists and engineers test and design space plasma instruments far faster and more reliably than previously possible.

"This facility is clearly one of the best in the world for this kind of calibration and development work," said Dr. David J. McComas, executive director of the SwRI Space Science and Engineering Division. "In addition to developing our own instruments, we're also looking to partner with other instrument development teams needing access to this kind of world-class facility."

A four-axis, computer-controlled position system situated within a large ultra-high vacuum chamber, and an energy and mass selected ion or neutral atom beam allow researchers to characterize their instruments' responses to the particles. Because a variety of particles come at the instrument from all directions in space, researchers move the instrument around in the chamber and expose it to a range of orientations, ion species, energies, and beam fluxes. The resulting data allow researchers to determine later the direction and distribution of the particles in the space environment.

Two 3,000-liter-per-second cryogenic pumps on the main chamber create a vacuum of 10-8 Torr within a few hours. The same vacuum conditions can take days to create in other calibration facilities, with some facilities never achieving such low pressures. This improvement allows researchers to develop instruments at unprecedented speeds.

"We can test in the morning, break vacuum and modify the instrument in the afternoon, and be testing in the 10-8 Torr range again the next morning," McComas said.

Spaceflight instruments that measure ions and neutrals, particularly those used on spacecraft built to examine the magnetosphere and heliosphere, can be tested or developed using this facility. SwRI researchers currently are using the facility to design an innovative extension of ion mass spectrometry for the proposed MMS (Magnetospheric Multi-Scale) mission. The facility already has been used to calibrate the first TWINS (Two Wide-angle Imaging Neutral-atom Spectrometers) instrument, scheduled to launch in 2003.

"We worked out a lot of instrument issues during the TWINS calibration and didn't have a single worry about the facility," McComas said. "In contrast, we had numerous problems the last time we did a calibration in the old facility. Now we get more data in days than we used to get in weeks."

The facility also is reliable and easy to operate. Safety interlocking systems protect the science instrument during testing and development so that control functions are allowed only when they're safe and appropriate. With science teams often working around the clock to calibrate and fine-tune their instruments, mistakes in the early hours of the morning are common. System interlocks prevent such errors.

"You can push a button to open a vent valve, but if that valve isn't supposed to be open while the pump is operating, the system won't let you do it," McComas said.

The SwRI chamber is entirely oil free. Calibration facilities that pump any oil leave very minute amounts of contamination in the chamber. Frequent residual gas analyses quantify the amount of contamination in the SwRI chamber to ensure the safety of the instrument. Complex hydrocarbons, in particular, can cause irreparable damage and greatly reduce the lifetimes of these types of spaceflight instruments.

In addition, the facility is arranged so that the door to the vacuum chamber opens into a clean room, while the vacuum system and components sit outside the clean room. This enables technicians to make system adjustments while preserving the integrity of the clean environment.

Team members from across the country also can access a web site that shows real-time temperatures, pressures, and status flags in the facility. Other computer monitors enable instrument data visualization and analysis while testing is in progress and observation of the particle beam. SwRI programmers engineered custom control and analysis software for the system.

SwRI funded development of the facility. In the future, the system will be modified to extend the upper energy from 30 to 50 kilovolts and may be adapted for electrons as well.

Contact McComas at (210) 522-5983 or david.mccomas@swri.org.

Study shows asteroid breakup

A new SwRI study has identified a recent asteroid breakup event in the main asteroid belt, the first time that an asteroid disruption event has been precisely dated.

Computer simulations have shown that the event occurred 5.8 million years ago, when a 15-mile-wide asteroid in the main belt region shattered into numerous fragments following a collision. The findings appeared in the June 13 issue of the journal Nature.

The main asteroid belt, a population of roaming boulders with masses ranging from Texas-sized rocks to tiny pebbles, lies between the orbits of Mars and Jupiter. Asteroids in this region frequently collide, possibly explaining why spacecraft and radar images of these bodies show them to have irregular shapes and heavily cratered surfaces. These highly energetic collisions provide critical insights into the physics of the much more massive impacts that helped shape early Earth.

"One problem with studying large-scale asteroid impacts," said lead investigator Dr. David Nesvorny, a researcher at the SwRI Boulder Office, "is that most of these events happened hundreds of millions to billions of years ago, long enough for collisional and dynamical evolution to have eroded most of the telltale features that could shed light on the impact process."

Nesvorny and SwRI team members Dr. William F. Bottke Jr., Dr. Luke Dones and Dr. Harold P. Levison carefully studied a cluster of asteroid fragments called an "asteroid family," a group of large and small rocks believed to be the leftover pieces produced by a highly energetic collision. Dubbed the "Karin cluster," after the name of its largest member, 11-mile-long asteroid (832) Karin, the orbits of 13 asteroids in the cluster were tracked backwards in time using computer models. The team found that 5.8 million years ago, all 13 bodies shared the same orbital orientation in space, making it possible to identify them as the by-product of a single asteroid disruption event.

"This convergence was not an accident," Nesvorny said. "Tests indicate that the probability of finding such an orbital alignment by chance was less than one part in a million over the lifetime of the solar system."

The relative youth and known age of the Karin cluster could help researchers answer several important questions about asteroid geology and impact physics. The Karin cluster serves as a natural laboratory for the study of asteroid collisions. For example, data from this disruption event could be used to validate computer simulations that show the effects of large bodies colliding at high velocities.

Contact Nesvorny at (303) 546-9670 or david.nesvorny@swri.org.

Telecommunications testing facility

The Institute has opened a 9,700-square-foot dedicated facility for Network Equipment/Building Systems (NEBS) testing, which enhances SwRI's environmental testing capabilities and provides greater flexibility and scheduling for client testing.

"We will be offering improved, more dynamic test facilities with this expansion," said Timothy A. Fey, NEBS program manager and manager of the Mechanical Sciences Section in SwRI's Mechanical and Materials Engineering Division. "We saw a need to better meet clients' schedules and to help them get their product to the market more quickly. Most of our tests will be centralized in this building, which will provide greater safety and control standards for the clients' product. Product moves will be minimized, increasing efficiency in testing time and also reducing risk to the equipment."

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 categories such as temperature and humidity, fire, electromagnetic compatibility, electrical, seismic, acoustic, and others. SwRI has more than 15 years of experience in NEBS-type testing and more than 25 years in environmental testing. The full range of NEBS compliance tests are performed at one location at the Institute's headquarters in San Antonio.

SwRI is incorporating additional environmental chambers in the new NEBS facility, including a large walk-in chamber and smaller test chambers, a large platform earthquake test facility, and various other equipment.

"We are designing and building a new earthquake test facility to meet the clients' needs for more force and for testing larger items," Fey said. "The new building will have larger platforms for horizontal and vertical earthquake testing. It should be completed and fully operational by this fall."

The earthquake facility will test up to 10,000 pounds of payload, compared to SwRI's current capacity for up to 6,000 pounds for the NEBS Zone 4 severity level. It also will have longer strokes to allow for higher energy in lower frequencies, a characteristic of earthquake ground motions.

Contact Fey at (210) 522-3253 or tim.fey@swri.org.

SwRI kicks off Mars initiative

SwRI has launched a major initiative to broaden its expertise in support of the NASA Mars program.

The two-year SwRI Initiative for Mars (SwIM) will invest more than $2.4 million in Institute internal research funds on a variety of Mars-related efforts. SwIM activities will include sponsoring Mars research and development projects, seminars and workshops, as well as recruiting senior Mars researchers and technologists.

Dr. S. Alan Stern, SwIM principal investigator, and Walter D. Downing, executive vice president for operations, have announced the selection of the first six projects.

Representing an investment of $566,000 in Mars-related research and development, these projects and their research teams were chosen from a field of 24 concept proposals. The selected research and development topics are as follow:

  • A comparison of Mars Rover powertrain energetics
  • The identification and interpretation of martian craters
    and climate history
  • The development of an SwRI Mars atmosphere model
  • A numerical simulation of the hydrological and geo-
    chemical environment of the martian subsurface
  • The development of a Raman probe for in situ analysis
    of Mars samples
  • An examination of stress and deformation on Mars time
    SwRI will announce the next selection of internally funded SwIM projects in December and expects to hire one or more Mars science experts by that time.

"We frequently transfer technologies developed for one application to a totally different application," Downing said. "This synergistic effect is common at SwRI because of the diverse scientific and engineering talent available. Such is the case for SwIM, where technologies originally developed for the nuclear waste and automotive industries now are being applied to Mars exploration."

Contact Bill Bottke at (303) 546-6066.

RAPTOR automotive modeling

Engineers and computer scientists at SwRI have developed a modular simulation tool for automotive designers to assess vehicle fuel economy and performance.

The Rapid Automotive Performance SimulaTOR for Vehicle System Modeling (RAPTOR™ VSM), allows designers to configure a virtual vehicle from a number of component and sub-component models. The component models and their associated data can be changed or added to component library databases.

In addition, component hardware can be put on a test stand and controlled within the framework of a virtual vehicle while other components are simulated in RAPTOR.

"RAPTOR is a product that has been years in the making," said Scott McBroom, manager of Advanced Vehicle Technology at SwRI.

"It includes all source code in SimuLINK™, programmed by engineers with test cell experience. This combination becomes evident in the value, features and utilities, making RAPTOR stand out above the rest," McBroom said. The software preserves data and model integrity, saving time and money for organizations that do large amounts of simulation, he said.

RAPTOR VSM is comprised of both integration-based or forward-looking models and derivative or backward-looking models.

Backward-looking models emphasize execution speed, while forward-looking models emphasize a higher level of detail and fidelity for hardware-in-the-loop, as well as component and controls development.

Component libraries contain models that characterize the operational behaviors of subsystems such as engines, torque converters, clutches, pumps, gearboxes, wheels, and final drives. Vehicle templates representing powertrain configurations feature a number of two-wheel and four-wheel drive variations, for passenger cars as well as light-, medium- and heavy-duty trucks.

RAPTOR is available from SwRI for $50,000 per package.

Contact Joe Fohn, Technology Today® editor, at (210) 522-4630 or jfohn@swri.org.

Turbocharger, coolant chiller facilities

The Institute now offers two new engine testing facilities: the turbocharger test rig and the coolant chiller system.

The rig, first offered in March 2002, is designed for testing complete turbochargers and turbocharger turbine and compressor components as used on gasoline, diesel or natural gas engines.

"The turbocharger test rig is ideal for manufacturers who want to test new systems or components, but don't have the facilities," said facility manager J. Corwin Snyder, a senior research engineer in the SwRI Engine and Vehicle Research Division. "It's also ideal for outsourcing any overflow testing."

Typically used on Class 8 and medium-duty natural gas and diesel trucks, motorcycles, boats, large marine diesels, Class 8 rigs, and industrial natural gas stationary engines, turbochargers increase engine power and performance by supplying compressed air to the cylinders, allowing the engine to burn more fuel.

In addition to testing the performance of new concepts and designs, the SwRI test rig measures basic turbocharger performance, such as compressor and turbine efficiencies and pressure ratios.

The test rig takes ambient air and provides high-pressure, high-temperature air into the turbine to simulate engine exhaust. Three large compressors are available to be used individually or in combination to pressurize air up to 200 pounds per square inch at 2,000 cubic feet per minute. The air also can be heated to 1,500 degrees Fahrenheit or higher with the addition of a booster heater.

"Manufacturers often test turbochargers by installing them on engines," Snyder said. "Because the SwRI test method uses a rig instead of an actual engine, clients save the time and expense of engine installation." The rig also can be expanded to test two or more turbochargers simultaneously for additional savings.

SwRI tests turbochargers to "SAE Standard J1826, Turbocharger Gas Stand Test Code Recommended Practices," an industry-driven standard. Customized test procedures also can be accommodated.

The Institute also offers a state-of-the-art coolant chiller system, designed specifically for SwRI, for engine durability and reliability testing programs, including deep-thermal shock tests.

The chiller, unique in size, provides expanded testing capabilities to industry.

"In addition to operating a single engine through a deep-thermal shock cycle, there is also capacity in the coolant chiller for other laboratory uses such as low-temperature intake air cooling for high altitude simulations and low-temperature after-cooling for special projects," said Bob Burrahm, manager of the Spark Ignition Engines Section in the Engine and Vehicle Research Division. "We use the chiller to perform deep-thermal shock tests, which force an engine or an engine component to endure the thermal conditions it would experience in its lifetime, condensed into a few days of testing."

The coolant supply in the chiller can be set as low as -30 degrees C (-20 degrees F). SwRI can perform deep-thermal shock tests to meet industry standards set by Ford, General Motors and other automotive manufacturers. The chiller also can be used for specialty durability testing and performance mapping. Cold-start testing is accomplished in a low-temperature enclosure capable of -32 degrees C (-25 degrees F).

The Institute is one of a few laboratories in the nation equipped to handle deep-thermal shock testing. While testing ranges from lawn mower to heavy-duty diesel engines, staff members also focus on components such as cylinder heads, head gaskets, exhaust manifolds, exhaust manifold gaskets, and water pumps.

For more than 30 years, SwRI has performed engine durability and reliability testing. SwRI's durability test cells can evaluate the life expectancy of a test specimen, often testing components to failure. All failure modes, including minor ones such as an oil leak, are recorded.

"When failures do occur, we can evaluate why the item failed and also engineer a fix," Burrahm said. "Our staff includes engine designers who can redesign a component or offer solutions to a problem."

The Institute offers a broad range of engine-design and testing services including conceptual design, cycle simulations, modeling, prototyping, and endurance testing. SwRI also has additional multi-purpose test cells available. Dozens of engine dynamometers are available in sizes ranging from 30 to 2,000 hp and at speeds up to 12,000 rpm.

Along with the coolant chiller system, SwRI also has installed quick-change carts, which save testing costs by reducing the amount of engine setup time from days to hours. The Institute has also upgraded its data acquisition and control systems for faster downloading of data and better control capabilities to run more complex test cycles, including semi-transient cycles.

As an independent, multidisciplinary research, development, and testing organization, SwRI provides a non-biased, third-party perspective. The SwRI Engine and Vehicle Research Division has achieved certification to ISO 9001, an internationally recognized quality standard, and is working toward ISO 14001 certification.

For more information, visit the engine durability web site at enginedurability.swri.org.

Published in the Fall 2002 issue of Technology Today®, published by Southwest Research Institute. For more information, contact Joe Fohn.

Fall 2002 Technology Today
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