Spring/Summer 2003
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Cover Story
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Contributions to a
Space Odyssey
NASA-funded projects yield basic knowledge
and enabling technologies.
By Jane M. Sanders
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FROM BASIC SCIENTIFIC STUDIES to the development of enabling technologies such as fuel cells and microelectronics, research funded by NASA continues its long and fruitful history at the Georgia Institute of Technology.
photo by Gary Meek
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In his current research, Professor Paul Neitzel is building upon a phenomenon discovered by an orbiting astronaut studying surface-tension-driven convection and the formation of a liquid bridge between two solid surfaces. Called "permanent non-coalescence," it occurs when two droplets of the same liquid will not recombine because of differences in temperature.
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Research occurs across a wide range of disciplines – among them mechanical engineering, aerospace engineering, electrical and computer engineering, materials science and engineering, biomedical engineering and bioscience, chemistry, earth and atmospheric sciences, and even human and cross-cultural communication (see sidebar titled "Teamwork in Space").
Following are some highlights.
Breaking Up Isn't So Hard to Do
In the School of Mechanical Engineering, Professor Paul Neitzel has conducted NASA-funded research for nearly 20 years. He also has served on some of the agency's key advisory committees, including one reviewing research operations on the International Space Station, and he now serves on the Physical Sciences Advisory Subcommittee of the NASA Office of Biological and Physical Research.
In his current research, Neitzel is building upon a phenomenon discovered by an orbiting astronaut studying surface-tension-driven convection and the formation of a liquid bridge between two solid surfaces. Called "permanent non-coalescence," it occurs when two droplets of the same liquid will not recombine because of differences in temperature. Convection driven by variations in surface tension drags the surrounding air in to form an air cushion between the two droplets, preventing their coalescence. "Permanent non-wetting," a variation of this process, can prevent a liquid droplet from wetting a solid surface. The phenomena occur both in space and on Earth.
courtesy of Paul Neitzel
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Neitzel's research on "permanent non-coalescence" made the cover of Physics Today in 1998. Possible applications of the phenomenon include bearings in low-load environments in space.
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Relating it to a common experience, Neitzel points to the temporary non-coalescence that occurs when coffee droplets from a drip coffee maker float on the liquid's surface without coalescing. Then, because the phenomenon is temporary, the droplets disappear.
"We've been studying permanent non-coalescence for the past several years to determine more about the fundamental nature of the phenomenon and the conditions in which it occurs and persists," Neitzel says. "Now, we're developing an eye toward applications."
Possible applications include bearings in low-load environments in space. For example, one of Neitzel's Italian colleagues is developing a positional device to allow experimental packages in a weightless environment to be held in place by non-coalescing liquid droplets.
Very low friction is associated with the lateral movement of non-wetting droplets on a surface. Offering little resistance, liquids can be moved rapidly and in infinitely reconfigurable directions on a surface by using heat from light, he explains. These properties would be beneficial to lab-on-a-chip technologies, such as DNA sample processing, ever-shrinking micro electro-mechanical systems (MEMS) devices and nanotechnology applications.
photo by Gary Meek
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School of Electrical and Computer Engineering Professor Paul Steffes simulates planetary atmospheres in this chamber in his lab. Doctoral degree student Priscilla N. Mohammed works with Steffes.
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"We liken these kinds of devices to the CPU of a computer," Neitzel says. "It can be infinitely reconfigured on the fly whereas devices with channels have limits. It's a neat idea, and it opens up a lot of possibilities."
Second Star to the Right
Meanwhile, in the School of Electrical and Computer Engineering, Professor Paul Steffes has spent more than 20 years investigating microwave and millimeter-wave radio signals that reveal the chemical makeup of planetary atmospheres. He first interpreted radio transmission data from a NASA spacecraft that sensed sulfuric acid vapor and sulfur dioxide in the atmosphere of Venus. Steffes compared that data to the microwave properties of a simulated Venus atmosphere he cooked in a high-tech oven and high-pressure gas chamber in his lab.
"We have been able in the lab to find out what chemical constituents can be sensed by spacecraft missions," Steffes says. "Our biggest recent success has been in sensing ammonia and phosphine in the outer planets."
Steffes' research team has interpreted data from NASA's Magellan, Pioneer-Venus and Voyager missions to the outer planets, including Jupiter, Saturn, Uranus and Neptune. They are now working with NASA on the Cassini satellite mission to Saturn and its moon, Titan. Cassini, launched in 1997, is expected to orbit around Saturn in July 2004.
"We have made it possible to use radio systems to more precisely monitor the atmospheres of Venus and the outer planets," Steffes says. "This allows us to understand the structure, circulation and dynamics of these atmospheres. And, in some ways, we can prove the capabilities of the telecommunications systems on NASA spacecraft. So it's both science and engineering."
Moons Over Jupiter
In the School of Chemistry and Biochemistry, chair and Professor Thomas Orlando and his students are investigating the effects of radiation on water and very low-temperature ices and brines, such as those found on the surfaces of Jupiter's moons.
courtesy of NASA
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A view of a small region of the icy crust of Jupiter's moon Europa shows the interplay of surface color with ice structures. The white and blue colors outline areas that have been blanketed by a fine dust of ice particles ejected by the formation of the large crater Pwyll. The image was taken in 1997 by NASA's Galileo spacecraft.
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Researchers believe that radiation physics is controlling the surface chemistry and producing important molecules such as oxygen.
"There's a lot of weird chemistry going on in the solar system," Orlando says. "It produces weird products because there's a lot of energy from cosmic rays or high-energy particles. When these energetic particles interact with grains and ices, very interesting surface chemistry can occur."
With specialized equipment in their laboratory, Orlando and his students simulated the surface chemistry of Jovian moons. They collected molecular-level data to build a model that yielded a spatial distribution estimate of oxygen that closely mirrored data collected by NASA spacecraft.
Now in a project recently funded by NASA, Orlando and his students are studying the general effects of radiation in forming non-Earth planetary atmospheres – more accurately stated as rarified or near-zero atmospheres. Researchers are examining how electron beams, cosmic rays and energetic particles play a role in the chemistry of these regions.
"We're also looking at the processing of mixed ices containing hydrocarbons and nitrogen compounds," Orlando explains. "We want to know the chemistry near or on Titan since this is an important topic of NASA's Cassini mission."
This research represents what Orlando calls a "marriage" between planetary science and surface chemistry and physics.
photo by Gary Meek
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In the School of Chemistry and Biochemistry, chair and Professor Thomas Orlando and his students are investigating the effects of radiation on water, very low-temperature ices and brines, such as those found on the surfaces of Jupiter's moons.
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"We look at things from a chemical physics point of view – a molecule at a time," Orlando says. ".... There is an incredible difference of 'scale' between chemical physics and planetary science viewpoints. The planetary scientists work on a time scale of millions of years, and their highest-resolution data is measured in kilometers. The chemical physicists work on the picosecond/femtosecond time frames and angstrom-scale spatial dimensions. The beauty of this marriage is that we can now interpret the data across this broad spectrum."
He adds that his group's research is providing the fundamental science to help planetary scientists interpret NASA mission data. "NASA scientists have problems and know the issues, and we have the tool set they need," Orlando says. "Together, we can attack some big problems."
Fly Me to the Moon, or Mars
In the School of Aersopace Engineering, researchers are investigating numerous topics with NASA funds. Last year, the school won several large awards (see the sidebar titled "New Technologies for the Final Frontier"), including one that created the University Research, Engineering and Technology Institute (URETI) for aero-propulsion based at Georgia Tech. Researchers led by Professors Ben Zinn and Dimitri Mavris are seeking basic improvements to make civilian and military aircraft engines work more efficiently. Another URETI based at the University of Florida involves Georgia Tech Associate Professor John Olds and his colleagues Jerry Seitzman and Suresh Menon in designing NASA's third-generation reusable launch vehicle.
photo by Gary Meek
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With his students, Aerospace Engineering Professor Narayanan Komerath developed a concept called acoustic shaping in which they used sound waves to force dust or other materials to form walls in the simulated microgravity environment of NASA's KC-135 jet that can provide close to a zero-gravity environment for about 40 seconds.
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Olds is developing overall design configurations for the spacecraft, while Seitzman and Menon are developing the supporting technologies – for example, engine performance, and mixing and combusting of supersonic ramjet fuel. Seitzman is doing the experimental work in collaboration with the University of Florida. Meanwhile, Menon does computational simulations on how fuel burns in a supersonic flow environment. Olds and a team of three graduate students are designing the vehicle layout, including the payload and engine size, and then simulating its trajectory to orbit to determine the fuel fraction requirement. Other tasks include engine performance simulation and weight and surface temperature estimation.
"My students and I work on conceptual aerospace systems," Olds explains. "We can use our imaginations to dream of what the future will be like. We speculate on the positive impact of some of these advanced aerospace technologies, should they be successfully matured."
In another project in the School of Aerospace Engineering, Professor Narayanan Komerath uses his expertise in aerodynamics and fluid mechanics to advise undergraduate and graduate students funded by the "NASA Means Business" program and the NASA Institute for Advanced Concepts based in Atlanta.
With his students, Komerath developed a concept called acoustic shaping in which they used sound waves to force dust or other materials to form walls in the simulated microgravity environment of NASA's KC-135 jet that can provide close to a zero-gravity environment for about 40 seconds. It's known affectionately as the "Vomit Comet."
courtesy of Narayanan Komerath
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Komerath and his students are studying the use electromagnetic fields to remotely build large structures from space rubble. Building on some concepts developed in the 1970s, students have proposed the construction of a 2-kilometer-long by 2-kilometer-in-diameter cylindrical habitat near the moon. They view the structure, which could house as many as 10,000 people, as a step in the process toward a space-based economy.
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"This was quite exciting," Komerath says. "Before, we knew that we could force a single particle into a given region of a box using very high-intensity sound. But we had not thought about doing this with millions of particles. So we showed that these particles would not all clump into one space, but would form walls of a specified shape."
This study led Komerath and his students to a project for the NASA Means Business program, which solicits student ideas for using business interests to further the cause of space exploration, specifically a Mars mission. Komerath's students suggested that NASA initiate a space-based economy by investing in infrastructure – such as could be constructed with the acoustic shaping technique. The process would eliminate the need for shipping expensive molds and materials into space. Researchers just need a chamber with large speakers and some air to create various shapes, Komerath says.
"If you have an infrastructure in space or on the moon, then a lot more things become possible," he adds. ".... A mission to Mars makes sense if it's part of developing an economy in space. This means you have an economy where the majority of trading and transactions occur between entities away from Earth."
With additional support from the NASA Institute for Advanced Concepts, Komerath and his students are exploring a related idea that would use electromagnetic fields to remotely build large structures from space rubble. Building on some concepts developed in the 1970s, students proposed the construction of a 2-kilometer-long by 2-kilometer-in-diameter cylindrical habitat near the moon. They view the structure, which could house as many as 10,000 people, as a step in the process toward a space-based economy.
"We can't test this concept anytime soon," he adds. "But we've done simulations and know it works with sound and that we can use a laser beam to push and pull molecules. Now one of our Ph.D. students is extending this theory to long-wavelength electromagnetic waves."
For more information, contact Paul Neitzel, School of Mechanical Engineering, Georgia Tech, Atlanta, GA 30332-0405. (Telephone: 404-894-3242) (E-mail: paul.neitzel@me.gatech.edu); John Olds, School of Aerospace Engineering, Georgia Tech, Atlanta, GA 30332-0150. (Telephone: 404-894-6289) (E-mail: john.olds@aersopace.gatech.edu); Narayanan Komerath, School of Aerospace Engineering, Georgia Tech, Atlanta, GA 30332-0150. (Telephone: 404-894-3017) (E-mail: narayanan.komerath@aerospace.gatech.edu); Paul Steffes, School of Electrical and Computer Engineering, Georgia Tech, Atlanta, GA 30332-0250. (Telephone: 404-894-3128) (E-mail: paul.steffes@ece.gatech.edu); or Thomas Orlando, School of Chemistry and Biochemistry, Georgia Tech, Atlanta, GA 30332-0400. (Telephone: 404-894-4012) (E-mail: thomas.orlando@chemistry.gatech.edu).
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Last updated: August 11, 2003
