Jan 6 2011
From The Space Library
NASA selects 101 of its high-performing interns and fellows for the agency's Student Ambassador Program. The students represent NASA at a variety of education and outreach events at schools and universities to help inspire future students interested in science, engineering, mathematics and technology, or STEM, opportunities.
The new ambassadors represent 31 states and 64 different universities. This third group of student ambassadors, known as Cohort III, joins 189 other student ambassadors selected in 2009 and 2010. NASA managers and mentors nominated the ambassadors from hundreds of current interns and fellows who have participated in various NASA Education projects.
"The ambassadors have demonstrated their ability to motivate students to enter the STEM workforce," said Leland Melvin, associate administrator for education at NASA Headquarters in Washington. "They play an important role in our effort to develop the next generation of explorers, because they can engage fellow students in a meaningful peer-to-peer dialogue. That’s something that more traditional approaches cannot accomplish."
The new student ambassadors will join a virtual web-based community, which allows them to interact with NASA staff and other ambassadors to share information and make professional connections. Through the website, the ambassadors also will have access to the latest NASA news, cutting-edge research and career resources.
NASA Research Team Reveals Moon Has Earth-Like Core
State-of-the-art seismological techniques applied to Apollo-era data suggests the moon has a core similar to Earth's.
Uncovering details about the lunar core is critical for developing accurate models of the moon's formation. The data sheds light on the evolution of a lunar dynamo -- a natural process by which our moon may have generated and maintained its own strong magnetic field.
The team's findings suggest the moon possesses a solid, iron-rich inner core with a radius of nearly 150 miles and a fluid, primarily liquid-iron outer core with a radius of roughly 205 miles. Where it differs from Earth is a partially molten boundary layer around the core estimated to have a radius of nearly 300 miles. The research indicates the core contains a small percentage of light elements such as sulfur, echoing new seismology research on Earth that suggests the presence of light elements -- such as sulfur and oxygen -- in a layer around our own core.
The researchers used extensive data gathered during the Apollo-era moon missions. The Apollo Passive Seismic Experiment consisted of four seismometers deployed between 1969 and 1972, which recorded continuous lunar seismic activity until late-1977.
"We applied tried and true methodologies from terrestrial seismology to this legacy data set to present the first-ever direct detection of the moon's core," said Renee Weber, lead researcher and space scientist at NASA's Marshall Space Flight Center in Huntsville, Ala.
In addition to Weber, the team consisted of scientists from Marshall; Arizona State University; the University of California at Santa Cruz; and the Institut de Physique du Globe de Paris in France. Their findings are published in the online edition of the journal Science.
The team also analyzed Apollo lunar seismograms using array processing, techniques that identify and distinguish signal sources of moonquakes and other seismic activity. The researchers identified how and where seismic waves passed through or were reflected by elements of the moon's interior, signifying the composition and state of layer interfaces at varying depths.
Although sophisticated satellite imaging missions to the moon made significant contributions to the study of its history and topography, the deep interior of Earth's sole natural satellite remained a subject of speculation and conjecture since the Apollo era. Researchers previously had inferred the existence of a core, based on indirect estimates of the moon's interior properties, but many disagreed about its radius, state and composition.
A primary limitation to past lunar seismic studies was the wash of "noise" caused by overlapping signals bouncing repeatedly off structures in the moon's fractionated crust. To mitigate this challenge, Weber and the team employed an approach called seismogram stacking, or the digital partitioning of signals. Stacking improved the signal-to-noise ratio and enabled the researchers to more clearly track the path and behavior of each unique signal as it passed through the lunar interior.
"We hope to continue working with the Apollo seismic data to further refine our estimates of core properties and characterize lunar signals as clearly as possible to aid in the interpretation of data returned from future missions," Weber said.
Future NASA missions will help gather more detailed data. The Gravity Recovery and Interior Laboratory, or GRAIL, is a NASA Discovery-class mission set to launch this year. The mission consists of twin spacecraft that will enter tandem orbits around the moon for several months to measure the gravity field in unprecedented detail. The mission also will answer longstanding questions about Earth's moon and provide scientists a better understanding of the satellite from crust to core, revealing subsurface structures and, indirectly, its thermal history.
NASA Chief Technologist Braun Receives AIAA Von Karman Award
WASHINGTON -- The American Institute for Aeronautics and Astronautics (AIAA) honored NASA Chief Technologist Bobby Braun with the Von Karman Lectureship in Astronautics.
The award is given annually to someone who has performed notably and distinguished themselves technically in the field of astronautics. Braun was recognized for significantly advancing the understanding of the challenge of Mars entry, descent, and landing, and for the development of systems concepts and technologies enabling Martian exploration programs.
As part of the award, Braun delivered the speech "Mars Entry, Descent and Landing Technology Advancements" Thursday during the AIAA's 49th Aerospace Sciences Meeting in Orlando. The award honors Theodore von Karman, an early astronautics pioneer responsible for breakthroughs in understanding supersonic and hypersonic airflow characterization and the value of the swept wing design.
"I am honored to be recognized by the AIAA and to speak at this year's conference about the challenging work done by the scientists and engineers in NASA's entry, descent and landing technical community," Braun said. "My hope is that engineering students around the country will share in the excitement of planetary exploration, developing new technologies and advancing our nation's forays in space. By investing in space technology, NASA makes a difference in our lives every day."
Braun has more than 20 years experience performing design and analysis of planetary exploration systems as a member of the technical staff at NASA's Langley Research Center in Hampton, Va., and the Georgia Institute of Technology. His research has focused on systems' aspects of planetary exploration, where he contributed to the design, development, test and operation of several robotic spaceflight systems.
NASA Administrator Charles Bolden named Braun chief technologist on Feb. 3, 2010. Braun served as the principal advisor and advocate on matters concerning agency-wide technology policy and programs.
Braun received a B.S. in aerospace engineering from Penn State in 1987, M.S. in astronautics from George Washington University in 1989, and Ph.D. in aeronautics and astronautics from Stanford in 1996.
