Steven Jeffrey Ostro, a senior research NASA scientist who pioneered the field of asteroid radar astronomy, died on December 15 at age 62, following a two and a half year battle with cancer.

Dr. Ostro was a New Jersey native who earned bachelor's degrees in liberal arts and ceramic science from Rutgers University; a master's degree in engineering physics from Cornell University; and a doctorate in planetary sciences from the Massachusetts Institute of Technology. Beginning in 1979 - after a personal invitation from Carl Sagan - Dr. Ostro served as an assistant professor at Cornell University. In 1984, he began creating his life's legacy through his work at NASA's Jet Propulsion Laboratory in Pasadena, California.

Essentially, Dr. Ostro created the field of asteroid radar astronomy, as well as mentoring and training the next group of scientists. Using the radar strength of radio telescopes such as the 305-meter telescope located at Arecibo Observatory in Puerto Rico and the telescopes at Goldstone Observatory in California, Dr. Ostro and his team produced fascinatingly detailed images of asteroids.

In applying radar techniques to asteroids, he not only revolutionized the capacity to study the position, shape, size, spin state and geological surfaces of these objects, but also greatly increased astronomers' ability to predict potential close encounters of asteroids with Earth, pushing predictions up to ten times further into the future. Dr. Ostro's work could also directly aid any potential manned missions to asteroids in future years, which could someday lead to the mining of these objects for natural resources.

Notable observations by Dr. Ostro include: 4179 Toutatis - a contact binary asteroid with an exceptionally unique rotation state; 1999 KW4 - one of the first binary near-Earth asteroids known; and 216 Kleopatra - the first asteroid confirmed to have a surface composition of nickel-iron. In addition to asteroid research, Dr. Ostro used the Cassini-Huygens RADAR instrument to observe the icy satellites of Jupiter and Saturn, while radar observations of the moons of Mars clarified knowledge of their orbits.

In 2003, the Division for Planetary Sciences of the American Astronomical Society awarded Dr. Ostro the prestigious Gerard P. Kuiper Prize for outstanding contributions to the field of planetary science. Each year, the 1, 200-member division honors one scientist "whose achievements have most advanced our understanding of the planetary system." In both 1991 and 2004, Dr. Ostro was awarded NASA Medals for Exceptional Scientific Achievement as a result of his scientific accomplishments as well as his excellent leadership. The asteroid 3169 Ostro, discovered June 4, 1981, is named to commemorate his work.

Dr. Ostro was known to have an unwavering thirst for knowledge and was an avid reader. He had a dedicated work ethic and always gave 100%, no matter what was the task at hand. Dr. Ostro is especially remembered for the way he articulated so deliberately and eloquently: he always captivated his audience, whether it was family, friends or colleagues. He led an active lifestyle and was a passionate practitioner of Tai Chi. Overall, he was a loving father and a devoted husband.

Dr. Ostro is survived by his wife, Jeanne; their three children, Marguerite, Brian and Julianna; his brother, Stu; cousins Shirley Kline Bennett, Florence E. Kline, and Judy Bari; an uncle, Justin Ostro; and an aunt, Renee Wexler.