Judith Arlene Resnik (April 5, 1949 – January 28, 1986) was an American electrical engineer, software engineer, biomedical engineer, pilot and NASA astronaut who died in the Space Shuttle Challenger disaster. She was the fourth woman, the second American woman and the first Jewish woman of any nationality to fly in space, logging 145 hours in orbit.

Recognized while still a child for her intellectual brilliance, Resnik was accepted at Carnegie Institute of Technology after becoming only the 16th woman in the history of the United States to have attained a perfect score on the SAT exam. She graduated with a degree in electrical engineering from Carnegie Mellon before attaining a PhD in electrical engineering from the University of Maryland.

Resnik worked for RCA as an engineer on Navy missile and radar projects, as a senior systems engineer for Xerox Corporation, and published research on special-purpose integrated circuitry. She was also a pilot and made research contributions to biomedical engineering as a research fellow at the National Institutes of Health.

At age 28, Resnik was selected by NASA as a mission specialist. She was part of NASA Astronaut Group 8, the first group to include women. While training on the astronaut program, she developed software and operating procedures for NASA missions. Her first space flight was the STS-41-D mission in August and September 1984, the twelfth Space Shuttle flight, and the maiden voyage of Space Shuttle Discovery, where her duties included operating its robotic arm. Her second Shuttle mission was STS-51-L in January 1986 aboard Space Shuttle Challenger. She died when the orbiter broke up shortly after liftoff and crashed into the ocean.

Judith Arlene Resnik was born in Akron, Ohio, on April 5, 1949, the daughter of Marvin Resnik, an optometrist, and his wife Sarah (née Polensky), a legal secretary. She had a brother, Charles, who was four years younger. Her father was the son of a rabbi, and he had been born in Preluke in Ukraine. His family had emigrated to Mandatory Palestine in the 1920s, and then to the United States after the 1929 Hebron massacre. He was fluent in eight languages and served in the U.S. Army during World War II in military intelligence, conducting prisoner of war interrogations and aerial reconnaissance in the Pacific Theater and the subsequent occupation of Japan. Resnik grew up in an observant Jewish home, studying at Hebrew school at Beth El Synagogue in Akron and celebrating her Bat Mitzvah in 1962, which at the time was not a common occurrence.

Resnik was noticed for her intellectual ability while still in kindergarten, and she entered elementary school a year early. She attended Fairlawn Elementary School, Simon Perkins Junior High School, and Harvey S. Firestone High School. She was an outstanding student, excelling in mathematics, languages and piano. She played classical piano, and at one point considered a career as a concert pianist. Before college, she attained a perfect score on her SAT exam, the only woman in the country to do so that year and only the 16th woman in US history. She graduated from Firestone in 1966 as valedictorian and runner-up homecoming queen.

Although her mother disapproved of her dating, Resnik had a series of boyfriends. She preferred to socialize with boys from the nearby Copley High School rather than from Firestone, where her intellectual reputation preceded her. She met Len Nahmi (who eventually became a pilot) at a basketball game. He was half Irish and half Lebanese, and her mother disapproved of him. Nonetheless, she continued to see him secretly, and when she stayed with a cousin in Cleveland while taking a college course available to high school students, she also met with him there. Her parents acrimoniously divorced while she was a teenager, and custody was given to her mother, as was the custom in the United States. Her mother's dislike of Nahmi became more intense, and Nahmi eventually ended their relationship to spare Resnik more pain. When she was 17, she prepared and filed a successful court case so that her custody could be switched from her mother to her father, with whom she was particularly close. She tore up letters from her mother unopened. Her father remarried, and she acquired twin stepsisters, Linda and Sandy, who were nine years older than she was, and with whom she became close.

At age 17, Resnik entered Carnegie Institute of Technology, where she joined the Alpha Epsilon Phi sorority. She began college intending to become a math major, but in her second year, after attending electrical engineering lectures with her boyfriend Michael Oldak, she developed a passion for the subject. She was one of three female students in electrical engineering. She was a gourmet cook and a navigator in sports car rallies, in which she took part many times with Oldak in his Triumph TR6. She earned a Bachelor of Science degree in electrical engineering from Carnegie Mellon University (as it now was) in 1970. She became a member of Tau Beta Pi, Mortar Board, and Eta Kappa Nu honor societies.