Johns Hopkins University’s Applied Physics Project manager Henry Riblet and NASA Goddard Space Flight Center project manager Marjorie Townsend inspect SAS-C prior to testing in 1974. (NASA)

Marjorie R. Townsend, an electrical engineer who became the first woman to manage a U.S. spacecraft launch, died April 4 at a hospital in Washington. She was 85.

A spokeswoman for the D.C. medical examiner’s office said the cause of death had not been determined.

In 1959, Mrs. Townsend became one of the first female engineers to join the National Aeronautics and Space Administration. In the next decade, she became the first female spacecraft project manager at NASA’s Goddard Space Flight Center in Greenbelt, Md.

From the mid-1960s to 1975, she managed the agency’s small astronomy satellite program, where she was responsible for the design, construction, testing and orbital operations of NASA’s first astronomical spacecraft.

Most notably, she oversaw the development and launch of Uhuru, the world’s first X-ray astronomy satellite. The space instrument, launched in 1970 in Kenya, was used to detect, survey and map celestial X-ray sources and gamma-ray emissions. It was the first U.S. spacecraft to be launched by another country (Italy) in a foreign location (the coast of Kenya).

Marjorie Townsend discusses the X-ray Explorer Satellite with a colleague in December 1970. (NASA)

According to the American Association for the Advancement of Science, the findings from the Uhuru mission “quadrupled the number of X-ray sources known at the time.”

“It was a really important moment in the history of astronomy,” Josh Grindlay, a professor of practical astronomy at Harvard University, told the science association. The data collected from Uhuru helped revolutionize the field of high-energy astronomy and astrophysics, which examines the universe in terms of wavelengths and examines high-energy phenomena such as black holes.

Mrs. Townsend served as the program manager for NASA’s applications explorer missions program before retiring in 1980. For her contributions, she received the agency’s Exceptional Service Medal and Outstanding Leadership Medal.

Marjorie Trees Rhodes was born March 12, 1930, in Washington. Her father was an engineer and inventor. She enrolled in college at 15 and, in 1951, became the first woman to receive an engineering degree from George Washington University.

“The thought seems to lurk in people’s minds that women go into a man’s field to catch a husband. In fact, there was a wager on the line when I went to school that I would get married and never graduate,” she told The Washington Post in 1957. “That gentleman had to pay” up.

Early on, she was a physical science aide at what is now the National Institute of Standards and Technology and worked on sonar-signal-processing mechanisms for anti-submarine warfare at the Naval Research Laboratory.

She moved to NASA’s Goddard Space Flight Center in 1959 and helped develop the first successful weather satellites, including TIROS-1 and the Nimbus satellite series.

After her retirement, she worked with Washington-area government contractors. She was director of space systems engineering at BDM International and then vice president for space systems development for Space America until her second retirement in 1996.

She was named a Knight of the Italian Republic Order in 1972 for her contributions to U.S.-Italian space efforts. She also was chairman of a local chapter of the American Institute of Aeronautics and Astronautics, past president of the Washington Academy of Sciences and a fellow of the Institute of Electrical and Electronics Engineers.

Her husband of 53 years, Charles E. Townsend Sr., died in 2001. Survivors include four sons, Charles “Chet” Townsend Jr. of Fort Denaud, Fla., John Townsend of Ellicott City, Md., Lewis Townsend and Richard Townsend, both of Potomac, Md.; 11 grandchildren; and nine great-grandchildren.