— Although they never flew in space together, astronauts David Hilmers and Marsha Ivins crossed paths aboard the same spacecraft on the same mission.

On Tuesday (Feb. 6), Hilmers and Ivins were announced as the next honorees to enter the U.S. Astronaut Hall of Fame. The two NASA veterans will be celebrated at a public ceremony on June 1 under the retired space shuttle Atlantis at NASA's Kennedy Space Center Visitor Complex in Florida.

Thirty-nine years ago, Hilmers and Ivins were both aboard Atlantis preparing for the launch of the orbiter's maiden mission, STS-51J, on Oct. 3, 1985. Ivins was a "Cape Crusader," an astronaut assigned to help configure the shuttle's controls and switches in the hours leading up to the arrival of the crew. Hilmers, as mission specialist 1, about to launch on his first mission.

Ivins climbed out of Atlantis' cabin as Hilmers climbed aboard the flight deck. With both of their spaceflight careers yet to begin, there was no way they could know that four decades later they would reunite near the same hatch to join the ranks of NASA's most prestigious space travelers.

"These two veterans of the space program have demonstrated outstanding accomplishments in furthering NASA's mission of exploration and discovery," Curt Brown, board chairman of the Astronaut Scholarship Foundation (ASF), which stewards the selection process, said in a statement. "Both Hilmers and Ivins represent the committed spirit of exploration, bravery and teamwork that make our space program a continued success."

"We are proud and honored to have them join the ranks of the space pioneers recognized in the U.S. Astronaut Hall of Fame at Kennedy Space Center Visitor Complex," said Brown, who as a space shuttle commander was chosen for the hall in 2013.

Following this year's induction ceremony, Hilmers and Ivins will be feted at a black-tie gala hosted by the ASF.

Hilmers and Ivins were selected four years apart to join NASA's astronaut corps. Hilmers, a naval aviator in the Marine Corps with a Master's degree in electrical engineering, was a member of Group 9, the second class of shuttle astronauts, named in 1980. Ivins was recruited in 1984 with Group 10 having a bachelor's of science in aerospace engineering and a position already working at NASA helping to develop the orbiter's cockpit layout, displays and controls, as well as flying as a flight test engineer on the shuttle training aircraft.

When, in 1985, Hilmers and Ivins parted ways atop launch complex 39A, it was the start of Hilmers' first of four missions. He flew three more times through 1992, ultimately logging more than 20 days in space. By comparison, Ivins flew on five shuttle flights between 1990 and 2001, spending over 55 days off Earth.

Half of Hilmers' missions were flown in service to the Department of Defense. Both STS-51J and STS-36, the latter in 1990, launched on Atlantis with payloads that remain classified to this day. Hilmers' other two flights were on shuttle Discovery, including STS-26 in 1988, NASA's "return to flight" after the Challenger tragedy in 1986; and STS-42 in 1992, which was focused on the effects of microgravity on a variety of types of life.

Ivins' first flight into space was the first of her two on space shuttle Columbia. On STS-32 in 1990, she and her crewmates retrieved the Long Duration Exposure Facility (LDEF), a school bus-sized free-floating materials science platform. Four years later on STS-62, she and her four crewmates continued to study the effects of microgravity on materials sciences and spaceflight technologies.

Ivins' three other missions were aboard Atlantis, making her one of the orbiter's three most frequent fliers. On STS-46 in 1992, she helped with the first attempted deploy of the Tethered Satellite System. On STS-81 in 1997, Ivins visited Mir on the fifth shuttle mission to dock with the Russian space station. Finally, on STS-98 in 2001, Ivins helped to install the U.S. "Destiny" laboratory for the International Space Station and brought supplies for the orbiting complex's first resident crew.

Hilmers began attending pre-med courses at night while training for his final flight into space. After leaving NASA in 1992, he received his Doctor of Medicine (M.D.) degree and second Master's degree, this time in public health. He is is currently a professor of internal medicine and pediatrics at Baylor College of Medicine and, in addition to his volunteer work in disaster relief and low-resource countries, Hilmers has been helping NASA determine what the requirements for medical expertise will be on missions to the moon and Mars.

Ivins continued to serve in the astronaut office after her last flight, supporting both the space shuttle and space station programs, including becoming the corps' expert in flight crew equipment. During her last four years with NASA, she led the astronaut office team supporting the Constellation program and the development of the commercial crew initiative.

Since leaving the agency, Ivins served as a consultant on "A Beautiful Planet," the last IMAX documentary to be shot in space, and supported proposal work on a human lunar landing vehicle. Today she is the director of human systems integration at Sophic Synergistics, a Houston-based design consulting firm, which supports human space exploration endeavors.

With Hilmers' and Ivins' addition, the U.S. Astronaut Hall of Fame honors 107 former NASA space explorers and travelers. The hall was founded in 1990 by the surviving members of the Mercury 7 astronauts. To be eligible for nomination, astronauts must be a U.S. citizen and a NASA-trained commander, pilot or mission specialist who has orbited Earth at least once on a flight 17 years or more before his or her induction.