Thirty years ago this week, NASA reached a milestone in human spaceflight when space shuttle Endeavour lifted off from Kennedy Space Center on Sept. 7, 1995, carrying seven astronauts on mission STS-69. The flight marked the 100th crewed space mission launched by the United States space agency, a tally that began with Alan Shepard's suborbital Mercury flight in 1961 and grew through the Gemini, Apollo, Skylab, and shuttle programs.
Endeavour's crew included commander David Walker, pilot Kenneth Cockrell, and mission specialists James Voss, James Newman, and Michael Gernhardt. The mission was primarily dedicated to deploying and retrieving two free-flying science platforms: the Wake Shield Facility and the Spartan 201 satellite. The Wake Shield Facility was designed to create an ultra-high vacuum in its wake to grow thin semiconductor films, while Spartan 201 carried instruments to study the solar corona and solar wind.
The astronauts also conducted a spacewalk to test tools and techniques planned for use during assembly of the International Space Station. Voss and Gernhardt spent more than six hours outside the orbiter evaluating hardware, thermal protection repair methods, and mobility aids. Their work provided critical data that informed the design of procedures later used during station construction missions.
STS-69 was the ninth flight of Endeavour, which had been built to replace the lost Challenger and first launched in 1992. The orbiter completed 19 missions before being retired in 2011, including the final Hubble Space Telescope servicing flight in 2009. Endeavour is now displayed at the California Science Center in Los Angeles.
The 100th-flight milestone came during a busy period for NASA, as the agency was preparing for the first shuttle docking with the Russian space station Mir and laying groundwork for the International Space Station program. The shuttle fleet flew 135 missions total between 1981 and 2011, with the 100th occurring just past the midpoint of the program's operational history.
Walker, who commanded STS-69, was on his fourth and final spaceflight. He had previously flown on shuttle missions in 1989, 1992, and 1994. Cockrell, Voss, Newman, and Gernhardt all went on to additional flights, with Voss and Gernhardt later logging time aboard the International Space Station. Newman flew three more shuttle missions, including two visits to the Hubble telescope.
The mission lasted 10 days, 20 hours, and 29 minutes, touching down at Kennedy Space Center on Sept. 18, 1995. During the flight, Endeavour orbited Earth 171 times, covering about 4.5 million miles.
The Wake Shield Facility experiment, developed by the University of Houston's Space Vacuum Epitaxy Center, was flown a third time on STS-69 after two earlier shuttle missions. The device was intended to demonstrate that commercial-grade semiconductor films could be grown in the vacuum of space, a concept that researchers hoped would lead to more efficient electronics manufacturing. Spartan 201, meanwhile, was a reusable spacecraft built by NASA's Goddard Space Flight Center that observed the sun's outer atmosphere during its two days of free flight.
NASA's 100th astronaut flight also carried a range of secondary experiments in the orbiter's middeck, including studies of protein crystal growth, materials science, and biological responses to microgravity. These investigations contributed to the growing body of research that shaped the agency's long-duration spaceflight programs.