'Sitting On A Controlled Explosion': 25 Years Since the Space Shuttle's Half-Century Mission

Twenty-five years ago, this week, Space Shuttle Endeavour—the youngest member of NASA’s fleet of orbiter vehicles, built to replace the ill-fated Challenger—rocketed away from the Kennedy Space Center (KSC) in Florida, on a mission of many firsts. Her crew included the first Japanese citizen to fly aboard a U.S. spacecraft, the first married couple to fly together on the same space mission and the first African-American female astronaut. And despite its numerical designation of “STS-47”, Endeavour’s second flight was actually the 50th mission of the 30-year Space Shuttle Program (SSP).

At this point, a little over a decade since the first shuttle flight and six years since the untimely loss of Challenger, the program had accomplished a number of spectacular successes in scientific research, satellite deployment and retrieval and spacewalking. International astronauts had flown shoulder-to-shoulder with their U.S. counterparts and, for the first time, women and ethnic minorities had flown routinely into orbit. The presence of Mae Jemison on STS-47 as the first African-American female astronaut was not lost on U.S. Vice President Dan Quayle, who was watching the launch on 12 September 1992 from the Firing Room in Florida. After chatting for a few moments with STS-47 Commander Robert “Hoot” Gibson, Quayle offered greetings to Jemison. A few months earlier, he had visited the newly-opened Mae C. Jemison Academy in Detroit, Mi.

The payload for the planned seven-day mission was Spacelab-J, a joint venture between the U.S. and Japanese space agencies, with a research emphasis on the life and microgravity sciences. Like several previous Spacelab missions, the seven-member crew was divided into two 12-hour shifts, in order that they could run the experiments around-the-clock. The “red” team of Gibson, Pilot Curt Brown, Payload Commander Mark Lee and Japan’s Mamoru Mohri were awakened at 4:58 a.m. EDT on launch morning, with the “blue” team of Mission Specialists Jemison, Jay Apt and Jan Davis rose about a half-hour later.

After breakfasting in the Operations & Checkout Building, the seven spacefarers donned their bright-orange pressure suits and headed out to the launch pad, where Endeavour waited for them. Liftoff at 10:23 a.m. was picture-perfect and within nine minutes the shuttle had settled smoothly into a 57-degree-inclined orbit at an altitude of 160 miles (260 km). For three members of the crew, the launch was not a new experience, but for Brown, Davis, Mohri and Jemison, it was their first flight into space.

“You are aware that you are sitting on a controlled explosion,” Jemison recounted, years later. “But you also realize that you’ve taken all the precautions. You trust the people you have been working with and you know they have worked to try to keep things safe. After that, you have to leave it alone. If you keep worrying about it, then you’re not going to be able to do your job.”

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