Twenty years ago this week, the singular space shuttle mission which marked the demarcation between past and future took place. Since the resumption of flights in September 1988, following the horrific loss of Challenger, NASA had steadily rebuilt the nation’s confidence in the capabilities of the reusable spacecraft, but the failure of Mars Observer to reach the Red Planet in August 1993 and the much-publicized problems with the Hubble Space Telescope in the aftermath of its 1990 launch left the space agency in an unenviable position. By the middle of the decade, NASA hoped to begin construction of Space Station Freedom—a project whose future still hung under the axe of possible cancellation—and a spectacularly successful Hubble repair mission was acutely needed to reinvigorate public and political enthusiasm. From 2-13 December 1993, that success was accomplished, when the crew of Endeavour on STS-61 broke virtually every record in the book and restored Hubble to its rightful place as the United States’ dazzling icon of science. It was a mission that every astronaut wanted. In the summer of 1992, Jeff Hoffman was in quarantine, preparing to launch aboard his third shuttle flight, when he fell into conversation with Don Puddy, the head of Flight Crew Operations at the Johnson Space Center (JSC) in Houston, Texas. Puddy was interested in Hoffman’s future plans. Several astronauts had already been approached about their willingness to be considered for flights to the Mir space station, but Hoffman’s height ruled that out. Only one other mission captured his attention. The first Hubble servicing mission stood out like a jewel on the shuttle manifest in December 1993, and as a professional astronomer Hoffman found that it exerted an irresistible pull. “What I’d really love,” he told Puddy, “is to go on this Hubble mission.” Puddy laughed. “Oh, yeah. You and the rest of the office!” Hoffman assumed that his chances of selection were minimal, but in addition to his flight experience he had one other credential which made him an attractive choice for the mission: He was one of few astronauts in the office, at that time, with EVA experience. Several years earlier, in April 1985, Hoffman had participated in the shuttle program’s first contingency spacewalk in a fruitless attempt to activate a deployment switch on the malfunctioning Leasat-3 satellite. With several intricate and complex EVAs scheduled for the Hubble mission, NASA mandated that all members of the four-person spacewalking team must have prior EVA expertise. This obviously disappointed several unflown members of the office, including rookie astronaut Leroy Chiao. “I was doing EVA training and showing some proficiency at it in the water tank,” Chiao told the NASA oral historian. He had been approached by Dave Leestma, then serving as deputy chief of the office and later to serve as head of Flight Crew Operations, with what Chiao perceived to be a strong hint that he was in line to receive one of the EVA spots on the Hubble mission. “I was very excited about that,” Chiao continued, “and my classmate Eileen Collins … had heard through the grapevine that she was going to get assigned as the pilot on that flight. Then I started hearing rumors that the crew for that flight was going to be changed. They didn’t want any rookies, at least on the EVA team. I have to say that was hard to swallow, because I had worked hard and I had shown proficiency and I had been told I was going to be on that flight and then, for political reasons or visibility reasons, they wanted to be able to say that it was an experienced crew if something had gone wrong.” Certainly, in March 1994 Flight International noted that Collins’ name had been proposed, “but was overruled because it was felt that an experienced pilot was needed.” It was not simply a case of NASA being overly cautious. With the loss of Challenger still fresh and the embarrassing failure of Hubble’s ability to resolve distant objects, due to a flaw in its primary optics, the mission to fix the $1.5 billion showpiece telescope was crucial. Congressional support for Space Station Freedom hung on the edge of a knife, and any failure on NASA’s part could spell its cancellation. Today, Hubble has earned itself a well-deserved reputation as one of the most successful space-based observatories ever launched. Across more than two decades of operations, its instruments have peered deeper into the cosmos than ever before. It has acquired images of distant galaxies, made breakthroughs in physics and cosmology by accurately determining the Universe’s rate of expansion, detected planets around far-off stars, witnessed the impact of a comet into Jupiter, tracked cloud movements in the atmospheres of Uranus and Neptune, and created the best currently achievable “map” of the surface of Pluto.