...There were 11 manned Apollo missions, they all brought their crews home alive. A failure rate of 0%. There would have and should have been more Apollo missions...”
Apollo 1 is the official name that was later given to the never-flown Apollo/Saturn 204 (AS-204) mission. Its command module (CM-012) was destroyed by fire during a test and training exercise on January 27, 1967 at Pad 34 (Launch Complex 34, Cape Canaveral, then known as Cape Kennedy) atop a Saturn IB rocket. The crew aboard were the astronauts selected for the first manned Apollo program mission: Command Pilot Virgil I. “Gus” Grissom, Senior Pilot Ed White and Pilot Roger B. Chaffee. All three died in the fire.
Although the ignition source of the fire was never conclusively identified, the astronauts’ deaths were attributed to a wide range of lethal design hazards in the early Apollo command module. Among these were the use of a high-pressure 100 percent-oxygen atmosphere for the test, wiring and plumbing flaws, inflammable materials in the cockpit (such as Velcro), an inward-opening hatch that would not open in this kind of an emergency and the flight suits worn by the astronauts.
That was an unexpected accident, not a reasonably foreseeable risk, and most importantly for this discussion it did not occur during a flight. When the shuttle launches the directors and the astronauts are taking many foreseeable deadly risks, significant risks, significant enough that it makes each shuttle launch the moral equivalent of russian roulette. Murder for one, suicide for the other.
Moreover that risk, once known, was completely eliminated.