Thirty years ago on January 28, 1986, NASA and the nation suffered loss of the space shuttle Challenger during launch from the Kennedy Space Center. Many Americans had been excited about this mission, even more than those that had gone before, because a member of the crew was a teacher who would be conducting a class from orbit. The Teacher in Space program, with the young and energetic Christa McAuliffe as its centerpiece, had been years in the making and was touted as a major step forward in education for young people. But the mission ended abruptly and tragically 73 seconds into the flight: a leak in one of two solid rocket boosters ignited the main liquid fuel tank, and Challenger exploded in a blazing fireball.
The accident, the worst in the history of the American space program, proved all the more devastating not only because of McAuliffe’s and her crewmembers’ deaths but also because of the close connections that other members of the crew had to groups in the United States. The seven crewmembers of the Challenger represented a richly diverse cross-section of the American population in terms of race, gender, geography, background, and religion. The explosion became one of the most significant events of the 1980s, as millions around the world saw the accident on television and mourned the crewmembers killed.
Following the Challenger accident, several investigations took place to understand the causes of the tragedy and to ascertain what changes should be made to the program to ensure shuttle safety and reliability. The most important investigation was the presidentially-mandated blue ribbon commission chaired by former secretary of state William P. Rogers. The commission grappled with the technologically difficult issues associated with the Challenger accident, firmly linking it to a poor engineering decision made years earlier to use O-rings to seal joints in the SRBs. These, they found, were susceptible to failure at low temperatures.
The Rogers Commission also criticized the communication system inside NASA, finding that concerns about irregularities in the O-rings had been voiced well before 1986, but that because of poor internal communication these concerns had not been raised to the appropriate level. In the words of one Rogers Commission member, NASA was “playing Russian roulette” because as long as the shuttle returned safely, the irregularities did not seem to affect successful operations. Only in hindsight did the O-ring problem appear so daunting that it required the cancellation of a launch.
On June 6, 1986, the Rogers Commission submitted its formal report to President Ronald Reagan. The report included nine recommendations for restructuring the shuttle program and safely returning to flight. Most important, the SRBs were extensively redesigned following the accident. This involved recertifying the boosters through a series of test firings at Morton Thiokol’s SRB facility in Brigham City, Utah. The redesign added an extra O-ring to the joints between the booster segments and greatly strengthened the physical connection between the segments. Heaters were added to the joints to prevent low temperatures from affecting the sealing capability of the O-rings.
In addition, NASA made extensive landing safety improvements. This included upgrades of the orbiter fleet’s tires, brakes, and nose-wheel steering mechanism; and adding a drag chute system. NASA engineers also made other safety improvements, including the installation of a crew escape system that allowed astronauts to parachute from the orbiter under certain conditions. Moreover, the space shuttle program was completely reorganized to ensure that all necessary information would be available to managers at all levels, including a means of raising problems anonymously from any level of the program staff.
Also in line with the Rogers Commission findings, experienced astronauts were placed in senior management positions within the program. Finally, through a series of open reviews, all significant issues were to be elevated to a Flight Readiness Review Board chaired by the NASA Associate Administrators for Space Flight and Safety. Through this process, NASA leaders hoped to foster full and open discussions of potential safety and operational issues.
Finally, President Ronald Reagan made two fundamental policy decision affecting the Space Shuttle program. First, he directed that NASA would no longer have a monopoly on the launch of satellites on the Space Shuttle. In so doing, the Department of Defense and other organizations could launch their applications satellites on any rocket they chose. This had profound implications for such things as reconnaissance satellites, which would thereafter be launched from Vandenberg Air Force Base, California, aboard expendable launch vehicles. Second, Reagan took NASA out of the commercial launch business, thereby opening that market to private sector launch services.
When the space shuttle retumed to flight operations with the launch of Discovery on September 29, 1988, it was a much safer program than it had been before the January 1986 accident. Despite the removal of commercial and Defense Department payloads, the shuttle had a surprisingly busy launch schedule after returning to flight. Through January 2003 there have been 86 shuttle missions since the Challenger accident. Counting all shuttle missions, including the Challenger, there have been 111 flights.
Once flight began again in 1988, the vehicle returned to its former status as a workhorse of space exploration. Perhaps most important, there were seven major scientific payloads that required the unique capabilities of the shuttle. Since 1988 the shuttle has launched the Magellan spacecraft to Venus, the Galileo spacecraft to Jupiter, and the Ulysses spacecraft to study the sun. The shuttle also has deployed the Gamma Ray Observatory, the Hubble Space Telescope, the Upper Atmosphere Research Satellite, and the Chandra X-Ray Telescope. In addition, the 16 Spacelab and Spacehab missions flown could not have been conducted by anything other than the Space Shuttle. The Spacelab and privately-funded Spacehab modules filled the payload bay and allowed significant scientific work to be accomplished before a Space Station was completed.
Between April 1981 and January 2003 the shuttle carried approximately 3 million pounds of cargo and more than 900 major payloads into orbit for commercial interests, other nations, and educational institutions. Its crews also conducted more than 70 extravehicular activities (spacewalks).