A Decade of Renewal
The Space Shuttle Program of the 1990s was a rebirth following the Challenger accident in 1986. It was not easy, according to former Shuttle Launch Director Bob Sieck, now retired.
"We had to ramp up to a realistic launch schedule and needed to meet new requirements in safety resulting from Challenger, as well as new tools and upgrades," he said. The team was learning to service complex vehicles under challenging conditions.
Image right: NASA Administrator Daniel Goldin (left) looks on as Bob Sieck shakes hands with Secretary of State Madeleine Albright after the successful launch of Space Shuttle Endeavour in December, 1998 on mission STS-88. Sieck is wearing the Distinguished Service Medal, the highest honor NASA confers on a government employee. Photo credit NASA/KSC + View Larger Image
Sieck considers the results of the ramping up a real milestone as the program achieved six launches in 1990 and 1991, eight in 1992, seven per year from 1993 to 1996, and eight again in 1997.
The high number of launches was made possible, according to Sieck, by a capable and resilient team.
A look at the launch history in the decade reveals technical problems that delayed liftoffs, such as hydrogen leaks. According to current Shuttle Launch Director Mike Leinbach, "Each instance was an opportunity to learn the nuances of the hardware and software in order to overcome the problems."
For instance, hydrogen leaks were traced to plate attachments, which were redesigned. The result of this and other lessons learned were fewer launch delays after 1995, other than those caused by weather.
Image left: Space Shuttle Columbia touches down at Kennedy's Shuttle Landing Facility in July, 1997, completing mission STS-83. Photo credit: NASA/KSC + View Larger Image
Even the weather has been less of an issue, Leinbach said, as there have been improvements in weather forecasting and lightning avoidance on the pad.
Sieck points to another technical milestone of the modification of the landing equipment. "The drag chute modification was the result of lessons learned about the need to relieve some of the stress on the main landing gear system on landing," he said.
Leinbach added that lessons learned and resilience of the team contributed to the STS-83 mission in 1997, "when one of the fuel cells failed shortly after launch." The shuttle flight rules require all three fuel cells to be functioning well to ensure crew safety and provide sufficient backup capability during reentry and landing.
"In the event of a failure, the rules say to return as soon as possible. Since the trans-Atlantic landing site was not available, we were told to wait a day," said Leinbach. "The orbiter continued to function well, so landing was put off another day. The team's understanding of the hardware enabled a consensus decision to change the rules and allowed the mission to continue a few days."
The mission management team finally opted to end the mission early, four days after launch, but a number of experiments planned for the mission were completed in that time.
Image right: In Kennedy's Payload Hazardous Servicing Facility, installation is under way of the mars orbiter camera on the Mars Global Surveyor spacecraft. Photo credit NASA/KSC + View Larger Image
Expendable Launch Vehicles
On the expendable launch vehicle side, the late '90s offered the major milestone of the decade, according to Ray Lugo, deputy manager of the Launch Services Program. "That was when Kennedy transitioned from a launch-only site to one providing processing, spacecraft integration and launch services," said Lugo, who was NASA launch manager at the time.
"Executing the transition plan was a big effort to work out the details with Goddard Space Flight Center and Lewis, (now NASA Glenn Research Center) of what models, tools and codes, and what people to include. From an original organization of 50 employees, we had to recruit and hire, find office space and find contractors not even launch related.
"It was an exciting time putting something new together. Looking back, we did OK," said Lugo.
Image left: Liftoff of a Titan IVB/Centaur launch vehicle carrying the Cassini spacecraft
and its attached Huygens probe on a seven-year journey to Saturn. Photo credit NASA/KSC + View Larger Image
The transition also enabled lessons learned to come into play. The transition team benchmarked procedures at the other sites and adopted the best of each. According to Lugo, they were able to document what worked or didn't. "We tried to take the variability out of the processes, using lessons learned of the people involved."
A successful milestone was the launch of the Cassini spacecraft on Oct. 15, 1997, one which Lugo oversaw. "It was the last big planetary mission, a multibillion-dollar one, and the first launch of a Titan IV rocket," said Lugo.
For more details about shuttle flights in the 1990s, please visit:
+ NASA Facts - Space Shuttle
and select Space Shuttle Mission Chronology Vol. 1
For expendable launch vehicle information, go to:
+ NASA Facts - ELV
NASA's John F. Kennedy Space Center