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До сега вятърът от НАСА беше, че Совалката е боклук, едва търпян, до като великия Орион с Арес 1 литнат в небесата. Други официални мнения бяха подтискани.
Сега Орион, Арес 1, Арес 5, Алтаир - всичките интелектуални бижута на старата НАСА администрация биват пре-разглеждани. Без цензура върху различни или разнородни мнения.
И?
Ми ето едно парче, което до края на миналата седмица не можеше, буквално, да "намери място" в официален сведомник! "Совалка надеждност остава безсъперничена".
Shuttle reliability remains unrivaled
Robert L. "bob" Crippen - special to the Orlando Sentinel
The space industry is approaching a fateful six-day period that has become an annual time of reflection and rededication, as it honors the memory of the three great space tragedies in our history: Apollo 1 (Jan. 27, 1967), Challenger (Jan. 28, 1986) and Columbia (Feb. 1, 2003).
These anniversaries serve as reminders that the price we sometimes pay for extending our reach beyond our earthly grasp can be high. For that reason, it is imperative that we base decisions about how to proceed with our nation's agenda in space on the right arguments.
There is an ongoing discussion among the aerospace and political community regarding the risks of flying the space shuttle beyond its current retirement date of 2010. Those who oppose it often cite aging and safety concerns. Too often, these arguments have been based on somewhat scary probability figures that, by themselves, are wholly inadequate to determine how much longer the shuttle should fly.
In weighing the options for our space program, the new administration will need qualified, independent sources to help define the associated risk, and a common language for discussing it. These kinds of discussions generally rely on one of two methods for defining and accepting risk: demonstrated reliability or predicted risk.
Using predictive models, the generally accepted number based on Probabilistic Risk Assessment of the shuttle is about a 1 in 77 chance for loss of a vehicle on any single mission.
However, as former NASA Administrator Michael Griffin has pointed out, PRA "depends very strongly on underlying assumptions, which are, in essence, impossible to verify. So, in the end, we can estimate risk levels but cannot know them accurately."
Furthermore, this approach does not factor in the multitude of safety enhancements made since Columbia, the ongoing improvement in the vehicle, or the performance of the team that maintains and operates it.
Orbiters returning from space today are among the cleanest in program history. From improvements to the thermal-protection system, to new wiring in the orbiter fleet and an enhanced process for building external tanks, the program never stops striving to improve performance and safety.
After 126 flights, the demonstrated reliability of the space shuttle is 98.4 percent. Other than the Russian Soyuz (98.2 percent), the demonstrated reliability of systems currently being considered for human spaceflight is zero, since those systems have not yet flown.
Ultimately, there is no way to eliminate risk in spaceflight. At best we can try to understand and manage it to an acceptable level. The risk of flying the shuttle has been successfully managed in 98.4 percent of the missions. The continuous efforts to improve the safety and reliability have resulted in a robust system that is, in many ways, safer each time it flies.
The decision to continue flying the shuttle involves a number of important considerations. As the new administration considers ways to meet the nation's goals in space, it should base its policy decisions on objective assessment of national needs, priorities and available resources.
(Crippen of Palm Beach Gardens is a former astronaut who served as pilot of the first space shuttle mission and commander of three other space shuttle missions. He is the former director of Kennedy Space Center in Florida and the former president of Thiokol Propulsion.)
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Новият вятър завея
