Shuttle Reviews: In-Flight Anomalies
Boeing troubleshooting experts fix Space Shuttle In-Flight Anomalies
When something as complex as the Space Shuttle flies, there are unexpected circumstances known as In-Flight Anomalies (IFAs) that a team of Boeing, United Space Alliance (USA) and NASA engineers investigate and resolve after each flight.
IFAs have occurred on every Space Shuttle flight and Boeing, as the original manufacturer of the Orbiters, often has the responsibility of investigating and resolving them as part of its contract with United Space Alliance. Boeing serves as the technical expert to NASA and USA on the design and operation of the orbiter fleet to ensure its continued safety, flight-readiness, efficiency and overall mission success. Boeing also performs overall Space Shuttle integration and payload support to NASA.
Tim Reith, Boeing Orbiter Integration manager and deputy chief engineer, says although it's not unusual to have IFAs on every flight, they must be fully understood before the next flight.
"When we have an unexpected result, we'll investigate and troubleshoot for the given conditions on whether the hardware acted properly," said Reith. "If the problem can be isolated to a specific piece of hardware, then it will be replaced with a spare. For situations deemed "unexplained" because the root cause cannot be determined, or if we can't recreate an IFA, we do a thorough assessment of all the things that could happen and determine if we have sufficient redundancy and work-arounds and measure the level of risk." In unexplained cases NASA makes the ultimate decision to accept that risk.
Following the Columbia accident, NASA rewrote the definition of IFAs and, as a result, more were listed on the last flight.
The process of troubleshooting an IFA begins as soon as Boeing engineers learn about the problem. "We'll start looking at it right away to determine the impact to the mission," said Reith. "For many of the problems, if there is not a big impact we can often wait until the Shuttle lands to troubleshoot."
All IFAs on the last flight had either a workaround or could be accepted as is with no safety impact.
Troubleshooting usually begins with engineers trying to recreate the problems on the ground to isolate and narrow down the problem further. Problem resolution teams define troubleshooting procedures to get a better understanding of the failure.
"If we are successful, then the component is replaced and we go into an investigative phase to figure out why the component failed," said Reith. "Traveling to space is a complicated engineering marvel and we do all we can to make it as safe as possible. Working with NASA and USA on IFAs is just one example of a robust process designed into the Shuttle program," added Reith.