When Mike Suffredini joined NASA in 1989, planning for the International Space Station was already well under way. This year, as the program's manager, he'll have the satisfaction of seeing the orbiting outpost finally completed after more than a decade of construction. This year's winner of the National Air and Space Museum Trophy for current achievement (on behalf of the space station program), Suffredini spoke with Executive Editor Paul Hoversten in January.
Air & Space: Before assembly began on the International Space Station, there was a lot of concern about the complexity of the project. Were those worries overblown?
Suffredini: I wouldn’t say they were overblown. There were an enormous number of spacewalks involving very complicated tasks. What happened was, we took heed and did a lot of work to try to mitigate the risks. Along the way, we added some training, particularly with the ammonia quick disconnects [used to cool station modules] which are difficult to operate on orbit. We did quite a bit of work on the ground to verify how the systems were going to operate on orbit before we flew them. So we took a number of steps to make sure we could accomplish all the objectives.
A & S: Did any surprises pop up during construction?
Suffredini: There were times when we found it more difficult to manipulate a mechanism. The use of the quick disconnects was a challenge. Over time, we’ve had challenges with many of the devices we had to manipulate, such as the power connectors, the ammonia connectors, and the bolts we drove. One surprise we had with the big external drill driver we use to drive bolts, was we found that we had a calibration issue and weren’t torquing the bolts to the right level. So we had to go back and retorque some of them.
A & S: Which element was the toughest to install?
Suffredini: Probably Node 2 [delivered by the STS-120 crew in October and November 2007]. Not because it was more difficult, but because when we came up, we docked where Node 2 ultimately had to go. So we installed it on a temporary port, on Node 1. And while it was docked there, we had to connect power to keep it warm enough. Then the shuttle left, and we had to disconnect the port we were docked to. During an EVA [extravehicular activity or spacewalk], we had to grab that module, put it on the end of the U.S. lab where the docking module was, then put the docking module on the end of Node 2. Then we had to hook up all the ammonia and power lines and all the rest of the reconfiguration.
A & S: How hard was it to ensure that modules and connectors built in different countries would fit together in space?
Suffredini: Yeah, and keep in mind that no two modules or trusses ever physically saw each other before they got to orbit. We had a test jig that that we brought for every common berthing mechanism interface, the way the modules tie to each other. And then the segment-to-segment systems, the way we put the trusses together. For every system, we had a test jig that we put up to it that drove the bolts and made sure everything was right. For avionics, in some cases we did integrated testing on the ground where we just ran wires from modules to modules or modules to trusses to confirm that those systems worked.
A & S: How has the ISS managed to avoid the sort of calamities, such as a fire, that occurred on Mir?