Mission management team hardly discussed foam strike
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: July 22, 2003
Editor's Note...The mission management team transcripts posted by NASA today included little or no punctuation. Punctuation, based on context and content, has been added to the excerpts below to make the passages more readable.
The transcripts, posted on a NASA web site today, include extensive discussions of relatively minor temperature control problems with Columbia's Spacehab research module and debate about the shuttle's slightly over-limit landing weight. But there is surprisingly little discussion about the foam strike investigators now believed doomed the ship 81 seconds after blastoff Jan. 16.
Instead, the management team unanimously accepted, with only a smattering of questions from Ham, the results of a hurried analysis that concluded the worst threat Columbia faced was possibly severe, but localized, tile damage that might require repairs between flights.
Ham has declined all interview requests since the shuttle tragedy and has not participated in any news briefings to this point. With the benefit of 20-20 hindsight, she has been criticized by some observers for not recognizing the severity of the foam strike and its potential for causing catastrophic damage. As chairman of the MMT, she also has been blamed for quashing efforts to obtain spy satellite photography of the shuttle to better characterize any potential damage.
But the widely reported, unsuccessful efforts to obtain spy satellite imagery were not discussed at the MMT meetings, the transcripts show, and in any case, sources say, those efforts primarily were derailed by lower level managers before reaching the MMT chairman.
Ham remains in the shuttle program office at the Johnson Space Center, but earlier this summer she was removed from her post as program integration manager and replaced by flight director John Shannon, who will assume at least some of her duties. Wayne Hale, a former flight director who now serves as deputy program manager under William Parsons, is expected to assume Ham's role in future MMT meetings.
As for Ham's role chairing the MMT meetings during Columbia's flight, the transcripts show no particularly unusual comments on her part or any obviously questionable decisions. But surprisingly, the foam strike was never a top-of-the-agenda item and it was discussed only sparingly, in summary format, and with no debate even though the strike was the most significant such impact ever observed.
When it was discussed, the team focused almost totally on possible damage to the heat shield tiles on the underside of Columbia's left wing and all but dismissed the possibility the foam strike could have damaged the reinforced carbon carbon - RCC - panels making up the wing leading edge. This was a particularly striking turn of events considering there was little or test data on how the carbon composite leading edge panels might respond to a strike by a large piece of foam and there was uncertainty about exactly where the foam had hit the wing.
During the third MMT meeting of Columbia's mission, held on Jan. 24, Don McCormack, representing NASA's mission evaluation room support team, told Ham engineers had started an assessment of potential tile damage using a program called "Crater."
While the analysis was not yet complete, McCormack said, "obviously there's potential for significant tile damage here, but they do not indicate, the thermal analysis does not indicate that there is a potential for a burn through. There could be localized heating damage. Obviously, there is a lot of uncertainty in all this in terms of the size of the debris and where it hit and angle of incidence and, uh, its difficult..."
"No burn-through means no catastrophic damage and localized heating damage would mean a tile replacement?" Ham asked.
"It would mean possible impact to turnaround repairs and that sort of thing, but we do not see any kind of safety of flight issue here, yet, in anything that we've looked at."
"No safety of flight and no issue for this mission, nothing that we're going to do different, there may be a turn around (issue)?"
"Right, right, It could potentially hit the RCC and we don't indicate, other than possible coating damage or something, we don't see any issue if it hit the RCC. Although ... we could have some significant tile damage, we don't see a safety of flight issue."
Ham asked him to elaborate - "what do you mean by that?" - and McCormack said the foam could have scooped out a fairly large area of tile on the underside of the left wing. Even so, Calvin Schomburg, a tile expert, reassured the MMT that no burn throughs were expected and the foam strike did not represent a safety of flight issue.
In the process of discussing potential tile damage, Ham and her colleagues never revisited the RCC issue even though there was little or no data presented about how the carbon composite panels would respond to a significant impact. And the impact seen during Columbia's launching was the most significant on record.
After complaints that MMT participants listening in by phone could not hear, Ham repeated that Schomburg, who had no expertise in RCC systems, "does not believe that there is any burn throughs, so no safety of flight kind of issue. It's more of a turn around issue similar to what we have had on other flights. That's it? All right, any questions on that?"
There were no questions. And with that, any lingering concern about the health of the RCC panels was dismissed.
The foam in question broke away from the left-side "bipod ramp" area of the external tank where two large struts attach the nose of the shuttle to the top of the tank. To keep ice from forming on the struts and falling onto the shuttle, foam insulation is sprayed on the tank and then sculpted by hand to form two aerodynamic ramps, or slopes, at the base of each strut making up the bipod.
Eighty-one seconds after Columbia blasted off from the Kennedy Space Center, a 1.67-pound chunk of foam from the left bipod ramp area broke free and slammed into the ship's wing at more than 500 mph. Engineers now believe it hit the leading edge on the lower side of RCC panel No. 8, punching a hole in the panel or causing enough damage to result in breach of some sort.
Recent tests at the Southwest Research Institute in San Antonio, Texas, clearly demonstrated such a breach was possible.
While the details are not known with certainty, engineers believe Columbia re-entered Earth's atmosphere Feb. 1 with a hole of some sort in the left wing leading edge. Sixteen minutes after falling into the discernible atmosphere, Columbia's flight computers lost control of the orbiter and the shuttle broke apart. Commander Rick Husband and his six crewmates were killed.
The foam strike was not discovered until engineers examined launch film the day after liftoff. The first of five mission management team meetings carried out during Columbia's flight was held earlier that day but there was no mention of the foam strike. Three days later, however, during the next MMT meeting on Jan. 21, McCormack briefed Ham and the rest of the team on the issue.
"As everyone knows, we took the hit ... somewhere on the left wing leading edge and the photo/TV guys are completed, I think, pretty much their work, although I know I'm sure they're still reviewing their stuff and they have given us, you know, approximate size for the debris and approximate area for where it came from and approximately where it hit. So we are, you know, talking about doing some sort of "parametric" type analyses and also, we're talking about looking at what you can do in event we really have some damage there. But..."
Ham interrupted, recalling shuttle mission STS-112 the previous October when a large piece of bipod foam fell off and struck one of the shuttle Atlantis' booster rockets. She said engineers should gather data collected in the wake of that launching, and after an earlier mission in which foam had caused damage, "and make sure that, you know, I hope we had good flight rationale then."
"Yeah, we'll look at that," McCormack said. "You mention 87, you know we saw some fairly significant damage area between RCC panels 8 and 9 and main landing gear door down at the bottom on STS-87. We did some analyses prior to the STS-89 so, uh..."
He was not referring to actual RCC damage, rather to tile damage between the landing gear door and the leading edge just behind panels 8 and 9.
In any case, Ham interrupted again, saying "And really, I don't think there is much we can do, so you know it's not really a factor during the flight because there isn't much we can do about it. But what I'm really interested in is making sure our flight rationale two flights ago was good. Maybe this is foam from a different area, I'm not sure..."
Ham was saying, in effect, there was nothing the crew could do about tile damage in orbit. But she wanted engineers to go back and re-visit the rationale for continuing shuttle flights with a known foam shedding problem to make sure the reasoning was valid.
Toward the end of the Jan. 21 meeting, Lambert Austin, representing the shuttle integration team, made one slightly alarming observation, saying the strike that occurred later in the ascent, when the shuttle was moving faster, than what had occurred during the STS-112 launching.
"And higher machs (velocity) is going to be worse," Ham observed.
"Yes, but that, you know the debris impact locations will be different so that's one of the reasons we have ... basically, like you said, give a little bit of parametric set of data to the orbiter (project) so they can decide what the worse-case scenario might be."
"OK," Ham replied.
At the next MMT meeting, on Jan. 24, McCormack reported that engineers believed there was no safety of flight issue based on the initial Crater results. Phil Engelauf, representing the mission operations directorate, told Ham flight directors had informed the crew about the foam strike and sent up a 16-second video clip "just so they are armed if they get any questions in the press conferences or that sort of thing. We made it very clear to them, no concerns."
Then, during the meeting after that - on Jan. 27 - McCormack provided an update, saying engineers still believed there was no safety of flight issue even if the foam had hit a sensitive area around the left main landing gear door.
"We looked at an area about the size of 30 inches by 7 inches, and, of course, you know, sloped, cratered out area, and our results there were similar to what we got elsewhere and that is, although local degradation of the door structure is likely if we were to have sustained a hit there, there is no predicted burn-through and no safety of flight issue."
"A turn-around issue?" Ham asked.
"If it were hit there..."
"If it were hit there, it's a critical area there on the door, but also the Integration guys had indicated that they thought it was a low probability location but it was still one that we went off and looked at," McCormack said.
"OK," Ham replied.
"So, that completes the thermal analysis from the debris hit and with that, that's all I've got."
The foam strike was mentioned a final time during the final MMT meeting on Jan. 30, two days before Columbia's re-entry. Ham wanted to make sure any film shot by Columbia's astronauts showing the external tank and, possibly, the area where the foam broke free, would be quickly extracted from the shuttle and returned to Houston for analysis. The foam issue would have to be addressed before the shuttle Atlantis could be cleared for launch on the next shuttle mission in March.
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