The exhaustive attention NASA now devotes to making sure shuttle heat shields are damage-free and safe for re-entry is a direct result of the 2003 Columbia disaster. But a blacked-out military flight 21 years ago still stands out as a warning to astronauts, engineers and managers, a frightening “close call” that had the potential to bring the shuttle program to an early end. [Article by Bill Hardwood, CBS News and reproduced in SpaceFlightNow.]
It was that close. “I will never forget, we hung the (robot) arm over the right wing, we panned it to the (damage) location and took a look and I said to myself, ‘we are going to die,'” recalled legendary shuttle commander Robert “Hoot” Gibson. “There was so much damage. I looked at that stuff and I said, ‘oh, holy smokes, this looks horrible, this looks awful.'”
He was seeing the worst tile damage any shuttle had ever experienced.
But a perfect storm of poor communications, caused in part by military restrictions that prevented the crew from downlinking clear images showing scores of chipped and broken tiles, ultimately resulted in a flawed analysis on the ground that indicated the crew had nothing to worry about. Flight controllers were not convinced the shuttle was seriously damaged at all. Some engineers apparently believed the astronauts had been misled by poor lighting conditions and grainy TV images.
The crew knew better. The images were crystal clear on the shuttle, and definitely alarming. But the astronauts reluctantly accepted the judgment of mission control and went on about their business. The mission still stands out as an example of how assumptions, poor communications and an unwillingness to challenge authority can put people in danger in high-risk endeavors like spaceflight.
“There was a big failure to communicate,” Gibson recalled in an interview this week. “When you talk about crew resource management, or cockpit resource management or any of that resource management stuff, it’s real easy to be talking and not communicating. In order to be really communicating, you’ve got to say ‘here is what’s on my mind.’ I think I was doing that to a major degree, but maybe I fell short by not arguing with them. But they really did not tell us what was on their minds.”
Gibson, a former Navy test pilot, “Top Gun” graduate, chief astronaut and veteran of five shuttle missions, was at the controls when the shuttle Atlantis blasted off Dec. 2, 1988, on the second post-Challenger mission. Carrying a top-secret spy satellite, the mission was fully classified and all communications with the astronauts were blacked out.
But 85 seconds after launch, a piece of insulation on the tip of the shuttle’s right-side solid-fuel booster broke away and struck Atlantis’ right side. The impact was not noted on NASA television at the time and after landing, NASA engineers said that while the shuttle had suffered more tile damage than usual, “it isn’t something that’s of a major concern.”
But as it turned out, the damage was, in fact, extensive. More than 700 heat shield tiles were damaged. One tile on the shuttle’s belly near the nose was completely missing and the underlying metal – a thick mounting plate that helped anchor an antenna – was partially melted. In a slightly different location, the missing tile could have resulted in a catastrophic burn through.
It was the most extensive shuttle heat shield damage ever recorded until Columbia took off on its final voyage.
Years later, Gibson would be asked to brief the Columbia Accident Investigation Board about his experiences aboard Atlantis and as the tale was told, “their jaws dropped,” he said.
Crewmate Mike Mullane devoted a chapter to the mission in his book “Riding Rockets: The Outrageous Tales of a Space Shuttle Astronaut,” writing that as entry approached, “the anxiety was exhausting.”
“I finally gave in to Hoot’s solution. The day before (entry), as he floated to the windows to do some sightseeing, he said, ‘no reason to die all tensed up.’ I would do my best to relax and enjoy the sights.”
Even so, he wrote, during Atlantis’ descent “I had visions of molten aluminum being smeared backward like rain on a windshield.”
Gibson, Mullane, pilot Guy Gardner, Jerry Ross and William Shepherd had no idea Atlantis had been hit during ascent. It was not until the next day that mission control called up with an unusual request. The crew was asked to use Atlantis’ robot arm to inspect the shuttle’s heat shield on the ship’s right side.
Mullane, the arm operator, dutifully carried out a procedure to maneuver the arm into position so a black-and-white television camera on the end could “see” the tiles in question.
“As I moved the arm lower the camera picked up streaks of white,” he wrote in “Riding Rockets.” “There was no mistaking what they were. … As I continued to drop the arm lower we could see that at least one tile had been completely blasted from the fuselage. The white streaking grew thicker and faded aft beyond the view of the camera. It appeared that hundreds of tiles had been damaged and the scars extended outboard toward the carbon-composite panels on the leading edge of the wing. Had one of those been penetrated? If so, se were dead men floating.”
Gibson, who flew for Southwest Airlines for years after retiring from NASA, recalled his impressions as the images snapped onto TV monitors in Atlantis’ cockpit and his immediate “we are going to die” reaction.
“So I get on the mic and I call Houston and I tell them, Houston, we are seeing a whole lot of damage on the right wing, in the chine area and back on the right wing in the tiles. … The ground comes back and says well, you know what, we need you guys to send us secure TV.”
Because the mission was classified, no pictures or television were being downlinked, even to mission control. When the decision was made to send down TV images of the tile damage, the video had to be encrypted.”
“So we send them secure TV,” Gibson said. “The problem with secure TV is, it takes a frame, it encrypts it, it ships that frame, it takes the next frame, it encrypts it, it ships the next one, so you get a frame about every three seconds.”
While the astronauts beamed down the images, Gibson was thinking the worse.
“I think the words ‘we’re in deep doo doo’ were said in the cockpit, this could be a problem, guys, you know? This looks bad. Now you know, I didn’t really think at that instant, yep, we’re as good as dead, write our wills and all that stuff. But I did look at it and say ‘holy smokes, we are going to die’ to myself.'”
The astronauts anxiously waited for mission control’s assessment. And they were stunned when the ground called back.
“We’ve looked at the images and mechanical says it’s not a problem,” the mission control CAPCOM said, according to Mullane. “The damage isn’t that severe.”
“We couldn’t believe what we were hearing,” Mullane wrote. “MCC was blowing us off.”
Gibson then chimed in, saying “Houston, Mike is right. We’re seeing a lot of damage.”
But mission control repeated the engineering assessment that the damage was not that severe.
“I’m just perplexed at this point,” Gibson said. “Because I’d never seen anything like this before. Never seen anything even close, and I’d been there since before day one. … He came back and he said ‘Hoot, they’ve looked at it and they’ve determined that it’s not any worse than what we’ve seen on other flights.’ And I am just perplexed. I think I was silent for maybe 30 seconds, because I didn’t know what to say. And I came back and I said something to the effect that well, all right. It looks pretty bad to us, but you guys are the experts, so OK.
“And I honestly believed at that point, the rest of my crew said, ‘Oh, OK, great, no problem.’ I did not. I did not believe them. I didn’t want to argue with them, I didn’t want to have a long drawn-out argument over the air, but I suppose I was probably remiss to some degree because I didn’t quiz them some more.”
Of course, it’s not clear what, if anything, could have been done if engineers had realized the severity of the problem. There were no tile repair tools on board the shuttle and no techniques for even getting an astronaut to the damage site. Changes to the shuttle’s re-entry orientation and trajectory could have been attempted, Gibson said, but whether anything like that would have worked is an unknown.
The real issue for Gibson – and the same issue was faced Columbia’s crew – was that no one took the extra step to make sure the problem was fully resolved.
“NASA does amazing things when they’ve got their back against the wall,” he said. “Like Apollo 13. I’ve seen us work out some really dramatic things in some of the missions when we had on-orbit problems and we did in-flight maintenance and things like that. You never know what you could have done because you didn’t try.”
Hoping for the best, Gibson and Gardner fired Atlantis’ twin braking rockets on Dec. 6 to begin the shuttle’s fiery descent to a landing at Edwards Air Force Base, Calif. The astronauts did not discuss any fears they may have had, but as the shuttle fell into the discernible atmosphere, Gibson kept his eyes on a gauge that showed how much the elevons at the back of each wing were deflected.
“I knew that what would happen was, if we started to burn through we would change the drag on that wing,” he said, “which is exactly what happened to Columbia. We would change the drag on the right wing and what we’d see happening is, we’d start seeing right elevon trim, you’d start seeing right aileron, if you will, trim, which means putting down the left elevon, moving the left elevon down.
“I knew we would start developing a split (between right and left wing elevon positions) if we had excessive drag over on the right side. The automatic system would try to trim it out with the elevons. That is one of the things we always watched on re-entry anyhow, because … if you had half a degree of trim, something was wrong, you had a bunch of something going on if you had even half a degree. Normally, you wouldn’t see even a quarter of a degree of difference on the thing.
“So I knew that that’s what I was going to see if it started to go,” Gibson said. “And therefore, that told me that I’d have at least 60 seconds to tell mission control what I thought of their analysis.”
But as it turned out, Atlantis did not suffer a burn through and Gibson guided the shuttle to a smooth landing at Edwards. Gathered on the runway after touchdown, the astronauts, engineers and NASA managers were astonished at what they saw.
“The damage was much worse than any of us had expected,” Mullane wrote. “Technicians would eventually count 700 damaged tiles extending along half of Atlantis’s length. It was by far the greatest heat shield damage recorded to date.”
During debriefing after the mission, Gibson finally learned why the engineering community had not taken the crew’s descriptions of the damage more seriously.
“Their conclusion, which they did not pass back to us, was ‘oh, you know what? That’s not tile damage, those are just lights and shadows we’re seeing in this video.’ So in other words, the resolution on the encrypted video was that bad that they based a conclusion on it that was in gross error. … If I had said hey, I think this is important enough for us to break the encryption and send you guys clear video, oh, it would have been pandemonium down there at DOD. But in hindsight, oh man, that’s what we should have done. Because they were drawing an incorrect conclusion from it and they were not telling us what their conclusion was.”
Wayne Hale, a veteran ascent-entry flight director and former shuttle program manager at the Johnson Space Center, agreed engineers were caught off guard by the severity of the damage when they finally saw the shuttle on the runway.
“We were struggling in those days to try to maintain the security classification, so on and so forth,” Hale said in a telephone interview. “When the crew reported they saw this stuff, we had a long negotiation as I recall with the customer to say well, can we look at the TV? Because we weren’t supposed to see any TV from on orbit. (They said) absolutely not. Could we look at the bottom side of the shuttle? That was the agreement, that we could, but we used this special slow-scan TV. And it was grainy.
“People were concerned, I suppose, but not nearly at the level that we would be today. And STS-27 has always been the worst tile damage flight we ever had. It set all the reference marks. It’s interesting that there is enough capability in that thermal protection system to take that kind of damage and survive.”
Reflecting on what Hale agreed “was a real close call,” Gibson said he believes NASA came close to losing the crew and along with it, the shuttle program. STS-27 was only the second flight after the Challenger disaster and unlike Columbia, the shuttle re-entered over the Pacific Ocean for a descent to Edwards. Had Atlantis been lost, most of the wreckage would have sunk and engineers might never have discovered the cause.
“We had spent all that money and all that time rebuilding and revamping and we launched one successful mission, we lost the very next one,” Gibson said. “I think the Congress would have said OK, that’s the end guys, we just don’t need to do this again. I think that just would have been the end of it.”