While NASA’s Michoud Assembly Facility (MAF) continues to work through a recovery effort following last month’s tornado, Steve Doering, SLS Stages Element Manager, has provided a recent assessment of the damage. He also overviewed the initial recovery efforts and mitigation work against potential impacts on the core stage production critical paths for the Space Launch System (SLS).

Witnessing the tornado:

For a facility that has a lot of history, the large tornado that angled directly through the Michoud Assembly Facility (MAF) in New Orleans, Louisiana, on February 7 was a significant event.

Fortunately, there were only a few minor injuries and the tenants at the facility, including NASA and its human spaceflight contractors, are well into recovery efforts; but what happened there in the space of several seconds is worth considering more closely.

Steve Doering is the SLS Stages Element Manager. Although he is based out of Marshall Space Flight Center in Huntsville, Alabama, he spends a lot of time at MAF, which is where SLS stages are beginning to be assembled.

“I was there for a program review, that happened to be scheduled for that Wednesday (February 8th),” he said in an interview with NASASpaceflight.com.

On the morning of February 7, Mr. Doering said there was an awareness at MAF of severe weather in the area.

“We knew all morning long that there was going to be some severe weather coming through.

“The local news stations (had been) talking about it since Monday (February 6) and that morning as the weather front came through we got a series of announcements over the site-wide loudspeakers to inform everyone that there’s lightning in the area, heavy winds, and severe rain.

“Those were coming fairly frequently as the storm cells were passing through; I don’t recall ever getting anything specifically about a tornado warning or tornado watch but we were getting a lot of announcements to be careful and stay inside due to the heavy weather we were getting.”

MAF is bordered to the north by Old Gentilly Road. On the west side of the facility, Building 350 faces the road with a parking lot in front. Moving east along Old Gentilly, Buildings 101 and 102 are strips of office space situated in front of the huge manufacturing area that NASA primarily occupies, Building 103. Two high bays are located on the west and east ends of Building 103, Building 110 and 115, respectively.

Late in the morning, Mr. Doering was moving between the office buildings near the road.

“(I was heading) from one building to the next, heading from where (Buildings) 101 and 102 are into 103 and as I walked between the buildings we kind of looked off to the northwest. I’m from Northern Indiana so I’m familiar with tornadoes – (I’ve) been around them a lot – and so I looked and saw what looked to me to be a funnel cloud, or what could form a funnel cloud,” he explained.

“We kind of stopped and looked at it and at the time there was no wind and no real rain and as it got closer we could start seeing the rotation of the clouds. There were maybe three or four of us standing in the doorway watching this form and then it hit the (industrial) buildings across the street and we started to see debris fly, which was basically sheet metal and roofing from these large buildings across the street which were empty at the time of people.

“What we didn’t know was one of the buildings was full of old cars, like salvaged cars; at one point we saw one of the cars was up in the air about two, three hundred feet flying, and at that point, we decided it’s time to hurry up and get inside. This happened over the course of maybe a minute.”

The National Weather Service (NWS) rated the tornado an EF-3 on the Enhanced Fujita Scale, with estimated maximum winds of 150 miles per hour. It initially formed to the west of MAF, moving in a northeast direction, and soon evolved into a larger, multi-vortex tornado over nearby residential areas. As it strengthened, the tornado developed three separate vortices revolving around each other and as different ones became the primary circulation, it turned in more of an easterly direction.

The tornado was continuing to move nearly due east when it reached MAF. It crossed Old Gentilly Road and hit the front of Building 350 along with the adjacent parking lot there; the primary tenant there is the National Finance Center of the U.S. Department of Agriculture (USDA).

Mr. Doering and others had been watching from just inside Building 103. “(We were) just looking through a doorway, so we walked into the building about twenty feet.

“Before we actually got into 103 is when we lost power. When it hit one of the (electrical) substations, the whole site lost power and so we sheltered along the wall between 102 and 103 where all of the restrooms are. We had a large group of folks that went into the restroom and sheltered in the restroom. We were in there (for) maybe three (to) four minutes.

“It went by and you could hear the rumble go away, so everybody walked outside and started looking at the damage and that’s when we realized that we really did get a direct hit because of the condition of the cars in the parking lot.”

“Also at that time, as we walked outside we started hearing the announcements on the site-wide speaker system for folks to clear the facility because there was a gas leak. One of the main gas lines that is an above-ground utility rack on the outside of 103 was ruptured and so we had a large gas leak.

“They (emergency operations) were telling us to evacuate the site while the emergency crews dealt with the gas leak and so folks had started to grab their stuff and leave. While we were doing that they came back on, about ten minutes later, and said to go back in the building and shelter in place because we had two more tornadoes coming through.”

The NWS counted six tornadoes in the Southeast Louisiana area during the outbreak. “They both went to the north and the south of us, but we stayed in the building for another 45 minutes or so before we got the all-clear,” Mr. Doering explained.

“(By that time) they had secured the gas leak, but they still asked all non-essential personnel to evacuate the facility. So those who could leave left. There were probably 200 cars between my team working on the Core Stage and USDA folks whose cars got damaged. About 30 or 40 of them were flipped on their sides or upside down or on top of others.

Most of the damage was debris impacts or as the pressure dropped as it went by, it just blew out all the windows. So there were cars with no glass left in them at all. Of course, those weren’t really driveable.”

Mr. Doering noted that those who now had no transportation got rides from other workers leaving the facility or assistance from local law-enforcement. “Pretty much over the course of the next hour or so (the) non-essential personnel left the facility and then we just began the task of recovery,” he said.

In spite of the damage and destruction, everyone on-site at the time survived.

“We’ve got 3500 people that work in the facility on a daily basis amongst all of the tenants – that’s not just the SLS folks – and to have only five injuries that were nothing more than cuts and scrapes is pretty remarkable given the state of the building, in particular the USDA building which is where about 1500 people sit,” Mr. Doering, who had been the director of MAF from 2009 to 2012, noted.

Tornado path:

Incredibly, the tornado cut right through essential areas of SLS assembly and production operations at MAF.

“The path came from across the street, from the north side of Old Gentilly and hit the front of Building 350 where the USDA folks reside, came across the street and up through the parking lot right in front of Final Assembly and directly over the top of Building 131,” Mr. Doering noted.

“131 is where we have all our thermal protection system spray booths. It then headed out into the field and then across the levee; some of the videos you see from MAF are basically the tornado moving past us.”

The NWS estimated the maximum width of the tornado to be 600 yards, just about a third of a mile wide. It also noted that parts of the brick facade of Building 350 were collapsed by the tornado as it swept across the front of the building and the parking lot.

As it crossed the street dividing Building 350 and the NASA complex at MAF, it went through a tightly packed set of buildings adjoining and adjacent to the western end of Building 103.

“It pretty much tore up the (western) front of Building 103, where the big roll up doors are in front of (the) final assembly (area and) did a significant amount of damage to the roof there on the west side of the building,” Mr. Doering explained.

“The high bay, Building 110, which is where the Vertical Assembly Center (VAC) and a number of our other assembly cells (are) located got a significant amount of damage to its siding. Its roof was (still) pretty good, but the siding was a mess.

“We were doing some lead abatement on the four corners of the building with a bunch of scaffolding and one corner of the scaffolding ripped itself away from the building completely and it fell on top of the electrical substation that powers that part of the building.

“So that had some severe damage and then as it (the tornado) went over the top of 131, it basically tore the roof off of Cell M, where we keep our pot room for the two parts that we mix the spray for our thermal protection foam. It damaged the doors of the two cells next to it (Cells N and P) and then it ripped the roof off of what’s called Building 114. 114, 110, and 103 are pretty much all tied together.

“110 is the high bay, 114 has some internal assembly cells, and 103 is our main assembly area. It tore a significant portion of the roof off of 114, which is where we do some additional foam spray work.”

As the tornado moved past the western end of Building 103 and the other buildings surrounding it, it also destroyed most of a Space Shuttle program historical piece.

Mr. Doering explained that the decades-old External Tank Ground Vibration Test Article (ET-GVTA) was still at the facility when the tornado hit.

“So we had all three parts of the ground vibration test article from the first external tank there on the facility,” he explained.

“The hydrogen tank and the oxygen tank were stored out in the parking lot south of 103, right in the direct path of the tornado. They were sitting in cradles. The intertank [was] inside of the building since we’re using it to help develop the foam spraying techniques for the SLS intertank. So the tank was in three pieces as it has been for quite a long time now.”

“The hydrogen tank flew directly towards the building, towards 103. The oxygen tank that was sitting next to it flew in exactly the opposite direction out towards the levee,” Mr. Doering explained.

“And they both basically exploded, we believe, because of the pressure drop and because of the orifices in the tank, the holes in the tank weren’t large enough for it to vent that quickly. So the LOX tank is out in the field in thousands of pieces.”

“The hydrogen tank as it came from the other direction, the two domes blew off – the two ends ‘blew off’,” he continued. “Now you’re left with a very poor (structure) – like a cardboard tube in a paper towel roll. It rolled over a car, completely flattened it, (and) hit the utility tray that runs along the back of 103. That I believe is where the gas leak was, because the gas lines run in a utility tray.

“(It then) flew over the utility tray and came to rest completely crumpled up as you saw in the pictures underneath another utility tray. And its domes were shredded – they’re all over the place in the general area.”

Initial damage assessments:

MAF remained closed for the rest of the week and weekend as more detailed damage assessments were made and priority cleanup and repair work on the infrastructure there started. The initial surveys focused on the area around the western end of Building 103. That building suffered damage to its roof and siding.

“The entire roof of 103 is made up of concrete panels and some of those concrete panels were lifted off or dropped down into the building or just broken,” Mr. Doering noted. “That was all on the west end of the building over Final Assembly and Area 6. Area 6 as you know is where we have the flight hydrogen tank, where it is currently being stored as it gets ready for its proof test. The roof over that was damaged as well. We still don’t have power at that end of the building.”

Friction plug welding to make the liquid hydrogen (LH2) tank flight article for the first Core Stage pressure-tight was recently completed in Area 6; although it was showered with roof and siding debris when the tornado passed through, the tank wasn’t seriously damaged.

“While it had a bunch of debris on and around it, none of it left any marks of any consequence or caused any damage,” Mr. Doering explained. “That was one of the very first things that the roofing crews did was to come in and put some nets over it (the flight LH2 tank) to prevent any further debris from falling while the crews were working on the roof and then to make that roof weather tight.

“That’s the way it sits today. We have to move that tank out of that cell so that they can (make) permanent (repairs) on that section of the roof.”

Without power though, the tank has to remain where it is. “They have yet to be able to (assess) whether or not the doors have been damaged. For one reason there’s no power to them, and the second reason is they need to fix the roof (to) keep (additional) debris from falling into the door mechanisms. They’re working on that fairly diligently.”

Building 110 suffered significant damage to its siding and to the electrical substation that provides power for the building.

“The scaffolding (on the roof of 110) fell and it punctured one of the big diesel tanks for the emergency generators there, so we had a pretty significant fuel spill we had to clean up after they cleaned up the scaffolding (but) before they could get in to assess the damage to the power station,” Mr. Doering explained. “They’ve got all that taken care of and now they’re working on recovering the power station that powers Building 110.”

“The other challenge we have is the siding on that high bay is made of a material called Transite, which is an asbestos material. We have very large chunks of the siding that have been ripped off – (there are) seventy-five foot long holes in the side of the building, if you will. And some of those panels were blown into the building and when they hit the floor they basically break up and you end up with powered chunks of the Transite all over the place.

“We had to cordon the whole building off for a couple of days until we could go in and do an asbestos clean up and then determine that it was safe for personnel to go in. So they’ve done that but we still don’t have power. Our assessment (February 22) is that we’ve made a real quick visual inspection of the Vertical Assembly Center, the big weld tool.

“It appears to be undamaged; we do have some concrete debris that is in the cleaning cell, Cell E, but we don’t yet know where it has come from or the extent of that damage. And we’ve got a little bit of damage, some minor damage in one of the stacking cells.

“Once we get power back that) will give us some lighting and some ability to get (into) the facility and use the cranes to get up high to see what we’ve got. Then we’ll be able to do a better assessment.”

Doering said that Building 131 sustained the most serious roof damage, but the assets inside survived relatively well.

“We’ve (done an) assessment internal to the buildings and the control rooms are in good shape and so are the cells and the equipment in the cells. We see no damage in there, but the building itself needs a lot of work,” he noted.

Close Calls:

MAF is so large, sitting on almost 830 acres, that areas to the east and the south of the tornado path and debris field received almost no damage and were able to return to work more quickly.

“The east end of 103, where Building 115 is (the other high bay, received almost) no damage at all. The only damage we had over there was one of the large rollup doors because of the pressure drop were either blown in or blown down, but no real damage to the building and so it’s virtually undamaged.”

The area where the engine section is assembled is adjacent to the areas that were seriously damaged, but somehow escaped the debris blown inside.

“We got really lucky,” Mr. Doering said. “All of the roof damage, where they have significant enough roof damage where they have to cordon off (the area) are all on the north and south side of the engine section (work area). Once we got power back we were able to get everyone back to work on the flight article and qualification article.”

As bad as the damage is, it could have been worse. In addition to the close call for the liquid hydrogen tank flight article in Area 6, the tank being used to develop and validate thermal protection foam sprays was spared by some lucky timing. The liquid oxygen (LOX) tank weld confidence article was in Cell N of Building 131, but it was supposed to slowly be moved elsewhere on the day of the tornado.

“We had finished a spray, our last big spray on Monday (the day before) and they were getting ready to roll it out.

“They were going to move it to another location, do a little bit of work on the control system in that cell, and then roll it back in a couple of days later. (It was fortunate) that we did not start that move because the doors are slow to open and close and had we had the tank partially out of the building we would not have been able to get back (into the building) in time. It would have been a real mess.”

As it was, if the doors had just been open before moving the tank, the damage would have been worse.

“The real risk would have been all of the debris flying,” Mr. Doering continued. “Especially in Cell N, because either a very large trailer or very large dumpster was picked up and thrown into the building – the door. And so had that door been open, that dumpster would have flown right into the (weld confidence) article.”

The other liquid hydrogen tank, the structural qualification article, was beginning proof test in Building 451 when the tornado just missed it.

“We were actually in the process of pressurizing the tank for its first initial proof test when the tornado hit. They had made it to about 1 psi, (so) they dumped the pressure and secured everything.”

He also noted that the building is designed to dissipate any energy from a test over-pressure and a tornado could have triggered that.

“Any time you do pressurized testing you don’t want your structure to contain the blast and make it worse if you’re going to have a bad day and your tank comes apart you want the building to come apart too. So had that tornado been another couple hundred yards to the right in its path we could have lost that whole building just because of its design – and it had our tank inside of it.”

For the same safety reasons, Building 451 is located away from the main building complex and in this case, Mr. Doering said work was able to resume more quickly.

“Last week we did our first two initial proof cycles for the tank. We’ll be doing another set of proof cycles, actually another series of proof cycles through the rest through March. Right now our expectation is to have it proofed to the point where we can say its ready for qual – structural testing – by the end of March.”

The Pegasus barge that is used to transport Core Stage elements to other NASA facilities is docked a little further to the south and west of Building 451 and was a little further away from the tornado.

“The barge in the dock is basically a big sail, so had it hit that we would have had significant damage to the barge cover,” Mr. Doering said.

In another example of lucky timing, two other large historical artifacts that sat in the direct path of the tornado were moved away from MAF in the last year.

The only remaining flight Space Shuttle External Tank, ET-94, left MAF last April for the California Science Center in Los Angeles. Two months later in June, a Saturn V first stage that had been on display for decades, S-IC-15, was moved not far to the Infinity Science Center in Mississippi, which itself is nearby the Stennis Space Center.

Prior to being moved, ET-94 was parked next to the ET-GVTA tanks that were destroyed and sent flying by the tornado.

S-IC-15 sat prominently along Old Gentilly Road in front of the western end of Building 103 that was heavily damaged.

“Had it (the Saturn first stage) been sitting there when the tornado came through I’m pretty sure it would have gone rolling over all the cars in the parking lot,” Mr. Doering said.

Recovery:

After several days of cleanup, most of the facility re-opened on February 13. In a media briefing on February 24 regarding the Exploration Mission-1 (EM-1) crew study, NASA Associate Administrator for Human Exploration and Operations Bill Gerstenmaier noted the tornado’s impact saying, “it’s probably slowed some of our tank production down by a couple months, (but) we’re still assessing what that means to the schedule.”

Mr. Doering noted that while tank production is currently on hold and may be in the assembly schedule critical path after the impact of the tornado is assessed, other areas are currently in the critical path of Core Stage assembly.

“The two critical path areas are (the) engine section and intertank and we focused on getting those back to work as quickly as possible and then the rest will potential be critical path impacts but later on down the road once we know more about what their condition is,” he said.

Structural assembly of the flight intertank is being done in an area towards the eastern side of Building 103 that escaped major damage. Work has also resumed on both engine sections, the structural qualification and flight articles.

“(With) the qual article, we’re just finishing up the last little bits of instrumentation, strain gauges that we’re going to put on it and then it will go, as soon as I can get power back to 110 it will go into Cell A so it can get stacked to its simulator and then it’ll get loaded on a trailer and shipped to Marshall.

“Right now it’s still got a couple of weeks in its current location, and so we’re really scrambling to go get power back to 110 and Cell A so I can do the stacking, so that the shipment is not delayed. And then the flight unit for the engine section is getting all of its internal structural members bolted in place and that work is ongoing.”

At the time of the interview, Mr. Doering said that power had been restored to all the manufacturing areas in Building 103, but was still out in the more heavily damaged areas.

“I don’t have power to Final Assembly and Area 6, but those aren’t critical path right now except for getting the flight tank out when it needs to come out,” he explained.

“I don’t have power to Building 110 for either welding of the LOX tank when it’s ready to go here in the next couple of weeks or for stacking of the engine section and its simulator. Our initial assessment is that I should have power back to the building on Friday (February 24). But once that happens then I have to do the assessment of and gradually bring back power to the equipment that’s in the building; we don’t yet know what we’re going to find when we start doing that.”

NASA spokesperson Tracy McMahan reported in an update that workers at MAF late last week were able to verify that the roll-up doors in the damaged areas of Building 103 and 131 are OK.

Power was fully restored to Building 103 and partially restored in Building 110; the plan is to have power fully restored to Building 110 early this week. One of the next recovery activities will be to move the flight LH2 tank out of Area 6.

(Images via NASA, L2 and Various Media).