Tropical Storm Ernesto and the Half Rollback

Every now and then, a little creativity goes a long way…….

As noted in my previous post, we were charged with protecting the Kennedy Space Center workforce and the hardware. But of course, we were in the business to launch the Shuttle, not stay on the ground indefinitely while maximizing the safety statistics. The basic tenet for all of us was “Get work done, safely.” Apply that to all aspects of Shuttle processing and launch. Meeting the manifest was important. Launching was important. Doing it safely was paramount.

Decisions that could affect the manifest required me to consult with the Shuttle Program managers at Johnson Space Center (JSC)—and for good reason. The “Program” was “theirs”, not “mine”, or KSC’s. So for major decisions like rolling back for storms two people needed to agree: the Launch Director (me, at KSC) and the Operations Manager (the JSC manager stationed at KSC). We conferred and jointly made those major manifest-impacting decisions.

Flashback to late August, 2006. Atlantis was on the pad preparing for STS-115’s assembly mission to the ISS. Atlantis was originally scheduled to launch on August 27. Our ground team made an unprecedented replacement of some parts on the shuttle with a week to go until launch, and we maintained the schedule. Then on August 25, one of the most powerful lightning bolts ever recorded at Kennedy Space Center hit the lightning mast at the top of the launch pad’s Fixed Service Structure. We needed at least 24 hours to assess the damage from that strike, moving the launch date to August 29.

That was all trouble enough. But meanwhile, a minor tropical weather disturbance had been forming in the Caribbean. Unimpressive—but like all such systems, we would monitor it in case the unexpected happened and it became a threat to us.

True to form, after days of watching the storm, now named Ernesto, its track and forward speed appeared likely to affect Florida’s Space Coast while Atlantis was still preparing for launch.

Decisions were coming, no doubt. We began the initial work to roll the shuttle back to the Vehicle Assembly Building as a precaution. This work could easily be reversed and still hold the launch date if the storm took an unexpected turn away from us. Discussions with the 45th Space Wing meteorologists were now being held every six hours to coincide with the official forecasts from the National Hurricane Center.

As Ernesto crossed western Cuba and headed into the Florida Straits, it grew to hurricane strength. The frequency of our calls went up to the rare every three hours, and then almost continuously. Ernesto was on a track to enter extreme south Florida and head up the eastern side of the peninsula, essentially right at us.

Meanwhile, Atlantis had a launch date that was sandwiched in between several other arriving and departing vehicles at the International Space Station, other Eastern Test Range operations, and other constraints that were beyond our control. If we didn’t launch before about the 12th of September (as I recall), we would have to stand down for another two weeks or so. Schedule awareness (not schedule pressure) was real.

The decision was coming. Stay at the pad and risk exceeding our wind limits and possible Shuttle damage? Or roll back to the safety of the VAB and miss the near term launch opportunity?

After numerous tense calls with the Launch Weather Officer, LeRoy Cain (the JSC Ops Manager) and I made the decision to play it safe and roll back. It was the morning of the day before the storm’s predicted arrival, approximately 40-44 hours hence. Rolling early enough to beat the winds was the game we needed to play.

But what if the storm changed course and became less of a threat? That became a real possibility after the wheels were already in motion.

As the ground operations team was rolling Atlantis off the pad for its eight-hour trip back to the VAB, the question came to me: Could we reverse the roll and return to the pad IF the storm really did weaken and veer off course, permitting us to stay at the pad?

The Crawler-Transporter (CT), built for Apollo, went in only one direction: forward. Forward toward the pad, and forward toward the VAB. What? The CT had two control stations—one on the east face, one on the west face. It was from either of these “cockpits” that the crew drove the vehicle. There was no way to turn that mammoth vehicle around on the crawlerway. To go the other way, you’d just stop, get out of the western control cab en route to the VAB, get into the eastern cab, and then start driving again, this time toward the pad.

I asked the Support Test Manager if his guys could do this. He went pale. Never before even contemplated, no procedures allowing it, the time required, etc., etc. all indicated a negative response was likely. But Bobby Briggs, being the best STM at KSC, said he’d “look into it.” His eventual answer was that if we decided before the CT was halfway to the VAB, his guys could do it.

Perfect answer.

Armed with that, I went to LeRoy Cain to see what he thought of the idea. He liked it immediately. If the storm veered away in the next four hours or so, we could stop and return to the pad.

For the sake of brevity, here’s the punchline. We did stop the roll and went back to the pad following the “final” call with the LWO, Kathy Winters. The storm would start to weaken coming up on its overland track, AND the track had it going a bit farther to our east. Atlantis would be on the best side of the storm.

As all of us watched the storm progress up the state from the safety of our homes. The favorable track was verified. It passed to the east of the pad by approximately 40 miles, as I recall. Winds remained within limits and no damage resulted.

We launched successfully Atlantis on September 9, 2006. Astronaut Brent Jett commanded the mission. He had been an integral part of the crew recovery effort after the Columbia accident.

As I look back on this achievement, I can’t help but think about this being just one example of team creativity and their can-do, will-do approach to all operational challenges. I can’t put into words how proud of them I was, and am to this day.

This ‘partial rollback’ was needed to do two things – protect the vehicle, and, because of the way things turned out, preserve a launch opportunity. Get work done, safely.

Damn, it was fun!

Hurricane Season and Rollbacks

June 1 thru November 30. The Atlantic Hurricane Season. As June 1 passed I was reminded how much ‘fun’ it was to experience.

From the earliest days of our manned spaceflight programs, the Launch Director was responsible for two things that outweighed all others, including launch itself. These were to protect the safety of the workforce, and to protect the flight and ground hardware. Obviously, these are everyone’s responsibility, and everyone took them very seriously. But when major processing decisions were required that had significant safety and/or processing implications, the LD made the final call.

Some of those decisions are well-known, the final decision to launch being the most obvious. Others were also the responsibility of the LD but not as visible. The decision to roll the vehicle out to the launch pad, establishing and enforcing the employee work time rules, and approving personnel exposure to launch pad hazards after external tank (ET) fueling are a few. The decision to roll the vehicle back to the Vehicle Assembly Building (VAB) from the launch pad was also given to the LD (along with a Shuttle Program rep that I’ll explain later).

What could drive us to roll back? Remember the woodpeckers and the damage they did to the ET that couldn’t be fully repaired at the pad? (That was STS-70, in June 1995.) How about the hydrogen leaks in the 1990s?

There was another event that could force us to bring the stack back to the VAB for safekeeping – threatening hurricanes.

If you recall, the vehicle spent about a month at the pad in preparation for launch. Unlike expendable rockets that can spend as little as one day at the pad, the Shuttle needed quite a bit more preparation time before launch. Payload installation, ordnance installations, hypergolic fueling, TCDT—those are just four of the numerous pre-flight jobs that had to be done at the pad. They were required for every mission regardless of the calendar.

Enter Hurricane Season. The Space Shuttle would spend that month of prep time on its seaside launch pad, less than ½ mile from the usually tranquil Atlantic Ocean. On occasion, that tranquility would be broken by the effects from tropical storms and hurricanes. If the Shuttle’s presence on the pad and tropical weather coincided, tough decisions would be required.

Protect the hardware. Protect the people.

The Shuttle program benefitted from the weather forecasts and advice from some of the best meteorologists in the world. The 45th Space Wing of the US Air Force provided weather support for us. Every day—not just during hurricane season, but every day—I would hold a 10-minute call with them for the daily forecast. Numerous processing groups would tie in to benefit from the information and how it might affect their work plans that day. If tropical systems began to form, the intensity on the calls would increase. If there were also a Shuttle at the pad, it would take on an additional air of importance and urgency. Daily calls would increase to twice per day, then every six hours, or even more as the threat got closer.

Ultimately, if the storm track, intensity, and speed combined to actually threaten KSC in the near future we would need to roll the Shuttle back to the VAB to ride out the storm. We could hunker down at the pad if the winds didn’t exceed 60 knots. But if the forecast had higher winds, we needed to get to the safety of the VAB, and this needed to be done early enough that allowed the workers time to get home to deal with their own, final storm preparations.

A lot went into those discussions, but for this entry it can be summarized as balancing the desire to stay at the pad and launch on time vs taking the protection option and delaying launch at least two weeks. But remember: the top priority was safety for the people and hardware. Launch schedules were secondary. But the balance needed to be struck, and it was the responsibility of the Launch Director and the Shuttle Program Manager (delegated to his KSC rep) to do it.

Why would it delay launch at least two weeks if we rolled back to the VAB? The three sets of required tasks, when combined, needed about two weeks to complete—rollback preparations including the roll itself, stay time in the VAB as the storm passed by, and then roll back out and re-perform pad operations undone in Step 1.

To get ready to roll back was at least two full days of activity—usually three—and was done with the storm bearing down on us and our families and homes. How long it took to prepare for rollback depended how close to launch we were when the decision to roll was made. The closer to launch meant more work had been performed that needed to be undone. The Payload Bay Doors needed to be closed after securing the payload. The aft compartment of the Orbiter needed to be closed with special doors, the side hatch closed, etc. Add to these relatively obvious preps things like hypergolic and ordnance systems securing, Pad-to-MLP disconnections (power, comm, gases, data lines, etc.), and you get the idea. The “final” disconnection was this contraption called the ‘9099 interface’ – a large bank of data and power lines on the side of the MLP. Once disconnected, all the work done to verify those systems were launch-ready became history—work that would have to be completely re-done once the Shuttle came back to the launch pad.

We had to roll the crawler out to the launch pad. The rollback itself was typically eight hours or so followed by rudimentary connections of the MLP to the VAB shore systems. Then the final workers could go home and shutter their houses.

Stay time on the VAB was storm-dependent of course, but let’s say three to four days until the “all clear” was declared to reopen KSC. If storm damage existed that would prevent normal work, add that repair time.

The workforce returned to work and got ready to roll back out to the pad. Two days minimum to get ready. Roll out was the same eight hours, and usually at night in the summer to avoid the afternoon thunderstorms. Once at the pad, you have to reconnect everything (reconnecting each interface means going through the complete set of checks to ensure that the connectors are properly mated again) and get back into the same posture as before the decision was made to ride out the storm in the VAB. Add back those three days or so. Then pick a new launch day, verifying that the new launch date doesn’t impact other planned launches at the Cape, other vehicles arriving at or departing the International Space Station, and so on.

All told, the decision to ride out a storm in the VAB meant an impact to the launch schedule of about two weeks.

No magic, just a lot of (necessary) work to protect the flight hardware.

Next week: Tropical Storm Ernesto and the “Half-Rollback”

The Day We Launched Early

This posting doesn’t relate to the Columbia accident, but it addresses a question I get on my monthly KSC tours offered through the Kennedy Space Center Visitor’s Center.

Why were the launch windows for flights to the International Space Station 10 minutes long, while others—especially early in the program—were 2.5 hours long? The answer is Rendezvous.

Without getting into a mini-course on orbital mechanics, for ISS missions we had to get to a specific point in orbit while the station was there. That’s pretty clear. The trick is that the Shuttle had to do it with the available fuels on board—those in the Solid Rocket Boosters, the Shuttle Main Engines, and the Orbital Maneuvering System and thrusters. Simplistically, that total is called the ‘performance’ of the entire system. The launch window was in large part defined by it. It said we had to launch at a time that when after the Shuttle reached orbit it was close enough to ‘catch’ the ISS with the least amount of maneuvering fuels necessary. If too far away, more fuel would have been needed than was available. Rendezvous would have been impossible. Mission failure. So that permissible distance in orbit defined exactly when launch had to occur. And the least fuel would be used if we launched at that precise time, called the ‘preferred time’. The available maneuvering distance once in orbit said rendezvous could still happen if we launched about 5 minutes before or 5 minutes after the preferred time, again, all based on fuel usage. Thus the 10 minute launch window.

In contrast, for missions not requiring rendezvous, like deploying a satellite or STS-107’s Spacehab mission, just getting to the proper orbit was the main objective. It didn’t matter quite as much when—just that the Shuttle got there. The length of the window was defined by other parameters. Usually the most constraining one was the length of time the astronauts could spend on their backs strapped in the Orbiter awaiting launch. This was 5 hours 15 minutes. Given the time the first astronaut (the Commander) got into the shuttle before launch was usually 2 hours 45 minutes before the scheduled T-0, it resulted in a 2.5 hour launch window. There you go!

But what about ‘launching early’? How can that be?

Flash back to August 10, 2001, Discovery’s launch day for STS-105. The mission was to take the Leonardo Multi Purpose Logistics Module (MPLM) to the International Space Station. Our launch attempt on the previous day was scrubbed due to weather. Today, all was going well in the Firing Room for launch, but a mid-summer storm was pounding Lake Okeechobee, approximately 110 miles south of the launch pad, and the storm was moving north. Heavy rain and lightning were heading at us with no expectation to dissipate. Time of arrival in our area was calculated to be about T-0. Weather launch commit criteria were going to be violated—no way around it. If we scrubbed today, we would have a several-day turnaround before the next launch attempt, as we would have to top off the cryogenics aboard the Shuttle. The only hope was to launch as soon as possible and beat the storm’s arrival.

By rule and practice, how the available launch window was used was at the Launch Director’s discretion (within reason of course!). I called the Flight Director in Houston and discussed my idea to launch at the beginning of the 10-minute window rather than in the middle as we had planned. He liked the idea, so we accelerated countdown beginning about 2 hours prior to liftoff, to save the 5 minutes.

All worked out well. We launched at the opening of the window, 5 minutes early, about 20 minutes before the lightning sensors went out of limits. We beat the storm!

Launching early worked. It was never done before or after. STS-105 holds the distinction as the only manned mission ever to ‘launch early’.

STS-105 launch ksc-01pp-1467
Whew! Discovery beats the storm, as STS-105 becomes the only manned mission to launch ahead of the announced launch time. (NASA photo)