Lightning, Hurricanes, Russians – and Space Shuttles
Launching Space Shuttles has always been complicated – thousands of people and millions of parts all have to work just right – all while nature (and sometimes human politics) cooperate. All it takes is one small thing – and a bit of bad luck – and a launch can be delayed again – and again.
This time NASA’s bad luck arrived in threes.
Over the weekend, almost over night, NASA found itself facing a “Perfect Storm” of launch-hindering events – all of which have conspired to bring a sudden halt to the launch of Space Shuttle Atlantis. A lighting strike hit the launch pad on Friday. Then Hurricane Ernesto turned on a heading for potential near hit. Both of these events presented challenges to the initial launch date – resulting in possibly further delays due to possible conflicts with a tourist-carrying Soyuz and lack of flexibility on the part of the sometimes inflexible Russians.
Under ordinary circumstance, dealing with just one contingency would be enough to occupy NASA’s time. This trio of issues resulted in “probably the most awesome training scenario I’ve ever seen” according to Bill Gerstenmeier, NASA’s Associate Administrator for the Space Operations Mission Directorate.
As a preface, the crew of STS-115 has been waiting for this trip for four years. After training for a year they were slated to fly right after Columbia in 2003. Now, as things focus on their launch, Nature has tossed two showstoppers at Atlantis – with a third resulting from the effects of the first two.
The first happened Friday when a lightning bolt – the strongest ever to strike a shuttle launch pad – zapped Pad 39B at 4:04 pm. Initial examinations of the pad yielded no obvious damage although here were some reports of strange smells. Over the next 24 hours, teams would pore over the orbiter. Eventually the orbiter and the External Tank were cleared. However the team examining the Solid Rocket Boosters (SRBs) were not able to make a final determination of the status of the SRBs and whether it would be safe to fly.
After late night examination Saturday, the MMT (Mission Management Team) meet to analyze the data collected thus far. It was decided that additional work needed to be done – and that the teams needed a little down time as well. Launch preparations continued as these post-strike examinations were conducted. NASA would eventually conclude that no damage had been done – but this took several days.
Meanwhile, Hurricane Ernesto made the leap from tropical storm to hurricane, bent its trajectory and headed for a potential landfall in the middle of Florida. During its trip over Cuba, its strength would wane, but open water would soon strengthen it again. Even if Ernesto’s worst weather stayed away from the east coast of Florida it was possible that peripheral winds would violate long standing rules for what Shuttles experience on the pad. As Ernesto worked its way north the path moved closer and closer to a near direct path very close to KSC.
Usually, the process for protecting shuttle begins 48 hours or so out from the potential threat. But before the actual “rollback” process begins, many decisions have to be made. Moving shuttle “stack” is not as easy as putting the large transporters in reverse. Moreover, you need to put the ongoing activities have taken up some of the workspace in the VAB.
In order to be ready to exercise that contingency NASA put both transporters out for a spin to see if they were up to the task.
These two items alone provided more than enough headaches – or training opportunities. As Gerstenmeier put it: “We have really two competing objectives. “One, we want to get the vehicle ready to go fly. The other objective is we want to get the vehicle ready to roll back to the VAB. At some point in the sequence you have to give up on either one or the other. That point hasn’t occurred yet, but it’s coming this (Sunday) evening and we’re going to have to make a decision.”
As Ernesto refined his path, and the lightning issue abated, NASA moved closer to decisions based mostly on the imminent threat posed by Ernesto. Sunday, you could see NASA moving closer and closer to the decision to roll Atlantis back to the VAB for safety – yet you could also see a number of people clinging to the waning hope that they might get a launch off on Tuesday.
By Monday morning it was clear that a storm was going to lash the launch site within 48 hours with winds that would likely exceed the 40 nm per hour sustained wind mark that mandates a roll back. Such a rollback takes 42 hours or so to complete. Once you commit to a rollback, you are a week or so from the earliest attempt to launch again.
As the day began on Monday NASA announced that the possibility of launching on Tuesday was scrubbed, and that preparations for a rollback were underway. They cautioned (again holding out hope) that the decision to actually start moving Atlantis would not happen until Tuesday.
NASA’s Mike Linebach expressed a concern that the weather might get bad sooner than NASA had thought only hours earlier and that he’d like to get things moving as early as 8:00 am EDT on Tuesday.
Again, this is a process with a thousand steps and many “offramps” – points at which NASA can pause to reassess the situation. However unlikely it now seemed, should the weather improve they could stop the rollback process and return to the pad. However, once that process has begun, the tasks required to install the shuttle on the pad would need to be repeated.
Given the time required to get everything back in place again, a launch by 7 September is more or less ruled out. This is the date when Atlantis’ current launch window closes. As such new dates now need to be assessed.
Technically, Atlantis could launch as late as 13 September. However this would cause problems for the Soyuz crew visiting the ISS – and the return of the Soyuz currently docked to the ISS. Right now ISS rules do not allow a visiting shuttle and a visiting Soyuz docked to the ISS at the same time. Therefore a later shuttle launch date in September would require a later Soyuz launch date.
Due to orbital mechanics and the way that Soyuz spacecraft land in Kazakhstan, going beyond a 7 September launch date would cause a slip in the Soyuz launch date and the conditions the returning crew would experience. The Russians do not want to go past 18 September since the longer the delay in landing, the greater amount of time the Soyuz crew would be situated in darkness. Given the dozen or so helicopters and personnel that need to find the spacecraft, this can present safety concerns- concerns the Russians are not likely to want to relax. An additional factor is the fact that this will be the first time a Soyuz recovery is performed by a new private contractor – and complications like this are even more unwelcome than they might otherwise be.
The alternative is to try and launch during a narrow window between the 26 and 27 October. However, lighting constraints of a different sort come into play here. NASA still requires that certain aspects of shuttle launches occur in daylight such that they can be photographed. While they are looking into how to make this window a little larger, they are more or less adamant that they launch wit sufficiently tight to allow documentation of Atlantis’ ascent to orbit.
There is also a one-day window on 23 December. If these dates are missed then the next acceptable window opens on 19 February 2007. Should all of these dates be missed, there is a chance that ISS assembly could be delayed by 5 months or so. Given that there is a finite number of missions NASA can launch between now and 30 September 2010, this would run a high risk of decreasing the number of flights to the ISS by at least one.
Dealing with the Russians is never pleasant. During a similar situation a few years back when Dennis Tito was going to ride aboard a Soyuz, Russia ignored NASA requests and went ahead to launch Tito and his crew. When asked about how this would be handled, NASA is leery of giving out any specifics. Multiple questions asked of Bill Gerstenmeier, Leroy Cain, and Mike Suffredini yield lots of discussion about scenarios and how everyone was working on a team – yet offered little in terms of what had actually been discussed with the Russians – and what they had to say in response.
Welcome to the way all remaining shuttle flights will be launched.
NASA’s current launch dilemma began to develop much along the lines of the 70’s movie – based on the 60s novel “Marooned” where a hurricane threatened the launching of a rescue mission to an orbiting space station. When things got tough – the Russians helped out – at the last minute. Things are not as dire this time around, but the confluence of various facts would make for a good book someday.
Weather has always been an issue for launches from Florida – and it always will be. Russians will be as obstinate as they can get away with – so long as they are in the equation for American human spaceflight aboard the ISS.
Given that NASA seeks to continue to use “shuttle derived” architecture and hardware – for several more decades – and continue to launch it from KSC – it has more or less guaranteed that such uncertainties will remain part of America’s human spaceflight for decades to come. Contrast this with how Russia launches its human crews: they pick a date, stack their rocket, ship it – and then shoot.
NASA’s current launch woes could be solved by some flexibility by Russia in September. Only time will tell. As was the case in the movies, the Russians may be difficult to work with at time, but we can still learn a lot from them – and given the situation we have put ourselves in – we have no choice but to do so.
