Art Thompson, Red Bull Stratos' technical project director, talks circuit breakers, wind shear and biomedical data
While Felix Baumgartner landed safely on the ground just a matter of hours ago, the internet is still resonating with the sound of tweets, status updates and YouTube clicks, all thanks to what was one of the most spectacular human endeavors in recent history. The mission was simple, to send a man up in a balloon higher than ever before, and have him safely jump to the ground. This kind of "simple" is usually anything but -- if you just look past the well-manicured exterior. Which, as luck would have it is exactly what we did.
With the cheers of success still ringing in his ears, we got some quality time with Art Thompson, the technical project director, and Baumgartner's earliest collaborator on the Stratos mission. We wanted to know a little bit more about what went on behind the scenes, and Thompson was more than happy to oblige. They're understandably proud of what they just achieved.
"We exceeded our expectations, which was a nice thing to do. That was the plan." That's Thompson's opening gambit, which is pretty impressive, considering how high expectations must have been already, given the nature of the project. But what does that translate to in actual technical achievement?
"Everything, all of the electronics on the vehicle itself, every component had its own solid-state circuit breaker so that we could turn things on and off, and control what was happening"
"There were so many technical things on this project, from dealing with life support systems, to the capsule," he explains. "One of the things early on that surprised me was that we assumed space programs in the past had resolved issues with circuit breakers at high altitude, or vacuum conditions. In a vacuum, a conventional circuit breaker -- which measures heat across a load -- doesn't work, because there, there's less or no atmosphere there to draw the heat off, so a conventional circuit breaker would trip. We soon realized, with other space craft, they don't need to worry about this because they always stay pressurized to 11.5 PSI."
This was not a luxury afforded to Baumgartner and his capsule, however, which is a 6-foot diameter pressure sphere. When it's depressurized at altitude, it becomes a near-vacuum, causing the aforementioned heat-transfer problem.
"When you slide that door open, all of the electronics are exposed to the near-vacuum, so we had to develop a solid-state breaker that was monitoring actual loads across that circuit," Thompson said. "In that development, we created circuit breakers that we could remotely operate from the ground. Everything, all of the electronics on the vehicle itself, every component had its own solid-state circuit breaker so that we could turn things on and off, and control what was happening."
This was just one of the challenges that the team encountered along the way, but one that resulted in a new technology that advances on what was there before, proving this wasn't just about the glitz of a media stunt to promote an energy drink. Not all challenges have a technological answer though.
"One of the biggest issues we had is actually what we couldn't control, which is the weather." And, contrary to what you might think. This wasn't just a waiting game. You can't just haul the whole team out there to New Mexico, and hope that it turns out alright. As you can imagine, with this much at stake, even old Mother Nature has the odd data-set you can refer to.
"What we did was look at data supplied by Don Day (weather specialist) over a nine-year evaluation, and then pick out on the map and analyze which part of the year the winds are high and low, etc. Then from that we picked out weeks that were favorable, based on my best guess from the data," Thompson said.
This allowed the team to narrow the window of opportunity right down, pretty much to a hand-picked week, which, once agreed upon among with the various parties (medical crew, scientific team, etc.) could be given the red-circle treatment.
With the team fully assembled, plus equipment, test jumps and years of preparation behind them, all that remained was the small matter of sending a man over 120,000 feet upwards. Even with the best-laid plans, you can never be sure what is going to happen on the day, and if there are any issues, you'd better have plans for that, too.
"...you can end up in a condition where it'll actually cut like a knife, and slice the top of the balloon right off."
"There were some concerns once we managed to get the balloon launched," Thompson said. "We knew that there was the potential for wind shear up around 45,000 - 50,000 feet, somewhere around there. If some wind shear would cross with another section a few hundred, or a thousand feet above it, you can end up in a condition where it'll actually cut like a knife, and slice the top of the balloon right off. Fortunately, during our flight, that condition stabilized, and we ended up with a situation where all the winds were going in the same direction, all heading east. That wind was traveling at 120 miles an hour, so we ended up with Felix in the capsule under this 30-million-cubic-foot balloon flying at 125 miles an hour to the east, which is amazing to think about, because at that altitude, it's the equivalent of about a 50-story building."
Amazing, if not a little scary. Traveling 120 miles an hour on a road built for cars can be perilous enough, but when you're -- almost literally -- heading into the unknown, it's a variable you can probably do without. But, potentially balloon-slicing winds weren't the biggest concern. Barely 20 minutes after passing that danger, Baumgartner started to be concerned about his face-heating mechanism not working. A frustrating situation when you know that it's been tested time and time again. Even more so when help is 68,000 feet away.
"That's where you saw that the live feed went dead. We put everyone together and started analyzing the best way to solve the problem. It isn't really even a question of if it was working or not working, it was a question of making Felix feel comfortable of whether it's working or not working," Thompson said.
He would go on to speak with Felix beyond the very public glare of the cameras; this was a critical moment in the ascent, and potentially one that could result in even worse problems further down the line. It's not just about keeping Felix's face warm, it's also about the very real danger of not being able to see where he is in relation to the horizon. Without that vital visibility, going in to a spin could be disastrous. A situation that ultimately did come to pass. Fortunately for us (and not least for Baumgartner) things were actually working properly when he needed them most.
"His faceplate heating worked all the way down, but we had to show him, and confirm with him, that that was functioning," Thompson said. "When he called to ask and talk to me on the radio, I was able to convince him that everything was functional."
This might just sound like something a simple chat over the radio can resolve, and normally it would be. The concern was, however, that once the umbilical was disconnected in the capsule, that Baumgartner would lose communications altogether, making him officially the loneliest man on (or off, rather) the planet. The antennas for his radio were actually in the legs of the suit, and transmissions were made using a small, handheld radio with output levels of only about 1.5 watts. This was due to the radio's installation on his chest, where it was decided that they didn't want anything outputting more than that. It's thanks to the high-gain antennas on the truck that they were able to communicate with him. In fact they could do so at a distance of more than 65 miles.
"When he goes out onto that step, and disconnects the umbilical, this huge team of expertise that I've assembled, that all goes away."
"When he did disconnect, the nice thing was we were still transmitting through the shell of the capsule, and we still had full communication," Thompson explained. "I was able to communicate with him that everything was fine." So, with everything back on track, all that was left to do was see out the remainder of the ascent, perform all the necessary checklists, and, well, jump. In the event that there was a serious issue, Baumgartner still had a choice. In the worst-case scenario, he could have asked to call things off, and ride the balloon back down to the ground.
As we know, however, he chose to continue.
"We went ahead and started the live feed again. I handed back off to Joe [Kittinger] who's really the focus of Capcom. I really am so amazingly impressed with Felix's ability throughout the process. When he goes out onto that step, and disconnects the umbilical, this huge team of expertise that I've assembled, that all goes away," Thompson said.
Anyone who watched the live feed will know exactly how breathtaking that moment was -- hearing Baumgartner's deep breaths, as he slowly edged forward out of the capsule. The tension was palpable, even if viewed remotely from the comfort of your own home. At once, millions of people held their collective breaths, and no doubt shared a moment of vertigo, and the Austrian stepped out into the dark, cold nothingness.
Undoubtedly, one of the other great triumphs from the whole Stratos project was the rich, near continuous flow of media and information. Red Bull set an amazing standard with regards to media coverage, and as 8 million people on YouTube will attest, this is the new model for live-streaming high-profile events. But, the visual aspect isn't just about pleasing stunt-hungry eyes. It's actually a valuable data set in its own right.
"What I love about the photography is that combined with the scientific data (we had accelerometers on board Felix, on board the capsule) and combining the biomedical data that's monitoring his heart rate, breathing, skin temperature and the forces of his body etc. Combining that with the high-resolution video gives us a scientific tool that's amazing. I can look in real-time at Felix, and all his body positioning, and understand what he's going through physically. What forces are going through his body when he goes into the speed of sound, when he's exiting, when he goes into flat spin -- all the way down to when he steps on the ground," Thompson explained.
And as it turns out, this might be one of the more long-lasting aspects of the whole endeavor. For the last 52 years, the equipment from Joe Kittinger's mission had been the reference point. Now, with Stratos successfully complete, future space programs from NASA, the Air Force or any other agency has much fresher technology and a more recent collection of data to rely on.
"We're going to take this data and process it over the next several months," Thompson said. "We could be working on looking at how to communicate the data over the next year. The team is really excited at the reams of technical data that's available, and how we look at how we'll be able to apply it." When asked what's next for him, Thompson advises, "Sage Cheshire Aerospace has a bunch of different projects in the background that we're working on as well, but it's going to be hard to top a project like this!"
We can believe that, but we look forward to watching someone try. We just hope it's not another 52 years until someone has the ambition, determination and not to mention funding to make it happen.
