It has taken three months to write this post, but justly so. Our members have been rightfully catching up on the three months of sleep we each lost as we readied Traveler II for launch in mid-May. With the chaos of a lab move, some rather tedious regulations, and composite material troubles, the semester started off slow. What resulted though, was an extensive to-do list for those brave souls willing to make TII a reality in the final weeks of school. The last month could not have been a more stark contrast thanks to the bureaucratic greenlight and an endless supply of willing hands.
To bring all readers up to speed, currently one of our main goals as a team is to be the first student group in the world to get a rocket into space. Traveler I was our first space shot vehicle intended to claim us said title, but it failed to reach space in September 2013. To launch a rocket of the scale that we build and at the altitudes we reach, there comes a number of necessary governmental regulations. Among these are the air space clearances that only the FAA and other organizations can sign off on.
For TII, the successor to TI, the FAA gave us two approved launch windows (read as “deadlines”) – one for the off days between classes and finals, and another two weeks later after graduation. Watching the days fly by, our first concern was producing a motorcase that could pass a hydro test. The hydrostatic pressure test is a qualification/proof test in which the case is filled and pressurized with water. Doing so ensures – or disproves – that the case will handle the pressure of the rocket motor in flight; it is the standard industry test for ensuring a mission-worthy solid rocket motorcase.
Upon baking our first TII motorcase, we lost vacuum during the cure process, allowing the carbon fiber and epoxy to swim around in what became a very psychedelic, but super ineffective carbon case. The oven proved to be the downfall of the next case as well, melting and burning everything onto the case.
Traveler II Mk.1, aka Mr. Squiggles
Ryan, Jordan, Brandon, and Sarah peeling burnt breather off Traveler II Mk.2, which would eventually become an obscenely strong door stop
The third case’s layup brought with it a new wave of anxiety. A motorcase layup is a time-consuming and laborious process, one that requires many people to be in the lab for long stretches of time. With finals quickly approaching, it became clear that if this case did not work it would mean missing the first launch window and not having the people necessary to build a new one in time for the second window. Luckily, this case seemed to elude the bad luck that claimed the first two cases during the curing process. Without any glaring problems, it was prepped for hydro test.
The first bulkhead was inserted into the case far enough to put in the second bulkhead, but not all the way to the end of the case. Seeing as pushing a resistant bulkhead down the entire length of a 7.5 foot motorcase is not exactly an easy-going process, we were relying on the pressure of the water to push it into place, as has been the process for other tests. With everything in place, the water began flowing. It takes a few minutes to get the case up to any substantial pressure, so the loud cracking noise that occurred within seconds was surprising to say the least. The motorcase failed at ~45 psi city water pressure, a far cry from the 1000 psi that is needed for a passable case. The bulkhead which was supposed to have been pushed to other end of the case by the water had instead cocked inside the case, damaging it beyond repair.
It almost would’ve been funny if the failure didn’t have such upsetting consequences. The reason it had dislodged inside the case wasn’t entirely clear, but crashing even before the pressure test had begun wasn’t a dignified way for case number 3 to go. Running out of options, we brainstormed how to proceed. It wasn’t fair to ask people to sacrifice hours of study time in the hopes that a fourth layup would produce a workable motorcase. However, with the nosecone, motor, and most of the fins already made, it seemed wasteful not to at least try for the second launch window. We decided to run with an untested idea that until then had only been discussed as a future project: we were going to filament-wind the entire motorcase.
Filament winding has been used as a part of each carbon fiber motorcase for a few years, but only for specific layers (making up about 1/3 of the total case). Creating a code that would allow the filament winder and the mandrel to cooperate at precisely the right speeds would not only optimize the fiber angles to create a stronger motorcase, it would mean that the time and energy consuming manual layup process would become unnecessary. Of course, the entire code driving the filament winder had to be entirely rewritten, but thanks to some dedicated individuals, Jordan and Ian, along with plenty of caffeine, we had a working code.
The brains of the code, Ian, Jordan, and Carter, overseeing the first filament-wound layer.
The finished Traveler II Mk.4: Our first filament-wound case!
Accomplishing a fully filament-wound case deserved more pomp and circumstance than we could afford in the strained timeline we were working with. After some celebratory energy drinks, it was right back to work. The case came out of the oven looking wonderful, with the exception of the bidirectional layers, which are responsible for reinforcing the motor retention section. We figured they might have been overcooked because they were dry and slightly frayed, but nothing so harmful as to call off the hydro test.
The fourth and final hydro test began around 3 pm on May 13th, four days before we were scheduled to head to Black Rock. The bulkhead had already been pushed (with difficulty) to the end of the case to prevent what happened to Traveler II Mk 3, but the absence of a loud crack as the pressure began to increase still came as a relief. This sought-after silence continued through the increasing increments of pressure, all the way up to 1000 psi, where it remained steady for over 2 minutes. We finally had a working motorcase!
Celebration
(Photo Credit: Susan Karlin)
The next four days were nothing but a race to the finish. Now that we had a case, everything started coming together as the final preparations for our trip to Nevada were made. Seeing as though this was going to be our first trip to Black Rock without attending a rocketry event called BALLS (where Traveler I was flown) we, in a brilliant stroke of creativity, named our own event: Not BALLS 2014 was a go!
Brandon, Ryan, and Allie bonding... oh, and attaching the fins to traveler
Congratulations, it’s a nozzle!
Jordan, Jeff, Kevin, and Ryan inspect the rocket after a beautiful tip-to-tip cure
(Photo Credit: Susan Karlin)
Brandon drilling one of six GoPro holes in the upper airframe
(Photo Credit: Susan Karlin)
The nosecone, although having been made months prior, looking as sexy as ever
(Photo Credit: Susan Karlin)
Brad and Kevin high-fiving after the trailer and the rocket have been successfully packed
(Photo Credit: Susan Karlin)
About a day behind schedule, but still with two full days left in the launch window, the caravan set off. With the exception of a well-deserved In-N-Out stop, there were no major holdups until about 6 AM when a tire melted. A quick stop at Home Depot and a bolt later, everything was back on track. Six hours after that, everyone had arrived in Black Rock and it was time to set everything up to launch that evening. As much as we did in the days leading up to Black Rock, there was still a lot to finish: integrating the motor, incorporating the recovery system, assembling and calibrating the launch tower, and doing last minute functional checks with the avionics. The first evening of preparations ran us slightly over our launch time, so we had to postpone the launch until the final day of our launch window.
RPL Fleet ready for action!
(Photo Credit: Susan Karlin)
Good morning sunshine
(Photo Credit: Susan Karlin)
Carter and Ian integrating the avionics sled into the nosecone
(Photo Credit: Susan Karlin)
Teamwork makes the dream work
(Photo Credit: Susan Karlin)
People struggling with the launch tower, but...
(Photo Credit: Susan Karlin)
Don't worry everyone, Kevin's got it!
(Photo Credit: Susan Karlin)
We won't be hitting any airplanes today, thanks to Brandon calling in the flight window
(Photo Credit: Susan Karlin)
Jake sticking it up the aft
(Photo Credit: Susan Karlin)
(Photo Credit: Susan Karlin)
In the morning of May 19th, the rocket was in the tower and ready to go. At 11:20 am, the countdown to space began.
3...
2...
1...
Up, up, and away!
(Photo Credit: Susan Karlin)
Traveler left the launch pad, skewing slightly in the air before exploding promptly after ignition, at around 4,000 ft
(Photo Credit: Susan Karlin)
Once the pieces stopped burning and it was safe to collect them, the reason for the failure was immediately apparent.
The motorcase had shredded at the reinforced bidirectional section responsible for forward motor retention. While it had withstood the slow pressure of the hydro test, the faulty carbon wasn't strong enough to take that same force so abruptly.
Holy battery fire Batman!
(Photo Credit: Susan Karlin)
Thumbs up for the fins and nozzle perfectly intact after hitting the ground from a 4,000 foot free fall
(Photo Credit: Susan Karlin)
As sleep-deprived and exhausted as each of us were, this second failed space-shot attempt did not dampen any spirits. Once again, our Traveler launch became a learning experience for us to understand and build upon. Just 24 hours after our arrival, we were packed up and on the road again.
Failure is a part of rocketry, but as the RPL team nobly demonstrated, it should not be viewed negatively. Seeing what faulty carbon can do to a motorcase, we have decided to start imposing stricter quality control over the products we use, and are already back into full swing this semester.
A special shout out goes to Titan America and his film crew (whom you can see in some of the pictures above), who not only machined the amazing nozzle that survived the worst of the impact, but also braved the desert to come out and support us. We also want to thank Susan Karlin, an amazingly dedicated journalist responsible for many of the photos above. We were so lucky to find someone not only willing, but enthusiastic about accompanying us on multiple 14 hours drives to the middle of nowhere.
To our fans and every person who helped with the Traveler II build, from the first motorcase to the moment right before the launch: you're incredible. It takes a special kind of person to sacrifice their time and energy towards a build (especially during finals) and still have the strength to see failure as a learning opportunity. Our team is full of these people, which is what makes what we do possible and worthwhile. You'll be hearing about more exciting projects in lab's future, but for now, Flight On!