July 9, 2009
Student-built rocket blasts more than two miles high
Eleven UW students are now able to say: “As a matter of fact, I am a rocket scientist.”
This year the UW’s Department of Aeronautics & Astronautics held its first hands-on graduate course focused on rocket design and construction. The course ended with a dramatic class test: A rocket launch in the Utah desert.
“There is understandably a lot of interest in the department in space,” said AA Professor Jim Hermanson, the lead instructor. “We decided to open up a brand new class, centered around developing a sounding rocket.”
Sounding rockets are research tools designed to carry instruments. Undergraduates in the UW’s Earth and Space Sciences department have used sounding rockets in the past, though less powerful rockets and for a different goal.
“Their focus is on the instrumentation to measure things [like air temperature or atmospheric pressure],” Hermanson said. “Our focus is on ‘How do you get up there?'”
Students in the AA department spent five months designing, building and testing a research rocket. Then for the first time, UW students competed in the Intercollegiate Rocket Engineering Competition, held June 25-26 outside Green River, Utah.
The contest, now in its fourth year, is put on by the Utah-based nonprofit Experimental Sounding Rocket Association. This year the rules asked each team to design a rocket to carry a 10-pound load up to 10,000 feet, nearly two miles. After the flight all the pieces had to be recovered and the rocket had to be in flying condition to earn maximum points.
The UW team won second place for its flight and also the award for technical excellence, bringing back two of the three awards presented this year.
The rocket was built by UW graduate students who registered in AA599G, “Sounding rockets and instrumentation,” a sequence of two classes offered in the winter and spring quarters.
Winter quarter consisted of lectures on topics such as propellants, combustion, nozzles, stability and control, structures and instrumentation. The curriculum also included project management skills.
During spring quarter students actually built and tested their craft. The power of the rocket meant they could not test the actual launch. Instead they tested components individually. At one point the students were beaming signals from one floating bridge to another to make sure the instruments could cover the necessary range. On another afternoon they set the rocket out on the campus lawn to pop off the nose cone to make sure the parachutes would deploy properly.
Bhuvana Srinivasan, an AA doctoral student, had built model rockets in the past but registered for this course to pursue her passion for rocketry.
“Building a little model rocket, you don’t have to put as much thought or analysis into it,” she said. “You buy a kit and it comes with instructions. This was a much bigger deal. We did wind tunnel tests; we used computational models to try to analyze how high our rocket would go — we had to think through everything.”
The UW’s rocket was named ACES, for active control energy system. (In rocketry, an active control system is one in which moving parts adjust during the flight to keep the rocket from spinning out of control.) A smooth exterior conceals a global positioning system, video camera, flight computer, radio transmitter and a beacon used to find the rocket after it had landed.
Students built the rocket entirely on campus, doing everything from soldering the metal parts to creating computer simulations of the rocket’s flight. They used a commercial motor. Solid rocket propellant was delivered to Utah so the team did not have to carry it across state lines.
Contest organizers received Federal Aviation Administration approval for the launch and made sure there were no inhabitants within a two-mile radius of the launch site. Not surprisingly, each team had to show proof of proper insurance before being allowed to compete.
Model rocket enthusiasts will know that what they built is no toy. The UW rocket measures 11 feet and weighed 50 pounds at launch. Some 600 pounds of thrust accelerate it to nearly the speed of sound in the first three seconds of flight, and then it coasts upward. Students built air brakes to deploy and slow the rocket’s flight as it neared the target altitude. After attaining the peak, a drogue parachute (a narrow parachute designed to slow fast-moving objects) deploys to slow the rocket’s descent. At 1,000 feet altitude the main parachute opens to cushion the final fall.
“It was a complicated system, and almost everything worked as designed,” Hermanson said.
Unfortunately, during the competition flight an electrical connection to the air brakes failed. The UW rocket overshot, reaching a peak altitude of 12,500 feet. The winning rocket, built by California State University – Long Beach, won first prize with a 8,233-foot flight, closer to the 10,000-foot target.
The UW team placed second in the competition for their flight.
“Our rocket performed beautifully. In a sense, it over-performed,” said instructor Adam Bruckner, professor and chair of the AA department. “We recovered it totally intact, it has just a few little scratches to the paint.”
The UW also won the Furfaro Award for Technical Excellence, an honor recognizing the team with the best technical paper, presentation, and level of student design and knowledge.
Other teams did not fare so well. Two competitors’ rockets failed: One rocket blew up on the test stand and another failed at 1,000 feet when it became unstable and a parachute deployed too soon. Two teams decided not to launch because of technical and safety problems.
The UW rocket is now on display in the Space Systems Lab in the basement of the Aerospace and Engineering Research Building. The laboratory and student rocket team received financial support from GenCorp, the parent company of Aerojet in Redmond, Wash.
Other co-instructors were AA Research Scientist Carl Knowlen and AA Associate Professor Tom Mattick. The department plans to offer the course again, Hermanson said, though there may be some changes to the format.
This was the first time Hermanson was involved in the actual construction of a rocket. His UW research is in aerospace propulsion, and earlier in his career he worked on a space propulsion system at Boeing. But this was the first time he was closely involved in a rocket-building project from initial design through construction to the final launch.
“It was a great experience,” Hermanson said. “It makes you feel like a kid, in a way. It reminds you of what inspired you to go into aerospace in the first place.”