CanSat challenges UAHuntsville students to design, build and fly small rocket payload

HUNTSVILLE, Ala. (Sept. 13, 2011) - The order seems simple enough: Deliver one raw egg, intact.

But it's backed by hard-boiled rules that eventually will make the difference in safely putting satellites in orbit, or humans on Mars.

Welcome to CanSat as students from The University of Alabama in Huntsville prepare for their fourth year going up against national and international university teams.

CanSat is a growing national college competition that challenges students to design, build, and fly a small rocket payload, about the size of a can of Pringle's potato chips, to loft a raw egg 1.1km (more than a half mile) high and safely return it to the ground.

"CanSat gets people familiar with high-speed design processes," said Eric Becnel, president of the UAHuntsville team. "Skills you develop in CanSat are very valuable. Everything you learn is useful."

The annual competition - organized by the American Astronautical Society (AAS) and American Institute of Aeronautics and Astronautics (AIAA), supported by the Naval Research Laboratory, NASA, and Ball Aerospace & Technologies Corp - is held each June on a farm at Cross Plains, Texas, near Abilene.

team in_the_field

"We placed second and third in recent years and fourth this summer," said Dr. John Gregory, director of the Alabama Space Grant Consortium at UAHuntsville. "We have been in contention every year we have competed. The field usually includes 15 to 20 teams a year, some of them high-power universities, like the University of Maryland and the University of California at San Diego. This year's prominence of Turkey, which took first place, and India is a new phenomenon."

As the name suggests, the payload has to fit into a volume approximately that of a can of potato chips or of tennis balls. Its purpose is to move beyond paper design competitions and put young space engineers through a miniature version of what they will face with larger projects.

"CanSat is one of a portfolio of programs that all have the same general purpose," said Gregory. "We are teaching young scientists and engineers to tackle questions for which the answer is not in the back of the book, or for which there are multiple answers."

Teams comprise up to 10 students, usually undergraduates, with a smaller limit on the number of graduate students who can be involved. They propose the mission, design, document, review, build, test and fly. And they have to fit it atop someone else's rocket, just like the real world. Teams are scored on schedules, design reviews, and the flight itself.

"We use real space missions as a template," Gregory explained. "The students must go through each of the stages as on a real mission, from proposal to post-flight report. And they learn to work with other people. It's been very successful."

"It's a very tightly controlled system," Becnel said. "A lot of systems have to work within these guidelines. The mechanical guy has to work with the electrical guy, and it all has to come together just right."

Indeed, with a 27-page instruction manual, one might wonder how original the teams can be.

"You have a lot of room for flexibility," Becnel assured. "It was amazing to see the differences between the various designs on the flight line in Texas."

Differences include various resources available at their respective schools. The UAHuntsville team, for example, used rapid prototyping equipment to build a container for their egg. They also came up with a conical fitting to soften impact (retrorockets and other neat touches are not allowed). Like other teams, they had to develop their own sensor to measure the rate of descent, and use a particular type of radio for tracking. And the price tag has to be less than $1,000.

A priceless aspect they are allowed is tapping the expertise of UAHuntsville and NASA scientists and engineers, but only to answer very specific questions.

Whatever the teams produce, it has to fit inside the volume of a can, 72mm (3 in) diameter by 280mm (11 in) long -larger than a soda can - and weigh no more than a half-kilogram (1.1 pound). The rocket lofts it 1.1km high, and parachutes have to deploy and slow the package to certain speeds. Onboard sensors control release of the payload and deployment of parachutes. Competitors may install a camera or impact recorder. Telemetry has to be broadcast during the flight.

This year UAHuntsville came in fourth because of two simple errors. The electronic crystal that times the flight sequence had a bit of contamination, so the payload never realized it had left the ground. Then the parachute failed when its ties to the payload pulled loose. The payload hit the ground at nearly 110km/h (68 mph) but stayed in one piece.

Scrambling the payload did not mean finishing last, though. Five teams lost their payloads altogether, whereas UAHuntsville was able to calculate their impact point to within 60 feet of where they landed, one of the performance criteria.

Both of the flight problems had a common cause and thus a big lesson: the UAHuntsville team started later than they should have and did not allow enough time to test it properly.

"You can't wait until the last minute to build these things," Becnel said. "You have to do a full system test to see if it's going to work." And indeed the sequencer worked fine, after the fact, when cleaned and reassembled properly.

The UAHuntsville team is avoiding that problem for the 2012 competition. Recruiting has started, and already there is enough interest that two teams may be formed with enthusiasm like Becnel's helping fuel the next launch to one kilometer and, eventually, Mars.

"I love it," Becnel said. "We work every single day, even in the summer, with no class credit. We're really enabled to come up with our own designs."

For more information,
contact Ray Garner 

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