May 21, 2006

"You can never have too much shock cord"

Well folks, another rewarding weekend spent watching the future of America has come and gone. The 2006 Team America Rocketry Challenge is over, and if you're so inclined I'll tell you all about it, from my vantage point as one of the volunteers.

First, I'll kick this off with a few factoids that I thought notable:

  • 100 teams of students from 37 states and the District of Columbia made it to the finals this year.

  • Some 7,000 students entered this year's contest.

  • Unlike last year, the vast majority of these teams were first time participants in the finals.

  • Plantation High School in Florida sent *six* teams to the finals!

The weather looked dicey all week, but when Saturday dawned it was cool, the winds were calm and although the sky was completely overcast, the clouds were high enough not to impact the contest flights. As the day went on, the ugly overcast moved out, leaving us with a glorious day in the mid-70's, breezes around 10mph, and a sky half full of fluffy white clouds. Perfect rocket weather.

This year, the contest flight goal had been simplified in an important way. Instead of making two-stage flights and lofting two fresh eggs, the requirement was to design and build a single stage rocket that only had to carry a single egg. The target altitude was lowered to allow single-stage flights, although two-stagers weren't prohibited. The reason for this change was to increase the number of qualified flights. In previous years around 35% of the entered teams were able to make successful flights (even if they didn't make it to the finals). This year, the number was - I believe - closer to 70%. To compensate for the reduced technical difficulty from previous years, the design goals were expanded. Rather than going for either a set altitude or duration in the air, the teams had to go for both a target altitude of 800 feet *and* a duration of 45 seconds from first motion to the first part of the egg capsule touching down. Obviously, a broken egg was a disqualification.

Due in large part to the simplification of the mission, we saw far fewer outright failures (translation: uncontrolled debris raining down out of the sky). There was a real effort made to not disqualify flights because of nitpicky rules interpretations, and I didn't hear of any flights DQ'd for other than gross and/or obvious rules violations.

Once again, the students amused and amazed with their ingenuity. We provided a 1/4" launch rod 6 feet in length, plus a single pair of electrical clips for ignition. Teams that clustered motors had to bring their own clip whips or other method of multiple-engine ignition, and could bring their own launch pads or electrical launch systems. Several did. I saw teams who had built mini-weather stations into launch towers, ranging from simple streamers to indicate wind direction to full setups including anemometers, thermometers and barometers.

One team used a tube launcher (see here for a description of different kinds of launch methods), and several brought rails. One enterprising group of MacGyvers cobbled together a large windbreak from scrounged cardboard boxes, duct tape, string and various pieces of scrap wood (I identified a 1"x2" and a length of broomstick in there). It was hideous, but it worked and was ingenious. Farther down you'll find out what the specific benefit was.

In previous years, I'd been in charge of parking, been part of the recovery teams (long poles to get rockets down out of trees), and handled access to the flying field. All needed tasks, but none that actually let me see the contest flights except from a distance. This year, I was up close and personal. I had the honor of working as part of the timer crew, each rocket being timed by a pair of NAR members using stopwatches to time the duration portion of flight in hundredths of a second. Our lead for the day was Jim Barrowman, author of the "Barrowman equations", which are still used to calculate stability of simple rocket designs. Here's a blip from his NASA bio:

James S. Barrowman served as a project and program manager at the Goddard Space Flight Center for 22 years, managing Attached Shuttle and Space Station Payloads, the Explorers Program, and the Hubble Space Telescope Program. He was awarded NASA's Exceptional Service Medal twice, as well as a Goddard Space Flight Center Award of Merit. He has also been the President of the National Association of Rocketry.

I should add that he's one heckuva nice guy.

So I spent the day talking to students from a quarter of the teams. Each team sent one student to the timer's area to point out which part of the rocket had the egg capsule. Some designs separated into as many as three pieces under separate parachutes.

The accuracy that these students were achieving was amazing. In the first hour we'd already timed a 45.3something, and the other timer teams were seeing similar results. Obviously, the determining factor was going to be the altitudes.

Each rocket carried aloft an altimeter that used barometric pressure to determine the altitude achieved. The altimeter would sound a series of beeps that the judges listened to which gave the results in feet. Later in the day, as the wind picked up, a problem with some rocket designs appeared where the pressure of the wind across the vent hole would create a venturi effect which would reduce the air pressure inside the rocket. This would trigger the sensor, causing it to think it had already reached maximum altitude and it would start to beep an altitude, usually something like 4 feet. The design solution is to not make your vent holes too large, the practical solution was to let each team make "one last check", listening to the altimeter just before starting the countdown. There were a few rockets that had to recycle through the launch queue in order to reset their altimeters.

This year, NASA sweetened the deal for teams that placed from 11th to 25th (out of the money, so to speak). Each school or group gets an invitation for a teacher to attend a workshop on how to include aerospace subjects into the curriculum. The workshops are held in Huntsville, Alabama (home of Space Camp), and NASA is picking up transportation costs for the teachers as well. In addition, each of these teams has been automatically entered into NASA's Student Launch Initiative (SLI) program where they build a high powered rocket designed to achieve one mile in altitude. The group gets a $2500 grant to do that. Plus (yep, there's more), the teams can design and submit a scientific package that may be selected to be launched on an actual NASA research sounding rocket. If their experiment is selected, they get to travel to the launch site and see the launch.

The top ten teams may get that in addition to the prize money, but it wasn't specifically mentioned.

Each of the winning teams went up on the platform to get their trophies, meet the VIP's (including Buzz Aldrin, who still looks great) and get their photos taken. There were some 40 "partner awards" given out by the various aerospace sponsors. This year, besides the Aerospace Industries Association (AIA) and NASA, DoD and the Civil Air Patrol were sponsors as well.

The second place team was all girls. More about them in a bit.

The first place team was three guys, and they dedicated the day to two of the original team members who'd been killed in an auto accident not too long ago.

Afterwards, there was a BBQ for all of the students, families, guests and volunteers. I wound up sharing a table with two young ladies from the team that finished in second place. Their parents were there too, and I found out that they were from Toledo, Ohio. I'd been one of the timers for their flight, and I remembered that they were incredibly nervous. Turns out that the team had entered TARC the previous two years without making the finals, but this year they made it and won big. Their rocket was very utilitarian, well constructed and painted plain white with signatures from various people being the only decoration. This team was comprised of three seniors and a junior (who vowed to be back with a new team next year), and one of the graduating ladies already had a scholarship to MIT.

Of course, there was plenty to see besides rocket contest flights. There were lots of booths and tables set up from colleges and organizations, handing out literature and goodies like pens and keychains and pins and stickers and frisbees. The creator of the RocketCAD design and simulation software package had flown in from Germany to attend, and a company from Finland was flying a weather balloon to 750 feet with weather radiosondes located up and down the cable to measure weather conditions at various altitudes. There was a simulator of some sort (I barely got a chance to walk through the displays, and had no chance to stop and look). The Marines from Cherry Point, NC sent two AV8-B Harriers to do a flyover after the National Anthem in the morning, and a recon UAV did a flyover demo during the lunch break, circling the field and (I presume) beaming back pictures to the ground where folks could see them in real time.

Murdoc would've loved the Stryker on display, as well as a Humvee. I did get a chance to talk to the soldier there with them.
He was about a month away from retirement, but was part of the battle that toppled Baghdad. As a platoon sergeant for an artillery company, he was doing recon towards the airport (which was one of the last parts of Baghdad to fall), when his main unit became engaged by Iraqi's with small arms fire. He turned his recon unit around and hit the unsuspecting Iraqi's from behind. Kicked their ass too. I thanked him for his service.

File this next bit under "Small World". When I first joined NOVAAR, the very first person I talked to was Roger. Roger is a nice guy, and his son Doug was often out at the field as well, testing rocket glider designs.

Doug recently received his Masters degree in aerospace engineering from Virginia Tech. When I heard the school, I asked Doug if he'd known Chris Hall, a professor there and long-time resident of the Rocket Jones blogroll as the author of Spacecraft. Sure enough, Professor Hall was on Doug's panel.

One last item, about the title quote. While timing one flight, I remarked upon an exceptionally long shock cord (the bit that keeps the various pieces together under parachute). The student told me that their team mentor always said that "you can never have too much shock cord", and I laughed because I say that too. Their mentor was fellow club member Ivan, and he and I are both known for using the longest length of shock cord that we can fit into a rocket.

Posted by Ted at May 21, 2006 07:02 AM | TrackBack
Category: Rocketry

Sounds like it was a tremendously fun and successful event. I never really got into rockets as a kid, but I am secretly hoping my son does!!

Posted by: Stephen Macklin at May 21, 2006 10:32 AM

No pics of the Stryker?!? What's wrong with you, man?

Sounds like a great time.

Posted by: Murdoc at May 22, 2006 07:32 AM

Excellent debrief.

Posted by: homebru at May 22, 2006 09:17 AM
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