Who Said Rocketry Was Easy?

Tim Young

Document Type

Article

Publication Date

4-23-2012

Abstract

Who Said Rocketry Was Easy?

UND Rocket Team’s recent trip to Huntsville, Alabama showed how complicated rocketry can be. This year’s 2012 team chose to fly a 2-stage rocket, mostly out of NASA’s requirements of flying an interesting payload to 1 mile in altitude.

Our rocket payload drew the interest of many people including NASA fuel scientists. The team was filming the combustion of the fuel inside the motor itself. How is this possible for university students? A clear motor casing. These types of motors are commercially available, but only in one motor size. That type of motor isn’t quite capable of getting up to 1 mile by itself. So in order to meet NASA’s University Student Launch Initiative requirement the team was forced to move to a 2-stage rocket. What was our team’s experience with two stage rockets – zero. But the team was driven; they had the motivation, interest and ability.

Our first two scale launches even without 2 stages didn’t go so well, both had parachute problems. The first one failed to open the main parachute. The rocket had correctly popped out a streamer at apogee (at the rockets highest point). But this was no match for gravity as the rocket was moving at 35 ft./sec when it landed.

Our second flight did the exact opposite the streamer didn’t release at apogee and returned to Earth at a very high velocity. The main parachute did come out but with devastating results. At that speed the components cannot survive such stress and disintigrate. We were a little behind at this point in meeting NASA’s requirements, so we had to go right to a 2-stage. This ended up being our most successful launch! In bitterly cold weather at sundown we managed to get the rocket off the launch pad, light the second stage and have all parachute on all stages work perfectly. We were motivated.

The full scale was next. It is larger version of the scale model and much more powerful. We launch it in Harwood, ND on an unseasonably warm April day. The launch went well but not as good as the 2-stage scale model. The booster staged nicely to the second stage and the rocket reached 4,000 feet, not quite the 5,280 ft. needed in the competition. That could be solved with the large motor in the booster.

The parachute at apogee went well, but the main had some problems getting out of the tube. The parachute was stuck and the rocket had rough landing, but with one week before the competition the team had to repair the rocket. We all worked hard and repaired the rocket.

Rocketry gets you hooked in just that way. It gives you the thrill of success enough times that it is enticing to continue. However we met out match in Huntsville last Sunday April 22. We had several electronic failures. First things were looking good the booster motor ignited and flew the rocket to 2,000 feet. At this point things started to go in the wrong direction the second motor did not light. This is serious, obviously there is no thrust and the rocket arcs over toward Earth.

At this point there should still be all the fail-safe parachutes that can compensate for this misfire. But on Sunday that did not happen. The parachute release mechanisms, two of them for both the drogue parachute and main parachute did not jettison the parachutes. The rocket impact destroyed most of the rocket. Not our expected result and very disappointing.

Over the next several weeks we will be analyzing the rocket crash and submitting a detailed report to NASA. Our team will pass on valuable knowledge to our 2013 USLI team and will only make us better. UND was the only team out of the 45 Universities that included a second stage. We know why, it compounds the probability of things to go wrong. Our bottom line is to try and prepare for that as much as possible, and next year we will be stronger because of that.

Funding from ND Space Grant, ATK, and UND foundations donors has made this project possible.

Tim Young

Associate Professor, Physics and Astrophysics

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