We are Students for the Exploration and Development of Space at Tennessee Technological University. SEDS for short.
We are a collection of students studying a variety of fields at Tennessee Technological University, in Cookeville TN. We all share a passion for space, and a desire to work in the space industry
The Students for the Exploration and Development of Space at Tennessee Tech (SEDS TnTech) is a chapter of an international, student-run organization that promotes student involvement in space exploration. We participate in rocketry competitions, engage in political advocacy in support of NASA and the space industry, outreach to local students, and – of course – launch high-altitude balloons! As students at Tennessee Technological University – located in Cookeville, Tennessee – we were directly in the path of totality during the August 2017 Eclipse and were thrilled to be able to capture the Moon's shadow passing over the Earth from 60,000 ft up! This is our 7th high-altitude balloon launch and the second time we have submitted an entry into the Global Space Balloon Challenge.
Shadow Eagle is a High Altitude Balloon (HAB) that was launched during the 2017 total solar eclipse. The primary objective for the HAB was to retrieve footage of the Moon’s shadow from a high enough altitude to see a majority of the shadow. The payload was also used to provide a platform for a 3rd grade class to send up a camera of their own. This HAB was designed and built by the SEDS chapter at Tennessee Technological University. The payload was recovered successfully and the footage was shared to Youtube.
Due to past high-altitude balloon launches, we have a good range of experience with different cameras. Prior to beginning this project, we had launched an inexpensive Polaroid Cube camera and a GoPro Hero 5, and had noticed battery life issues for both of them. Then last spring, we launched a balloon to test a RunCam 2, a GoPro Hero Session 5, and backup lithium polymer batteries in preparation for our eclipse launch. We discovered that the GoPro Session and RunCams can last throughout a four hour launch when running on external batteries. As an added bonus, they give much higher quality footage than either of the cameras we have previously used.
On this launch, we used four RunCams and one GoPro Sessions to achieve multiple angles both for redundancy and “cool-factor.” We also used three 1800mAh, 4 cell, lithium polymer batteries to provide power to the cameras. Since these components added a lot of weight to our payload, we decided to make a frame out of fiberglass rods instead of using the traditional styrofoam cooler. The base of the frame was an upside-down triangular pyramid. Cameras were placed at the following positions:
In footage from our past HAB launches, we have noticed a lot of spinning. We hypothesized that this was caused by coupling with the balloon. In our launch last spring, we attempted to decouple the balloon from the payload by replacing the tether rope with a long length of fishing line and connecting the parachute to the payload with a swivel. We also discovered a research paper that had attempted to reduce the spin by placing the balloon’s radar reflectors on boons out from the center of the payload to increase the moment of inertia and balance the wind pressure (James Flaten 2015). While we are not sure which variable was responsible, we know from camera footage that the spinning was reduced a great deal. We replicated these changes on the balloon we launched during the Eclipse. The three radar reflector boons were attached to the bottom point of the pyramid frame.
We added a hand-held digital camera, that was given to us by a local 3rd grade class, to the bottom of the payload. This is part of our program this year to enable this class to achieve their goal of launching a high altitude balloon in the spring. The camera took pictures every 30 seconds, but unfortunately, the drop in temperature depleted the battery life and caused the camera to shut off before the eclipse. Despite this, we intend to show them our footage to inspire the class to build their own high altitude payload.
We uploaded two compilations of the best footage from our cameras to our youtube channel. We recommend that the footage be watched to gain a full appreciation for the performance of the payload.
48 minute compilation: https://www.youtube.com/watch?v=WuyNTpWouo4
10 minute compilation: https://www.youtube.com/watch?v=5G3WASlDMR0
We gathered temperature, pressure, altitude, and light intensity data using a custom-built circuit board based around the Arduino microcontroller. This involved designing a layout for the following components and soldering them onto a perforated board:
ATMEGA328P (the “brain” of the Arduino)
SD card reader/writer
BMP180 temperature/pressure/altitude sensor
Two photocells (light sensitive resistors)
Several graphs representing the data we collected were made in excel can be seen in the full design report here: