March 7, 2015 – Air Force Academy cadets landed a rocket upright on all three fins, well under budget and on time, during a series of launches February 24 at Fort Carson, Colorado.
A team of 14 senior, junior and sophomore astronautics and aeronautics cadets tackled the challenge to design, build, test and launch three levels of rockets multiple times while integrating diverse payloads.
The challenge began the second week of January as independent research with a limited schedule, a limited budget and a range of objectives and thresholds, said Maj. Douglas Kaupa, Air Force Academy astronautics professor and launch coordinator.
Cadets had a launch window at the end of February to meet, and a total budget of $3,000 for all components for launches of Level I, Level II and a Level III rocket.
Incorporating commercial, off-the-shelf components was necessary, allowing cadets to focus specifically on payloads. The cadets came in on time to meet the limited launch window of February 23-24, and $1,400 under budget.
The first payload was a cadet-created novel rotosail in place of a parachute for swift and accurate recovery launched by a Level I rocket.
“We launched our Level I rocket with a normal parachute as a baseline, recovered it, and then sent it up a second time try a rotosail parachute,” said Cadet 2nd Class Pat O’Shea, who designed the rotosail. “Holes are cut in the rotosail parachute in a certain way to make it rotate on the way down, slow its return and increase landing accuracy.”
The rotosail parachute showed a significant increase in accuracy and slowed the rate of descent. The rocket went up 1,800 feet above ground level and then landed gingerly 200 feet from the launch tower. This met one of the program requirements in having the rocket land within 50-2,000 feet from the tower.
The Level II rocket’s payload was a National Oceanic and Atmospheric Administration provided radiosonde. The rocket soared to 9,000 feet above ground level, with the radiosonde sensing temperature, humidity and pressure during the 150 seconds of descent. More importantly, the rocket landed just over a mile downrange, upright on all three fins, demonstrating to NOAA that the right rocket and the right launch team can replace expensive and bulky balloon equipment.
The third rocket was the largest of the day, an 8-foot tall Level III rocket known as “the Colossal,” carrying a United Launch Alliance robotics test board. The Colossal reached nearly 5,000 feet above ground level, but its parachute didn’t deploy, resulting in a spectacular but final landing downrange.
“A short investigation reviewing telemetry shows battery power was applied to deploy the parachute, yet the parachute igniter was plugged into the wrong port,” said Maj. Kaupa. “The cadets reviewed the telemetry and saw electrical power being sent to the igniter, yet the igniter was wired into the wrong position. We will rebuild the 8-foot rocket over the next couple of months.”
Two research papers are now in the works, and a third research paper will be done after the NOAA radiosonde project is reflown. In the process, the Air Force Academy’s Department of Astronautics is maintaining its internal corporate knowledge in planning and executing successful launch program with undergraduates, from the days of its FalconLaunch program.
Future launches call for multiple staged rockets and testing vibrations while exceeding Mach 1.