RockeTiltometer.com was pleased to be a part of an adventurous project by a team of engineering students at the University of Central Florida.
The team constructed a "rockoon" that launched in the late summer of 2011.
A rockoon (from rocket and balloon) is a solid fuel sounding rocket that, rather than being immediately lit while on the ground, is first carried into the upper atmosphere by a gas-filled balloon, then separated from the balloon and automatically ignited. This allows the rocket to achieve a higher altitude, as the rocket does not have to move under power through the lower and thicker, layers of the atmosphere.
The Recoverable Ionospheric Rocket Project aimed to launch a relatively inexpensive rocket using readily available parts into the lower ionosphere, defined for this project as 51 miles above sea level. This would be accomplished by launching the rocket from a frame lifted by a high altitude weather balloon.
Since it is difficult to control the attitude at which the rocket launch platform will be when ignition is applied, a specially modified RockeTiltometer 2 (RTOM2), dubbed a "RockoonTiltometer" (RKTM), was added to the ignition control systems to help assure a safe, vertical launch.
The standard RTOM2 firmware was altered to monitor the tilt angle of the launching plaqtform, as well as the rate at which the platform was tilting through pure vertical, or the rate that it was "swaying".
By monitoring both the tilt and the rate of tilt, the system could be programmed to initially only allow ignition if the sway was small and the critical angle shallow. If after a period of time, conditions were such that the RKTM was not able to fire ignition in time to allow the motor (N5800) to properly pressure up within the narrow critical angle, the critical angle was then "stepped up" - increased to allow a wider critical angle margin for launch.
If the sway was such that this second stage envelope was still too tight, a final stage was set whereby the critical angle was further widened up to the full allowed critical angle. If the conditions of the platform were still too "wild" to allow ignition at the maximum allowed critical angle during this final period of time, ignition was completely aborted.
The hope of this stepped widening of the critical angle was to have the best chance of a near virtical launch initially, but still allow a less than desireable launch angle if conditions were bad and the sway great.
The balloon had a cutdown feature designed to return the balloon to the surface after a prescribed amount of time regardless of wheterh the rocket was launched or not.
The rockoon was set to be launched from an uninhabited beach in the early morning hours, then drift out into open ocean waters near Coco Beach, FL, all the while lifting the rocket up to an estimated 100,000 feet prior to launch. Once at the prescribed altitude, the ignition control systems would take over and hopefully launch the rocket.
The rocket was to be launched autonomously, and then to return to Earth via a deployed parachute, splashing down in the ocean - hopefully to be recovered using a radio beacon.
This project was for the 2011 University of Central Florida MMAE Senior Design class, an official American Institute for Aeronautics and Astronautics program at UCF. It aimed to provide an example of low cost method of reaching space as well as prove the viability of a balloon launched rocket.
No rocket built by an academic institution had up to that time ever reached space. The team hoped that successful completion of this project would give increased credence to UCF’s engineering schools, as well as reinforce the view that Florida is still at the center of this nation’s space industry.
Unfortunately, all did not go as planned and though the balloon was released and tracked for a period of time, tracking was lost once the balloon haqd drifted out over the ocean. It was not recovered. All indications are that the rocket did not fire and the balloon with the rocket still aboard most likely fell to the ocean several miles out to sea, well to the east of the liftoff point.
Though the project was not considered a complete success, it did allow the team a great life and learning experience. The team plans to try again at some point down the road.