CASE STUDY: The TUPEX-6 Experiment
This year the TUPEX-6 was built for the annual REXUS 26 mission and launched on 19th March 2019. Each year two REXUS rockets and two BEXUs balloons are launched from Kiruna, Sweden at Estrange Space Center. The TUPEX-6 was the ideal program for launching REXUS/BEXUS into the upper atmosphere. Additionally it provides University students the opportunity to conduct, design and built scientific and technological experiments. 
The TUPEX-6 Experiment
Brian and his team were asked to conduct an experiment to demonstrate the capabilities of the picosatellite fluid-dynamic actuators (pFDA). The payload of TUPEX-6, an experiment vehicle, was developed. Data handling and the distribution of power systems required deliberation. Additionally, the team had to ensure that the communication system was via Globalstar satellites. This would enable the TUPEX-6 ground station to receive GPS data.The 'Vehicle'
The free-falling unit (FFU) is said vehicle. The rocket-borne equipment onboard the REXUS rocket was launched inside. After being ejected at high altitude, the FFU experiment autonomously conducts and falls back to Earth, to be recovered. The FFU is designed based on the CubeSat Design Specification and resembles a single unit (1U) CubeSat (cubesat.org). The dimensions were close to conventional 1U CubeSats:- Outer Dimensions: 10 x 10 x 13 cm³
- Weight: 1.3 kg approximately,
STINGR Devices
The Globalstar STINGR Simplex Modems sent one-way data messages via the Globalstar Simplex Network. In fact, this device is the only modem on the market that would meet the team's tough requirements. We required a solution to reliably send both altitude and latitude messages from within the arctic circle while at altitudes of above 50km. The device also had to be compact enough to fit within our small experiment and survive the harsh environments. These environments included temperatures as low as -30 degrees Celsius, a vacuum, launch vibrations and a launch acceleration reaching 15g. Our experiment and the integrated STINGR module survived all qualification testing. However, sadly we lost contact with our experiment shortly after lift-off. This was due to a power failure with our experiment. - Brian Treacy, Team Leader.
The Launch
The TUPEX-6 experiment, for the REXUS 26 mission, launched at 10:40 on 19th March 2019. Both devices worked reliably when sending messages on proprietary mode every 2.5 minutes. Only occasional messages were missed, most likely due to the high latitude. Fortunately, the configuration of both devices transmitted higher rates of every 30 seconds. This more than satisfied our needs. - Brian Treacy, on using two STINGR modems for their experiment.
