Overview of the TRYAD Project: A Fleet of Two 6U CubeSats for Research on Terrestrial Gamma Ray Flashes

The fleet of two 6U CubeSats of the Terrestrial RaYs Analysis and Detection – TRYAD – project will explore the spatial structure of Terrestrial Gamma Ray Flashes produced by thunderstorms. At the core of this NSF supported project, is the ability to obtain simultaneous data from two CubeSats and VLF ground stations. Time synchronization is vital for correlating data from the three sources. The project is a collaboration between the University of Alabama in Huntsville (UAH) and Auburn University (AU). Also involved in the project are the NASA Goddard Space Flight Center and the Sci_Zone company. The UAH team (Drs. M. Briggs and P. Jenke) is in charge of developing the science instrument, determining the science data collection activities during flight, analyzing these data and publishing the results. The AU team (Drs. J-M Wersinger, M. Fogle, S. Biaz, and D. Harris) is in charge of developing the CubeSat platforms carrying the science instrument, of securing all interfaces, obtaining a launch, operating the satellites during flight, obtaining and forwarding data to UAH. NASA GSFC scientists and engineers, under the direction of Dr. G. de Nolfo are developing the gamma ray detector. Mr. A. Santangelo, CTO of Sci_Zone is providing and implementing the Linkstar radios (a duplex and a simplex) that will give access to science data in real time over 40% of the orbit as well as a beacon everywhere along the orbit. The Linkstar radios are communicating through the network of Globalstar satellites. Mission success requires the ability to modify and control the separation of the two satellites along a common orbit. To this effect, the project is using differential drag. The two satellites, TRYAD 1 and TRYAD 2 are equipped with adjustable fins making them look like darts. Fin angle with the body of the satellites is adjusted through commands from the ground changing ionospheric drag on the satellites. The satellite with the largest drag loses more altitude than the other one, goes to a lower orbit and thus increases its speed. This speed difference allows for satellite separation modifications and control. At end of mission, both satellites’ fins are put into maximum drag configuration shortening the satellites’ lifetime in space. The satellite development is done by undergraduate students organized in technical and management teams. Each team has a lead and a deputy. New recruits are added twice a year, join a team and are trained by the senior members of their team. The project emphasizes good management practices and uses the NASA Systems Engineering approach. Most of the elements of the satellites are designed and built by the student teams. The only significant elements purchased are the Linkstar radios and DHV solar panels. The satellites carry over 100 sensors. The central computing unit is a BeagleBone Black (BBB) supplemented by two micro-controllers. Thermal control of satellite elements is obtained by radiative coupling with Earth through one of the large sides of the satellites and by heating elements controlled by the BBB