The goal of the Firefly cubesat is to unambiguously determine if Terrestrial Gamma Ray Flashes (TGFs) are produced by lightning, and to determine the characteristics of lightning that produce the fluxes of gamma rays observed at high altitude. This information will strongly constrain the processes that accelerate electrons to ~35 million electron volts (MeV) above thunderstorms, since these electrons are thought to be the source of TGFs. Firefly will detect a minimum of 50 TGFs, with a goal of more than 200, to definitively determine the types of lightning that produce gamma rays. TGFs are of inherent interest, as they result from the most powerful natural particle acceleration process on Earth, in which thermal electrons are energized to tens of MeV in less than 1 millisecond. These energized electrons create copious bremsstrahlung gamma and X-rays that can be observed from orbiting platforms, and the electrons themselves may escape to magnetospheric altitudes and populate the inner electron radiation belt. By studying the TGF phenomena and the acceleration processes responsible for them on Earth, the investigators will improve understanding of other regimes of electron acceleration, including the radiation belts, solar flares, cosmic shocks, and other planets, including Venus, the outer planets, and dust devils and dust storms on Mars. Firefly CubeSat satellite will be designed, built, tested, and operated on-orbit as part of this project. Firefly consists of two instruments: a gamma-ray detector (GRD) and a very low frequency receiver/ photometer experiment (VP). GRD will measure photons between 10 keV - 10 MeV, and up-going energetic electrons over an energy range of 10 keV to a few MeV. The Firefly team is a collaboration between the NASA Goddard Space Flight Center and Siena College, with the Hawk Institute for Space Sciences serving as the spacecraft bus provider, and the systems engineering, education, and public outreach lead. Students will be involved in all aspects of the project, from design and development, through fabrication and test, to mission operations and data analysis. Firefly will help to train undergraduate students at Siena College and the University of Maryland Eastern Shore (UMES), as they get hands-on experience designing, building, testing, and operating the spacecraft, as well as analyzing the data. Local high school students and interns will also have access to the Firefly data, educational materials, and website. Finally, the Firefly project includes the installation of two World Wide Lightning Location Network ground stations at Siena and UMES, giving the students access to a tool that can be used for many data analysis projects, and that will be a permanent addition to the educational infrastructure at these institutions. Firefly will support the development of a website, with continuous updates on the development of the instrument and spacecraft, and on-orbit mission status, open access to the data and science results, a "data users' manual", and a Firefly manual, including lessons.
