The investigators will develop, build, test, and deliver a suite of miniaturized detectors, called Firestation, for optical, radio, and energetic radiation measurements of lightning to be flown on the International Space Station (ISS). The instrument suite is based on the NSF-funded Cubesat Firefly and will be included in a DOD Space Test Program platform on the ISS as part of an experiment, the SpaceCube 2.0, built at NASA Goddard Space Flight Center, which is scheduled for delivery to the ISS in 2013. The hardware for FireStation relies heavily on existing flight spares from the Firefly CubeSat, with some modifications needed to interface with Space Cube, rather than the Firefly CubeSat bus. The instrument suite consists of: a sensitive miniaturized radio receiver, a novel so-called phoswich energetic radiation detector, based on an ultrafast inorganic scintillator, and a multi-channel photometer system, including multi-wavelength filters and high speed readouts, providing accurate localization of lightning flashes, as well as accurate timing at high resolution, and multi-wavelength observation. The shared main goal of Firefly and FireStation 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 MeV above thunderstorms, since these electrons are thought to be the source of TGFs. 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 million electron volts in less than 1 millisecond. These energized electrons create copious bremstrahlung gamma and X-rays, which can be observed from orbiting platforms and the electrons themselves may escape to magnetospheric altitudes and populate the inner electron radiation belt. Undergraduate students at Siena College will be involved in all aspects of the project, from design and development, through fabrication and test, to mission operations and data analysis. Not only will these students get a very rare opportunity for hands-on, end-to-end experience on a real-life space project, they will also get a chance to travel to national meetings to talk about their work on FireStation, and to learn from other scientists and engineers. Students at Siena College and the Universidad Privada Boliviana (Private University of Bolivia) will also work together on deploying a VLF ground station capable of providing location information on lightning events.
Lightning discharges represent the release of enormous amounts of energy and are associated with familiar and powerful manifestations near the Earth's surface: thunder, a bright flash, and powerful currents that can shatter trees and turn sand to glass. Lightning gives rise to x-ray and gamma-ray bursts, and unlike the well-known flashes of light and claps of thunder, these energetic rays are channeled upward and can be detected only from space. FireStation and Firefly will explore the relationship between lightning and these bursts of radiation called Terrestrial Gamma Ray Flashes (TGFs). These missions demonstrate the capability of small missions such as CubeSats to do important, focused science, with abundant student involvement, and with a minimal budget and available resources. The attached figure shows a cartoon of the processes involved in TGF generation. TGFs were first discovered by the Compton Gamma Ray Observatory in the mid-1990s. Since their discovery, the RHESSI, Fermi, and AGILE satellites have convincingly tied these events to lightning discharges, demonstrated that the gamma ray emissions extend up to millions of electron volts, and shown indirect evidence for energetic electrons and positrons that can escape the Earth’s atmosphere and be magnetically trapped in the Van Allen radiation belts. These electrons are generated by secondary interactions of the TGF gammas with the upper atmosphere. However, none of these previous missions were dedicated to the study of TGFs and energetic electrons generated by thunderstorms. Firefly is the first dedicated mission to study TGFs, their link to lightning, and their effect in producing energetic electrons that may become stably trapped in the inner radiation belt. 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 millions of volts in less than 1 millisecond. By studying TGFs, we can learn fundamental physics critical in understanding not only lightning, but also solar flares, cosmic shocks, black holes, and even dust storms on Mars. The FireStation and Firefly team is collaboration between Siena College and NASA. Students at all levels (grade-school to college) are involved in all aspects of the project, from design and development to mission operations and data analysis. FireStation and Firefly Education and Outreach Both missions helped train undergraduates at Siena, as they will get hands-on experience designing, building, testing, and operating the spacecraft, as well as analyzing the data. In addition, several high school students made significant contributions to these missions. These students will also travel to national meetings to talk about their work and to learn from other scientists and developers in the space science and satellite community. Specific course and tutorials at Siena College related to FireStation will include: Orbital Dynamics Satellite Design and Engineering Spacecraft Instrumentation STK Certification Students at Siena College worked on and/or started development of the following: 1) Experiment Expansion Modules FFT, Filter bank, advanced triggering mechanisms etc. 2) AWESOME VLF Receiver Development, Ground-based VLF support 3) GSE, MATLAB Instrument Control Toolbox 4) Instrument modeling, Optical photodiode collimator optimization 5) Data Processing and Analysis 6) LEGO Firefly Mission Development 7) Geographic Information System, Worldwide lightning network 8) STK, Satellite Toolkit Orbit Development Local high school students and interns will also have access to the FireStation data and educational materials. Finally, the FireStation project will also involve the operation of two VLF ground stations, providing student 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. The Siena undergraduate team will further 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.
