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Astrophysics research group wins $1 million NASA grant

Will develop a prototype of new stratospheric balloon system

University of Hawaiʻi at Mānoa
Peter W. Gorham, (808) 956-9157
Professor, Physics and Astronomy
Gary Varner, (808) 956-2920
Professor, Physics and Astronomy
Posted: Aug 31, 2011

A group of particle astrophysicists led by Professors Peter Gorham and Gary Varner in the UH Mānoa Department of Physics and Astronomy have been approved by NASA for a $1 million grant to begin development of a radical new design of a stratospheric balloon-based astrophysics observatory. The ExaVolt Antenna (EVA) project will attempt for the first time to integrate a huge radio-frequency antenna system right into the outer fabric of a NASA stratospheric balloon.  EVA's goal is to make measurements of radio impulses produced by ultra-high energy cosmic particles that are a hundred times better than current systems, including the state-of-the-art ANITA balloon project, which Gorham and Varner also lead.
EVA's approach effectively creates a balloon-based sub-orbital radio dish as large as some of the largest ground-based radio telescopes.  It relies on the recent development of a new type of stratospheric balloon, known as a super-pressure balloon, which retains its shape with much better stability than older models.  The EVA design takes advantage of the already curved super-pressure balloon surface to focus radio waves from a reflective band around the balloons equator into the balloon interior.  There an inner inflated membrane will carry receivers that can capture the signals of interest and transport them using fiber optics outside the balloon and down to a conventional payload instrument hanging below it. 
The current NASA grant will support an initial phase of the project to develop a scale model prototype about 60-80 ft in diameter (about 1/5 the size of the full balloon) which will then be flown sometime in the next few years on a tether within a large airship hangar to confirm the performance of the system. If all goes well, the group then hopes to scale up to and fly the full-scale EVA soon afterwards.