New Miniature Satellite to Investigate Ionospheric Turbulence that Disrupts RF Communications

On December 15, SRI International launched the Ionospheric Scintillation Explorer (ISX) - a miniature satellite on a space-weather mission.

The mission, supported by a grant from the National Science Foundation (NSF), aims to investigate regions of natural ionospheric turbulence. These patches of disturbed ions and electrons corrupt radio transmissions and wreak havoc on essential Earth and space-based communication and navigation channels.

According to Hasan Bahcivan, Ph.D, research physicist and SRI principal investigator for the ISX mission - The understanding for the life cycle of these turbulent patches is quite limited, as we lack means to regularly probe their 3D structure. To date, we have little insight into how far the disturbed patches extend along Earth's geomagnetic field and have limited options to adapt the communication systems to operate within these regions.

Dr. Bahcivan's novel approach for the ISX investigation is to examine thousands of digital terrestrial television (DTT) channels known to penetrate the patch regions for evidence of signal corruption. Because the powerful ground-based DTT transmitters have fixed locations and stable operating frequencies, they form a global network of signals ideally suited for imaging the internal structure of the disturbed ionospheric patches. As the ISX orbits, it will receive signals from multiple DTT transmitters to form a 3D image of emergent disturbances, an observational technique similar to a medical CAT scan.

The DTT scan technique relies on a multi-channel digital radio receiver developed at SRI International specifically for the ISX space weather mission. The design and operation of this receiver is based on two prior NSF space weather missions, the Radio Auroral Explorers (RAX-1 and RAX-2), which discovered similar ionospheric turbulence patches driven by the aurora in Earth's polar regions.  SRI researchers have also designed, assembled, and successfully flown radio and ultraviolet sensors on space-weather research missions for NASA, NSF, and the U.S. Air Force.

The SRI International ISX receiver is installed in a 3-liter miniature satellite (CubeSat) designed by students at the California Polytechnic State University, San Luis Obispo. The CubeSat is the eleventh spacecraft designed at Cal Poly and is the eleventh space research mission launched since 2008 with support from the Atmospheric and Geospace Sciences division at NSF.