Space@VT from Bradley Department of Electrical and Computer Engineering at Virginia Tech university in Blacksburg are leading a project of deployment of Autonomous Adaptive Low-Power Instrument Platform (AAL-PIP) in Antarctica. Each system has three instruments: a Flux gate magnetometer, Search coil magnetometer and a custom made dual frequency Global Positioning System (GPS) receiver. A magnetometer measures Earth's magnetic field which changes in strength and / or direction because of the disturbances on the Sun such as a solar flare, a coronal mass ejection, solar storm, solar wind or simply varying solar magnetic field. A GPS receiver makes scintillation measurements: the GPS signal fades and scintillates because of the free electrons and ions in the ionosphere the same way a star's light twinkles due to the Earth's atmosphere. This project is funded by the National Science Foundation (NSF) and has a number of groups, scientists, engineers and students involved from many institutes namely, Virginia Tech, Atmospheric and Space Technology Research Associates (ASTRA) at Boulder, University of Texas at Austin, University of Michigan at Ann Arbor, University of New Hampshire, Miami University at Oxford, Coherent Navigation.
The goal of the project is to understand the interaction of space plasma with the Earth’s magnetosphere and ionosphere and thus to predict the properties of the complex solar-terrestrial environment (space weather) by establishing a chain of 7 of these autonomous platforms along the 40 degree magnetic meridian in the southern polar region. This chain will be conjugate to the chain of magnetometers on the west coast of Greenland along the 40 degree magnetic meridian. This will enable inter hemispheric conjugate measurements.
In simple words, the magnetometers will measure the variation in Earth's magnetic field during the solar storms. The GPS scintillation measurements will tell us about disturbances caused in the ionosphere because of the storms. The studies together can reveal some mystery of ionospheric magnetospheric interaction. Furthermore, the following artist's impression of Earth's magnetosphere during a Solar storm gives an idea of how the polar regions are the interesting areas in terms of space science. The converging magnetic lines of the Earth bring a lot of solar wind in there creating the spectacular auroras.
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| Credit: NASA/SOHO/ESA |
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| Auroras over Antarctica |
The Earth has an oddly aligned dipolar magnetic field, thus the magnetic poles and geographic poles don't match each other. That enormous bar magnet (if that is how we picture the dipolar field) does not go through the center of the Earth. These anomalies along with the fact that the Earth's spin axis is tilted by 23.5 degrees makes the complex interactions of solar wind with the magnetic field of the Earth - different in two polar regions. The northern polar region has mostly been studied. The southern part was undiscovered so far because the harsh continent made it difficult to do any science. Now, with 100+ years of efforts by numerous explorers, scientific research in Antarctica is possible.
Our space science research will be accomplished through our participation in the Polar Experimental Network for Geospace Upper-atmosphere Investigations (PENGUIn) team formed under a collaborative NSF proposal. The AAL-PIPs we developed are deployed to run on a test basis at the South Pole in 2010-2011. In a year, we aim to establish a confidence that these instruments will run autonomously without any technical failure in the extreme conditions on the East Antarctic plateau, we will deploy them out in the field in the next Antarctic summer. Many of the electronics and the magnetometers have already been tested on the ice in some previous projects.
Each system has six 40 Watts solar panels connected to 16 - 12 V lead acid (car) batteries. We can communicate with the system (retrieving the housekeeping information and instrument data, and modifying the software) via an Iridium antenna. The stations are designed to talk to each other via Iridium and HF antenna. The fluxgate and search coil magnetometer collect magnetic field measurements at different frequencies/ resolutions. A GPS antenna is connected to a custom built (by UT Austin) GPS - Connected Autonomous Space Environment Sensors (CASES) receiver to look for and measure ionospheric scintillations.
All the electronics for all these instruments is housed in a thermally insulated electronics box. The platform is designed to run all instruments continuously throughout the summer when with a 24-hour sun, there is abundant power supply. During this time, a lot of power is saved to be later consumed during the winter. During winter, we keep storing data on a flash drive to save power on Iridium communication, only housekeeping data is transmitted. You can see the housekeeping data and current status of a magnetometer system deployed in 2009 at http://mist.nianet.org/. When the system starts running out of power, it shuts itself down until the sun comes up and starts charging the batteries again.
A team of four led by the Principal Investigator of the project Dr. Robert Clauer included a post-doctoral researcher Dr. Hyomin Kim, and graduate students Kshitija Deshpande and Joseph Macon. Here are some pictures of the two deployed systems at the South Pole during season 2010-2011:
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| Joseph working on the Solar tower, Bob shoveling to make a huge electronics and battery box pit. |
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| Joseph and Hyomin assembling lead acid batteries. Weight lifting with each 72 lb battery in snow, isn't that hard? |
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| Finished tower and covered electronics and battery box pit. |
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| Search Coil magnetometer about 200 ft away from the tower. |
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| Fluxgate magnetometer about 60 ft away from the tower. |
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| Field team with the finished system. |
