What am I doing here III – SuperDARN

Around Halley I’m the radar dude. Its only two of them but they are mine. Besides the Medium Frequency one, I’m also babysitting SuperDARN – Super Dual Auroral Radar Network.

If someone decides to do a welcome card for the scientific work that is done around here, the ideal image would be this radar, or rather its imposing antennas on the horizon. Unlike MF, whose antennas can easily be mistaken with half a dozen of old telephone poles lost in the middle of the ice, in SuperDARN’s case, it is obvious that those antennas are for some really dangerous scientific experiment.

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I’m talking about 16 steel towers in total, 6 metes high, each with several elements, aligned over the horizon and easily visible from the south side of the station. Like a line of 16 TV antennas, but giant ones.

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My fist question about this system, after knowing that I would be scrapping ice from the other radar’s antennas throughout the whole Winter, was “How the hell do you remove ice from a 6 meter high antenna?”. The answer was simple: you don’t. The trick is in the several elements (the line of aluminum pipes on top of each one). The old TV antennas were just like that: a main tube with several other smaller and thinner perpendicular tubes – the elements. And for what? So that we could get more than one TV channel with the same antenna. Otherwise we would need a different antenna for each available channel or we were stuck with just one.

These are Yagi antennas and they allow us to transmit and receive in a frequency range instead of just one, which is quite convenient. That’s because, unlike the MF radar that uses always the same frequency, SuperDARN is continuously monitoring the 8 – 16 MHz band and transmits only in a frequency inside that range that produces the data with better quality. Like the other radar, these antennas are also used for receiving the reflected signal.

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The objective and principle behind this radar is very similar to the MF one: “light up” pockets of ionized gas located between the magneto and ionosphere, two layers of our upper atmosphere, and with this information construct space weather maps.

Imagine that pretty map that appears in the end of the evening news with the whole country covered with little shining suns or little clouds of rain, but for an altitude of 300 km, which for that matter, we consider it to be space already. At those altitudes, instead of tropical storms we have solar storms. Instead of high pressure zones we have high ionization areas. Instead of a Summer evening breeze we have solar wind, which is pretty much a deadly jet of ionized particles.

Ionosphere and magnetosphere are two of the outer layers of Earth’s atmosphere. They belong to an area where gases are too thin to be breathable and at a height were we can see a whole face of our planet at once. The International Space Station orbits at 400 km of altitude. We use this radar to light “things” at 300 or so kilometers.

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But is one these radars enough to look out at the whole planet? Not even close. Fortunately the “N” in SuperDARN stands for “Network”. Halley’s SuperDARN in just one of the 35 that compose the global network. There are a few other radars here in Antarctica (actually this continent is possibly the one with better radar coverage since the majority of SuperDARN’s in the Southern Hemisphere are operated from Antarctic Research Stations) and most of them are actually in the Northern Hemisphere, normally in Northern countries like Canada, Iceland or Finland. The data obtained here are just pieces of a larger puzzle that needs the other 34 to get some sense into it. There is no “ownership” in the capitalist sense over the the data since it by itself is not that useful. The more radars are added to the effort, the more detailed and useful the final image becomes. Science, defeating nationalist barriers since 1587.

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What do you need a space weather map then? Well, it is quite more important today than 40 years ago. Today there are thousands of artificial satellites orbiting our planet, used for telecommunications, “normal” weather, GPS, etc… Presently we are more dependent of such objects than never. Just think in all the applications that are relying in a GPS signal. Now, these satellites not only cost loads to built but you also need to spend as much to throw them into space. NASA and ESA don’t launch space rockets every day. As such its necessary to protect them as much as possible since it is not feasible to send a technician up there with a Phillips screwdriver and a soldering iron whenever something breaks up. One of the most harmful things for these satellites, specifically to the delicate electronics in its interior, is the Sun turbulence. To us it may seem a shinny ball in the sky that invites us to buy ice cream, but in reality the Sun is a ball of very, very hot gas, quite violent too. It is continuously spitting hot jets of gases at high speed in all directions. There are few things that can survive a furious jet of solar plasma and a delicate man made satellite certainly does not qualify as that. We can rest easy since Earth protect us with its magnetic field. You see, all these ejected particles are ionized, i.e, they have electrical charge. Has such they can be diverted by the magnetic field, that works just like a shield. Besides, even if a few can cross this barrier, they still have several atmospheric layers to go through before hitting us in the head. We can spend a whole day in the Sun and all we get is a really nasty burn and a week peeling dead skin of our backs. But the satellites are too far away from the magnetic field protection and they can literally fry if they get one of these solar jets dead on.

But as with everything, there are areas where this is more likely to happen and other where it is not.

These space weather maps allow us to identify safer zones where we can set our expensive and fragile satellites, among other valuable information that is.

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Its not possible to guarantee absolute safety since the Sun is quite unpredictable in that sense, but it is already a great help for someone that spends millions so that we can watch all the cute cat videos on Internet, even in Antarctica.

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