If you venture too close to one of Earth's poles, you'll notice something rather strange happening to any gadgets using radio waves, satellite connections, or GPS. Now, NASA is on a mission to find out why.
Well, three missions to be exact. NASA is backing a range of initiatives to investigate the northern polar cusp, a funnel in space that's thought to be behind some of the weird space phenomena happening above the poles.
This funnel, and the matching one at the South Pole, allows solar winds from the Sun to get right down to Earth's atmosphere – in other words, here the solar winds aren't reflected back out into space by the Earth's magnetic field, as they are across the rest of the planet.
The aim of the three missions is to get a closer look at what's happening, and to investigate other strange occurrences in the same place – like the unexplained patch of dense atmosphere in the northern polar cusp.
"A little extra mass 200 miles [322 kilometres] up might seem like no big deal," says space physicist Mark Conde from the University of Alaska Fairbanks, the principal investigator on the Cusp Region Experiment-2 (CREX-2) mission.
"But the pressure change associated with this increased mass density, if it occurred at ground level, would cause a continuous hurricane stronger than anything seen in meteorological records."
This strange blob of density could potentially cause problems for spacecraft and satellites (knocking them closer to space debris, for example). The extra mass interferes with GPS and communications beamed back down to Earth too, because of the additional atmospheric turbulence that's created.
Another operation, the Cusp Irregularities-5 (ICI-5) mission, launched this week with the intention of measuring that atmospheric turbulence, and hopefully then distinguishing it from electric waves that are also able to disrupt communication systems.
"Turbulence is one of the really hard remaining questions in classical physics," says space physicist Jøran Moen from the University of Oslo in Norway, who is heading up ICI-5. "We don't really know what it is because we have no direct measurements yet."
Unfortunately, an update from NASA reveals that preliminary data from the Tuesday launch shows that the mission did not perform as planned, and the scientists are reviewing what might have gone wrong. In any case, we may have to wait to find out about the progress of ICI-5 and what, if anything, it can tell us, or if another launch will be required.
The last mission in the current group is the Cusp Heating Investigation (CHI), tasked with measuring the flow of plasmas and gases in the cusp – how they heat up, how they accelerate, and how they interact with each other.
All of this measuring and data collection should help scientists better understand what they're dealing with, and better predict how the cusp is going to behave in the future – which is crucial if we're going to avoid serious interference with our low-orbit and Earth technology systems.
CREX-2, ICI-5, and CHI are part of a broader initiative of nine different missions investigating the northern polar cusp, a number of which have already been run.
"Each mission has its own strengths," says physicist Miguel Larsen from Clemson University in South Carolina, who is in charge of CHI.