The lights of the aurora borealis are often described as “dancing,” since they fluctuate in shape and brightness. Inside, the charged particles that generate the aurora dance too, and scientists are still trying to figure out exactly how that movement is structured.
Swenson is the lead scientist on the Auroral Spatial Structures Probe (ASSP)—one of five suborbital rockets that are being launched into an active aurora over the next few weeks. The researchers behind ASSP hope the project will help them gain a clearer understanding of how solar radiation, weather, and the Earth’s magnetosphere mix together to influence climate and global communications.
The aurora borealis, or Northern Lights, are caused when charged particles from the sun crash into oxygen and nitrogen molecules in the Earth’s atmosphere. The energy from the solar particles excites the molecules, making them give off colored light. (Earth’s magnetic field drags the solar particles to the magnetic north and south poles, which is why auroras are typically only seen near those areas.)
NASA has been cruising rockets through auroras for 30 years or so, and those missions have raised a fundamental question, says Swenson. As the rockets fly through the aurora in a straight line, the instruments record rapidly changing voltages and currents, but scientists aren’t sure whether those changes are occurring across space or time, or both.
It’s a question that can’t be answered by taking just one measurement. Ideally, scientists would send up a bunch of instruments that could hover, stationary, inside the aurora, to measure its changes over time. But since anti-gravity technology has yet to be invented, researchers have had to get creative. That’s where ASSP comes in. Sometime between now and January 27, when the weather is right both on Earth and in space, ASSP will launch on a 17-foot, 11,000-pound rocket from the Poker Flat Research Range in Alaska .
ASSP will fly through the Northern Lights collecting data for about 10 minutes before splashing down in the Arctic Ocean. While it’s airborne, the rocket will fire off six coffee can-sized payloads using an air cannon (or as the team likes to call it, a ‘pumpkin chunker’). The payloads will jettison out at a velocity of up to 131 feet per second, and as they fall to the ground, they will constantly record the electric field, magnetic field, and ion density in the surrounding environment.
While that question primarily benefits scientists who want to accurately model the aurora, the mission is also looking at how the aurora affects heat distribution in the atmosphere, which can affect satellite communications.
Other aurora-exploring experiments launching within the next few weeks will help to elucidate how solar storms contribute to ozone depletion, and how the atmosphere mixes within the aurora.