Scientists Fire Rockets At Aurora

Scientists Fire Rockets At Aurora

Shawn Estabilio, Reporter

Just before midnight, an aurora rips an iridescent gash along the northern horizon. Sixty miles below, down on Poker Flat Research Range in Alaska, Marilia Samara is fiddling with a two-stage rocket, and trying to stay warm.

Samara’s team at the Southwest Research Institute has passed several fruitless evenings in the bitter cold, waiting to launch a million-dollar sounding rocket into the Northern Lights. But tonight is not their night. “For somebody who had never seen an aurora, it was a pretty good one,” says Samara. “But it wasn’t good enough. To launch, you need an appropriate aurora.”

The mesmerizing hues that enliven Arctic nightscapes occur when charged light particles collide with oxygen and nitrogen in Earth’s atmosphere. But the specifics of this ethereal interaction remain a scientific mystery. Samara and her team resolved to study an aurora up close and—with a NASA-funded rocket in tow—travelled to Alaska for the launch.

Why Rockets?

Auroras can exist up to 200 miles above the Earth’s surface. “A helicopter can’t fly that high,” Samara says. “Nothing can fly that high except for rockets.” While NASA has used space shuttles in the past to get a bird’s eye view of the aurora, those photographs have taught scientists little about the actual particles behind the lights.

The solution is a sounding rocket, which carries scientific instruments into space. This particular rocket is outfitted with devices that can measure the particles present in an aurora. “The space shuttle just takes images,” she says. “We actually want to measure the particle population that is creating the aurora.”

The trick to launching a million-dollar NASA rocket at a wisp of light? Don’t miss your target. “It’s really hard to predict where to launch,” Samara says. Once the team has spotted a worthy aurora, there is a mad dash to launch before the slippery devil disappears or changes location. Between setup, launch and travel time, it can take a sounding rocket up to 14 minutes to rendezvous with its target.

“In those 14 minutes, a lot can happen in the aurora,” Samara says. “It’s possible that you could launch and see absolutely nothing.

Why Auroras?

The Northern Lights have inspired and amazed humanity for generations. But there’s more here than a pretty light show.

“It’s kind of like studying a rainbow,” Samara says. “At first look, it’s pretty and aesthetically pleasing, but the presence of the phenomenon indicates something more important—that there’s heavy rain in that region.” An aurora gives off beautiful light, but at the same time its luminescence marks a series of complex interactions between solar energy and the Earth’s atmosphere.

A better understanding of these collisions near low-Earth orbit could help scientists ensure that extreme solar events don’t interfere with communications satellites. One such extreme solar event caused a power outage throughout Quebec, Canada in 1989. That geomagnetic storm was famously accompanied by an impressive light show.

“While some people were probably outside enjoying the aurora, everybody else was losing power in a pretty big region of Canada,” Samara says

The Perfect Aurora

“I always get excited, even when it’s just small fuzz in the sky,” Samara says. But the researchers at Poker Flat cannot simply fire their rocket at every flash of Arctic light. Only specific auroras can answer Samara’s questions about how light particles interact with atmospheric molecules.

“We’re looking for a dynamic aurora that can create tear flow and curl shapes, which usually happen when you have a dynamic Arctic outbreak overhead,” Samara says.

The location of the aurora is perhaps more important than the quality of the aurora itself. Researchers on the ground take great care in mapping the direction of the lights, to determine whether the rocket will be able to intercept the aurora at its highest point.