Waiting for the sun at Poker Flat

Ned Rozell
April 11, 2024

Two smiling women lean on an outdoor deck railing with a snowy field and rolling hills in the background.
Photo by Ned Rozell
Astrophysicists Lindsay Glesener, left, and Sabrina Savage enjoy the sunshine on an observation deck at the Neil Davis Science Center on a hilltop at Poker Flat Research Range north of Fairbanks.

POKER FLAT RESEARCH RANGE — Under a bluebird sky and perched above a resilient winter snowpack, two sounding rockets point upward, ready to blast through the thickness of our atmosphere to gain a better look at the sun.

Inside a building on this sprawling complex within the Chatanika River valley north of Fairbanks are two women. Each will give a command to launch one of the rockets, the second about a minute after the first.

Both astrophysicists — Lindsay Glesener from Minnesota and Sabrina Savage from Alabama — are trying to find out more about solar flares during the five minutes the rockets will arc above northern Alaska. 

Their two daytime launches are a rare event here at Poker Flat, owned by the University of Alaska Fairbanks Geophysical Institute. Most rockets have blasted off at night since the range began life in 1969. 

Since then, more than 300 sounding rockets, most more than 20 feet tall, have flown over Alaska. Many have carried instruments that have allowed scientists to study the aurora and other phenomena of the upper atmosphere more than 50 miles above our heads.

Glesener’s and Savage’s separate rockets will each carry instruments designed to gather some of the best information ever obtained on solar flares. Solar flares are explosions on the sun that spew charged particles out into space. Sometimes they head toward Earth, causing brilliant auroras and — when they are powerful enough — disabling satellites and power grids.

Two rockets sit upright in the bottom of a valley between tree-covered, snowy hills.
Photo by Ned Rozell
Two sounding rockets, lower left, point toward the sky at Poker Flat Research Range north of Fairbanks.

In this second day that the rockets have been ready to launch, Glesener of the University of Minnesota and Savage of the NASA Marshall Space Flight Center are watching live readings from satellites orbiting in the 93 million miles of space between the sun and Poker Flat. 

Instruments aboard those satellites will show a dramatic uptick when a large solar flare is erupting. When Glesener and Savage determine the flare is large enough, they will begin a three-minute countdown to launch the two rockets.

Though it is a brilliant sunny day here in Chatanika, the satellite data displayed on monitors show that no flares of the desired magnitude are exploding our way. But this day, early in the experiment and with no large solar flares predicted, has been devoted in part to solving problems and tweaking equipment.

“Today is like a dress rehearsal, one that could be real,” Glesener says outside her launch team’s room in the Neil Davis Science Operations Center on a hill at the 5,000-acre Poker Flat complex. 

If not today, Glesener and Savage will one day soon make decisions to fire the rockets when the sun erupts with a flare. Flares may spew from the sun for about 10 minutes. Once launched, the rockets will carry their instruments out of the dense molecules of Earth’s atmosphere within two minutes. 

When the rockets are above that 30-mile shell of gases, panels on the rockets will open, deploying telescopes optimized to see the energy emitted by solar flares. Their high-resolution view of the solar flares will last for just five minutes.

After the payloads within the rockets get their measurements, gravity will pull them back to the ground in northern Alaska. Workers for the range will recover the rocket stages and their parachutes by helicopter.

As the morning turns to afternoon, the satellites continue to show no remarkable solar flares. That does not seem to stress Glesener and Savage. Because of the predictable rotations of the sun and Earth, the scientists are optimistic that a flare of adequate size will point toward Earth in a few days.

A map shows the location of the Poker Flat Research Range in central Alaska.
Illustration by UAF Geophysical Institute
A map of Alaska shows the location of Poker Flat Research Range.

There is time to wait, as the launch window for this experiment is open for another week. 

Until then, a few dozen team members helping Glesener and Savage, as well as the Poker Flat staff, will show up here in Chatanika early every morning and get ready for countdown.

A person whose amplified voice has counted down those seconds many times is Kathe Rich, the director of the range. She is now two miles down the hill, closer to the Chatanika River, in a building called the blockhouse.

Rich is with a few dozen other people in a squat building with walls 2 feet thick. They sit just 300 feet from the closest of the two rockets. 

The blockhouse has been Rich’s place since she was present at her first Poker Flat rocket launch in 1991. She has bunkered in that windowless, somewhat subterranean control room for 154 launches since then, most of them on dark days with subzero temperatures.

A red and white rocket leans over a road where a car drives through a raised gate. A sign sits next to the rocket. Spruce trees line the road. A hill rises in the background.
Photo by Ned Rozell
Members of a rocket-launching team leave Poker Flat Research Range north of Fairbanks after a day when they did not launch the rockets, due to the lack of a desired condition on the sun.

Though she has been very close to all those detonations that rang through this forested valley, Rich has never seen a rocket launch through anything but a video monitor. Having worked with dozens of scientists with experiments embedded in rockets and students who are dependent upon the information gathered during launches, Rich says the stakes are high.

“This payload has taken four years to get from the design-and-build process to the point of being on the rail,” she says. “If we have a failure, a lot of students won’t get the data they need for their degrees. There’s a lot of years and tears that went into these payloads.”

In contrast to Rich’s insulated vantage point, Glesener and Savage and the other people stationed up here at the Davis Science Center will have a sublime view of the launches, with the backdrop of nearby Pedro and Wickersham domes and the snow-white peaks within the White Mountains National Recreation Area. 

As the sun arcs to the west and the clock strikes 4 p.m. with no solar flares detected, the researchers decide to call it for the day. After a debrief with the team, they hop into their rental cars and head back to their hotels in Fairbanks. 

Tomorrow, they will be here again in the silent Chatanika River valley, hoping to send those rockets skyward and get the data for which they traveled so far.

Since the late 1970s, the University of Alaska Fairbanks' Geophysical Institute has provided this column free in cooperation with the UAF research community. Ned Rozell is a science writer for the Geophysical Institute.