Puzzles Within Puzzles

The SnowEx aircraft fly in "lines" above field sites set up on Grand Mesa, Colorado. Here, a satellite image of Grand Mesa in summer shows the topography with the flight lines superimposed on top. Credit: NASA/ Joy Ng
The SnowEx aircraft fly in “lines” above field sites set up on Grand Mesa, Colorado. Here, a satellite image of Grand Mesa in summer shows the topography with the flight lines superimposed on top.
Credit: NASA/ Joy Ng

by Ellen Gray / WESTERN COLORADO /

Eugenia De Marco loves puzzles. Her face lit up and she grinned broadly when asked what it was like to figure out how to get NASA instruments that measure snow on the ground attached and running on a Naval Research Lab P-3 plane.

“These aircraft have deliberate holes where things kind of hang off of or look out of so we can get data. But all the holes are different sizes, or in different locations in the aircraft,” she said as she described fitting aboard five unique instruments that have been designed to fit on several different types of aircraft. “These are all little puzzle pieces that you need to keep in mind when you design something.”

Eugenia De Marco is Snow Ex's lead integration engineer for the P-3 aircraft, responsible for each instrument aboard getting the data they need. Credit: NASA/ Joy Ng
Eugenia De Marco is Snow Ex’s lead integration engineer for the P-3 aircraft, responsible for each instrument aboard getting the data they need. Credit: NASA/ Joy Ng

As a mechanical engineer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, De Marco is part of a team that designs science instruments for airborne missions that study Earth. Many of these instruments are early versions of what may one day fly on satellites. For the past year, she has been working with a program called SnowEx, a five-year airborne campaign that is trying to figure out one of the most challenging puzzles in Earth observation: how do you measure from the air the amount of water in snow that’s on the ground?

Snow on the ground is easy to observe from space or the air, but not so easy to measure how wet or dense it is, and thus how much water may flow downstream into reservoirs and agricultural fields when it melts in the spring. One instrument is unlikely to be able to give scientists the observations they need, especially on rugged mountain slopes whose steep angels can complicate things. But many instruments, whose observations fit together like puzzle pieces to illuminate the bigger picture, just might.

Five of those instruments were De Marco’s responsibility aboard the Naval Research Lab’s P-3 aircraft this February during SnowEx’s first trip to their testbed, the snow-covered Grand Mesa and Senator Beck Basin outside Colorado Springs, Colorado. As the lead integration engineer for the aircraft, her job during the flights was to coordinate with the pilots and the instrument scientists to make sure that each instrument collects the data it needs.

Engineer Eugneia De Marco consults with instrument scientists Alex Coccia during a SnowEx research flight aboard the Naval Research Laboratories P-3 aircraft. Feb. 16 2017. Credit: NASA/ Joy Ng
Engineer Eugneia De Marco consults with instrument scientists Alex Coccia during a SnowEx research flight aboard the Naval Research Laboratories P-3 aircraft. Feb. 16 2017.
Credit: NASA/ Joy Ng

“The pilots will call down to me and usually, in general, to everyone, ‘We’re this close to our target,’ and then I make sure everybody’s ready to go and then science starts happening. In the meantime, I keep track of every time we hit the line and start and stop [data collection],” she said.

The “line” she mentions refers to the pre-determined path the airplane flies along so that it will fly above ground stations set up by scientists below to measure snow directly. Dozens of researchers from a variety of universities and government agencies were camped out on Grand Mesa and in Senator Beck Basin, going out each day on snowmobiles, skis or snow shoes to dig snow pits or set up other sensors directly on the snow in the mountains.

“They’re doing that to compare what we’re seeing with our instruments,” De Marco said.” Our instruments will say, ‘Hey, we just saw ten feet of snow,’ and the ground will say, ‘Yep that was ten feet of snow.’ It’s a data comparison-type deal.”

Grand Mesa in the Colorado Rockies is NASA and its partners' testbed for figuring out how much water content is in snow. Credit: NASA/ Joy Ng
Grand Mesa in the Colorado Rockies is NASA and its partners’ testbed for figuring out how much water content is in snow. Credit: NASA/ Joy Ng

On a given flight, the P-3 aircraft flies 12 lines that lasts from three to ten minutes each. One instrument that looks at how light scatters after bouncing off snow on the ground actually needs to fly in a circle around a ground station so it can capture all the angles. Sometimes problems with the instruments crop up, usually small glitches that can be fixed on board, and De Marco will rejigger the flight pattern so when the instrument is ready to go again, they can still fly over that instrument’s line.

Weather, however, is the biggest thing that can impact a flight, said De Marco. Clouds get in the way of some instruments’ observations, so the plane may try to fly above or below them depending on the instrument. Choppy air can complicate flying over the lines. When planning flights, De Marco and the science team try to fly in good conditions, but with weather over the mountains difficult to predict, they often go out in less than ideal weather and adjust their flight plan as they go.

“I think the most exciting thing is when we land and we know that we hit those lines and everything was working well and the sky looked great and the weather was great,” De Marco said. “I mean that just feels really good and makes all that hard work totally worth it.”

A ‘Dizzying Dance in the Air’ for Science

by Joy Ng / WESTERN COLORADO /

As I walked down the aisle of a plane with a camera clasped between my two sweaty palms, I had two thoughts on my mind: First, my footsteps feel very heavy; second, I hope I can film without vomiting. As you might guess, this was no ordinary flight.

Scientists Alex Coccia (left) and Albert Wu during a SnowEx science flight over Colorado. Credit: NASA/Joy Ng
Scientists Alex Coccia (left) and Albert Wu during a SnowEx science flight over Colorado. Credit: NASA/Joy Ng

Why did this flight feel like a nauseating roller coaster ride? The Navy’s P-3 Orion aircraft was outfitted with a variety of instruments that required various flying maneuvers to collect data. The plane flew back and forth in a straight line and around in tight circles. It was literally a dizzying dance in the air.

The P-3 Orion aircraft in the Peterson Air Force Base in Colorado Springs just before take-off. Credit: NASA/Joy Ng
The P-3 Orion aircraft at Peterson Air Force Base in Colorado Springs just before take-off. Credit: NASA/Joy Ng

This science flight was carried out as part of a new NASA-led campaign called SnowEx. At the moment, we have satellites that can see snow cover but no instruments in space that can accurately measure how much water they hold. Such a measurement is important, considering that roughly one-sixth of the world’s population relies on snow for their water resources. The campaign is exploring instruments and technologies for measuring snow that may eventually result in a snow-observing satellite.

One of the biggest land areas where snow falls is boreal forest, so SnowEx chose its first flights over the forests of Grand Mesa and Senator Beck Basin in western Colorado. Because leaves and branches can act like obstacles for some snow-measuring instruments, scientists are using these forests to investigate what combination of instruments can successfully measure snow over this kind of terrain.

The Grand Mesa in Colorado is one of the sites for this year’s SnowEx campaign. Credit: Ryan Cook
Grand Mesa in Colorado is one of the sites for this year’s SnowEx campaign. Credit: Ryan Cook

At the same time, scientists are working on ‘ground-truthing’ the airborne measurements. This involves more than 100 scientists measuring snow depth and density on the ground to get accurate snow measurements that can validate the measurements taken by the airborne instruments.

Travis Roth, Oregon State University looks at snow consistency at various depths as Jinmei Pan, Ohio State University logs data. Credit: Ryan Cook
Travis Roth, Oregon State University, looks at snow consistency at various depths as Jinmei Pan, Ohio State University, logs data. Credit: Ryan Cook

Collecting these in-flight measurements is tricky. Each instrument works at specific altitudes, over specific types of snow, and only in certain types of weather. This means that the aircrew and scientists have to work together to come up with a detailed flight plan—one that can change day to day—that allows all instruments to collect data successfully.

Lt. Denise Miller from the U.S. Navy speaks with Principle Investigator Edward Kim during a science flight. Credit: NASA/Joy Ng
Lt. Denise Miller from the U.S. Navy speaks with Principle Investigator Edward Kim during a science flight. Credit: NASA/Joy Ng

While I was on the plane, most of the scientists were in seats next to their instruments. I, on the other hand, was swerving side to side as I did my own little dance to capture my shots. It’s not the ideal film set. The light is constantly changing. Every surface of the plane is vibrating and it’s very loud. In these conditions, I had one priority in mind: stabilization. Luckily, I used a handheld gimbal—an electronic device that counteracts any minor movements—that allowed me to film smooth shots while my feet were to the contrary.

The view outside of the P-3 Orion aircraft during a science flight. Credit: NASA/Joy Ng
The view outside of the P-3 Orion aircraft during a science flight. Credit: NASA/Joy Ng

I managed to capture some great footage and discovered that, for me, the mountaintop views were a good remedy for any motion-induced mishaps.