Those of you who follow this blog know that, on top of launching satellites into space, NASA has a suite of Earth-observing instruments, a robust airborne program of instruments mounted on planes, and science ships.
Final frontier? I don't think so. Our catch phrase should be more like "Frontiers are us." We're all over the place.
Recently, Chris Mertens, a NASA scientist interested in galactic cosmic rays, shepherded a NASA balloon all the way to the top of Earth's atmosphere. The balloon, which stood a couple hundred feet tall and held 11 million cubic feet of helium, had a flight train attached to it with a payload of four science instruments and a parachute. He watched it lift off from NASA's Columbia Scientific Balloon Facility in Fort Sumner, New Mexico, and float away on a 24-hour research journey. "It was pretty surreal seeing it drift vertically away," he told me. "The apparatus looked big in the flight facility but looked so small as it was going up. It floated so gracefully, effortlessly."
Up, up and away
As the balloon lifted off, chief engineer Amanda Cutright could hear two sets of cheers, one at the location and a second over the delay at NASA's Langley Research Center where members of the team were watching a broadcast of the event. But she was "still holding her breath," waiting for the data to come in.
Mertens and Cutright, along with project manager Kevin Daugherty and the rest of the Radiation Dosimetry Experiment (RaD-X) team, had spent the past few weeks prepping the balloon and payload in the deserts of New Mexico and had been anxiously awaiting its launch. (Dosimetry is the science of determining radiation dosages received by the human body.) Daugherty told me they'd been waiting for the winds to stagnate in the upper atmosphere so they could fly over the southeastern U.S. for 24 hours without going into the populated areas of Mexico or Los Angeles.
Up in the air
The project actually began years ago when Mertens heard a pilot say, "I'm exposed to radiation and I don't know how much." See, someone on a one-way plane trip from Chicago to Germany on a normal day is exposed to approximately one chest X-ray's worth of radiation. Because commercial airline pilots and aircrew fly so frequently, they are actually radiation workers. So, with his background in cosmic radiation and space weather physics, Mertens knew he could develop a model to predict the radiation levels in Earth's upper atmosphere and answer that question. With this balloon flight, the RaD-X team expects to learn more about the amount of radiation flight crews receive on a daily, monthly or yearly basis and throughout their careers.
Up, up, up, up
About two hours after launch, the balloon reached the middle of the stratosphere, about 110-120 thousand feet up, right on the edge of space. That's about three times as high as commercial airplanes normally fly. From on-board cameras, "we could see the curvature of the Earth and watch the clouds recede," said Cutright. The team wanted to look at the incoming galactic cosmic rays and radiation from the sun above the region where the particles interact with the atmosphere and break up into smaller particles. "Earth's radiation environment is complex," Mertens explained. "Our magnetic field has a dynamic response to the solar wind and varies with latitude. At the polar regions, radiation exposure is maximum because the magnetic field lines are vertical. This means that during a solar storm, the incoming charged particles at the polar cap are parallel to the magnetic field lines, so there's no deflection by the magnetic field."
Yes, Earth's magnetic field is seriously rad.
Just past sunset, they purposely let enough helium out of the balloon to lower it to the 70-89 thousand foot range and have it float there overnight. All four dosimetry instruments collected data at both altitudes to feed into NAIRAS, an analytical model that simulates tissue and how radiation impacts it.
For the rest of the flight, the RaD-X team watched visuals from the onboard cameras, gathered near real-time data on their computers and tracked the balloon flight path from the control room.
"At one point late at night," said Cutright, "we were watching the Earth and we could see the moon. We could see a lightning storm over Oklahoma, all the way from the edge of Texas and New Mexico."
After sunrise, the team watched the parachute deploy so the payload could descend safely; from the camera view, they watched the Earth getting bigger and bigger. The payload was cut from the balloon and a large hole ripped on the side of the balloon so it could fall on its own off to the side. The balloon landed in a rancher's field and the Columbia Scientific Balloon Facility out of NASA Wallops recovered it.
Thank you for reading and for your comments.
P.S. 100 low-cost Cubes in Space experiments from 100 classrooms across the country were also on the flight. Some of their experiments included kernels of popcorn to see if they pop at altitude and seeds and electronics to find out how radiation affects them. Now that you know NASA helped students send kernels of popcorn to the edge of space, aren't you dying to find out if they popped or not? I am. I'll try my best to find out and post it here.