NOAA’s new unmanned glider set to help dramatically increase high-altitude search
The Earth’s upper stratosphere is cold and isolated. Few planes are able to fly so high or linger for so long. So while the stratosphere is important for understanding climate change – and is routinely probed from a few places by small balloons to monitor the planet’s protective ozone layer, the number of direct measurements taken at these altitudes is relatively unimportant.
It’s about to change.
The High Altitude Operational Unmanned Return System (HORUS). Credit: Sonja Wolter, NOAA & CIRES Global Monitoring Laboratory
This fall, scientists at NOAA’s Global Monitoring Laboratory are tweaking a low-tech, cost-effective system to lift a small payload of specialized measuring instruments to the edge of space and then return it to the launch site . Nicknamed HORUS, after the Egyptian falcon-headed god, the high-altitude operational return unmanned system relies on a standard weather balloon to hoist a small remote-controlled glider carrying scientific instruments tail-first to altitudes ranging from up to 90,000 feet. When the balloon bursts, the glider, with its six-foot wingspan, can be flown for a soft landing at the initial launch site.
The system has the potential to usher in a new era of atmospheric research, said Colm Sweeney, who heads the laboratory’s aircraft program.
“We still have obstacles to overcome. but conceptually we’ve licked a big deal… finding a good way to get a balloon vehicle back, ”Sweeney said. “Now we can launch from many places we couldn’t launch before – rough terrain, islands, even ships at sea.”
This diagram represents a theoretical flight plan in unrestricted airspace for operational flights of the High Altitude Operational Unmanned Return System (HORUS). Photo credit: Sydnee Macias, NOAA Global Monitoring Laboratory
During a test flight in May at NASA’s Armstrong Flight Research Center at Edwards Air Force Base in Calif., HORUS successfully returned from a drop point 75,000 feet above the desert floor, dragging a parachute toward a smooth belly landing a few feet from its initial launch site.
NOAA scientists are currently working to obtain a certificate of clearance from the Federal Aviation Administration for routine HORUS flights in the Pawnee Grasslands of northeast Colorado. With a successful flight in Colorado, the technology will officially become operational.
How is the upper atmosphere sampled?
Weather balloons have long been the most common method of sampling the upper atmosphere, but recovering the payload of the instrument can be difficult. Once the balloon has burst, the instruments – usually enclosed in a Styrofoam box – descend to the surface supported by a parachute. But upper winds can cause instruments to drift for several kilometers during ascent and descent, and land randomly in hard-to-reach places. As a result, most research balloon launches are planned in less populated and easily accessible rural areas.
In contrast, the HORUS glider can be launched from virtually anywhere and reliably return to the launch point. During the May test flight, HORUS reached speeds of over 200 knots above ground at the start of the glide phase, more than sufficient to navigate the 60 knot winds it encountered at 40 000 feet.
Additionally, the HORUS cell offers flexible space for up to 10 pounds of scientific instrumentation, which will allow scientists to capture air samples and perform in situ measurements.
Why is this technology revolutionary?
Today’s weather and climate models require large amounts of precise, high-resolution observations covering large areas of the atmosphere over long periods of time to generate accurate forecasts and predictions. With the ability to efficiently retrieve high-value, high-precision instruments, HORUS offers a cost-effective way to expand high-altitude air sampling globally and improve the accuracy of data used by air carriers. climate and weather models.
Scientists also use research planes, which can carry heavier payloads, but the planes rarely reach 75,000 feet and are too expensive for the frequent sampling required by next-generation climate models. Even more expensive satellites provide continuous monitoring of the atmosphere, but their instruments make estimates of atmospheric composition based on the reflection or absorption of light, rather than direct measurements.
“With HORUS, we now have the unique ability to probe the atmosphere in many under-observed regions, filling critical gaps in our surface observing networks both geographically and in rarely sampled areas of the stratosphere,” said Bianca Baier, CIRES scientist at the Baier Global Monitoring Laboratory, co-leader of the project, evaluated data collected from the HORUS test flights by a payload that included another NOAA innovation, the AirCore, which captures air samples sequentially as it descends into the atmosphere.
With the successful May test, NOAA scientists seek to bring HORUS to operational status by spring 2022. Development of the technology is funded by the NOAA USRTO and the NOAA Uncrewed Systems Operations Center of the Office of Operations. maritime and air.
“The ability to recover high altitude sensor assemblies is just one more way for NOAA to apply unmanned systems technologies to advance scientific research,” said Captain Phil Hall, director of NOAA Unmanned Systems Operations Center.