NASA's unpiloted Global Hawk aircraft drone has successfully completed its first science flight over the Pacific Ocean.
The flight, the first of five scheduled for this month, is part of the Global Hawk Pacific (GloPac) mission, intended to study atmospheric science over the Pacific and Arctic oceans.
NASA?s Global Hawk is a robotic plane that can fly autonomously to altitudes above 60,000 feet (18.3 kilometers) roughly twice as high as a commercial airliner and as far as 11,000 nautical miles (20,000 kilometers) half the circumference of Earth.
In Wednesday's flight, the plane flew approximately 4,500 nautical miles (8,300 kilometers) along a flight path that took it from Dryden to just south of Alaska's Kodiak Island, at 150.3 degrees West longitude and 54.6 degrees North Latitude.
The flight lasted a total of 14.1 hours, and the plane reached heights of up to 60,900 feet (18.6 kilometers) in altitude.
The aircraft system carries 11 instruments to sample the chemical composition of Earth's two lowest atmospheric layers, to profile the dynamics and meteorology of both, and to observe the distribution of clouds and aerosol particles. Project scientists hope to take observations from the equator to the Arctic Circle, and also west of Hawaii.
"The Global Hawk is a fantastic platform because it gives us expanded access to the atmosphere beyond what we have with piloted aircraft," said David Fahey, co-mission scientist and research physician at NOAA's Earth System Research Laboratory in Boulder, Colo. "We can go to regions we couldn't reach or go to previously explored regions and study them for extended periods that are impossible with conventional planes."
NASA pilots and flight engineers, working with colleagues from the National Oceanic and Atmospheric Administration (NOAA), pre-program a flight path, after which the Global Hawk flies itself for up to 30 hours, staying in contact through satellite and line-of-site communications to the ground control station at NASA's Dryden Flight Research Center in California's Mojave Desert.
The aircraft can take off, fly its mission and land without any pilot or scientist intervention. Though the plane is designed to fly on its own, pilots can change course or altitude based on the atmospheric conditions. Researchers have the ability to command and control their instruments from the ground.
"The Global Hawk is a revolutionary aircraft for science because of its enormous range and endurance," Paul Newman, co-mission scientist for GloPac and an atmospheric scientist from NASA's Goddard Space Flight Center in Greenbelt, Md, said in a statement. "No other science platform provides this much range and time to sample rapidly evolving atmospheric phenomena."
The mission is also an opportunity to demonstrate the unique capabilities of the Global Hawk, while also gathering atmospheric data in a region that has until now been poorly sampled, he added.
GloPac researchers will measure and sample greenhouse gases, ozone-depleting substances, aerosols, and constituents of air quality in the upper troposphere and lower stratosphere.
GloPac flights should also allow scientists to observe the breakup of the polar vortex, a large-scale cyclone that dominates winter weather patterns around the Arctic and is especially important for understanding ozone depletion in the Northern Hemisphere.
Sampling the atmosphere
Researchers have already gathered some measurements from the polar vortex from Wednesday's flight.
Scientists also expect to gather data between 45,000 and 65,000 feet (almost 14,000 and 20,000 meters), where many greenhouse gases and ozone-depleting substances are destroyed. This will help researchers measure dust, smoke and pollution that cross the Pacific from Asia and Siberia that affect U.S. air quality.
Several instruments will measure aerosols, which play an important but incompletely understood role in Earth's energy budget. Some aerosols absorb warming sunlight, while others reflect it back to space and cool the planet. High-altitude particles can serve as nuclei for the formation of clouds.
GloPac will make several flights directly under the path of NASA's Aura satellite and other Earth-observing satellites, "allowing us to calibrate and confirm what we see from space," Newman said. GloPac missions are being conducted in conjunction with NASA's Aura Validation Experiment (AVE).
During its first science flight, the Global Hawk flew under the Cloud-Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO), a joint project of NASA and France's Centre National d'Etudes Spatiales.
The Global Hawk was originally flown in the Advanced Concept Technology Demonstration program sponsored by the Defense Advanced Research Projects Agency. Two test models were transferred from the U.S. Air Force to NASA in 2007, and a third was transferred in 2009.