Phil Hall travels the world without moving.
“The longest flight I’ve done is about 28 and a half hours,” says the US space agency pilot. “We flew from California almost to the North Pole, did two loops in the Arctic, and came back.”
Although the plane clocked up around 16,000km (10,000 miles), Hall did not move much further than the bathroom and the coffee pot down the hall.
That’s because Hall is one of Nasa’s UAV (Unmanned Autonomous Vehicle) pilots, responsible for flying the Global Hawk drones used by the agency.
These robotic craft are “piloted” by Hall and his colleagues from Nasa's Dryden Flight Research Center at Edwards Air Force Base in California. There, pilots sit in front of banks of large screens that show the view from the nose of the craft in real time and related data about it speed, position, altitude and so on. Their job is to watch over the craft, making occasional course changes and corrections and ensuring the giant robotic craft completes its preprogrammed mission.
Prepare for turbulence
UAVs are perhaps best known for their use by the military, but they are increasingly finding civilian uses. In the United States alone the FAA (Federal Aviation Administration) predicts that there will be 30,000 drones in the country’s skies in less than 20 years.
Nasa uses them for earth science, flying missions to collect data about the planet. Since the two craft first came into service in 2009, they have flown around the Pacific, cruised over the Arctic and collected data from a host of places previously too dangerous or too remote for other scientific craft flown by Nasa, such as a civilian version of the military U2 craft known as the ER-2.
“One of the limitations of the U2 is its flight duration,” says Hall. “It only has one pilot, who has to get into a very expensive pressurised suit and get into the aircraft. With this aeroplane we can fly for up to 30 hours with the pilots on the ground.”
The Global Hawk – built by Northrop Grumman - is a bulbous-looking craft more commonly flown by the military for high-altitude reconnaissance. The two owned by Nasa are actually the first and sixth planes ever built and were used to prove the concept of the vehicle.
They each have a wingspan of 35m (115ft), meaning they rival a Boeing 737 for hanger space. The body looks short by comparison at 13.5m (44ft)and contains a bay a bay at the front that allows them to be equipped with a variety of instruments, depending on the mission. A single Rolls Royce jet engine powers the plane. Its 20,000km (11,000 nautical mile) range and ability to fly as high as 18,000m (60,000ft) means it can be used for a wide variety of measuring, monitoring, and observing missions.
In August this year, the craft will fly over the Atlantic, as the hurricane season goes into full force. The Global Hawk can fly over a weather system for around 15 hours, which will give scientists an unprecedented view of these natural phenomenon.
“During that time we can actually see how the hurricane changes,” says Hall. “It gives us a glimpse into areas of discovery that we haven’t had before.”
The plan is to use both of Nasa’s drones on those future missions. One will look at the inner core of the hurricane, and the other wider environment, dropping disposable instruments to charecterise the wind fields. The delicate dance of very expensive machinery and the full force of mother nature will be the ultimate test for the planes.
But for the pilots, it will just be another day in the office.