Droplet Measurement Technologies is currently participating in NASA's Global Hawk Pacific Mission. The campaign, dubbed GloPac, involves sending a remote-controlled Global Hawk plane over the Pacific Ocean and Arctic regions to gather data about the troposphere and stratosphere.


NASA's Global Hawk — Photo Courtesy of NASA Dryden

Global Hawks have been used by the U.S. Air Force for surveillance. However, the GloPac campaign is the first time that a Global Hawk has been used for scientific research. The plane can fly unmanned for up to 30 hours at altitudes of 60,000 feet, making it an ideal vehicle for gathering data about the earth's atmosphere.

DMT Senior Scientists Bruce Gandrud and David Thomson have been working closely on the GloPac campaign. Thomson and Gandrud have been modifying a DMT Ultra-High Sensitivity Aerosol Spectrometer (UHSAS) so it can be outfitted on the Global Hawk.

DMT Scientists Bruce Gandrud (left) and David Thomson (right) work on the Ultra-High Sensitivity Aerosol Spectrometer — Photo Courtesy of NASA Dryden

The UHSAS is designed to measure atmospheric particles as small as 60 nm, or about 0.1% the width of a human hair. On the Global Hawk, the instrument must work under some unconventional operating conditions. First, since space on the aircraft is in high demand, the UHSAS shares its sample inlet with another instrument. But more importantly, since the Global Hawk is an unmanned aircraft, the UHSAS needs to communicate with control centers on the ground. Thomson therefore added special software to enable such remote communication. This software allows the instrument to relay information about its status and receive a limited set of commands.

All of the Global Hawk research instruments must be able to communicate this kind of operational information remotely. However, only some of the instruments have been designed to communicate research data real-time to the ground. The UHSAS is one of these. To transmit research data, Thomson and Gandrud implemented several data paths, using both the aircraft's Iridium link and the K_u satellite line. After data collected by the UHSAS and other Global Hawk instruments is received on the ground, NASA transmits it across the internet via a password-protected website. This system enables scientists across the globe to see the data instantaneously.

Click here to see a press release from NASA and more information about the GloPac plane.