Space Exploration-A Question of Perspective

E-mail Tom Kevan

While the big headlines are about the exploration of distant planets, such as Mars, Jupiter, and Uranus, some important work with cutting-edge sensor technology is focused on our own planet. These programs will deliver more immediate and tangible benefits than those derived from Buck-Rogers projects.

Planet Earth
On October 4, 1957, humans began space exploration in earnest with the launch of Sputnik 1. In subsequent years, the Voyager, Magellan, Ulysses, Galileo, and Mars Pathfinder flights focused our attention outward to the limits of our galaxy. But not all of our efforts look away from Earth. Some, in fact, take advantage of their bird's eye view to better understand the planet we live on.

These efforts rely on earth-orbiting satellites to provide a platform for a growing number of sensors used to gather information that will help us better understand Earth's weather, climate, and seas. By combining the resources of private companies and federal agencies such as NASA and the National Oceanic and Atmospheric Administration (NOAA), we've been able get a more timely and complete picture of forces that influence our lives. Consider the following examples.

Weather and Climate
On April 28, Ball Aerospace & Technologies Corp., working with NASA, launched the CloudSat and CALIPSO satellites from Vandenberg Air Force Base in California. The payload of scientific instruments on these satellites included the CALIOP LIDAR and wide-field camera (WFC). It was hoped that these platforms would provide a glimpse inside Earth's storms and improve our understanding of Earth's weather, climate, and air quality by revealing 3D details of clouds and the hidden characteristics of aerosols.

CALIPSO's instruments were turned on sequentially, with the first images from its infrared imaging radiometer arriving on May 11, followed by images from the WFC on May 18. The LIDAR delivered images that showed the layering of the atmosphere and included a volcanic plume over the equator near the Philippines and a large polar stratospheric cloud above Antarctica.

CloudSat's cloud-profiling radar was activated on June 2. Four days later, NASA released pictures showing a storm over the North Sea in the North Atlantic approaching Greenland. CloudSat's millimeter-wavelength cloud-profiling radar is more than 1000 times more sensitive than typical weather radar.

Scientists hope to use data from CALIPSO to construct 3D models of the atmosphere that will improve our ability to predict future climate change, understand the role of clouds and aerosols in weather, and study how long-range transport of pollutants affects air quality.

Tsunamis
In another project, Iridium is providing satellite data links for a new system of 31 ocean buoys that the NOAA is deploying to detect and monitor tsunami waves in the open ocean. The $37.5 million implementation of the second-generation Deep Ocean Assessment and Reporting of Tsunamis (DART II) system consists of pressure-sensitive tsunameters on the seafloor and buoys on the ocean surface. The buoys use acoustic modems to receive data from the seafloor sensors and data modems to transmit pressure measurements to Iridium's low-earth-orbiting satellites. The pressure measurements are then relayed to NOAA warning centers. The data links support two-way data communications, permitting technicians at the warning centers to request tsunameter data from any specific buoy.

"The DART II technology will make it easier and faster for warning centers to alert coastal areas in time to evacuate residents quickly," said Jack Rowley, SAIC DART manager. "The implications for saving lives are tremendous."

Irony
When there is a shuttle launch, images from the Hubble telescope, or new data from a Mars landing, it's all over the news. But let the government and technology providers build sensing infrastructures that provide new insight into the workings of our weather, climate, or storms, and we conceal that information in books and brief news releases. Go figure.

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