‘Star trackers’ to monitor Earth’s weather

The National Oceanic and Atmospheric Administration is planning to launch by the end of the year the first satellites using “star trackers” instead of Earth sensors to monitor weather patterns more precisely.

Scheduled for release in December, the Geostationary Operational Environmental Satellite (GOES) series is expected to produce more precise storm images. The star tracker technology uses the positions of stars to estimate altitude and requires no information from the ground.

The three satellites in the series will show short-term meteorological activity, commonly called “now-casting.” All GOES satellites, including four others already in space, hover above one spot on the Earth’s surface as they match the planet’s rotational speed 22,300 miles overhead.

They act as trigger alerts for severe weather such as tornadoes, flash floods, hailstorms and hurricanes. Their coverage area is about one-third of the Earth, concentrating on North America and South America.

With the planned launch, NOAA has said it will retire one of the satellites in space — GOES-8 — by putting it through the Earth’s atmosphere, where it will incinerate. GOES-8 monitored the eastern and central United States, the Atlantic Ocean, the Caribbean and the Gulf of Mexico.

NOAA’s administrator, retired Navy Vice Adm. Conrad C. Lautenbacher, noted the retirement by saying, “GOES-8 has served America well as our eye above the storm.

“During the 10 years GOES-8 was operational, our tropical and severe weather forecasts improved. That was key to saving lives in the face of potentially deadly conditions,” he said.

The satellite tracked many significant storms that included five tropical cyclones in 1995 and Hurricane Mitch, which struck Central America in 1998.

Next week, a NOAA conference will be held in Broomfield, Colo., to focus on a series of satellites to be launched starting in 2012. Those satellites are expected to scan the Earth five times faster and provide 50 times more data than those now in use.