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Polar orbiter going up to improve weather forecasting

Posted: October 24, 2011

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A satellite whose mission will touch the lives of everyone on Earth by taking the planet's environmental pulse daily for global weather forecasting and meticulous tracking of the changing climate will be launched into space Friday morning atop what's potentially the final Delta 2 rocket.

An artist's concept of the NPP spacecraft. Credit: Ball Aerospace
The $1.5 billion mission of the NPP spacecraft will extend the data records from NASA's aging science observatories and serve as a gapfiller in NOAA's polar-orbiting weather satellite constellation for a half-decade while waiting for the next generation.

"There is value to knowing what tomorrow will bring. Whether by tomorrow we mean literally as in the weather forecast, or by tomorrow we mean something longer -- the future Earth environment that we can expect to be living in months, years, decades from now, and that our children and grandchildren will be living in," said Waleed Abdalati, NASA's chief scientist.

The U.S. has been flying weather satellites that circle from pole to pole since the dawn of the space age. Unlike the geostationary platforms parked 22,300 miles above the Earth's equator that monitor only a portion of the planet, the polar birds fly much lower and survey the whole globe to see conditions develop and give warning of incoming storms.

"What happens in far away places matters in places where people live," said Abdalati.

Friday's liftoff is targeted for 2:48 a.m. local time (5:48 a.m. EDT; 0948 GMT) from California's Vandenberg Air Force Base, located on the Pacific coastline about 140 miles northwest of Los Angeles.

The venerable Delta 2 rocket, making its 151st and possibly last launch, has no further missions on the manifest. Maker United Launch Alliance has five more of the vehicles available for sales to the U.S. government and commercial satellite operators, but it remains to be seen if any will fly.

For this its 50th ascent in service to NASA, the Delta 2 will haul the 2.5-ton payload into a 512-mile-high orbit tilted 98.7 degrees to the equator, enabling the craft to cover the entire planet.

"We get to watch it fly south over the Pacific Ocean and on into orbit, then we all rush back inside, tell our team on the east coast to get to work on flight ops, make sure we got into the correct orbit and our solar array deployed," said Scott Tennant, NPP program manager at satellite-builder Ball Aerospace.

"Then we party."

An artist's concept shows the Delta's second stage accelerating NPP into orbit. Credit: NASA TV
Engineers working on the satellite have been waiting years to see NPP launch. Construction of the craft's core structure was completed in 2005, but then came a lengthy delay to finish the state-of-the-art instruments.

NPP carries five sensor packages to provide imagery, atmospheric temperature and humidity profiles, and land and ocean surface temperature observations, all of which are key ingredients for weather forecasting. In addition, the satellite will measure ozone levels and reflected solar radiation from the planet.

"The nation isn't always aware of the benefits of taxpayer investment into big projects like NPP. But with more sophisticated Earth observing sensors aboard NPP, the National Weather Service will be able to demonstrate this value by saving even more lives and reducing economic losses with more-accurate forecasters and longer lead times," said Jack Hayes, director of the National Weather Service.

While NOAA uses NPP to test the vitality of the modernized sensors for watching the weather, NASA will add the satellite's measurements to its long-term compilation of climate data.

"People often confuse climate and weather. Weather is what's going to happen tomorrow or this upcoming weekend; climate is what happens over years and decades," said Jim Gleason, the NPP project scientist from NASA's Goddard Space Flight Center.

"Climate is long-term behavior, weather patterns over time. These are the patterns that make it easier to grow corn in Iowa than in Arizona. Simply put, climate is what you expect, weather is what you get."

The three large science satellites in NASA's Earth Observing System -- Terra, Aqua and Aura -- were launched in 1999, 2002 and 2004, respectively, and won't last forever. NPP will continue writing their data records about the planet's atmosphere, oceans and vegetation during its planned five-year mission.

"NPP is a bridge to next-generation of Earth observing satellites that will provide climate data that are critical to NASA's Earth science research. NPP will help us understand what tomorrow will bring -- whether by tomorrow we mean tomorrow's forecast or we mean years and decades from now," said Andrew Carson, NASA's NPP program executive.

"NPP will continue these key measurements which are critical to understanding the health of our planet now as well as how things might change in the future."

For meteorologists, they are looking forward to the enhanced data from NPP to improve the quality of forecasting the weather.

"As end users the global data we will receive from this advanced satellite, we at the National Weather Service are really excited in anticipation of getting it into operations as quickly as we can," said Hayes.

"In addition to the advanced sensors' higher resolution technology, NPP will give us critical information from the entire Earth surface twice a day. This additional data will give National Weather Service forecasters more knowledge days in advance about the strength of a storm."

An artist's concept illustrates NPP's polar orbit. Credit: NASA
Sophisticated numerical models run on the world's fastest computers ingest over a billion observations per day to generate daily weather forecasts.

"The backbone of that global observing system is the polar satellite data that both NASA and NOAA have worked on for decades to improve the operational forecast systems. So the launch of the NPP is a big deal for America," said Louis Uccellini, director of NOAA's National Centers for Environmental Prediction.

"With NPP's advanced microwave, infrared and visible data feeding NOAA's operational weather prediction models, we expect to improve our forecast skills and extend those forecast skills out to five-to-seven days in advance for hurricanes, severe weather outbreaks and other extreme weather events," Uccellini continued.

"Beyond the weather forecasting, NOAA will use NPP data to track ash plumes from volcanic eruptions to enhance aviation safety, monitor crops, vegetation, the potential for drought and fires, measure variation in the Arctic sea ice and detect harmful algae blooms and other hazards that might endanger fisheries in fragile ocean ecosystems."

At the Space Launch Complex 2 pad, technicians plan to load storable hypergolic propellants into the Delta 2 rocket's second stage Monday and Tuesday. The Launch Readiness Review will be held Wednesday, leading into the countdown activities that begin Thursday afternoon. You can follow launch preparations in our Mission Status Center with journal updates and live streaming video.

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