Alexandra Witze, Earth in action

Loss of eyes in the sky hurts science on the ground

SN Prime | September 19, 2011 | Vol. 1, No. 14

In a clean room at the Vandenberg Air Force Base in California sits the next great hope of the United States’ Earth-monitoring program. About the size of a minibus, it is covered in gold foil, riddled with electrical wires, and very clean.

This $1.5-billion satellite is state-of-the-art, carrying five advanced instruments to measure everything from sea-surface temperature to atmospheric winds. NASA plans to launch the satellite in October, as the bridge between the current and next generation of operational  environmental satellites.

In true bureaucratic form, its name is an acronym nested within an acronym: NPP, for NPOESS Preparatory Projectin which NPOESS stands for National Polar-Orbiting  Environmental Satellite System, a project that no longer exists.

The “preparatory” part of NPP’s name signals that it was supposed to be a prototype, a chance to experiment with new technologies before having to fly them for real. But the project has taken so long that NPP must now succeed; without it, scientists will have no reliable eye in the sky to maintain a consistent record of key satellite-based climate data.

Like a mosquito buzzing the planet, NPP will fly the all-important polar orbit, from nearly 90° N latitude to 90° S. This vantage point will allow NPP to cover the full globe, helping forecasters develop weather predictions for five to 10 days out. Hurricanes, tornadoes, severe floodingall need to be seen from polar orbit as well as from the more traditional equatorial orbit of most weather satellites. “NPP will improve our forecasting skill for the severe and lasting storms that have impacts on people’s lives,” says Jack Hayes, director of the National Weather Service.

NASA’s current polar-orbiting satellites known as Terra, Aqua and Auraare far beyond their design lifetimes and could give out at any time. Fundamental science could soon suffer because the country can’t keep a reliable series of environmental satellites running. Think of the stunning images of Hurricane Irene moving up the East Coast: Many of those came from satellites whose existence we take for granted.

“When it comes down to it, there’s value in knowing what tomorrow will bring,” says Waleed Abdalati, NASA’s chief scientist. “These kinds of satellite observations, with multiple sensors, help to put the story together. Earth is a mosaic of stories, with little ones all telling one big one.”

But without continually taking the planet’s vital signs, that big story doesn’t get told. Take Charles David Keeling, who gathered super­sensitive measurements of carbon dioxide in the atmosphere above Mauna Loa, Hawaii, starting in 1958. Keeling struggled for decades to keep his monitoring program funded, even as managers asked him to guarantee a minimum of two discoveries per year. Today, the Keeling curve of carbon dioxiderising from 316 parts per million in 1959 to 388 parts per million todayis the starkest proof of how humans alter the environment by belching planet-changing gases into the atmosphere.

Imagine trying to keep a patient alive in a hospital without knowing his temperature, blood pressure or heartbeat. The business of gathering planetary data is not sexy, but it’s crucial. “Monitoring is science’s Cinderella, unloved and poorly paid,” Euan Nisbet, a geologist at the University of London, wrote in 2007 in Nature.

NASA’s ice-monitoring satellite, IceSat, has died; its replacement is years away, even as the planet’s ice sheets melt. The U.S. Geological Survey’s Landsat series of satellites provides key information on vegetation cover, carbon dioxide and other landscape information, yet the latest in the series, launched in 1999, has problems collecting and sending data. Its replacement won’t launch before 2012 at the earliest.

For now, the big shiny bus of NPP is freighted with the hopes and fears of many U.S. scientists. If it succeeds, it will bridge most of the gap between the dying satellites and the next generation of Earth-monitoring satellites, which are not expected to launch before 2016.

In other words, NPP had better go up on October 25 as planned, and work. Even the technicians putting it together in the clean room know that.

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