NPP Runs the Gauntlet of Environmental Testing

The NPP satellite sits surrounded by 144 rock concert speakers. They're stacked in a circle 16 feet high in a testing room at Ball Aerospace in Boulder, Colorado.

As engineers set up for the environmental test, Pink Floyd's song "Money" plays gently in the background. The music stops. The room clears. Then the sound engineer wearing earplugs and headphones in the control room next door flips a switch.

Slowly, the noise of thousands of pounds of exploding rocket fuel builds louder and louder until it blasts the satellite at a deafening 143.6 decibels loud enough to cause serious damage and pain to unprotected ears. "I was outside the building when they did the full level acoustics," says Glenn Iona, NPP Chief Engineer at NASA Goddard Space Flight Center, Greenbelt, Md. "and I could feel the ground shaking."

The acoustic test is one of a gauntlet of environmental tests a satellite must pass to prove that it can survive launch and life in space. For Large Class Observatory mission NPP, this process took years to plan, 15 months to execute and was fraught with as many engineering challenges as building the satellite itself.

The NPOESS Preparatory Project (NPP) is the prototype for the next generation of Earth-observing satellites that will monitor daily weather and long-term ozone levels and climate change.

NPP's five instruments will continue data collection now done by an aging fleet of satellites. NASA's oldest Earth Observing System (EOS) satellites are more than 10 years old, with instrument designs and technology dating back to the early 1990s. NPP is the bridge between the original EOS missions and the Joint Polar Satellite System (JPSS). JPSS, previously called the National Polar-orbiting Operational Environmental Satellite System (NPOESS), will be developed by NASA for the National Oceanic and Atmospheric Administration (NOAA).

Testing to evaluate whether a satellite is ready for space occurs at several levels. Some individual parts and each individual instrument from the satellite go through three types of testing: dynamic, electromagnetic compatibility, and thermal vacuum.

Then the parts are integrated onto the main satellite bus, a wedge-shaped block the size of a four-door sedan. The bus has propulsion systems, a flight computer, a data processing computer, data storage and a solar panel wing that powers it all. Engineers then put the spacecraft and instruments through their paces to get a performance baseline before the whole satellite is run through the suite of environmental tests again.