Like a celestial version of Pixar's industrious robot Wall-E, environmental-monitoring satellites continually whiz overhead, quietly performing their allotted tasks of taking data and beaming the information down to climate researchers and weather forecasters.

But a recent U.S. Government Accountability Office (GAO) report highlights the fact that this monitoring network—which weather forecasters and climate researchers rely on—is in trouble.

That's because these U.S.-owned satellites are aging, and there are serious concerns about whether their replacements will be ready by the time they start to break down, said J. Marshall Shepherd, president of the American Meteorological Society and a professor at the University of Georgia in Athens. (Read about the history of satellites.)

The replacement program, known as the Joint Polar Satellite System (JPSS), has suffered under ballooning budgets, mismanagement, and political wrangling. That's partly what prompted the GAO to put weather data on its list of government operations at high risk.

The report stated that "potential gaps in environmental-satellite data beginning as early as 2014 and lasting as long as 53 months have led to concerns that future weather forecasts and warnings—including warnings of extreme events such as hurricanes, storm surges, and floods—will be less accurate and timely."

"But even a 17-month gap, [the shortest estimate for a potential data gap], dramatically affects weather forecast ability, which could lead to challenges to protecting life and property," Shepherd said.

Basic research would also suffer from the loss of data, said Scott Rayder, senior adviser to the president of the University Corporation for Atmospheric Research. "Long-term weather data is climate data, so these [satellite] sensors are important in figuring out how the atmosphere works."

Cause for Concern

Information forecasters incorporate into their models comes from two sets of satellites run by the U.S. National Oceanic and Atmospheric Administration (NOAA) and NASA—geostationary satellites and polar-orbiting satellites, the American Meteorological Society's Shepherd explained.

Onboard instruments measure environmental factors including atmospheric moisture, sea surface temperature, and atmospheric ozone. This helps scientists keep tabs on things like precipitation and the health of the planet's ozone layer.

The current concern is focused on replacements for polar-orbiting satellites.

Traveling 517 miles (833 kilometers) above the Earth in a pole-to-pole direction every 90 minutes, NOAA's current crop of Polar Operational Environmental Satellites (POES) are nearing the twilight of their life cycles, Shepherd said.

The POES satellites were built with a two- to three-year operational lifetime in mind, said James Gleason, of NASA's Goddard Spaceflight Center in Maryland.

"And they've lasted a long time, some [for] more than a decade," he said. The most recent POES satellite, NOAA-19, was launched in 2009.

Dire Situation

NOAA has another polar-orbiting satellite, called Suomi NPP, that's also taking weather data. Launched in 2011, it was supposed to be a proof of concept in order to test instruments slated to fly on JPSS, said Shepherd.

But due to repeated delays in the JPSS program, NOAA is using Suomi NPP as an operational satellite. "It's working swimmingly," he said.

"We're pretty sure [Suomi] NPP will last until 2016," said NASA's Gleason, senior project scientist for JPSS.

But JPSS isn't scheduled to launch until early 2017—and that depends on what happens to funding in the federal budget and whether the sequester kicks in, Gleason said.

NOAA is currently working on a plan to bridge any gap, should it occur, in data from their satellites. One possibility includes using a fleet of satellites owned by the U.S. military, called the Defense Meteorological Satellite Program, to gather needed weather data.

The agency put out a call last year asking for suggestions on how the community could deal with a gap.