(CNN) -- They hover above our heads, out of sight, zooming in and taking pictures.
They aren't interested in the latest celebrity wedding or covert military operation. And the images they take aren't going to make the front page of any magazine or website.
But maybe they should.
That's because the data collected by these powerful satellites have helped save countless lives by allowing meteorologists to warn people about dangerous storms -- sometimes a week before they strike -- with pinpoint accuracy.
Seven days before Superstorm Sandy hit the United States on October 29, computer models based on the data from these satellites predicted the storm would make landfall in New Jersey.
It landed just five miles from where the earliest forecasts said it would.
"It is unprecedented," said Chad Myers, CNN's severe weather expert and meteorologist. "(No) other storm in recent memory has been forecast that good for that long.
"We knew days in advance, much more in advance, 48 hours in advance more than we knew in Katrina (in 2005)."
It could have been a much different story.
A month before the 1,000-mile-wide storm struck the Northeast, at the height of the hurricane season, the geostationary satellite that monitors the Caribbean and Atlantic -- where Sandy gathered strength -- stopped working. While there are dozens of American weather satellites in orbit, these geostationary spacecraft are crucial to predicting dangerous weather patterns.
Luckily, the National Oceanic and Atmospheric Administration, or NOAA, had a backup satellite to scramble into place. Without it, the early warning for Sandy's impending strike on the northeast might not have been as accurate.
That close call has meteorologists worried that, in this era of shrinking budgets, aging satellites might not get the expensive repairs they need to operate, and NOAA might not be able to purchase backup satellites.
Satellites like these are expensive -- $1 billion each -- and they take five years to build and launch.
Compare that to the cost of major storms, like Sandy which is estimated to have inflicted nearly $80 billion in damage in New York and New Jersey alone. Not to mention the cost in human lives.
"If there's a major failure of the satellites, that would be a major disaster and indeed we would be blinded in many respects," explained Kevin Trenberth, who heads climate analysis at the National Center for Atmospheric Research.
"We would not be able to see what's going on in the Earth's system as well as we can now."
Scientists can only wonder how many lives this technology could have saved on September 8, 1900, when a Category 4 hurricane slammed into Galveston, Texas, with no warning, killing at least 8,000 people. It would be another 70 years before satellites were used in weather forecasting.
A major failure of these satellites could pose a serious threat as climatologists and meteorologists warn that storms like Sandy could become more frequent and more powerful in the near future.
Lessons from Katrina
Seven years ago, the only thing protecting the low-lying city of New Orleans from a massive storm surge was an inadequate and outdated system of levees and floodwalls.
After Hurricane Katrina slammed into the U.S. Gulf Coast in 2005 -- killing 1,800 people and inflicting $100 billion in damage -- Congress said never again.
Federal lawmakers spent $14.5 billion, mostly federal funds, to build a fortress around New Orleans.
Today the city is protected by 350 miles of stronger levees and higher flood walls that form a circle around New Orleans to keep any deadly storm surges at bay.
Among its most powerful new weapons: the largest storm-surge barrier in the world.
The massive barrier wall extends nearly 200 feet into the earth, and towers 26 feet above the water. It's reinforced by 350,000 tons of steel -- 50 times the amount in the Eiffel Tower.
The fortress has turned New Orleans into a giant bathtub. To prevent that bathtub from filling up during a major storm, the city built the world's largest water pumping system.
"(One station) can pump about 30,000 cubic feet of water per second, which is just extraordinary," said Garrett Graves, who is overseeing the state's new hurricane protection plan.
At that rate, Graves explained, each of the 77 pumping stations could "fill an Olympic size swimming pool in about 4½ seconds."
It's arguably the best hurricane protection system in the country -- but Malcolm Bowman hopes it won't be for long.
That's because Bowman wants to build a barrier system across the 5-mile-wide opening to New York Harbor that he says could have protected America's most populated city from Sandy's devastating storm surge.
"If barriers and sand dunes had been properly built in the last eight years, none of this would have happened," he said.
Bowman leads the Storm Surge Research Group at Long Island's Stony Brook University. The group promotes a plan to create an elaborate system of barriers and causeways that would virtually flood-proof much of metro New York.
They say their "Outer Harbor Gateway" plan would cost billions of dollars less than the damage that Sandy inflicted upon the state of New York.
Bowman has spent years warning officials of the storm surge risk to New York City.
Less than a month after Katrina, he wrote an op-ed in the New York Times warning that the same thing could happen to New York City -- and outlining his storm barrier system solution to prevent it from happening.
He tried again in 2008 as part of a climate change panel convened by New York City's Mayor Michael Bloomberg.
But no barriers were built.
Today, Bowman is hopeful that New York authorities will green-light his plan. Gov. Andrew Cuomo is awaiting recommendations from a commission that he tasked with finding long-term solutions to protect his state from future weather calamities.
Two commissions on disaster preparedness and response have already offered their recommendations to the governor, who is expected to announce several proposals during his "state of the state" address on Wednesday.
Bowman's idea is not new: Similar barriers already exist in Stamford, Connecticut, and Providence, Rhode Island, and massive barriers are already in operation in the Netherlands and Russia.
With the rising sea levels -- a result of the shrinking polar ice cap -- experts including Bowman say the risk of massive flooding events is increasing each year -- and not just in low-lying communities like New Orleans.
"We have to start planning," Bowman said. "It's no longer every person for themselves. There's too much at risk. We have to do it."
The polar problem
Over the past 20 years, the global sea level has risen more than two inches as a result of Greenland's shrinking ice masses, according to Dr. Kevin Tremberth with the National Center for Atmospheric Research. That's because warmer temperatures are melting the polar ice caps.
Recent satellite images from NASA showed unprecedented surface ice melt, with about 97% of Greenland's ice sheet showing signs of thawing.
These changes in the polar region are closely monitored by climate scientists, like Daniel Steinhage, whose team surveyed Greenland's shrinking ice with Polar 6 one of the most advanced research aircraft in the world. It will take months to evaluate the data gathered by the aircraft, including ice samples thousands of years old taken from deep within the ice sheet.
The Arctic is something like an archive of the Earth's climate and within its layers, researchers can find information on temperatures, the amount of precipitation, dust particles and ash from volcanic eruptions dating back 100,000 years.
"If we can explain the past, what happened there, then we can use the same programs to run them forward to see what the future will bring us," said Steinhage of Germany's Alfred Wegener Institute.
Long before the official lab analysis, scientist Sepp Kippstuhl can identify some unique patterns even with his naked eye.
What he and the other scientists are seeing is that Greenland's ice sheet is vanishing quickly -- a fact confirmed by the 2012 NOAA Arctic Report Card.
What's not entirely clear is how quickly, how often, and why temperatures changed in the past, something that these scientists are studying to better understand how our climate is evolving today.
For now, one thing is clear: Melting ice and rising sea levels increase the potential of a damaging storm surge.
"We expect several more feet in the next century," said climate scientist Adam Sobel. "So if you start with higher water ... the storm surge will be added on top of that. And so, we'll get a higher flood."
Who's going to pay?
Superstorm Sandy brought a record-breaking 15-foot storm surge to New York Harbor (the storm surge is the level of water generated by a storm that's above the normal high tide). As Sandy approached New York, one buoy in the harbor measured a 32.5-foot wave -- nearly seven feet taller than the highest wave churned up by Hurricane Irene in 2011.
The enormous amount of water combined with the storm's powerful winds washed out the low-lying beachside neighborhood of Breezy Point, New York. The flooding is believed to have sparked a fire that burned down more than 100 homes.
Bowman said all of that devastation could have been avoided.
He said 30-foot-high sand dunes would have been enough to keep Breezy Point dry.
Projects such as that are expensive to build -- but sometimes the cost isn't the only hurdle standing in the way.
Some oceanfront residents in New Jersey have stymied a federally funded effort to build storm-protecting dunes -- even after witnessing the devastation from Sandy and Irene.
It comes down to a property rights issue: Homeowners must cede part of their land to the government through easements, where the dunes will be built. Some homeowners want the government to compensate them for land; others just don't want to allow the government to control the property.
"If we did sign it, we give up our land," Long Beach Island, New Jersey, resident Dorothy Jedziniak told National Public Radio. "Assignment means that your local politicians could assign a walkway, toilets, whatever."
Bowman believes the cost is too high for residents living near the coast not to act.
"People who lived here are paying for it in terms of human misery," he said. "But if you talk about paying for it in terms of rebuilding and the dollars, where are the dollars going to come from? And are the people of the Midwest going want to pay for protecting these privileged few people who are lucky enough to live on the ocean's edge? I don't think so."
CNN's Tricia Escobedo wrote this story based on reporting from CNN Correspondents Ed Lavandera, John Zarrella, David Mattingly, Jason Carroll, and Frederick Pleitgen.