Imagine an attack by a swarm of armed micromachines ... or a bioweapon small enough to fit in a suitcase and deadly enough to destroy the human race.

It's the stuff of Hollywood storylines, but to the U.S. government such plots are potentially very real and very dangerous. So the government has turned to an unlikely source for help in identifying these threats: science-fiction writers.

Sci-fi writers were envisioning nightmarish scenarios like these well before the technology emerged to make them possible. Now the government is hoping their imagination will help protect against whatever may come next.

Some leading science-fiction writers and computer designers have formed SIGMA, the creation of prolific author Arlan Andrews, and they're offering their time — and minds — free of charge. Their only incentive is keeping America safe.

Since the end of the Cold War, “any given spot is in more danger than before,” said Andrews, who was a White House Science fellow under George H. W. Bush. “More than 200,000 Americans are putting their lives at risk. If we were too afraid to accept responsibility for our ideas, we would be too wimpy and not American.”

I recently had the opportunity to sit in on a Department of Homeland Security meeting with SIGMA in Los Angeles.

Click here to see SIGMA members speak about their work.

SIGMA — it takes its name from the Greek letter used as a summation symbol in mathematics — is similar in concept to the JASON group, a team of physicists, biologists and chemists that has advised the country since World War II.

Originally a group of 10, SIGMA has swelled to include 35 members. Most have Ph.D.s and all are popular writers and designers in their own right.

These sci-fi writers are particularly adept at envisioning new technologies and planning against “disruptive technology,” according to Andrews. He said he would pit his group “against any other in the world.”

Those in the know in government clearly agree, since SIGMA members have long consulted with agencies like the Homeland Security and Defense Departments, DARPA, Sandia Labs, NASA and the CIA. Some current members are employed by NASA and the Navy; one is a director at Los Alamos National Laboratory.

So just what have these guys been thinking up?

Andrews recently proposed “intelligent bullets” that could correct their own course and loiter in the air before landing. Designed to suit current weapons, these bullets could contain explosives or even video equipment and be useful in urban operations. Instead of relying on distant video feeds from unmanned aerial vehicles, soldiers could fire short bursts into the air that would transmit decrypted, de-spun video straight to their goggles.

To help shore up border security in an emergency, one SIGMA member suggested a plan for C130 planes to fire pointed telephone poles, equipped with sensors and hooked up electronically, into the ground every half mile.

Another idea they developed to help patrol large borders was to disperse millions of tiny sensors the size of maple seeds with half-inch-long transmitters. The sensors would then transmit to a tower if people passed by.

SIGMA has also considered how to mitigate and prevent damage caused by natural disasters. Greg Bear, writer of bestsellers such as “Quantico,” has been looking at how to prevent plant pathogens from wiping out crops in Florida.

They also floated a plan to defuse the devastating power of hurricanes by spraying aerosolized dry ice into a storm to cool it down. To alert authorities to escalating water levels, members proposed designing dikes with sensors that could rapidly feed back data and hasten emergency response.

There are even plans to create a virtual world that could test current security planning in computer models of major cities — like a "Second Life" or "World of Warcraft" for terror activity. Designed using supercomputers, these virtual cities and countries would match the real ones in incredible detail.

Once inside those computer-constructed cities, SIGMA would operate as a "red team," whose job would be to work like terrorists and move around a virtual Baghdad, Fallujah or even New York, launching attacks in order to test the consequences.

That could be invaluable, as sci-fi writers have been notably prescient in envisioning unorthodox technologies. Sci-fi writers anticipated critical military advances like stealth technology, artificial intelligence, communications satellites and the laser, Andrews said.

So even as real terrorists are exploiting Second Life and other virtual-world games for recruitment, planning and financing, SIGMA is turning the tables to give the United States a home court advantage in the fight for the future.

Ballet dancer turned defense specialist Allison Barrie has traveled around the world covering the military, terrorism, weapons advancements and life on the front line. You can reach her at wargames@foxnews.com or follow her on Twitter @Allison_Barrie.