WASHINGTON (Reuters) - NASA called on backyard astronomers and other citizen-scientists on Tuesday to help track asteroids that could create havoc on Earth.

Tourists take pictures of a NASA sign at the Kennedy Space Center visitors complex in Cape Canaveral, Florida April 14, 2010. REUTERS/Carlos Barria

The U.S. space agency has already identified 95 percent of the potentially planet-killing NEOs - near Earth objects - with a diameter of .62 miles or more, a size comparable to the space rock many scientists believe wiped out the dinosaurs some 65 million years ago.

Now NASA wants to work with individuals, government agencies, international partners and academia to "find all asteroid threats to human populations and know what to do about them." More information is available onlinehere .

Between 50 and 100 amateur astronomers are doing what is called light-curve analysis on space rocks, making repeated images of the astronomical bodies to help determine their characteristics, said Jason Kessler, program executive for what NASA calls Astroid Grand Challenge.

“We’re certainly going to need more help with that as our detection rate goes up,” Kessler said by telephone. He acknowledged that what NASA aims to do, at least in part, is to crowd-source asteroid detection.

Even smaller space rocks can be dangerous, whether or not they hit the Earth. In February, a meteorite about 19 yards in diameter exploded over central Russia, shattering windows, damaging buildings and injuring 1,200 people.

Earlier this month, an asteroid the size of a small truck zoomed past the Earth four times closer than the moon, crossing within about 65,000 miles over the Southern Ocean south of Tasmania, Australia.

Estimates suggest less than 10 percent of NEOs smaller than 328 yards across have been detected, and less than 1 percent of objects smaller than 109 yards in diameter have been detected, NASA said in a statement.

The initiative aims to detect all NEOs of 33 yards or larger, Kessler said.

The space agency has also announced plans for a mission to capture a small asteroid, redirect it into a stable orbit and send humans to study it as early as 2021.

U.S. lawmakers have also become interested in NEO. In March the House of Representatives’ science committee held a hearing on “Threats from Space” that reviewed efforts to track and mitigate asteroids and meteors.