Astronaut Soichi Noguchi joined some of his predecessors in New York City to ask world governments to prepare to protect humanity from asteroids on a collision course with Earth.

Three former U.S. astronauts and one from Romania on Friday appeared along with Noguchi on behalf of the Association of Space Explorers, a professional organization for crew on space flights.

“The very first step is to find where those objects are and track (them),” Noguchi said at a news conference at the American Natural History Museum.

To that end, the five astronauts said governments around the globe should help fund the launch of a space-based telescope by 2020 and start a mission to test asteroid deflection capabilities within ten years. Only 1 percent of potentially dangerous asteroids have been detected by ground-based telescopes, they said.

They also emphasized the need to include asteroids in national disaster plans and budgets, and to designate each country’s national agency in charge of responding to asteroid threats. Once spotted, a potentially devastating asteroid could be pushed off a collision course by a spacecraft.

Their proposed defense system could prevent an asteroid of up to 400 meters in diameter from striking the earth. For an even larger one, multiple rockets could be used to fragment it.

An asteroid over 150 meters in diameter falling into the sea would likely cause a tsunami, the astronauts warned. The meteor that exploded in February over Chelyabinsk, Russia, injuring around 1,200 people, measured only around 17 meters wide.

“It’s the culmination of all of our space knowledge,” former NASA astronaut Edward Lu said of the process of detecting asteroids, calculating their paths decades in advance and sending a craft to bump them off track.

The event was held the same week that a U.N. General Assembly committee reached “broad agreement” on the peaceful uses of outer space, including the threat of near-Earth objects such as asteroids.