CAPE CANAVERAL, Florida (AP) -- Imagine last year's tsunami, last month's earthquake in Pakistan, and Hurricanes Katrina, Rita and Wilma all rolled into one -- and then some. If nations can't handle those calamities, what's going to happen when an asteroid collides with Earth?In 30 years, there is a 1-in-5,500 chance that a smallish asteroid will land a bull's eye on our planet. At 360 yards wide, it could take out New York City and much of the surrounding area.Fortunately, experts believe further observations of the asteroid, 99942 Apophis, will almost certainly rule out an impact in 2036. Nevertheless, it's precisely that kind of predictable and preventable threat -- and the thought of being ill-prepared for it -- that alarms the world's normally intrepid spacefarers who are calling for action.They issued an open letter at the Association of Space Explorers' annual congress last month in Salt Lake City, making a rare, united push for strategies and spacecraft to prevent a cosmic pileup.Two of the astronauts -- Apollo 9's Rusty Schweickart and shuttle and space station veteran Ed Lu -- have even helped establish a foundation to spotlight the issue."There are always natural disasters and it always seems as though the preparation is somewhat less than adequate. But we have had a series of quite substantial ones here in the last year," Schweickart said in an interview with The Associated Press.Hollywood's depiction of cosmic collisions -- think "Armageddon" and "Deep Impact" -- has heightened public awareness, "but regrettably with the wrong solutions and overdramatization," Schweickart said."You don't want to send up Bruce Willis and others to save us. That's Hollywood silliness," he said, chuckling. Instead, technology is far enough along that an asteroid could be deflected before hitting Earth, he said.For now, the astronauts are being cautious -- some say too cautious -- in their approach."A lot of the folks working in this area are really attuned to not being Chicken Little, saying, 'Hey, this is going to kill us, it's going to kill us,' " Lu said. "That's not what we're saying. We're saying that you need to start thinking about it ahead of time because afterward is way too late."The possible consequences are way worse than your run-of-the-mill natural disasters like earthquakes and tsunamis and hurricanes. As bad as they may be, this can dwarf them."Astronauts know better than most just how small and fragile and vulnerable the planet is."When you go around it in an hour and a half, again and again and again and again, day after day, in some cases now, month after month after month, the Earth becomes a pretty small place," Schweickart said. "And then, of course ... most astronauts tend to be aware of things like asteroids and their impacts. I mean, we romped around the moon after spending years in preparation by looking at every impact crater and volcano here on the Earth."It's time, the space explorers say, for NASA to step up to the plate.The association wants NASA to expand its Spaceguard Survey, a program that discovers and tracks near-Earth objects -- asteroids and comets -- that are at least two-thirds of a mile across. So far, 807 of an estimated 1,100 of these big rocky asteroids have been discovered in the inner solar system along with 57 comets; California's Jet Propulsion Laboratory is plotting their future tracks.An asteroid two-thirds of a mile wide, at impact, would be enough to easily take out a good-sized European country. By comparison, an asteroid or comet believed to be six to seven miles across wiped out the dinosaurs 65 million years ago. Former astronaut Rusty Schweickart holds a 3-D model of an asteroid near a spot on the globe where it could hit the Earth.The space explorers want the many smaller, but still dangerous asteroids tracked as well. Altogether, 3,611 near-Earth asteroids of all sizes have been discovered, with an estimated 100,000 more capable of setting off a tsunami the size of the one that shook the Indian Ocean last December.Scientists are carefully watching Apophis, which will whiz by Earth in 2029, passing within an unnerving 18,640 miles. That's a few thousand miles closer than many communications satellites and 220,000 miles closer than the moon. In 2036, the concern is that it will move in even closer, leading to the 1-in-5,500 chance it will strike.For a few hundred million dollars, the astronauts say, NASA could launch a scouting mission to Apophis in the next decade or two to place a radio transponder on the surface and thereby plot its course. But Donald Yeomans, manager of NASA's near-Earth object program, contends that mostly likely, radar and telescope observations will ultimately rule out any risk of impact.Schweickart agrees that based on the current odds, a deflection mission for Apophis would be a waste of money. "But the question is, do I agree with it when it's 1-in-100, when it's 1-in-50, if it's 1-in-20. That is a policy question. At what probability do you begin to spend hundreds of millions or billions of dollars in order to do something?"That's not the only sticky policy question.Are some places on the planet more dispensable than others? The point of impact, for instance, could be inadvertently shifted from one part of the world to another by an intervening spacecraft, jeopardizing one country instead of another. Who's liable if an asteroid-deflecting mission goes awry? Indeed, who decides if such a mission is needed and how far in advance should that decision be made?Nuclear electric propulsion would be ideal for quickly getting spacecraft to potential killer asteroids and nudging them out of Earth's way, the astronauts say. But the technology for such an "asteroid tugboat" is on hold, a recent casualty of budget cuts.Rep. John Culberson, R-Texas, is sympathetic to the astronauts' concerns and has asked NASA to see what might be needed to protect Earth from asteroid impacts.Nuclear-powered spacecraft could either land on the asteroid and apply a small but continuous force over months in order to alter its Earth-smashing course, or hover above the asteroid and use its gravity to push it aside. Forget about any sensational last-minute asteroid crackups, "Armageddon" style; the pieces could wind up on a collision course with Earth.Schweickart and Lu's B612 Foundation -- named after the home asteroid of the Earth-visiting prince in Antoine de Saint-Exupery's "Le Petit Prince" -- is pushing for an orbit-altering demonstration by 2015 on a harmless, way-out-of-the-way asteroid.The European Space Agency also is proposing a practice mission called Don Quixote to alter an asteroid's course, but it's yet to be formally approved. NASA's Deep Impact spacecraft smashed into a comet for scientific reasons in July; by design, it barely altered the comet's path."We're sitting in a shooting gallery, with hundreds of thousands of these things whizzing around in the inner solar system. So it's just a matter of time," said Schweickart, board chairman of the B612 Foundation.Fortunately, the technology to protect us is ready for the task, he said, and that's "the beauty of it."Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.