For most people, going into outer space would be enough of a claim to fame — but the way astronaut Rusty Schweickart sees it, saving the world from killer asteroids is far more significant.

"Apollo and Skylab were great experiences for me personally, but my NEO [near-Earth object] work may really save many, many lives ... ultimately," the 77-year-old Schweickart, who flew on Apollo 9 in 1969 and served as backup Skylab commander, said during a NEOShield Tweetup this month.

Schweickart and four other astronauts on Friday urged the international community to put two missions high up on the agenda for space spending: a deep-space infrared telescope to detect near-Earth asteroids, and an asteroid-deflecting probe that could set the stage for a planetary defense system.

The Sentinel Space Telescope, a project backed by the nonprofit B612 Foundation, may be among the best candidates for the deep-space spotter. The foundation says the Sentinel could be launched five years after the go-ahead is given — but that depends on raising enough money to cover the estimated $400 million price tag.

Meanwhile, the other mission would shoot a high-tech cannonball at an asteroid to find out what it would take to divert a threatening space rock. NASA's Deep Impact mission tried something like this on a small scale in 2005, and an international consortium is proposing a larger-scale smash-up for a mission called Asteroid Impact and Deflection Assessment, or AIDA. The two-part AIDA probe could be sent to the asteroid Didymos and its companion in 2022, at an estimated cost of $344 million.



An alternative approach would be to put up a "gravity tractor" — a spacecraft that would use gravitational pull to change the course of a potentially deadly asteroid.

Heightened awareness

The astronauts' call to action came during a panel discussion at the American Museum of Natural History in New York. Joining Schweickart on stage were former NASA astronauts Tom Jones and Ed Lu, plus Japan's Soichi Noguchi and Romania's Dumitru-Dorin Prunariu. Hayden Planetarium director Neil deGrasse Tyson moderated the event.

Their timing couldn't have been better: This week, a committee of the U.N. General Assembly considered an international plan to deal with potential asteroid threats, and last week, a worldwide hubbub erupted over a potentially threatening space rock known as 2013 TV135.

That particular asteroid is "nothing to lose sleep over," said Jones, who chairs the Association of Space Explorers' Committee on Near-Earth Objects. Earth's risk of collision with 2013 TV135 in the year 2032 is almost certain to shrink to zero as more observations come in. But someday, humanity will have to figure out how to deflect a killer asteroid — or go the way of the dinosaurs.

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Schweickart told NBC News that February's spectacular meteor blast over Russia has heightened awareness about the asteroid threat. But he thinks the world might need an even louder wakeup call. "My guess is that we'll probably get hit once or twice before there's enough of an incentive for people to say we've got to do something ... and take a risk to eliminate this threat for everybody," he said.

The U.N. has a plan

That's where the U.N. plan comes in: Experts have proposed setting up an International Asteroid Warning Network, plus a network for coordinating asteroid-related missions by the world's space agencies. The United Nations and its Committee on the Peaceful Uses of Outer Space would be available to help sort out any political and diplomatic issues associated with diverting an asteroid, a la Bruce Willis in "Armageddon."

"It is, in some ways, not much ... in that what we now have is a 'skeleton' for international decision making on the impact threat," Schweickart said in an email. "But it is now the whole world that has agreed to this! The next step will be to begin putting the nerves and muscle onto that skeleton. Hopefully, in the end, we’ll be ready when a serious impact threat emerges."

Will that be a bigger story than the Apollo moonshots or the International Space Station? It'd rank right up there, said Ed Lu, a former space station astronaut and Google executive who is now CEO of the B612 Foundation.

"My work on preventing asteroid impacts clearly has the potential to be the most important work I've ever done (either as a scientist, as a NASA astronaut, or at Google)," Lu told NBC News in an email. "A friend and former colleague from Google told me that I am likely the only Googler who left because Google wasn't doing something big enough! When it comes to building and flying the B612 Sentinel Mission, I think the question becomes, how can we not do this?"

Jones, a veteran space shuttle astronaut, said the stakes are at least as high as they were for the Apollo era.

"Apollo was very important for the Cold War," he told NBC News. "But in the 21st century, I think using robotic technology and human spaceflight as tools to address this will be paramount for our survival as a species."



Update for 2 p.m. ET Oct. 25: During Friday's discussion, Jones laid out the Association of Space Explorers' five-point plan for planetary defense against asteroids:

U.N. delegations brief policy makers on the hazards posed by near-Earth objects, and on the latest U.N. actions.

Policy makers address asteroid impacts in their disaster planning and budgets.

Governments each assign a responsible lead agency to plan for asteroid impact response. (Three years ago, White House science adviser John Holdren said NASA has the lead role for the U.S. government.)

Governments contribute funds to support launch of a space-based asteroid search telescope by 2020.

Policy makers direct an international asteroid deflection demonstration mission, to launch by 2023.



On that fourth point, we've already mentioned the Sentinel space telescope, but that's not the only option on the table. NASA is already reactivating its Wide-field Infrared Survey Explorer from hibernation for an extended asteroid survey mission known as NEOWISE. That could open the way for a proposed mission called NEOCam, which would launch an infrared space telescope to hunt for near-Earth objects.

"We are working on space-qualifying our arrays now and plan to propose to the next Discovery opportunity," the Jet Propulsion Laboratory's Amy Mainzer, principal investigator for NEOWISE and NEOCam, told NBC News in an email. "We also continue to hone our asteroid-hunting skills with NEOWISE, which is cooling down now."

NEOCam's specifications are similar to Sentinel's, but Bad Astronomy's Phil Plait says that their missions are complementary. "The best thing to happen would be for both missions to be locked, loaded and looking for potentially hazardous rocks, " Plait wrote last year.

Update for 3:20 p.m. ET Oct. 30: I have fine-tuned the references to the U.N. action plan to reflect its status more precisely.

More about asteroids:

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding +Alan Boyle to your Google+ circles. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.