Asteroid Watch- page 1 | Space | Air & Space Magazine
Fifty thousand years ago, the mile-wide Meteor Crater was formed when a meteorite 150 feet across smacked into Arizona. Is another like it headed our way? (

Asteroid Watch

A team of NASA alums is building a spacecraft to protect Earth - and you can help.

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Forty minutes east of Flagstaff, Arizona, just south of I-40, the desert plain gives no hint of what lies ahead. Then the sudden break in topography comes into focus: a weathered plateau, where 50,000 years ago a nickel-iron meteorite half the size of a football field slammed into the ground at 26,000 mph. The meteorite blasted a crater as deep as the Washington Monument is tall—550 feet—and three-quarters of a mile across, with the force of more than 20 megatons of TNT. Hurricane-force winds ripped across the plain for 20 miles in all directions.

This is the kind of event that Ed Lu thinks about often. A retired NASA astronaut who spent six months aboard the International Space Station in 2003, Lu is the co-founder and CEO of the B612 Foundation, named for the asteroid in Antoine de Saint-Exupéry’s 1943 story, The Little Prince. The non-profit foundation is now focused on an extraordinary mission: raising about $400 million in private philanthropy to build, launch, and operate an infrared space telescope for finding Earth-threatening asteroids. (Asteroids are rocky objects, smaller than planets, orbiting the sun; meteorites are asteroids that have survived passing through the Earth’s atmosphere and hit the ground.) The mission, expected to launch late in 2017 or early 2018, is called Sentinel.

“If you really sit here and think about what is the most important thing I could be doing, I think this is it,” says Lu, who left NASA in 2007 and joined Google to lead teams that developed imaging technology for products like Google Earth. In addition to leading the foundation, he also works as chief of innovative applications for Liquid Robotics, an ocean data services company in Silicon Valley.

“It’s not that this is something that ...we need to mobilize everybody for. You don’t,” Lu says. “We are talking about building the wing of an art museum.” That analogy is something the leadership at B612 uses often.

No one at the foundation underestimates the challenge of raising close to half a billion dollars. But Lu seized on the idea after giving a talk in 2011 at Google about how humans might be able to deflect an asteroid on a collision course with Earth—B612’s focus for more than a decade. Plans to protect the planet, however, are useful only if scientists know where those asteroids are and where they’re headed. Lu argued that this kind of large-scale identification and tracking required a space telescope dedicated to searching for asteroids whose orbits approach Earth, known as Near Earth Objects, or NEOs.

“One of the guys there raised his hand and said, ‘Why don’t you just do that?’ ” Lu recalls. He gave what he thought was the obvious answer: money, as much as a few hundred million dollars. The attendee replied that he’d just donated to the Museum of Modern Art in San Francisco, which was then raising around $400 million to build a new wing, and that no one involved in that project seemed to think this level of fundraising was an insurmountable task.

Lu consulted with people experienced in philanthropic capital campaigns—from museum executives to university administrators to the people who raised funds for the Keck telescopes in Hawaii—and it put the task of raising money for a space telescope in perspective.

“I think we can convince some tiny fraction of the populace, a tiny fraction, that this is something worth supporting,” Lu says. “Can we raise as much as the citizens of San Francisco [are raising] to build a wing of an art museum? I think we can.”

The plan is to put Sentinel in an orbit near that of Venus for its six-and-a-half-year mission. From there, the telescope can scan for NEOs, looking out toward Earth and beyond, focusing on a range roughly between 0.7 and 1.3 astronomical units (1 AU is the distance between Earth and the sun, about 93 million miles). In a 2007 report, NASA wrote: “Observatories located in a Venus-like orbit are the most efficient at finding NEOs inside Earth’s orbit, a population which has the most uncertainty yet still poses a hazard due to gravitational orbit perturbations [deviations in orbit].” Gareth Williams, associate director at the Minor Planet Center at the Smithsonian Astrophysical Observatory in Massachusetts, a clearinghouse for asteroid discoveries, says that there are an estimated 14,000 NEOs larger than 460 feet. An asteroid this size could hit the planet with the force of more than 27,000 Hiroshima-class bombs, and only a third of them have been found and tracked. When it comes to a smaller but still dangerous category of NEOs—those larger than 100 feet—there could be more than 300,000 orbiting nearby, and only about one percent have been tracked. It was something from this smaller-size group that scientists believe exploded above Tunguska, Siberia, in 1908 with the force of about 1,000 Hiroshima-class bombs.

Sentinel’s goal, to identify 90 percent of NEOs larger than 460 feet in diameter, comes from the 2005 NASA Authorization Act, in which Congress ordered the agency to expand its survey, which was then focused on NEOs one kilometer (0.6 mile) and larger—the size that could cause global extinction. NASA balked, issuing that 2007 report that evaluated expansions to the program, including a dedicated infrared space telescope to find the smaller asteroids. The agency concluded that Congress had not approved enough funds to expand the program.

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