Spaceship Earth just took two celestial shots across its bow as, first, a meteor struck Russia, showering the Chelyabinsk region with fragments and reportedly injuring several hundred people, and second, as Asteroid 2012 DA14 whizzed past on 15 February. Traditionally, a torpedo across the bow is fired as a warning to change one's behavior – and this coincidence of events should be a warning to humanity that meteors are not always as benign as "shooting stars" and that the next asteroid might not miss! Will we, the crew of SS Earth heed this warning?

We can look at asteroid 2012 DA14 (or DA14 for short), which will have missed the Earth by a mere 17,000 miles, in two ways. DA14 can be seen as one of about 10,000 near-Earth asteroids that have been discovered in the past 15 years that pass close to our planet, threatening an impact. However, since we have seen these asteroids and are currently tracking them, we can predict any upcoming impacts. Happily, none of those we've found to date pose any substantial threat of impact.

Nevertheless, the Earth is hit by one of these relatively small DA14-sized asteroids about once every 300 years, on average. And "small" is far, far from insignificant. The DA14-like asteroid that hit Earth in 1908 did so in a remote region of Siberia, where the explosion (the equivalent of about 250 Hiroshima nuclear bombs going off at one time) destroyed over 800 square miles of the countryside. This disaster zone, superimposed on any city in the world, would have wiped it and all its residents from the face of the Earth. I refer you, as a graphic reminder of the power of such explosions, to the post-facto Hiroshima bomb pictures readily found online.

The second way to view DA14 is to realize that, until just about a year ago, it was one of about 1 million similarly sized, near-Earth asteroids, which we know are out there, statistically, but that we haven't yet seen. Consequently, until we find them in our telescopes, we are like sitting ducks in a shooting gallery with nothing more than luck to prevent a disaster. Regrettably, the Earth-based telescopes we've been using to discover and track these objects have, practically speaking, reached their limitations for finding the vast majority of these cosmic torpedoes.

Why do we care about finding them if there's nothing we can do about it? Because, unknown to most people, is that if we have adequate early warning, our current space technology is sufficiently advanced to deflect these asteroids. For smaller impacts, even a last-minute warning of several days could enable a local evacuation and save many lives.

Deflection, however, will generally require several decades of warning. Fortunately, due to the relatively pure nature of space dynamics, forecasting an asteroid impact 100 years in advance is possible once its orbit is well known. The sine qua non, therefore, is finding them.

Over the past 15 years, NASA has, thankfully, discovered over 95% of the largest asteroids that cross the Earth's orbit and that would have planet-wide consequences on impact. Unfortunately, due to the limitations of the telescopes, we have discovered less than 1% of their smaller DA14-like cousins "only" capable of wiping out a metropolitan area; 99% of the job remains to be done.

There is good reason for hope, however. Several high-level expert groups over the past five years have recommended placing an infra-red space telescope into a Venus-like orbit around the sun, in order to discover the bulk of Earth-threatening smaller asteroids. Such a telescope would look outward at the Earth's orbit as it circled the sun every 230 days or so, detecting and tracking, in its 6.5 years of operation, the missing 99% of potentially Earth-impacting asteroids.

The B612 Foundation (named for the asteroid home of the "Little Prince" in Antoine de Saint Exupéry's classic child's story), a US non-profit organization of former astronauts, scientists, engineers and supporters, is mounting precisely such a mission. This Sentinel telescope is planned for launch in 2018, and in its first month of operation alone, it will discover more new near-Earth asteroids than the current programs have found in 15 years.

By the end of its planned lifetime, Sentinel will have discovered well over 90% of the asteroids that could destroy entire regions of Earth on impact (those larger than 350ft in diameter) and more than 50% of the currently unknown DA14-like near-Earth asteroids.

The B612 Foundation has undertaken this Sentinel project as a non-governmental initiative, somewhat akin to a growing number of private space ventures originated in the past few years. The foundation, however, is not undertaking this project for profit; we are a non-profit corporation. Our motivation is strictly to ensure the survival of life on Earth – all of it. And while NASA is cooperating with us by providing certain communication and analytic services, we are excited, as a private venture, to welcome the participation of all the crew of spaceship Earth in this great endeavor.

So, having taken a couple of torpedoes across our collective bow, we have a choice to make. Do we, as a crew, raise our awareness and accept responsibility for our voyage into the future? Or do we sit back as passengers, comfortably assuming that there must be a captain and crew doing this job on our behalf?

The B612 Sentinel mission is testament to our belief that we, together, are responsible for the future of life on our small planet; we invite you to join us in addressing this cosmic challenge.