Earth resembled a cosmic shooting gallery this month after a meteor exploded over Russia. And then, a few hours later, an asteroid passed closer to Earth than most weather and communications satellites.
These two events, happening so close to each other, alerted people to the dangers posed by near-Earth objects such as asteroids, comets and other celestial debris lurking in outer space.
Several government agencies worldwide have programs to find and track these potential intruders.
This week, the Canadian Space Agency became the latest member of the international science community to join the effort, launching its NEOSSat spacecraft aboard an Indian PSLV-C20 rocket.
Also known as Canada’s Sentinel in the Sky, the experimental microsatellite is designed to detect and track near-Earth objects and space debris.
Other organizations also plan to keep an eye on these threatening space objects.
The B612 Foundation, a private organization comprised of notable scientists, including two former NASA astronauts, hopes to develop an early warning system to alert people to incoming danger.
Founded in 2001, the group originally focused on asteroid deflection research and advocacy. Later it realized that to protect humanity from a potentially destructive impact, an early warning system would be required. The group went to work developing technology to make that possible.
The group plans to design, build, test, insure and launch a privately-funded spacecraft called the Sentinel Infrared Space Telescope.
With its Sentinel spacecraft, the B612 foundation hopes to discover and catalog 90 percent of asteroids, larger than 140 meters, which pass through Earth’s region of the solar system.
The mission team also hopes to document a significant number of smaller asteroids, down to a diameter of 30 meters.
So what if an asteroid or comet is found to be on a collision course with our planet?
Former NASA astronaut, Russell “Rusty” Schweickart (Apollo 9), warns against trying to completely destroy such an object with a nuclear explosion.
Schweickart, one of the founders of the B612 foundation, favors a deflection technique, which would mean giving the space object a nudge to veer off of its projected collision path with Earth.
According to Schweickart, in order to deflect a space object, preventative efforts must start several years to a decade ahead of the projected impact with Earth.
This would be done in two stages. The first involves running the object off with an adequately sized spacecraft.
If you ran into the side of the object facing Earth, according to Schweickart, the object would slow down; hitting it from the opposite direction would speed it up. That step alone could prevent a possibly catastrophic impact with Earth.
But to ensure that object has been properly and safely nudged away from hitting Earth, a gravity tractor would need to follow, according to Schweickart.
A second spacecraft would pull up next to the object and hover either in front of it to speed it up, or behind it to slow it down. The mutual gravity between the hovering spacecraft and the space object, he says, will pull the object toward the gravity tractor very slightly, but enough to cause a precise change in its orbit, deflecting it away from Earth.
Schweickart believes high-powered nuclear devices should only be considered if the approaching object happens to be enormous, something that occurs once every several million years.
Rather than using the nukes to blow the asteroid-like object to smithereens, Schweickart says the devices should be detonated near it.
This, he says, would make the object extremely hot on one side, boiling off that side which will push it off in the opposite direction, deflecting it away from Earth.