‘Earth not prepared for surprise asteroid strike’
While the possibility of a catastrophic asteroid slamming into Earth is extremely rare, it may only be a matter of time before this threat becomes a reality.
But experts have warned that humans are not prepared for an asteroid impact, and should one head for Earth, there are not much we can do about it.
A United States Aeronautic Space Agency (NASA) scientist has said that our best hope is building an interceptor rocket to keep in storage that could be used in deflection missions.
NASA is planning an ambitious mission that will see a robotic spaceship visit an asteroid to create an orbiting base for astronauts.
The robot ship will pluck a large boulder off the space rock and sling it around the moon, becoming a destination to prepare for future human missions to Mars.
NASA plans to study the asteroid for about a year and test deflection techniques that one-day may be necessary to save Earth from a potentially catastrophic collision.
Dr. Joseph Nuth, a researcher at NASA’s Goddard Space Flight Centre in Maryland was speaking at the annual meeting of the American Geophysical Union earlier this week.
He said: “The biggest problem, basically, is there’s not a hell of a lot we can do about it at the moment.”
While dangerous asteroids and comets rarely hit Earth, Nuth warned that the threat was always there.
He said: “They are the extinction-level events, things like dinosaur killers, they’re 50 to 60 million years apart, essentially. You could say, of course, we’re due, but it’s a random course at that point.”
In the past, comets have come very close to hitting Earth.
In 1996, a comet narrowly missed our planet, instead flying into Jupiter, and again in 2014, a comet passed “within cosmic spitting distance of Mars,” according to Nuth. And comets are often only discovered when it’s too late to launch a deflection mission.
Nuth said: “If you look at the schedule for high-reliability spacecraft and launching them, it takes five years to launch a spacecraft. We had 22 months of total warning.”
Nuth advises that NASA should build an interceptor rocket alongside an observer spacecraft, which he says could cut the five-year delay to launch in half.
And if a rocket could be devised that could launch within a year, Nuth says it ‘could mitigate the possibility of a sneaky asteroid coming in from a place that’s hard to observe, like from the sun.’
Various techniques for deflecting a potentially hazardous asteroid could be tested on Arm to enable planetary defense capabilities.
These techniques include Ion Beam Deflection, Enhanced Gravity Tractor, and kinetic impactors.
In Ion Beam Deflection, the plumes from the thrusters would be directed towards the asteroid to gently push on its surface over a wide area. A thruster firing in the opposite direction would be needed to keep the spacecraft at a constant distance from the asteroid.
The Ion Beam Deflection approach is independent of the size of the asteroid, and it could be demonstrated on either mission option. In the Enhanced Gravity Tractor approach, the spacecraft would first pick up a boulder from the asteroid’s surface as in mission Option B.
The spacecraft with the collected boulder would then orbit in a circular halo around the asteroid’s velocity vector.
The mass of the boulder coupled with the mass of the spacecraft would increase the gravitational attraction between the spacecraft and the asteroid.
By flying the spacecraft in close formation with the asteroid for several months the very small gravitational forces would produce a measurable change in the asteroid’s trajectory. A kinetic impactor could also be launched as a secondary payload with the spacecraft or on a separate launch vehicle, and it would collide with the target asteroid at high velocity while the spacecraft observed the impact.