(ORDO NEWS) — There’s an old joke that the dinosaurs only died out because they didn’t have a space agency.
The implication, of course, is that, unlike our Reptilian ancestors, we humans could have escaped an impending asteroid impact, given our six and a half decades of spaceflight experience.
But the fact is that although we have achieved amazing results since Sputnik launched the space age in 1957, very little effort has been put into developing asteroid deflection technologies so far.
We are extremely inexperienced in this area, and apart from Hollywood drama films, we have never tested our capabilities in practice. But that will change soon.
Wu Yanhua, deputy head of the China National Space Administration (CNSA), announced last week that they plan to conduct an asteroid deflection test as early as 2025, part of a larger asteroid monitoring and defense system that CNSA is developing in its early stages.
The monitoring system will consist of ground-based and space-based instruments used to catalog near-Earth objects that may pose a threat.
Monitoring systems are especially important because the sooner an approaching asteroid is caught, the easier it is to deflect it.
A distant asteroid may only need a slight change in direction to fly past Earth. The later an asteroid is seen, the more difficult it will be to change its course.
You can rest easy knowing that space agencies around the world have already built reliable asteroid monitoring systems and cataloged many thousands of solar system objects.
None of them pose a real threat over our lifetime (currently the riskiest object, known as 2010 RF12, has a 4.8 percent chance of hitting Earth in 2095.
This 7-meter asteroid will cause a fireball similar to the Chelyabinsk meteorite in 2013). However, there may be more that we haven’t seen yet, so the new CNSA monitoring project is a welcome addition.
When it comes to hunting for asteroids, the smallest objects are the hardest to see, but like the shooting stars that streak harmlessly through the sky every night of the year, they are unlikely to cause damage.
On the other hand, the largest asteroids are capable of causing an extinction-level event, but they are easy to spot and track.
In fact, medium-sized asteroids are the most dangerous – they are large enough to cause local damage, but small enough that we might not detect them in time.
Observing asteroids up close also helps us figure out how best to deflect them. NASA‘s OSIRIS-Rex mission, which recently visited the near-Earth asteroid Bennu, discovered that Bennu is a loose gravel pit of the asteroid. Such a target would require a different deflection technique than a uniform, solid piece of rock.
Given enough time and warning, potential options include a gravity tractor (gently pulling the asteroid by the mass of an orbiting spacecraft) or whitewashing the asteroid’s outer surface (changing the way the Sun heats and cools the asteroid, slowly affecting its orbit via the Yarkovsky effect).
The simplest solution, of course, is to just hit the asteroid hard.
The new CNSA monitoring program will be combined with engineering efforts to develop and build a high-thrust rocket capable of carrying a kinetic impactor: a payload designed to strike an asteroid with enough force to change its orbit. The target asteroid on which the impactor is planned to be tested has not yet been announced.
NASA and ESA are also taking the first steps towards developing kinetic asteroid defenses. NASA’s DART mission, launched last November, will attempt to change the orbit of Dimorphos, the tiny moon orbiting the asteroid Didymos, by crashing into the moon at high speed.
This is the first test of its kind, and the resulting trajectory change is likely to be very small. This is largely why DART is targeting the moon rather than a lone asteroid: it will be easier to measure tiny changes in Dimorphos’s orbit when the asteroid Didymos is nearby to take as a point of reference.
The DART mission will collide with Dimorphos this September and will be followed by the ESA Hera mission in 2027, which will observe the aftermath of the collision up close.
The existential threat of an asteroid impact is small in the short term, but almost certain in the (very) long term.
Therefore, asteroid monitoring systems and deflection testing, such as DART and the new CNSA impactor project, are important first steps in keeping the Earth safe and preventing us from following the path of the dinosaurs. Now, if only we could control climate change…
—
Online:
Contact us: [email protected]
Our Standards, Terms of Use: Standard Terms And Conditions.