When it comes to avoiding an asteroid-affected apocalypse, we get all the help we can, and NASA’s recently launched next-generation asteroid impact tracking system helps us sleep a little easier in our bed.
A new system, called Sentry-II, can take data collected from telescopes and develop the asteroid’s trajectory in the next century. The updated system is particularly good at predicting special and unusual situations that are not covered by the original Sentry system.
In other words, if an asteroid can hit, we can get a huge amount of warning about it in advance – or at least that’s a theory. While there are always uncertainties in predictions, our advanced warning settings are now more complex than ever.
“The first version of Sentry was a very capable system that worked for almost 20 years,” said automation engineer Javier Roa Vicens, who now led the development of Sentry-II at SpaceX’s Starlink, NASA’s Jet Propulsion Laboratory (JPL). .
“It was based on very clever math. In less than an hour, you could confidently get the probability of a newly discovered asteroid impacting over the next 100 years – a remarkable achievement.”
Each time a new asteroid (NEA) is detected close to Earth, astronomers work to determine its most likely orbit around the Sun based on its location and velocity, as well as the gravitational effects of other objects in the Solar System. These orbits are intelligently calculated and generally believable, but do not include every small effect.
One such example is called the Yarkovsky effect: a small force, but can vary large enough over time.
When these special cases occur – as in the case of the Apophis and Bennu asteroids – many additional, time-consuming manual calculations are required to make predictions. Sentry II now includes this important detail in its calculations.
Another difference is how the two programs determine the probability of a random encounter with our planet. Crossing roads is one thing – crossing while we are on the road is another.
First, Sentry examines points at equal distances across the uncertainty zone and then analyzes each one in depth based on known trajectory assumptions, while Sentry-II uses thousands of random points across the uncertainty zone without any assumptions about them. are more likely to hit than others.
While astrophysics is very complex, this means that Sentry-II has less idea of which points in the asteroid’s potential orbit it could pass through – it covers the most important scenarios that Sentry could miss. Researchers liken this to looking for a needle in a haystack, and the Sentry-II is able to reduce the size of the hay.
“In terms of numbers, the specific cases we find were a very small fraction of all the NEAs we considered likely to be affected,” says Roa Vicens.
“But as we move into NASA’s planned NEO Surveyor Mission and the Vera C. Rubin Observatory in Chile online, we’ll find more of these special cases, so we need to be prepared.”
Even without the new and more powerful space surveillance equipment mentioned by Vicens, we detect about 3,000 NEAs each year, for a total of 28,000. These are too many asteroids to move and track.
Another improvement in the new system is the best way to track asteroids that pass very close to Earth. The gravitational pull of our planet can lead to a lot of uncertainty in terms of asteroid trajectories, but the Sentry-II is better adapted to this gravitational factor.
What would happen if we were on a collision course with an asteroid – which is another event – could involve distracting the asteroid or shattering it – but with Sentry-II, we know that the NEA could be hit need Even if the land is as low as a few chances at 10 million.
Steve Chesley, a senior researcher and astrodynamicist from JPL, said: “Sentry-II is a remarkable breakthrough in finding the small impact probability for so many scenarios.”
“If the consequences of a future asteroid impact are too great, it will pay to find even the slightest shock risk hidden in the data.”
A study describing the capabilities of Sentry-II has been published Journal of Astronomy. You can also see the data collected by Sentry and Sentry-II here.