According to scientists’ estimates, the huge asteroid Bennu has between 1 and 2,700 chances of hitting Earth sometime in the 22nd century. Due to its dangerousness, NASA has already launched a plan to try to deflect the asteroid, if it gets too close to our planet, something of which, as we see, we are not certain from the calculations. It is possible that when the calculations are revised in the future, there is no longer the slightest risk, but better safe than sorry.
What the scientists have proposed is to send a ship called HAMMER ( Hypervelocity Asteroid Mitigation Mission for Emergency Response ) and make it act as a ram to deflect Bennu or, if necessary, destroy him into a thousand pieces with a bomb. nuclear. The two possibilities are on the table .
Bennu would strike with the force of 1,200 megatons of kinetic energy (around 80,000 Hiroshima bombs) and the possible impact date calculated by the researchers is September 25, 2135, a not too distant date, hence the experts expose our emergency options.
“The possibility of an impact seems slim right now, but the consequences would be dire,” says one of the national planetary defense teams, Kirsten Howley of the Lawrence Livermore National Laboratory (USA). “ This study aims to help us shorten the response timeline when we see a clear and present danger so that we have more options to divert it. The ultimate goal is to be ready to protect life on Earth.”
The HAMMER design
The HAMMER spacecraft (at the moment only one concept) would weigh about 8,000 kilograms and would have a height of 9 meters. The asteroid Bennu, by comparison, is about 492 meters wide, and weighs about 79 billion kilograms, about 1,660 times heavier than the famous ocean liner Titanic.
HAMMER would be sent to Bennu aboard a Delta IV Heavy, the second largest launch rocket in the world, behind the SpaceX Falcon Heavy. The moment to put the plan into action is crucial, as a launch too early will make it difficult to predict what the asteroid will do; and launching too late will make the gigantic rock much more difficult to move from its orbit.
NASA has not yet received authorization to build the spacecraft but it will likely never receive it, as it is an incredibly expensive project.
As we can imagine, there are many variables in this scenario, and even more so considering that there are more than 100 years to go. Fortunately, Bennu passes close to Earth every six years, so we can closely observe what it is doing (thanks to the OSIRIS-REx mission) and the route it is taking and gather more information about it.
So far NASA has detected more than 10,000 near-Earth objects, and around 2,500 are estimated to be the same size as Bennu . Hence the importance of forecasting and having an action plan.
If something of that size were to hit us, experts predict that it would not annihilate humanity as we know it. An asteroid would need to be at least 1 kilometer wide to cause a mass extinction event, as did the dinosaurs.
Of course, a collision with an object of any considerable size would be catastrophic for at least part of the planet, so vigilance is key.
Referencia: Options and uncertainties in planetary defense: Mission planning and vehicle design for flexible response. Brent W.Barbee, Megan Bruck Syal, David Dearborn, Galen Gisler, Kevin Greenaugh, et al. Acta Astronautica 2017. DOI: https://doi.org/10.1016/j.actaastro.2017.10.021
