This is NASA's plan if an asteroid is heading to Earth.

The following are  NASA's plan if an asteroid is heading to Earth

 Step 1:
A text message would be sent to a team of 12 scientists.

 Step 2:

The scientist immediately start tracing the asteroid's path

 Step 3:

 They measure the size of the object and predict the time of impact

 Step 4:
They confirm with authorities whether the impact is unavoidable.

 Step 5:
A public statement would then be issued.

Photo by Bryan Goff on Unsplash


Then NASA and emergency agencies how best to protect the Earth.
They have simulated this experiment many times and come up with a few defensive options.
They include firing lasers into the asteroid.

Crashing a spacecraft into an approaching asteroid is another possibility.

As is detonating a bomb next to an incoming object.
There is no risk at the moment though.
NASA can't detect any asteroid currently heading towards us. No large object is likely to strike for at least several hundred years.