A report submitted by NASA to the U.S. Congress outlined the various ways that governments can save Earth from a possible major asteroid impact. The report included assessments for both nuclear and non-nuclear options.

NASA’s report focused on analyzing details related to near-Earth objects (NEO). These include tracking, detecting and deflecting the asteroids.

The first anti-asteroid solution that NASA tackled involves detonating a nuclear device near an approaching space rock. In theory, the explosion should be able to push the asteroid away from its trajectory.

According to the agency, this option is more effective than the other non-nuclear alternatives discussed in the report. It is also much safer than detonating a nuclear device on the surface of an asteroid.

“Nuclear standoff explosions are assessed to be 10-100 times more effective than the non-nuclear alternatives analyzed in this study,” the agency stated in the report.

“Other techniques involving the surface or subsurface use of nuclear explosives may be more efficient, but they run an increased risk of fracturing the target NEO.”

Another method that NASA is considering is a non-nuclear kinetic impactor. This method involves delivering a large amount of momentum on an asteroid to force it to change its course. In other words, crashing a spacecraft on a NEO will produce enough force to push the asteroid away from a collision course with Earth.

NASA is also prepared to alter an asteroid’s orbit using various means such as using gravity to pull it away from its current path. This can be done by flying a large spacecraft next to an asteroid for a very long time. The gravitational attraction between the spacecraft and the asteroid will then allow the former to pull the latter and change its orbit.

Other options the agency is looking at include landing a nuclear explosive on the surface of the asteroid and detonating it at an optimal time. A pulsed laser which will focus on the surface of the space rock could also "boil off" its surface and deflect its path.

As NASA noted, these methods will only be effective as long as an asteroid is detected long before its projected impact.

Pictured; an artistic illustration of an asteroid flying by Earth. NASA