NASA's Double Asteroid Redirection Test (DART) spacecraft to launch Wednesday

In the event of an asteroid threatening all life on Earth we might not have to rely on Bruce Willis and Ben Affleck if a new NASA test proves successful.

The two actors appeared together as miners-turned-astronauts in end-of-days classic Armageddon in order to nuke a world-threatening lump of rock heading our way.

However Wednesday's (NZ time) Double Asteroid Redirection Test (DART) launch, which has been in the works since 2017, will show whether deliberately crashing a spacecraft into an asteroid can bounce it away from the earth instead.

NASA has been working with Elon Musk's SpaceX on the system since 2019 and, after the completion of a fire test at the weekend, the company tweeted the DART spacecraft will launch this week.

"Targeting Tuesday, November 23 at 10:21 p.m. PT for Falcon 9's launch of NASA's Double Asteroid Redirection Test," SpaceX wrote.

"NASA will intentionally crash the DART spacecraft into an asteroid to see if that is an effective way to change its course, should an Earth-threatening asteroid be discovered in the future."

Fortunately we aren't in any immediate danger, as DART is targeting a binary asteroid that will pass safely past Earth in both 2022 and 2024.

The binary asteroid is called Didymos, the Greek word for 'two forms'. Didymos A is the larger of the two, at around 780m in diameter, with the 160m diameter Didymos B orbiting it as a 'moonlet'.

It's the smaller of the two that the spacecraft will be deliberately smashed into.

If all goes according to plan, the actual crash event will happen sometime after September 2022, with the DART hitting the moonlet at 6km/s.

"DART will simultaneously test new technologies and provide important data to enhance our modelling and predictive capabilities and help us better prepare for an asteroid that might pose a threat to Earth, should one be discovered," NASA has previously said.

"The DART spacecraft is designed to demonstrate that an asteroid that could cause regional devastation can be deflected by intentionally crashing a spacecraft into it. 

"This method, called kinetic impact deflection, is just one of several proposed ways to redirect potentially hazardous asteroids, but it's the one currently assessed as the most technologically mature."

After the impact an investigation team will measure the deflection and change in momentum on the asteroid by using telescopes and planetary radar.

Didymos was discovered in 1996, and came relatively close to the Earth in 2003, passing around 7 million km away.

It was previously the target of a similar joint collaboration between NASA and the European Space Agency (ESA) called Asteroid Impact and Deflection Assessment (AIDA), which was cancelled in 2016.