By Terry Eliasen, WBZ-TV Exec. Weather ProducerBy CBSBoston.com Staff

BOSTON (CBS) — We’ve all seen the disaster movies. Typically, they feature a happy, blissful existence that is suddenly thrown into chaos by the news of impending doom. Be it an asteroid, comet or some alien ship, something scary from outer space is headed directly for Earth. In the movies, of course, we turn to Bruce Willis, Ben Affleck or perhaps The Rock to save us.

But did you know that there are some real-life heroes that are actually working on saving our planet as we speak? Wednesday at 1:21 a.m. our saviors from NASA will be launching a first-ever mission to redirect an asteroid. Important side note here: THE ASTEROID IS NOT A DANGER TO EARTH. This is purely a test mission. However, this mission will give NASA valuable insight should we find ourselves on the brink of extinction one day in the future.

The DART test mission will attempt to knock an asteroid off course (Image credit: NASA)

The mission is fascinating. The DART spacecraft (Double Asteroid Redirection Test) will be sent on a voyage to intentionally collide with an asteroid known as Dimorphos. Dimorphos is about the size of the Washington Monument (in height, but much wider) and is actually in an orbit around a bigger asteroid known as Didymos. The goal is for DART to crash into Dimorphos, slightly altering its orbital period around Didymos, providing us here on Earth with a potential planetary defense strategy for the future.

The DART spacecraft will not reach the asteroid until next September, so we will need to wait a while to learn of the results. The collision will occur more than 6 million miles from Earth and the DART craft will come in at a speed of about 15,000 mph. Three minutes before impact, a small camera will be deployed from DART and will record what happens while streaming the video of the impact back to Earth (better set your DVRs that day!)

Astronomers will immediately begin observing through telescopes to determine how much, if any, the orbital period of Dimorphos was altered. There will also be a follow up mission/investigation conducted by the European Space Agency a few years after impact.

The test DART mission aims to deflect an asteroid (Image credit: NASA)

Could the collision destroy the asteroid? No. The DART spacecraft is nearly 100 times smaller than the asteroid. The goal is simply to give it a nudge.

Why not just launch a nuclear missile or find some way to blow up an asteroid you may ask? NASA scientists say this is a “terrible idea” as that could turn one potential impact into several thousand.

Again, there are currently no known asteroids that pose any impact to Earth in the next 100 years or so, however there remain countless asteroids that haven’t been discovered as of yet. Better to have a plan should we find ourselves in the path of one, wouldn’t you agree?

To watch the launch of DART live on Tuesday night: Follow @NASA_LSP for live coverage and watch the broadcast beginning at 12:30 a.m. ET: youtu.be/E0OUvEh3HWk.

Follow Terry on Twitter @TerryWBZ

CBSBoston.com Staff