Blast off: ESA launches rocket as part of Hera mission

Image source, Reuters

Image caption, Hera has lift off

The European Space Agency (ESA) has sent a rocket into space as part of a mission that is aiming to protect our planet from danger.

The mission is called Hera, and as part of it the ESA has sent a probe to check out an asteroid called Dimorphos.

It's a continuation of Nasa's DART mission from 2022.

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DART stands for Double Asteroid Redirection Test, and with it Nasa was trying to see if it could knock potential planet-threatening asteroids out of the way if they ever came hurtling towards Earth.

It was the first mission of its kind - and it worked.

Dimorphos was the asteroid they hit, and the ESA now wants to have another look at it to see what affect the impact of Nasa's satellite had.

Image source, ESA

Image caption, An illustration of what the ESA's satellite will look like when it reaches Dimorphos in 2026

What is an asteroid?

  • An asteroid is a small rocky object that orbits the Sun
  • These become meteors when they burn up in the Earth's atmosphere
  • They come in lots of different sizes. Vesta is one of the biggest at 530km (330 miles) in diameter - that's bigger than the distance from London to Paris.

Image source, Getty Images

Image caption, Meteors burning up in Earth's atmosphere are what give us shooting stars

What was the DART mission and why did Nasa do it?

There are lots of asteroids in space, and while most get burned up in the Earth's atmosphere if they come anywhere close to our planet, if they're big enough, they could cause a lot of damage.

For example, it was an asteroid hitting Earth that wiped out the dinosaurs millions of years ago.

So scientists at Nasa wanted to see if they could create technology that would send dangerous asteroids flying in another direction should they ever make a beeline for our planet.

And they did.

Image source, Nasa

Image caption, This is an illustration of what Nasa's DART satellite looked like just before impact with Dimorphos

They found an asteroid called Didymos, and orbiting it was Dimorphos.

They sent a satellite into Dimorphos do see if they could change its orbit, and after giving it a small nudge, they successfully changed its path.

What is the ESA's Hera mission hoping to do?

Hera is a continuation of Nasa's planetary defence mission.

They want to investigate Dimorphos looking at things like the kind of crater caused by the impact, and whether it changed the shape of the asteroid.

The mission will take two years.

The first phase will see a satellite fly past Mars and get some rare images of Mars' moon Deimos in March 2025.

It will then travel to Didymos in February 2026, and enter its orbit to have a closer look at Dimorphos.

Image source, PA Media

Image caption, The ESA wants to get a closer look at the crater DART left behind on Dimorphos

There are current around 27,000 asteroids in near-Earth orbit, and any that are 140 metres (460ft) and larger in size and come nearer than 4.7 million miles (7.5 million km) are classed as potentially dangerous.

Mike Willis, space environment programme leader at the UK Space Agency, said that while an asteroid strike is "incredibly unlikely in the next 200 years", the Hera mission will play "a key role in future work to help protect our planet from space risks".

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