A few months ago we told you about the spacecraft 'Rosetta' that has been making its journey through the solar system for 10 years.
And Wednesday morning, scientists released a landing craft from Rosetta that successfully touched down on a comet, something that's never been done before. A scientist working on the mission says the comet had to be in just the right position to allow Rosetta's landing craft, known as Philae, to "free fall" onto it.
It's was delicate procedure, since the landing craft could not be steered once released.
Here you can see an animation of what scientists are hoping will happen.
Scientists hope the probe will help us learn more about the composition of comets and how they react when they get close to the sun.