September 30, 2016 will surely be written in the history books. Today (September 30) marks the end of the 12.5-year space journey of the historic Rosetta spacecraft mission built by the European Space Agency.

The Rosetta spacecraft has orbited for 2 years around Comet 67P/Churyumov-Gerasimenko before land-crashing to its surface. According to Space.com, project managers received the last signal from Rosetta around 7:19 EDT as it made a controlled impact on the comet.

Rosetta is a spacecraft probe expedition launched on March 2, 2004 that has been created by the European Space Agency. Carrying a suite of 11 scientific experiments and its lander module named Philae, Rosetta flew around the space for 12.5 years. In that historic journey, it reached a lot of milestones. This includes sailing past Mars and two asteroids, 21 Lutetia and 2867 Steins.

But the most notable achievement of Rosetta space probe is that when it becomes the first spacecraft to orbit a comet, escorting the object around the sun and deploying Philae around the surface. As the comet 67P/Churyumov-Gerasimenko and the Rosetta spacecraft dashed away from the sun, the solar power spacecraft started to run low of power.

To get every last bit of science in this space mission, ESA managers decided to conclude the expedition by crash-landing on the comet near the pit called Deir el-Medina.

Rosetta was not made to crash-land on the comet. But by making a controlled descent and impact, it was thought probable to collect more pictures and data on its way down.

The expedition has made notable discoveries like the discovery of landing craft Philae to the 16 organic compounds which included 4 that had never seen in comets before. According to CNN, that discovery is very important because some of those chemicals form the building blocks for the ingredients of life.

ESA said that the Rosetta spacecraft expedition cost about 1.4 billion euros or $1.57 billion since the start of the project, per CNN.

But even if the Rosetta spacecraft bids "sayonara" or farewell, the work isn't over yet.

"We have 80,000 images to look at," Mohamed El-Maarry, a postdoctoral researcher with Rosetta's OSIRIS team, from the University of Bern in Switzerland, told reporters yesterday. "It's going to keep us busy for years to come." per Space.com.