• NASA's TESS exoplanet hunter has completed its 2-year primary mission
  • It will still go on an extended mission, which will last until 2022
  • During its primary mission, it discovered exoplanets and observed cosmic phenomena

NASA's exoplanet hunter has finally completed its primary mission but continues on its search for new worlds beyond the solar system.

July 4 marked the end of the primary mission of NASA's Transiting Exoplanet Survey Satellite (TESS), about two years after it was launched aboard a SpaceX Falcon 9 rocket in 2018. During the two years of its main mission, TESS managed to image 75% of the sky, creating a giant mosaic that NASA Goddard Space Flight Center shared in a video celebrating the completion of the mission.

In the video, one can see the mosaic is made up of 26 sector images, each being a 24- by 96-degree patch of the sky. Thirteen of these sector images were observed during the first year of the mission, while the rest was monitored during the second year.

The video also shows some of the incredible discoveries that TESS made during its second year. This includes the discovery of three exoplanets orbiting red dwarf star GJ-357 just 31 light-years away, one of which is a massive exoplanet that's within the habitable zone of the system.

It was also during its second year that TESS spotted the smallest exoplanet it has discovered.

All in all, during its primary mission, TESS discovered 66 new exoplanets as well as over 2,000 others that are still waiting to be confirmed. Many of these exoplanets' atmospheres can then be observed in finer detail using the James Webb Space Telescope, which is set to launch in October of 2021.

Apart from exoplanets, however, TESS also observed other cosmic phenomena, from eclipses in a binary star system to a black hole shredding a Sun-like star. It even captured the explosion of a comet in our solar system in incredible detail.

"TESS is producing a torrent of high-quality observations providing valuable data across a wide range of science topics," TESS Project Scientist Patricia Boyd said in a feature from NASA. "As it enters its extended mission, TESS is already a roaring success."

Now that its primary mission is over, TESS will still continue watching the skies during its extended mission, during which TESS will capture and collect images three times faster than it did during the primary mission. This extended mission is set to continue until September of 2022.

Image: The poster to celebrate the completion of the primary mission of NASA's TESS. It features a montage of images representing TESS's many achievements during its first two years. NASA's Goddard Space Flight Center