The Powerful TESS Satellite

TESS, which stands for Transiting Exoplanet Survey Satellite, is a satellite that has been built by the cooperation of MIT, Harvard, and NASA. The technology is so powerful that it has the capability of monitoring 200,000 stars. The satellite launched on April 18, 2018, and so far it has been constantly discovering exoplanets, witnessing extreme explosions, and allowing scientists to research the details of exoplanets (planets that orbit a star that is not located in a set solar system) that would not have been discovered if it was not for the TESS.

TESS has so far discovered 50 planets. Recently, TESS has discovered exoplanet HD 21749b, which is 53 light years away. It was an unexpected discovery since it is a planet a few hundred degrees cooler than a usual exoplanet since most exoplanets near stars have a high surface temperature. Not only that, but cooler planets are usually located farther from a star’s orbit than a warmer planet, which consequently makes it difficult to detect them. “We know a lot about atmospheres of hot planets, but because it’s very hard to find small planets that orbit farther from their stars and are therefore cooler, we haven’t been able to learn much about these smaller, cooler planets. But here, we were lucky and caught this one and can now study it in more detail,” said Diana Dragomir, a researcher in Massachusetts Institute of technology.

The image shows a red dwarf star being orbited by an exoplanet.

How does TESS work?

The satellite is able to capture details of planets and stars through the transit method. The transit method detects exoplanets by looking for “dips in the visible light of stars.” Constant pictures are taken in order to show the planet orbiting. Through transit photometry (which observes the light radiated off the surface of the planet) researchers can look at planets and catalog thousands of exoplanets. Afterwards, this satellite determines which are not exoplanets and verifies others. To verify exoplanets, it simply needs to determine the mass and orbit of the planet. In order for the transit photometry method to work effectively, the satellite is equipped with high technology cameras that are aligned in “sectors” that can cover 24×90 parts (a part is a unit used to describe the allotment of sectors in the sky) of the sky.

Kepler vs. TESS

Kepler was the satellite that was used in November of 2018 that accomplished the mission of surveying the skies for exoplanets, especially those that have the capability to support life. It calculated shape and orbits just like the TESS technology and determined properties of stars and planets. Just like the Tess satellite, it used the transit method to verify planets. The technology was sent for several missions over the past decade and monitored 150,000 stars and served astronomers well until it started to fall apart in 2013 and eventually “died” in 2018. The new TESS satellite is more effective since it can monitor 200,000 stars in one third of the time that Kepler would monitor stars. And because of the satellite’s four powerful cameras, it can verify and determine the characteristics of planets more accurately, giving scientists better access to quality pictures for their observations.  The major difference between TESS’s missions and Kepler’s mission is that they are stationed in different orbits. TESS has the capability to survive in difficult environments in order to determine cooler planets, while Kepler, due to its weak infrastructure, could not be placed in difficult orbits.

In conclusion, astronomers and other scientists that work in identifying and observing planets have high expectations for TESS and hope that it can revolutionize the astronomy world. The new satellite is expected to discover planets one to two times the size of Earth, and they even hope it can even determine biological components in exoplanets that can point to life. With this new technology, the major goal of scientists is to find what they hope exists: “Earth’s twin.” The astronomy world praises the new technology and hopes that with its incredible cameras and transit method, it can find cool planets that contain life just like life on Earth.



  1. Nice article! I really enjoy astronomy, so I find satellites and planets very interesting to read about! =)