NASA’s new exoplanet telescope, the TESS (Transiting Exoplanet Survey Satellite), was launched April 18, 2018 and is expected to find 20,000 exoplanets during its 2 year primary mission. This is huge increase compared to the 3,933 that are currently confirmed. Among these planets will hopefully be multiple rocky planets in the habitable zone, or zone where liquid water can exist. TESS is sensitive enough to see planets a little bigger than Earth for perhaps 1,823 stars and Earth sized ones for 408 of them. In an article by NASA, Lisa Kaltenegger is quoted explaining that “life could exist on all sorts of worlds, but the kind we know can support life is our own, so it makes sense to first look for Earth-like planets,” thus explaining why the data of these planets in the habitable zone are garnering special attention.
A fascinating detail about the TESS satellite is its orbit. It is in a highly elliptical orbit that’s apogee is almost as far away as the moon and perigee that comes as close as 108,000 km (about 3.5 times closer). TESS is in a 2:1 resonance with the moon, meaning that it orbits the Earth twice for every moon orbit, and is timed to be about 90° away from the moon thus minimizing the moon’s interference in TESS’s orbit.