NASA’s new satellite brings the search for Earthlike exoplanets closer to home By Daniel CleryApr. 19, 2018 , 4:30 AM

Updated: NASA’s new satellite brings the search for Earthlike exoplanets closer to home

By Daniel CleryApr. 19, 2018 

After a 2-day delay for extra checks, NASA’s latest exoplanet-hunting satellite, TESS (Transiting Exoplanet Survey Satellite) was launched yesterday on a SpaceX Falcon 9 rocket. Within an hour, the solar arrays that will power the spacecraft were deployed. TESS is the first of a new generation of exoplanet hunters that will home in on temperate worlds close to Earth.

The brainchild of researchers at the Massachusetts Institute of Technology (MIT) in Cambridge, the $337 million project aims to identify at least 50 rocky exoplanets—Earth-size or bigger—close enough for their atmospheres to be scrutinized by the much larger James Webb Space Telescope (JWST), due for launch in 2020, or giant ground-based telescopes currently under construction. "Where do we point Webb?" TESS Principal Investigator George Ricker asked rhetorically at the American Astronomical Society annual meeting at National Harbor in Maryland in January. "This is the finder scope."

Yesterday's launch went smoothly, but it will be a couple of months before TESS starts work. Over the next several weeks, TESS will use boosters to elongate its orbit until it reaches as far as the moon. It will then use the moon’s gravity to boost it into a particular 13.7-day orbit, never before used by a satellite, that swings between 400,000 and 100,000 kilometers above Earth. To save on power, TESS will take advantage of each close approach to Earth by turning its antenna towards home to transmit data it has collected in a 3-hour download. The orbit is synchronized with that of the moon; for every lunar orbit, TESS does two. This helps by using the moon’s gravity to stabilize TESS’s orbit, so it can stay on this trajectory for decades with little need for adjustment by thrusters.