Transiting Exoplanet Survey Satellite (TESS)




What is TESS?

TESS, a NASA Explorer Mission scheduled to launch in 2017, is a two year all-sky photometric survey for exoplanets transiting nearby stars.

The satellite will tile the sky with 26 observation sectors:

  • at least 27 days staring at each 24° x 96° sector
  • brightest 100,000 stars at 1-minute cadence
  • full frame images with 30-minute cadence
  • map Northern hemisphere in rst year map Southern hemisphere in second year
  • sectors overlap at Ecliptic poles for sensitivity to smaller and longer period planets in JWST Continuous Viewing Zone (CVZ)

TESS will observe from unique High Earth Orbit (HEO):

  • unobstructed view for continuous light curves
  • two 13.7 day orbits per observation sector
  • stable 2:1 resonance with Moon’s orbit
  • thermally stable and low-radiation


Why build TESS?

The NASA Kepler Mission showed that planets are abundant throughout the Galaxy, but most of the Kepler planets orbit stars too distant and dim for further study. The NASA TESS Mission will find exoplanets transiting nearby, bright stars: the best targets for followup characterization with JWST, Hubble, and large ground-based telescopes.

TESS is designed to:

  • monitor nearby, bright stars for transits
  • focus on Earth and Super-Earth size planets
  • cover 400X larger sky area than Kepler
  • span stellar spectral types of F5 to M5

For planets that transit, it is possible to observe:

  • fundamental properties: mass, radius, orbit
  • dynamics: planet-planet interactions, mutual inclinations, moons, tides
  • atmospheric composition + structure: transmission spectrum, emission spectrum, albedo, phase function, clouds, winds

Such studies are achievable only for nearby planetary systems like those TESS will discover.

An illustration of the Transiting Exoplanet Survey Satellite (Model courtesy of the TESS Team)