TESS, short for the Transiting Exoplanet Survey Satellite, is NASA's latest effort to plumb the depths and darkness of outer space in search of other Earth-like planets-including those that could potentially support life.
It will stare at stars, hoping to catch the dip in brightness as their faces are traversed by orbiting worlds.
Key among these will be the successor to Hubble - the James Webb space observatory, due in orbit from 2020. This allows for newly detected planets and their atmospheres to be characterized more easily.
The more people that look through the data, the better, the scientists believe.
TESS is one of several important pieces of what NASA calls the "Exoplanet Missions", which got off the ground with the hugely successful Hubble Space Telescope. These so-called "transits" may mean that planets are in orbit around them. Further study can then be done by regular scientific telescopes. First and foremost, it is a wide-field survey. It will divide the sky into 26 different sectors and monitor each for at least 27 days in order to cover the complete zone.
Scientists at MIT planned the mission say they could discover thousands of new worlds within 24 months - including 50 Earth-size planets that might be habitable to aliens.
NASA is on the brink of sending a satellite into space that it believes will discover thousands of new planets within the next few years. This telescope should be ready for launch by the year's end.
Ricker and other scientists said the planetary catalog generated by TESS could well become the guidebook for that armada. "Our objective will be to very accurately measure the size of planets that have already been identified. So mass and size together give us an average planet density, which tells us a huge amount about what the planet is".
TESS uses the same method as Kepler for finding potential planets, by tracking the dimming of light when a celestial body passes in front of a star.
This variability is a effect of resonances in the outer layers of the stars, and it allows the British professor to pull out a lot of extra information. "They appear to be everywhere we look". Christiansen said. "We can resolve competing theories about how planets form".
Lift-off for Tess's rocket is scheduled for 6.32pm local time (10.32am NZT).
The Transiting Exoplanet Survey Satellite separates from the Falcon 9 rocket in its elliptical high Earth transfer orbit.
Mission planners have designed a novel orbit that will see Tess corralled by the gravity of the Moon. That will enable it to have a long-term mission beyond its two-year objective.
By focusing on planets dozens to hundreds of light-years way, TESS may enable future breakthroughs, he said. At its farthest point, or apogee, TESS will have an unobstructed view of the sky and will move beyond interference from the Van Allen radiation belts, which encircle Earth. "The thing that we can imagine is that there's this armada of nanosatellites that'll be sweeping out from the Earth to send back information".