Launch is now scheduled for 18 April.
The observatory is 4 feet across (1.2 meters), not counting the solar wings, which are folded for launch, and weighs just 800 pounds (362 kilograms).
A new NASA satellite created to detect more Earth-like worlds around stars beyond our solar system is due for launch aboard a SpaceX rocket from Florida on Monday, on a quest to expand the known inventory of so-called exoplanets that might harbor life. It will send TESS into a high-elliptical orbit around our planet, like that of the Moon.
Guidance, navigation and control is always important for a space mission - but for TESS, the task is particularly complex.
NASA's Kepler telescope, launched nine years ago and nearing the end of its mission, found thousands of exoplanets by staring at a tiny sliver of the sky. After the launch of the satellite, there will be a two-month testing before the real data starts flowing back to Earth from TESS.
The $200m piece of hardware was given the go-ahead to launch aboard the Falcon 9 rocket by NASA's administrators only as recently as February. Satellite maker Orbital ATK's Robert Lockwood said he expects Tess to take exoplanet discovery to a whole new level. Using the known planet size, orbit and mass, TESS and ground-based follow-up will be able to determine the planets' compositions.
The Tess satellite will scan nearly the entire sky, staring at the brightest, closest stars in an effort to find any planets that might be encircling them. TESS is an Earth-orbiting instrument meant to spot faraway planets circling some 200,000 stars within 300 light-years of Earth.
Scientists hope to discover about 50 small, rocky planets that may be habitable to alien life.
Four wide-view cameras are surrounded by a sun shade, to keep stray light out as they monitor any dips in brightness from target stars. This dimming could signal a planet is moving in front of the star. The teeny telescope will replace the Kepler/K2 mission, which has already discovered thousands of exoplanets. Kepler stared at 250,000 distant stars in a cross-shaped area equal to 0.25 percent of the sky, and identified the signatures of more than 5,000 confirmed planets and candidates.
But it will not be easy, and "we're going to need extremely large telescopes to start to really put the signatures of the atmospheres into perspective and search for life signs", she said.