Just a couple of decades ago, the notion of finding habitable planets - or any planets at all - was a mere fantasy, said Paul Hertz, astrophysics division director at NASA.
This mission will take about two years.
"We know of several thousand planets now, and with Tess, we expect to find maybe 10,000 more planets", added Tom Barclay, a research scientist at NASA's Goddard Space Flight Center. Bigger and more powerful observatories of the future will scrutinize these prime candidates for potential signs of life. He started the series of tweets with the acknowledgment that "This is gonna sound insane", and then said, "SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon". The company hopes to land this first stage on a floating ocean platform following liftoff, and reuse it on a space station supply run for NASA this summer. NASA's newest planet-hunting spacecraft is poised for a Monday evening launch.
NASA calls the spacecraft TESS, which is short for Transiting Exoplanet Survey Satellite.
The Transiting Exoplanet Survey Satellite, or TESS, is scheduled to launch Monday at 6:32 pm (2232 GMT) atop a SpaceX Falcon 9 rocket.
Depending on available light, NASA can determine the size of the star as well as its planets and the length of orbits, which can give an indication of the planet's proximity to the star, which in turn can help experts determine the conditions on that planet and the chance of it supporting life.
This image made available by NASA shows an illustration of the Transiting Exoplanet Survey Satellite (TESS).