Update 7:55 EDT: The Falcon 9 second stage conducted its second engine burn and successfully deployed the TESS spacecraft in orbit. TESS deployed its solar arrays, and it will now use its own thrusters to raise its altitude in preparation for a lunar flyby on May 17, sending it on its way to a final orbit where it will begin its search for worlds beyond the solar system.
Update 7:05 p.m. EDT: The Falcon 9 rocket carrying TESS lifted off on schedule. The first stage conducted a successful landing on a drone ship in the Atlantic Ocean, and the second stage of the rocket, carrying TESS, conducted the first of two engine burns to bring TESS to the desired orbit. The second engine burn is planned for 40 minutes and 50 seconds after liftoff, with spacecraft deployment to follow 7 minutes and 52 seconds later.
SpaceX is poised to launch the newest space telescope for NASA, the Transiting Exoplanet Survey Satellite (TESS). Liftoff is scheduled for 6:51 p.m. EDT. SpaceX had scrubbed the first scheduled attempt to launch TESS on Monday to review guidance, navigation and control (GNC) systems.
The Falcon 9 rocket that will carry TESS to space is vertical on the pad at Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.
You can watch SpaceX's live webcast of the mission below, with coverage beginning about 15 minutes before liftoff. You can also watch coverage of the mission on NASA TV, beginning at 6:30 p.m.
TESS is a photometric survey telescope, with four wide-field cameras that will measure the brightness of thousands of nearby stars within about 300 light-years. The satellite will look for transits, or the dip in a star's light that occurs when a planet passes in front of it from our point of view. The mission is NASA's successor to the Kepler space telescope, which has found more than 2,500 exoplanets by searching for transits.
TESS is expected to discover thousands of nearby exoplanets during its initial two-year survey, and perhaps as many as 20,000 if the satellite receives a mission extension from NASA. In the future, bigger telescopes can be used to study the atmospheres of TESS's planets to search for chemical signs of life, such as oxygen or methane gases.
The launch will carry TESS to a unique polar orbit called L2. The space telescope will fly in a large ellipse that takes it out beyond the moon and then in close to the Earth to downlink its data. Each orbit will last a little less than two weeks. TESS will observe a specific patch of the sky to look for transits for two orbits before moving on to a new area.