COLORADO SPRINGS — A SpaceX Falcon 9 successfully launched a NASA science mission April 18 that will look for planets orbiting other stars.

The Falcon 9 lifted off on schedule at 6:51 p.m. Eastern from Space Launch Complex 40 at Cape Canaveral, Florida. The launch was scheduled for April 16 but postponed because of a guidance, navigation and control problem with the launch vehicle.

The launch, the eighth SpaceX mission of 2018, included a successful landing of the rocket’s first stage on a drone ship in the Atlantic Ocean.

The rocket’s payload, the Transiting Exoplanet Survey Satellite (TESS), separated from the rocket’s upper stage 49 minutes after liftoff. The Falcon 9 placed TESS into a highly elliptical orbit, and the spacecraft will use its own propulsion to move into its final orbit, a stable high Earth orbit in a 2:1 resonance with the moon, by mid-June.

The mission, SpaceX officials said, was not much different from launches of geostationary orbit communications satellites. “It looks like a GEO transfer orbit, but going further out towards the moon,” said Hans Koenigsmann, vice president of build and flight reliability at SpaceX, at a pre-launch press conference April 15.

The 362-kilogram TESS satellite, built by Orbital ATK, carries four wide-field cameras that will monitor the brightness of more than 200,000 stars. Those camera systems will look for minute, periodic dips in brightness of those stars caused when orbiting plans pass in front of, or transit, the stars.

The same approach has been used by NASA’s Kepler spacecraft, launched in 2009. However, Kepler’s prime mission focused on a single small area of the sky, while TESS will scan the entire sky, focusing in particular on nearby, bright stars that could be targets for follow-up observations by ground- and space-based telescopes, including the James Webb Space Telescope.

“TESS forms kind of a bridge between what we’ve learned about exoplanets to date and where we’re headed in the future,” said Jeff Volosin, TESS project manager at NASA’s Goddard Space Flight Center, at the pre-launch press conference. “That’s a big part of our mission: to enable future exploration by providing a giant dataset all over the sky of where these exoplanets are.”

The mission was the first NASA space science mission launched by SpaceX. While the company is a major provider of International Space Station cargo services for the agency, the only other NASA science missions launched by SpaceX are the Deep Space Climate Observatory in 2015 and Jason-3 in 2016, both missions carried out in cooperation with the National Oceanic and Atmospheric Administration.

NASA had to certify the “Full Thrust”, or Block 4, version of the Falcon 9 for the TESS launch. “We’ve been working hand-in-hand with SpaceX to get to the certification to be able to fly the type of mission that TESS is,” said Omar Baez, launch director for NASA’s Launch Services Program, at the pre-launch briefing.

SpaceX, though, is in the process of retiring the Block 4 and older versions of the Falcon 9 in favor of the Block 5, which incorporates improvements that will enable the first stage to be reused 10 or more times. The first launch of a Block 5 Falcon 9, carrying the Bangabandhu-1 communications satellite for Bangladesh, is planned for early May.

“This is the last new, not flight-proven yet Block 4,” Koenigsmann said of the rocket that launched TESS. “We will continue flying flight-proven Block 4 stage one boosters for a couple more times, but we will then switch over to Block 5.”