SpaceX launches NASA's Pandora exoplanet mission, 3 dozen other satellites (video)

NASA's next exoplanet mission has reached the final frontier.

A Falcon 9 rocket carrying about 40 payloads, including NASA's Pandora exoplanet satellite, launched from California's Vandenberg Space Force Base on Sunday (Jan. 11) at 8:44 a.m. EST (1344 GMT and 5:44 a.m. local California time).

SpaceX called the mission "Twilight," because it delivered the satellites to dusk-dawn sun-synchronous orbit, a path that straddles the line between night and day on our planet. And the mission did deliver: the payloads were deployed on schedule, during a 90-minute stretch that began about an hour after liftoff.

During its yearlong orbital mission, the 716-pound (325 kilograms) Pandora will study at least 20 known exoplanets using a 17-inch-wide (45 centimeters) telescope, which it will train on the worlds as they "transit," or cross the face of, their host stars from the satellite's perspective.

Such transits cause a small dip in the host star's brightness, which exoplanet hunters have used to great advantage: Most of the more than 6,000 alien planets we know of have been discovered via the "transit method."

Transits also allow astronomers to characterize known exoplanets, especially their atmospheres. Different elements and molecules absorb light at specific wavelengths, so studying the spectrum of starlight that has passed through an atmosphere can reveal a great deal about that atmosphere's composition.

However, such work is complicated by stellar complexity. Star surfaces are not uniform; they often feature patches of varying brightness, like the sunspots that speckle our own star. Pandora will help astronomers account for such complexity, if all goes to plan.

"Pandora aims to disentangle the star and planet spectra by monitoring the brightness of the exoplanet's host star in visible light while simultaneously collecting infrared data," NASA officials wrote in a mission description. "Together, these multiwavelength observations will provide constraints on the star's spot coverage to separate the star's spectrum from the planet's."

Pandora will focus on planets with atmospheres that are dominated by water or hydrogen, agency officials added.

The other three dozen or so satellites that went up on the Twilight mission are a diverse group. Among them were 10 of Kepler Communications' Aether spacecraft and two of Capella Space's advanced new Acadia Earth-imaging radar satellites.

SpaceX is no stranger to rideshare missions like Twilight. To date, the company has launched 15 such flights in its Transporter series and four via a different program known as Bandwagon.

The Falcon 9's first stage landed back at Vandenberg as planned about 8.5 minutes after liftoff on Sunday. It was the fifth mission for this particular booster, according to SpaceX.

Editor's note: This story was updated at 12:45 p.m. ET on Jan. 11 with news of successful launch, rocket landing and satellite deployment.