10:22 ET update: This tweet by Elon Musk says that the payload fairing splashed down "a few hundred meters" away from the recovery ship.

9:30am ET update: The launch of the PAZ satellite Thursday morning was nominal, as the Falcon 9 rocket took off under clear, dark skies along the California coast. Two Starlink broadband demonstration satellites were expected to deploy shortly, as well. However, the webcast ended without providing any information about the success (or lack thereof) of an experimental attempt to "catch" the payload fairings. We hope to find out more information soon.

Original post: SpaceX had to scrub the Wednesday launch attempt of its Falcon 9 rocket due to upper-level winds but will try again Thursday morning. The instantaneous launch window opens (and closes) again at 9:17am ET. This launch will occur at Vandenberg Air Force Base in Southern California.

There is heightened interest in this launch because, for the first time, SpaceX will attempt to "catch" one of the two payload fairings that enclose the satellite at the top of the rocket. The value of these fairings is about $6 million, and recovering and reusing them would both save SpaceX money and remove another roadblock on their production line for Falcon 9 rockets. These fairings will separate from the rocket at about three minutes after launch and are "steerable" in the sense that SpaceX hopes to guide them back to a target located in the ocean.

"Going to try to catch the giant fairing (nosecone) of Falcon 9 as it falls back from space at about eight times the speed of sound," SpaceX founder Elon Musk said on Instagram Thursday morning. "It has onboard thrusters and a guidance system to bring it through the atmosphere intact, then releases a parafoil and our ship with basically a giant catcher’s mitt welded on tries to catch it."

The primary mission on Wednesday is the launch of the PAZ satellite to low-Earth orbit. This is a synthetic-aperture radar satellite that can generate high-resolution images of the Earth's surface, regardless of whether there are clouds covering the ground. The customer is Hisdesat, a Spain-based commercial satellite company.

The Falcon 9 rocket will also carry a second payload of note: two experimental non-geostationary orbit satellites, Microsat-2a and -2b. Those are two satellites that SpaceX has previously said would be used in its first phase of broadband testing as part of an ambitious plan to eventually deliver global satellite Internet. Further satellites will be launched in phases, with SpaceX intending to reach full capacity with more than 4,000 satellites by 2024.

The webcast below, presuming upper-level winds are better Thursday morning, will open about 15 minutes before the launch.