The twin GRAIL spacecraft sit on the launch pad at Cape Canaveral Air Force Station Florida. Image credit: NASA/JPL-Caltech/United Launch Alliance, Thom Baur

The GRAIL spacecraft were set to launch this morning but the launch was scrubbed due to upper level winds. The launch will be attempted again tomorrow at 08:33 a.m. EDT and if that is not “a go” there is another chance at 09:12 a.m. EDT.

There will be a launch blog up and running at 06:00 a.m. EDT. You can watch online with a live chat on Ustream TV, and by the way this is a pretty fun way to go and there is also Twitter at http://twitter.com/NASAJPL and http://twitter.com/NASA are good choice especially if you can watch NASA TV.

Me? Um, I think I’ll be watching at the Ustream link.

NASA put a interesting launch milestone list up, so I included it here:

Launch
At liftoff, the rocket’s first-stage engine and six of its nine strap-on solid rocket motors will ignite, and the rocket will be airborne, carrying GRAIL up and over the Atlantic Ocean.

First six solid rocket motors are jettisoned
GRAIL’s Delta II is carrying nine strap-on graphite-epoxy motors. The first six will be ignited at the time of liftoff. The remaining three will be ignited shortly after the first six strap-on motors burn out.

Fairing separates
After the Delta’s first stage completes its tour of duty, its second stage, which will provide 9,645 pounds of kick for GRAIL, will begin the first of two scheduled burns.

Shortly after ignition of the rocket’s second stage, the Delta’s 30-foot-long (8.88-meter-long) nose cone, or fairing, will separate and be jettisoned as planned, providing the GRAIL twins with their first taste of exo-atmospheric existence.

Parking at 17,500 miles per hour
The Delta’s second stage will temporarily stop firing, as planned, and the rocket and GRAIL will begin a planned coast phase, also known as a “parking orbit” at about 90 miles (nearly 167 kilometers up).

GRAIL heading from Earth to the moon
The Delta’s second stage will begin a second burn. This approximately four-and-a-half-minute-long burn will place GRAIL on its desired trajectory to the moon.

Spacecraft begin to separate from second stage
The GRAIL-A spacecraft begins its separation process from the Delta’s second stage. The GRAIL-B spacecraft separates about 8 minutes later. At this point, the moon is three-and-a-half months away.