Look to the skies early Saturday. The Mars InSight spacecraft, set to take off between 4 and 6 a.m., will be the first launch to another planet from the West Coast.

If the sky is clear, NASA says, the launch will be visible to more than 10 million Californians. If the launch is postponed, NASA will try again each morning for a month.

Historically, NASA’s Jet Propulsion Laboratory, based in La Canada Flintridge, has launched its robotic missions to Mars out of Cape Canaveral. Florida is ideal because the close proximity to the equator means NASA can take advantage of the Earth’s rotation to fling the rocket into space, Hoffman said.

InSight is able to launch from California because the Atlas V is much larger than the Delta II rockets used in older missions to Mars, Hoffman said. Those rockets, which are no longer in production, would not have enough energy to launch from Vandenberg.

Because of the rocket’s path, they’ll be in the southern part of the state, from Santa Maria to San Diego. The first opportunity for the launch from Vandenberg Air Force Base is 4:05 a.m. PDT Saturday. A two-hour launch window is scheduled each day through June 8. Those outside the viewing area can watch the event online.

InSight is expected to land on Mars on Nov. 26. The $1 billion U.S.-European mission is dedicated to studying the innards of Mars, with a robotic geologist digging 15 feet into the Martian soil.

A pair of briefcase-size satellites will launch aboard InSight, break free after liftoff, then follow the spacecraft for six months all the way to Mars. They won’t stop at Mars, just fly past.

The point is to test the two CubeSats as a potential communication link with InSight as it descends to the planet.

JPL is managing the InSight project for NASA’s Discovery Program. The spacecraft, including cruise stage and lander, was built and tested by Lockheed Martin Space in Denver.

Vandenberg launches can create spectacular views across Southern California skies.

Such a launch, staged by Hawthorne-based SpaceX in December, set off delight for many people – and panic for others. The sight, which could be seen as far away as San Diego, was so alarming that police were called across Southern California.

“We got quite a few concerned calls with people saying there’s a light in the sky,” said Torrance police Sgt. Paul Kranke. “We didn’t know what it was but, fortunately, someone at work follows rocket launches and we were able to tell people what it was.”