Just after sundown on Sunday, people around Los Angeles and other parts of Southern California looked up and spotted the red glare of a rocket .

Mara Altman was at a fund-raiser dinner on a farm outside San Diego. A mariachi band had just started playing when the guests caught sight of the rocket . “I had no idea,” she said. “People were like mesmerized.”

The trumpet player put down his instrument and took out his phone to record the rocket’s flight. The singer continued to sing, while gazing at the sky. “It was just an added part of the party,” Ms. Altman said.

It’s a scene that people in Southern California should expect to see in their skies more often as privately-owned rocket companies expand their use of a nearby launch site.