About two weeks after the Fourth of July, people have still been shooting off rockets into the air above Champaign.

But these rockets are legal.

Model rocket enthusiasts launched their work at Dodds Park, 1501 N. Mattis Ave. in Champaign, on Saturday underneath a partly cloudy sky. The launch was organized by Central Illinois Aerospace, an organization partnered with the Champaign Park District and made up of local enthusiasts dedicated to everything model rockets.

The roots of the organization began in the late 1960s in the days of the Cold War and moon walks, when Jonathan Sivier, 55, took an interest to rockets in high school.

Many years after launching some rockets for the first time on one Fourth of July as high school students, Sivier and his friends decided to organize a launch in Mahomet on July 4, 1990. After organizing another launch on the same date a year later, they decided to form Central Illinois Aerospace in 1992.

Since then, the organization has continued to make Independence Day the staple launch date during the year, calling it the “Great Annual Rocket Launch,” and hold launches throughout the year at Dodds Park, near Parkland College, and other local open spaces, such as farmland.

Joined by his two nephews, Springfield resident Matt Joseph enjoyed his second time out with the Central Illinois Aerospace at Dodds Park on Saturday.

“I did it when I was a kid,” Joseph, 37, said of model rocket launches. “I took a break for girls and cars then came back as an adult.”

Besides launching for fun, Joseph extends his knowledge of model rocketry to helping his son’s Cub Scout pack organize a launch.

Under a launch waiver from the Federal Aviation Administration, they cannot fly rockets that weigh more than 3.3 pounds or fly higher than 3000 feet, Sivier said.

“That’s a lot of rocket, and that’s very high,” he said.

Most of the rockets are made of balsa wood, fiberglass, cardboard and other lightweight materials. They are strong enough to withstand decades of launches — some of Sivier’s models date back to the 1970s — but light enough to inflict minimal damage in case of an emergency like a failed parachute.

“The premise is that if the rocket hits something, the rocket should break and not whatever it hits,” he said.

When he was younger, St. Joseph resident Gary Slater would get up at 2 a.m. to watch the moon walks. After a launch of his blue and yellow rocket Saturday, he deemed it the most successful of the model’s five launches.

With a lifelong passion for rockets and space, Slater, 56, became interested in model rockets in his 20s and got back into rocketry soon after Ohio native Steve Eves launched a one-tenth scale model of the Saturn V rocket in April 2009.

“I’m what you call a born-again-rocketeer,” he said.

While Slater’s rocket only went a few hundred feet from the launch site, some of the other participants’ models were not so fortunate.

It can take a long time to find a rocket that has drifted many hundreds of feet after the launch, but Sivier said it is all part of the four “F”s of rocketry:

“Fabricating, flying, fixing and finding.”