Craig Picture riding shotgun in a race car traveling about 190 miles per hour.
Now, imagine the force exerted on the body when that car turns a curve in the Indianapolis 500.
Double the force, and you get an idea of what Roger Spears once felt in a space shuttle simulator.
The experience was one of five seminars he's taken with the National Aeronautics and Space Administration since 2004. Spears, a Moffat County High School science teacher, is one of almost 200 people initially selected for a NASA program tailored specifically for educators.
As a member of the program, Spears will mentor high school students interning with NASA scientists from June 16 to Aug. 8 at Kennedy Space Center at Cape Canaveral, Fla.
The experience will mark the sixth sessions Spears has completed with NASA in four years.
Taking a spin in a space shuttle simulator was part of one trip. During that experience, Spears said he underwent forces up to six times the force of gravity.
In 2003, however, Spears had a chance to fly in the real thing. That year, he said, NASA reopened a program allowing teachers to join its space missions.
The program closed in 1986 after the space shuttle "Challenger" exploded Jan. 28 in midair, killing all seven crewmembers, including Sharon Christa McAuliffe, the first teacher to fly in space.
After the program reopened, 27,000 nominations for potential teacher astronauts flooded into NASA, Spears said.
"I was one of those," he said.
Out of the nominees, about 8,000 teachers completed a 32-page application for the program.
Again, Spears was among them.
He made it to the second-to-last stage in the selection process, in which NASA officials culled 196 applicants for a battery of physical and psychological tests. However, Spears' poor vision barred him from going any further.
Another 35 of his colleagues qualified for further, more in-depth testing. From those, three teachers emerged as astronauts.
"I know all three of them," Spears said.
Still, NASA wasn't finished with Spears.
Response to the resurrection of the teacher astronaut program was "overwhelming," he said - so much so that NASA officials decided to create a program using the 196 applicants to help promote students' interest in science, engineering, technology and math.
The result of their labors: Network of Educator Astronaut Teachers. Program participants go through various trainings that give them a taste of what astronauts experience in the field.
"It gives us a sense of ownership," Spears said. "They're here to help train us."
After the trainings when participants return home, they conduct outreach programs for the community where they act as a link between NASA and educators, Spears said.
In addition to riding in a flight simulator, Spears' past trainings include a research project in California's Mojave Desert.
Space exploration has long been one of Spears' passions.
"I think growing up in the 1960s was a really important part of it," he said.
During those years when the nation's space program was in its infancy, Spears said updates on shuttle missions were prominent in television and radio.
"It occupied everyone's minds," he said, including his.
Spears said he remembers watching a TV broadcast of the first moon landing when he was a second-grader.
"It's a great curiosity," he said.
Spears' interest in space exploration hasn't waned since he saw Neil Armstrong take his first steps on the moon's chalky surface almost 40 years ago.
Now, however, like his colleagues in the field, he's turned his attention to Earth's neighbor: Mars.
Phoenix, NASA's Mars lander, touched ground on the red planet May 25. Its mission is to analyze water frozen beneath the planet's northern arctic region, according to NASA's Web site.
Spears believes finding water on Mars, even in ice form, could have significant scientific implications.
"If you find water, you have a better chance of finding life," he said, "or, at least, life at one time."
Still, the Mars lander holds additional meaning for Spears, namely in the people who helped build it.
Lockheed-Martin, a company based on the Front Range, constructed the lander.
"These (are) Colorado people who have put (Phoenix) on Mars," Spears said. "That makes you pretty proud right there."
In Spears' view, exploring space is part of human nature.
"It will always be there, whether people agree with it or not," he said. "It's in our psyche to be explorers."