Lawrence Lockhart Jr., 83, was supposed to be at a St. Louis nursing home visiting his wife.
Friday, he was killed in a hit-and-run crash near Waters Avenue and Sheldon Road in Hillsborough County.
The other driver took off and left behind a smashed, stolen Cadillac.
"I just can't believe it," said Linda Lockhart, the victim's daughter-in-law.
She said the family is still in shock, especially after watching the surveillance video from a nearby convenience store. Detectives said it shows the driver who slammed into Lockhart's car.
The suspect was captured on video leaving the scene.
Shortly after the crash, that female driver is seen asking someone for a ride, getting into that vehicle and leaving the scene.
"It just makes you angry, seeing some woman in a stolen car," said Linda Lockhart. "She was all safe, he wasn't. I just hope they catch her."
Family members said, even at 83 years old, Lawrence Lockhart was a hard-working engineer. He helped make the first heat shield for the Apollo mission that went to the moon. But family members say he would never gloat about that.
"He's very modest," said Linda Lockhart. "I'd always say he's probably a multi-millionaire living in a little trailer."
Linda Lockhart said their dad was all about knowledge and he was an excellent driver.
The family just hopes the surveillance video leads detectives to the woman who slammed into his car - then left him to die.
Anyone with any information reference the traffic crash or the female is asked to contact the Hillsborough County Sheriff's Office at 247-8200 or if you would like to be eligible for a reward contact Crime Stoppers at 1-800-873-8477.