What Would Have Happened in Real Life: After building an unlicensed aircraft in his yard and boasting about shooting his girlfriend and her 17-year-old brother into outer space, Reed Richards is promptly brought up on charges of criminal negligence and child endangerment, his name tarnished in the scientific community. Richards flees the US to avoid prosecution, taking a teaching position at the Universidad de San Carlos in Guatemala. Since Guatemala has the lowest literacy rate in Central America, he spends most of his class time playing cards with his students and cursing his "total bitch" ex-girlfriend, who took advantage of Reed not bombarding her with space radiation by launching a successful acting career.
A Second Possibility: Reed Richards wisely decides to keep quiet about his goal to beat the Communists to Mars after noticing the horrified looks on his colleagues' faces, and so manages to get into outer space without tipping off the authorities. Once there, the four are bombarded with cosmic rays and, as advances in radiation can attest, nothing much happens initially. Since it takes the better part of a year to reach far-off Mars, Reed and co. settle in for the voyage, playing charades and watching Ben Grimm's astonishingly comprehensive collection of amateur pornography.
After a month of lethal radiation, Johnny develops a cataract in his left eye and Ben Grimm becomes sterile. After two months, Susan's hair begins to fall out in clumps and Richards starts pooping blood. By the time they reach Mars, every one of them has cancer. Luckily, due to the heavy nuclei in cosmic radiation all are profoundly brain damaged at this point, and nobody even notices. Now piloting a spacecraft while legally retarded, Reed suggests they abandon their Mars mission and fly off in the direction of a distant galaxy instead, on the grounds that it looks like ice cream. They are never heard from again.