Martin Fettman, then only 36 years old and having received his DVM just 13 years earlier, climbed aboard the Columbia spacecraft on the morning of October 18, 1993. As the prime NASA payload specialist for Spacelab Life Sciences-2 (SLS-2), he departed Earth’s gravity with six others on STS-58 and returned 14 days later. This was the first time hands-on biomedical experiments were conducted on animals in space, affording a unique opportunity to compare human and animal physiologic responses to microgravity both before and after return to Earth’s gravity.