On this day, 23 years ago, Dr. Bernard Harris became the first black person to walk in outer space.

Harris earned a Bachelor of Science degree in biology from the University of Houston and earned his medical degree from Texas Tech University.

Harris joined NASA in 1985 to complete his National Research Fellowship. His research was centered around musculoskeletal physiology and disuse osteoporosis. He completed the fellowship in 1987, and began working at the Johnson Space Center as a flight surgeon and clinical scientist. Four years later, he became an astronaut.

His first mission was aboard the Space Shuttle Columbia in 1993. His second mission, in 1995, made him the first black astronaut to walk in space.

Harris went onto to spend more that 438 hours in space, traveling over 7.2 million miles. In addition to his historical first, he pioneered research that made way for devices which allow astronauts to stay in space for prolonged periods.

After retiring from NASA in 1996, he started the Harris Foundation, a nonprofit that encourages STEM education for children from marginalized populations. The organization’s most popular initiative is the ExxonMobil Bernard Harris Summer Science Camp. Ninety-eight percent of those who attend the camp graduate from high school and attend college. Of those students, 75 percent pursue STEM degrees.

In addition to his philanthropic efforts, Dr. Harris is CEO and managing partner of Vesalius Ventures, Inc., a venture capital firm that invests in companies that produce healthcare technology.

According to a bio on the Harris Foundation’s website, Harris credits his accomplishments to education and hard work.

“Dr. Harris’ goals in life have been achieved through self-empowerment and self-determination,” the site reads.  “He believes that education and effort will allow anyone to meet any challenge in life, inspiring others to reach for the stars.”