April 12 is the International Day of Human Space Flight. This day commemorates the beginning of humanity's space era and reaffirms the significant contributions of space science and technology.

Sally Kristen Ride (May 26, 1951 – July 23, 2012) joined NASA in 1978 and, in 1983, became the first American woman and the third woman to fly in space, following cosmonauts Valentina Tereshkova in 1963 and Svetlana Savitskaya in 1982.

NASA selected Nicole Aunapu Mann in June 2013. She is the first indigenous woman from NASA to go to space. She is registered with the Wailacki of the Round Valley Indian Tribes.

She launched to the International Space Station (ISS) as commander of NASA’s SpaceX Crew-5 mission aboard the SpaceX Crew Dragon spacecraft, Endurance, on October 5, 2022.

The Crew-5 astronauts lived and worked aboard the ISS for six months as part of Expedition 68.

During their mission, Crew-5 contributed to hundreds of experiments and technology demonstrations, including cardiovascular health, bioprinting, and fluid behavior in microgravity, to prepare for human exploration beyond low-Earth orbit and to benefit life on Earth.

The crew of four spent 157 days in orbit. Mann conducted two spacewalks totaling 14 hours, 02 minutes.

The California native holds a Bachelor of Science in Mechanical Engineering and a Master of Science in Mechanical Engineering. Mann served as a combat fighter and test pilot in the F/A-18 and Super Hornets.

Jessica Watkins recently lived and worked on the International Space Station (ISS).

During her time on the Space Station, she posted about the new science that kept astronauts busy in a jampacked Lab module. However, they had a lot more space, with access to three dimensions.

In one experiment, she checked out how immune cells age in microgravity in support of the Immune Senescence study.

Watkins is a planetary geologist and the lead author of a manuscript titled "Burial and Exhumation of Sedimentary Rocks Revealed by the Base Stimson Erosional Unconformity, Gale Crater, Mars," which was accepted for publication in JGR: Planets.

As part of NASA's SpaceX Crew-4, Watkins served as a mission specialist for approximately six months.

Watkins grew up in Lafayette, Colorado, and studied geology at Stanford University and the University of California, Los Angeles.

She gained significant knowledge about the surface of Mars while contributing to NASA's Jet Propulsion Laboratory in Pasadena, California, where she worked on the Mars Science Laboratory rover Curiosity.

In 2017, she was selected as a NASA astronaut.

Jeanette Epps was selected by NASA in 2009 as an astronaut. She completed astronaut candidate training, which included scientific and technical briefings, spacewalk training, robotics, T-38 flight training, and wilderness survival training.

Before joining NASA, Epps was a NASA Fellow during graduate school and authored several journal and conference articles related to her research. She also worked for Ford Motor Company, writing provisional and U.S. patents.

Epps then joined the Central Intelligence Agency (CIA), serving as a Technical Intelligence Officer for seven years before becoming an astronaut. She worked in the ISS Operations Branch, focusing on issues that supported space station crews.

Dr. Epps trained for NASA's SpaceX Crew-8 mission to the International Space Station and was a mission specialist for the launch in March 2024.

On this International Day of Human Space Flight, we celebrate humanity’s first flight into space made by Yuri Gagarin in 1961, as well as the first Space Shuttle launch in 1981. Now, it’s time to go back to the Moon and on to Mars with @NASAArtemis. pic.twitter.com/P6GND7FCzX

— NASA (@NASA) April 12, 2025

41 years ago, Sally Ride became the first U.S. woman to go to space.

Find a #SallysNight event with this @AirAndSpace guide and celebrate her legacy of encouraging students - especially girls - to pursue careers in science, math, and technology: https://t.co/UaPZTKodGe pic.twitter.com/yOFo3CNY5T

— NASA (@NASA) June 18, 2024

June 2013, Nicole Aunapu Mann was selected as one of eight of the 21st NASA astronaut class. She launched to the ISS as commander of NASA’s SpaceX Crew-5 mission aboard the SpaceX Dragon spacecraft on October 5, 2022. She is the first indigenous woman from NASA to go to space. pic.twitter.com/Pefx3uwmxU

— San Diego Air & Space Museum (@SDASM) March 20, 2023

Just another day in the life on @Space_Station, doing microscopy on the ceiling. Our Lab module is jam-packed with science, but access to 3 dimensions opens up much more space! Here, I'm checking out how immune cells age in microgravity in support of the Immunosenescence study. pic.twitter.com/wnJ2Oh96ZK

— Jessica Watkins (@astro_watkins) August 3, 2022

I have been in space for 50+ days now. It has been an amazing experience so far. I have so many highlights. One of the highlights was getting a video of the eclipse. It was eerily beautiful, and what an opportunity to see it from the @Space_Station! pic.twitter.com/INhu5Zsrn6

— Jeanette J. Epps, PhD (@Astro_Jeanette) April 26, 2024