Ada Lovelace, English, is considered the first computer programmer. She wrote a program to calculate a series of Bernoulli numbers in her notes on Babbage's Analytical Engine.
Grace Brewster Murray Hopper, American, created the first compiler for a computer programming language and popularized the idea of programming languages that are independent of the machine using it.
Margaret Hamilton, American, was the lead flight software designer for Apollo and Skylab. Her work prevented an abort of the Apollo 11 moon landing.
Annie Jump Cannon helped develop first stellar classification system and classified nearly 400,000 stars - more than any other human before or since.
Barbara McClintock won a Nobel Price for her discovery that genes could move in and between chromosomes.
Rita Levi-Montalcini won a Nobel prize for her discovery of a nerve growth factor.
Joyce Jacobson Kaufman was a chemist who developed the concept of conformational topology.
Mary Sherman Morgan was a rocket scientist who invented hydyne, a liquid fuel that powered the USA’s Jupiter C-rocket.
Ruby Hirose was a chemist who conducted vital research about an infant paralysis vaccine.
Marie Tharp was a scientist who mapped the floor of the Atlantic Ocean and provided proof of continental drift.
Patricia E Bath is ophthalmologist and the inventor of the Laserphaco Probe, which is used to treat cataracts.
Cecilia Payne determined the most abundant element in the universe, she also discovered what the sun is made of (Henry Norris Russell, a fellow astronomer, is usually given credit for discovering that the sun’s composition is different from the Earth’s, but he came to his conclusions four years later than Payne—after telling her not to publish).
Rosalind Elsie Franklin was instrumental in discovering that double helix form of DNA with Watson and Crick but is relatively unknown because she did not receive the Nobel Prize with them as she had died.
Yanping Guo is the mission design leader and one of the women who made up 25% of the New Horizons team. She configured the entire mission trajectory, including Jupiter and Pluto flybys. New Horizons actually arrived 72 seconds early after travelling for almost 10 years straight to its destination.
Marsha P. Johnson and Sylvia Rivera were two of the central figures in the Stonewall riots.
Mary Shelley invented science fiction and post-apocolyptic fiction genres.
17 year old Jackie Mitchell struck out Babe Ruth and Lou Gehrig during an exhibition game against the Yankees. Her contract was then voided because baseball was "too strenuous" for women. She continued to play with the House of David while wearing a fake beard.
I know that's more than three, but there are so many influential women in history and we're never taught about them.