2011 – Space Shuttle Discovery STS-133 makes its final landing after 39 flights.
2005 – Cassini flys by Enceladus & Tethys, moons of Saturn.
2004 – Astronomers unveiled the deepest portrait of the visible Universe ever achieved, called the Hubble Ultra Deep Field (HUDF).
1997 – Comet Hale-Bopp: Observers in China, Mongolia
and eastern Siberia are treated to a rare double feature as an eclipse permits Hale-Bopp to be seen during the day.
1996 – STS-75, the 19th mission of Columbia, landed at 13:58 GMT. Mission duration: 15 days, 17 hours, 40 minutes, 22 seconds
1979 – 
Linda Morabito, an imaging scientist at NASA’s Jet Propulsion Laboratory, identified the volcanic activity in images from Voyager 1 spacecraft, one of Jupiter’s moons, revealing a dynamic and active environment on a moon previously thought to be geologically dead.
1974 – Mars 7 Mars Flyby (Soviet Union).
1961 – Sputnik 9 successfully launches, carrying a human dummy nicknamed Ivan Ivanovich and a dog named Chernushka, and demonstrating that Soviet Union was ready to begin human spaceflight. Both the dummy and the dog were successfully recovered.
1955 – Walt Disney personally introduced the first television show of ‘Man in Space’, which aired on ABC. Wernher von Braun, the rocket engineer and Walt Disney, the artist, used the new medium of television to show that humans might go to the Moon and beyond based on future technologies and the desire to explore and discover.
Birthdays
1934 – Yuri Gagarin, a Russian Soviet pilot and cosmonaut. He was the first human to journey into space and complete an orbit of Earth, aboard a Vostok spacecraft on 12 April 1961. He died 27 March 1968 due to a crash of his training vehicle.
1564 – David Fabricius, discoverer of the first variable star (Mira, or Omicron Ceti).