Day in Engineering History Archive - April 11

April 11

1875: Samuel Schwabe, who first documented the roughly 10-year sunspot cycle, died. 1900: The U.S. Navy acquired its first submarine. 1908: Masaru Ibuka, who founded the company that became Sony Corporation, was born. 1921: KDKA broadcast the first radio sporting event - a boxing match. 1945: During World War II, American soldiers liberated the Nazi concentration camp of Buchenwald. 1957: A Ryan X-13 Vertijet became the first jet to take-off and land vertically. 1970: Apollo 13 blasted off on a mission to the moon that was disrupted when an explosion crippled the spacecraft; the astronauts managed to return safely. 1984: Challenger astronauts completed the first in-space satellite repair on the Solar Max. 1986: Halley's Comet made its closest approach to Earth this latest appearance. 2001: China Agreed to Release 24 Crewmembers of a U.S. EP-3E Surveillance Plane.

| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |

Note: These historical tidbits have been collected from various sources, mostly on the Internet. As detailed in this article, there is a lot of wrong information that is repeated hundreds of times because most websites do not validate with authoritative sources. On RF Cafe, events with hyperlinks have been verified. Many years ago, I began commemorating the birthdays of notable people and events with special RF Cafe logos. Where available, I like to use images from postage stamps from the country where the person or event occurred. Images used in the logos are often from open source websites like Wikipedia, and are specifically credited with a hyperlink back to the source where possible. Fair Use laws permit small samples of copyrighted content.