This Day In Space History: August 3

1596

http://www.onthisday.com/events/august/3
David Fabricas observes Mira as the first variable star (brightness fluctuates).

http://www.yearinspace.com/the-week-in-space/486-august-3-2015-milky-way-looks-in-the-mirror

2004

https://www.space.com/37183-today-in-space.html
Costing $450 million, MESSENGER spacecraft is launched from Cape Canaveral at 6:15 EDT to Mercury.

2005

https://airandspace.si.edu/stories/editorial/day-first-spacewalk-under-shuttle
Stephen K. Robinson makes the first space walk under a shuttle in order to make the first in-flight repair.

For a complete list of today’s Space History, see  http://www.astronautix.com/a/august03.html