1958 – First solar-powered spacecraft launched
Vanguard 1. The Soviet Premier, Nikita Khrushchev, made fun of its size, (6″ diameter), calling it a “grapefruit.” It actually discovered the Earth is slightly pear-shaped. It carried a temperature sounder and a radio transmitter. It’s power system stopped in 1964 although it had been expected to orbit earth and transmit data for a 1,000 years. Recent calculations have reduced the time in orbit to 240 years. As Vanguard 1, Vanguard 2, and Vanguard 3 are still orbiting with their drag properties essentially unchanged, they form a baseline data set on the atmosphere of Earth that is over 60 years old and continuing.
2012 – Messenger spacecraft wraps up a year-long campaign performing the first orbital reconnaissance of the geochemistry, geophysics, geologic history, atmosphere, magnetosphere, and plasma environment of Mercury.
2004 – ESA’s INTEGRAL gamma-ray observatory, solving a 30 year mystery, has resolved the diffuse glow of gamma rays in the centre of our Galaxy showing that most of it is produced by a hundred individual sources. INTEGRAL’s science observations ended on February 28, 2025 with the spacecraft expected to re-enter Earth’s atmosphere in February 2029.
diffuse glow of gamma rays
Birthdays
1930 – James Irwin, American colonel, pilot, and astronaut he served as Lunar Module pilot for Apollo 15, the fourth human lunar landing. He was the 8th person to walk on the Moon (d. 8 August 1991)