1902 – S-type asteroid 482 Petrina was discovered from Heidelberg on March 3rd by Max Wolf. It was his sixty-second asteroid. Petrina is a fairly small asteroid with a diameter of about 46 km. According to Lutz Schmadel’s Dictionary of Minor Planet Names (Springer Verlag) it was named after Wolf’s dog, Peter.
1959 – Launch of Pioneer 4, the first US spacecraft to escape Earth’s gravity. It managed to get within 60,000 km of the Moon before entering a heliocentric (around the Sun) orbit.
Some spacecraft are bigger than others, and its not always obvious from their photographs what kind of scale is involved. So here’s a photo of Pioneer 3 under construction, which will probably make you think something along the lines of “It’s tiny! Are they all that small?”.
1969 – Launch of Apollo 9 under commander James McDivett (with command module pilot David R Scott and lunar module pilot Russell (Rusty) Schweickart. The mission is noteworthy for including the first manned flight of a lunar module, and the fist docking of two US spacecraft.
2009 – March 4th of 2009 saw the discovery of the extraordinarily small moon Aegaeon within Saturn’s G Ring. It is estimated to be about one and a half kilometres long and half a kilometre in diameter. Unsurprisingly it now holds the title of Saturn’s smallest known moon.