Today in 1971, David Scott, James Irwin and Alfred Worden became the first philatelists in space. Their attempt to smuggle unauthorised postage stamps to the Moon and back to be sold later did rather put a bit of a downer on the reputation of the fourth Moon landing, which was a shame, because the mission (including the first use of the lunar rover), was otherwise a great success.
Apollo 15 was the first manned craft to land somewhere other than a lunar mare, and was longer than previous visits, with over 18 hours spent outside the lunar module. The landing site chosen for Apollo 15 was Hadley Rille, a valley to the southwest of Mons Hadley, a ‘massif’ in the Moon’s northern hemisphere.
It was Scott and Irwin who went to the surface with their Lunar Roving Vehicle. This allowed them to travel much further than before and still keep in touch with Mission Control, and indirectly the command module, using the Lunar Communications Relay Unit on the front of the rover. In total the astronauts drove for over 17 miles (27 km), reaching a distance of just over three miles from the lunar module. Unfortunately their distance record only stood for a year and a half; Apollo 17 smashed it in their rover by traveling 22 miles (36 km), and getting to 4.7 miles (7.6 km) from their lunar module.
1958 – launch of Explorer 4. Launched this day in a blaze of secrecy, Explorer 4 spent the summer of 1958 collecting data on the Van Allen radiation belts. The Explorer family is the longest running series of spacecraft ever, from Explorer 1 in 1958 to Explorer 78 in 2000.