NASA - Neil ArmstrongApollo 11, July 21, 1969. Buzz Aldrin installs the solar wind particle collector . Period chromogenic print on " A Kodak Paper" paper . Image: 19.5 x 24 cm Sheet: 20.4 x 25.4 cm Buzz Aldrin is deploying a system to collect solar particles. It is the absence of atmosphere on the Moon that allows particles to reach its surface. On Earth, particles are trapped by the magnetic field and accumulate in the Van Allen belt. They are, among other things, at the origin of the polar aurora.