Can telescopes spot footprints on the Moon?
In 1969, the Apollo 11 astronauts walked on the Moon. Can we still see the marks left by the mission using telescopes?
Telescopes on Earth cannot see the objects that were left on the Moon by the Apollo missions – they are too small.
Not even the Hubble telescope can see Apollo objects on the Moon’s surface. For that to be possible, the objects would need to be almost 100 metres long, and the biggest object is only about 4x5 metres. But the Lunar Reconnaissance Orbiter, which is orbiting the Moon, came as close as 24km from the surface, and in 2012, the probe photographed a series of landing sites of different lunar missions.
The images of the Apollo 11 landing area clearly show several abandoned objects, and some of Neil Armstrong’s footprints during an unauthorised excursion to the Little West Crater about 50 metres away – the furthest an astronaut has moved away from a landing site. The probe returned to the landing sites several times to take photos from the same angle at different solar altitudes, and could thereby observe shadows cast by the abandoned objects.
Most of the flags that the astronauts planted were found to be still on the Moon’s surface. This surprised scientists, as they had not expected that the flags could withstand 40+ years with temperature fluctuations of hundreds of degrees, a vacuum, and powerful UV radiation from the Sun. Only the very first flag, the one planted by Neil Armstrong, is no longer flying, as it was blown over by the exhaust when the astronauts took off from the Moon.