Astronaut footprints are still visible on the Moon due to several factors:

• Lack of Atmosphere: Unlike Earth, the Moon has virtually no atmosphere. This means there's no wind or weather to erode or disturb the footprints.
• Absence of Water: There is no liquid water on the Moon's surface to wash away or degrade the footprints.
• No Biological Activity: There are no living organisms (plants, animals, or bacteria) to disturb or decompose the footprints.
• Fine Lunar Soil: The lunar surface is covered in a fine, powdery soil called regolith. This material is easily compressed and holds its shape well, preserving the footprints.

Because of these conditions, the footprints and other traces left by astronauts during the Apollo missions could remain visible for potentially millions of years, unless disturbed by a significant event like a meteorite impact.

For further information, you can refer to these resources:

• The Planetary Society: How Long Will Footprints Last on the Moon?
• NASA: Moon Facts