Footprints made by astronauts on Earth's moon are likely to last a long time even though they have not been turned to stone (lithified). This is because there are few (if any) forces on the moon that could destroy them. There are no bodies of moving water to disturb the dust the footprints were made in. There are no winds to blow them away. Unless they are stepped on by another astronaut, rolled over by a machine, or hit by a meteor, those moon tracks will probably last a very long time. Footprints made on Earth are not as likely to survive.