A California preservation panel has taken the unusual step of naming the 1969 Apollo 11 moon landing site as a state historical resource.
The vote by the California State Historical Resources Commission is part of an effort by several states to have Tranquillity Base become a national historic landmark and then a world heritage site.
The designation applies to everything left on the moon by astronauts Neil Armstrong and Buzz Aldrin, not the lunar surface.
State Historic Preservation Officer Milford Wayne Donaldson said similar moves will be made in Texas, New Mexico, Georgia and Florida - the other states highly involved in the Apollo programme.
The Apollo 11 lunar module Eagle set down on the moon's Sea of Tranquillity on July 20 1969, with Armstrong calling to mission control: "Houston, Tranquillity Base here. The Eagle has landed."
In all there are more than 100 items that the astronauts had to leave behind, Donaldson said.
They include science instruments, tools, rubbish and the spider-legged descent stage of the lunar landing craft.
The astronauts used the upper half of the craft to return to the command module orbiting the moon, which took them home.