If China gets to the moon next year as planned, they're going to find a lot of stuff waiting for them: about 187 tons of space probes, spacecraft parts, and pieces of scientific experiments - plus a couple of golf balls.
If the Chinese bring a flag to plant, they won't be the first: American astronauts on the Apollo missions have planted six flags on the moon. According to recent scientific observations, five of them are still standing upright.
New pictures from NASA's Lunar Reconnaissance Orbiter Camera show that the flags at five of the sites are still casting a shadow. But the flag planted by astronauts at the initial moon landing is no longer standing, corroborating astronaut Buzz Aldrin's account of seeing the flag knocked over by Apollo 11's exhaust as it took off on the journey home.
"Personally I was a bit surprised that the flags survived the harsh ultraviolet light and temperatures of the lunar surface, but they did," LROC and Arizona State University researcher Mark Robinson wrote in a blog post last week.
Though still standing up proudly, the flags might be a bit worse for wear after decades of exposure to the harsh lunar climate. The flags have been bombarded by radiation, tiny meteorites and dealt with temperatures as high as 242 degrees Fahrenheit and as low as -280 degrees Fahrenheit.
It's likely that the flags have faded badly - which is rather poignant, as Lunar and Planetary Institute scientist Paul Spudis pointed out last year, considering that the U.S. space shuttle program was grounded permanently.
"America is left with no discernible space program while the Moon above us no longer flies a visible U.S. flag," Spudis wrote in a post for the Smithsonian Air & Space Museum in July 2011.
The oldest man-made object on the moon is the USSR's Luna 2 craft, which crashed onto the surface in 1959. The youngest objects on the lunar surface are parts of the U.S.'s Lunar Crater Observation and Sensing Satellite that were deliberately crashed into the moon in 2009 to generate a dust plume so the satellite could search for traces of water ice in the moon's craters.
Aside from flags, the crashed space probes and the aforementioned golf balls -- hit by Apollo 14 astronaut Alan Shepard -- the moon's surface is also home to other more personal effects. Apollo 12 astronaut Alan Bean left a silver lapel pin on the moon in 1969. The pin was issued by NASA to all those that have completed astronaut training, but he would soon be wearing the gold pin given only to those who have actually been to space.
A sadder piece of memorabilia on the moon is the Fallen Astronaut, a small sculpture left by the Apollo 15 crew to commemorate cosmonauts and astronauts that died in the line of duty. The statuette is just over 3 inches tall, and was made by Belgian sculptor Paul Van Hoeydonck.