The moon is the final resting ground for scads of landed and crashed spacecraft, many of which have been pinpointed recently by sleuthing scientists.

Using observations by NASA's sharp-eyed Lunar Reconnaissance Orbiter, for example, researchers have located and imaged Apollo moon landing leftovers, old Soviet-era spacecraft and, more recently, the impact locales of NASA's twin Grail spacecraft that were deliberately driven into a mountain near the moon's north pole.

But the search is ongoing to find the exact location of several pioneering moon landers. [The Moon: Space Programs' Dumping Ground (Infographic)]

No luck so far

"We are still looking for [the Soviet Union's] Luna 9 and 13," said Jeff Plescia, a space scientist at the The Johns Hopkins University's Applied Physics Laboratory in Laurel, Md.

"Those were the small 'beach ball' shaped spacecraft," Plescia told SPACE.com "The beach ball might be hard to find, but it made a descent on a larger vehicle which then popped the beach ball off."

Plescia said he had assumed that it would be possible to find the landing sites of Luna 9 and 13 by spotting albedo marks — a change in the lunar surface brightness made by their descent engines.

Plescia is joined in the hunt by Mark Robinson of Arizona State University, principal investigator for the Lunar Reconnaissance Orbiter Camera, or LROC.

"We've both looked, but no luck so far." Plescia said.

Yet another search involves the impact sites of Apollo lunar module ascent stages, hardware discarded once moonwalking crews were snug within their respective command modules. Ascent stages were intentionally impacted into the surface as part of the Apollo Passive Seismic Experiment that studied the propagation of seismic waves through the moon to yield a detailed look at the body's internal structure