Look what we got!It's LTA-5, or Lunar Test Article 5, and is the lunar module ascent and descent stages. It was built by Grumman and tested at White Sands Test Facility (WSTF) in the early 60s.
Engineers at WSTF were able to attach all the lunar module engines to this frame and test them in all conditions. The results of the tests were used to improve the design of the lunar module and ensure that it was safe and reliable for the Apollo missions to the moon.
It may look very odd because there's no "skin" (metallic covering) on the lunar module and no legs attached. But that's what makes this quite special... you can see the internal structure of the lunar module. LTA-5 is now being stored at the Museum of Space History's support center until it can be put on display.