Lunar Module LTA-3D

Sitting in the Franklin Institute's "back yard" sits Lunar Test Article 3D. It certainly is an odd place for a lunar module!

The Franklin Institute has a page regarding the lunar module test article. The pictures there were apparently taken some time ago, as the side CCW from the hatch features an American flag and the side CW from the hatch has a patch of gold foil; these were absent when I visited.

Just by looking at it, one would be inclined to think it was just another boilerplate, of so-so fidelity. However, according to the Apollo Experience Report - Lunar Module Structural Subsystem, LTA-3 was a "structural test vehicle," used during the design verification process. It underwent the same types of conditions in the same experience that would be experienced during an actual mission, including ascent stage cabin pressurization and exposure to vibration tests to simulate both the ascent and descent engine loads. It was loaded in a SLA, stacked with a CSM, and exposed to vibration and acoustic tests to simulate a launch. It also underwent drop tests to simulate a lunar landing.

Various problems cropped up, uncovering defects in the manufacturing process and flaws in the design; appropriate corrective actions were taken. In preparation for one test, stress corrosion cracks were discovered in aft equipment rack support struts; an inspection revealed 23 cracked struts. This resulted in changing the manufacture of the struts for production lunar modules.

LTA-3's final series of tests was to verify the docking interface structure; information about this test can be found in Plan for Unit Load Tests of LTA-3 and CM 2S-1 (Docked Configuration).

At some point, the ascent and descent stages of LTA-3 were split up; this is apparently the descent stage with a fabricated ascent stage more representative of the design which landed on the Moon. LTA-3's ascent stage is at the Kansas Cosmosphere.