#lta-4

Grumman Aerospace developed a series of prototypes to test different aspects of the Lunar Module before it went into production. Like the Block I version of the Apollo Command and Service Modules, there are gaps in the production of the LTAs. This post is what I able find as far what was intended and what they ended up being used as.

LTA-1: House Spacecraft No. 1. It was built to iron out problems during fabrication, assembly, checkout and testing electrical systems at Grumman's Bethpage facility. The Ascent Stage of LTA-1 is displayed with the Descent Stage of LTA-11.

Smithsonian Institute: A19740648000

LTA-2: Launch Vehicle Dynamics Test Article. It was shipped to Huntsville for vibration testing to see if it could withstand launch pressures.

LTA-2R: Later it was refurbished to replace the cancelled one of two Flight Test Articles. It was flown on Apollo 6 and burned up in the atmosphere.

LTA-3: structural test article. Used for structural and vibration tests to define component vibration levels.

LTA-3A: Ascend Stage was combined with LTA-5 for structural shakings, vibrations, and engine firings in White Sands, New Mexico.

Currently on display at Kansas Cosmosphere and Space Center, Hutchinson, Kansas. source

LTA-3DR: refurbished descent stage.

LTA-3DR on display at the Franklin Institute, Philadelphia, Pennsylvania. source

LTA-4: Environment Test Article at the Grumman factory vacuum chamber. Grumman suggested for use on Apollo 8 as a mass simulator for the Lunar Module. NASA ended up using LTA-B. Its construction cancelled by NASA as an unnecessary expense.

LTA-5: Propulsion test article. It was built with a complete production Descent Propulsion System (DPS)

LTA-5D: Descent stage. The DPS developed a leak during testing and caught fire, requiring a refurbishment and redesignated LTA-5D.

LTA-5D was transferred to the New Mexico Museum of Space History and is waiting to be put on display. source

LTA-6: construction cancelled by NASA as an unnecessary expense.

LTA-7: Environmental Test Article. Its construction cancelled by NASA as an unnecessary expense.

LTA-8: Dynamic test and evaluation test article. This LTA was meant to be the third production model built, after LM-1 and LM-2 and the first to be human rated. The previous two were only intended for uncrewed missions (Apollo 5 and second follow up mission which was cancelled). The plan was LTA-8 was to be sent to White Sands Missile Range to undergo full duration firings in a test stand. This was eventually cancelled and the LTA-8 was modified for vacuum tests.

LTA-8A under construction at Grumman's Bethpage facility. NASA ID: S67-27042

LTA-8A: Thermal Vacuum Environment Test Article. It was used for thermal-vacuum testing at Chamber B the Johnson Space Center, near Houston, Texas. Manned by John Bull and Apollo 15 astronaut Jim Irwin, the spacecraft was tested to verify the habitability of the Lunar Module cabin pressure and temperature through simulated conditions it would face during Apollo missions.

LTA-8 on display at Space Center Houston. Posted on Flickr by Wally Gobetz: link

LTA-9: Atmospheric tethered operation tests article. Possibly intended as a landing gear test model. Similar to LTA-8, meant to be a manned production version and would have seen the LTA delivered to White Sands, New Mexico and would have used its DPS to lift it while tethered to a helicopter or fixed base. The atmospheric testing was cancelled along with its construction by NASA.

LTA-10: Lunar Module and SLA structural test article. It was built to be used in fit checks and separation tests by North American for its SLA work in Tulsa. Only the descent stage was constructed, with construction the Ascend Stage, landing gear and propulsion systems cancelled.

LTA-10R: LTA-10 was refurbished to replace the cancelled one of two Flight Test Articles and flown on Apollo 4 and burned up in the atmosphere.

LTA-10R at the Kennedy Space Center, prior to integration with the Apollo 4 Spacecraft.

LTA-11: it was built to iron out problems during fabrication, assembly, and checkout at Grumman's Bethpage facility. Only Descent stage built. See LTA-1 for current whereabouts.

If you made it this far, I thank you. This took a lot of time to research and comb through to find about the ones that were not built or their original purpose. Some, like LTA-6, have very little info available online.

source, source, source, source, source

National Air and Space Museum Archive: A19761784000