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Source of Acquisition NASA Goddard Space Flight Center

a New F for the LOLA Laser Cavity

W. Lawrence Ramsey , NASA,GSFC

enn Rosecrans , SGT ,GSFC

https://ntrs.nasa.gov/search.jsp?R=20070035099 2020-08-07T11:48:25+00:00Z

The Lunar Orbiting Laser Altimeter (LOLA) will fly on the Lunar Reconnaissance Orbiter (LRO).

The laser is based upon the one in the Mercury Laser Altimeter (MLA) . LOLA will fly two lasers instead one in laser cavity.

The MLA aser has a six year flight to station.

Lasers can fire in air with 0 2 present.

During testing and on orbit, LOLA wil in vacuum.

* The laser cavity must be sealed against molecular and particulate contaminants.

Mission to Moon wi start with 60 days of

Ouralshs ]ua~ ayl a]~n@~a-a~ o] apem SBM UOTST~~P .

Drawing o MLA Fi

Proposed So

* To prevent cross contamination, put a fence between lasers.

* Clean the parts and reduce outgassing more than MLA.

* Prevent known "bad" laser materials from being used.

* Increase venting rate, add more vents, and change locations.

ions Chosen

Convened expert panel.

Eliminated changes in Be housing.

Redesign metal filter vent hole.

Clean NVR to A13 instead of A12.

Use and RGA to ensure that bad compounds are gone - Principa y: Silicones and

Design o New Ven gassing

Insert graph of MLA venting showing ow outgassing

gassing Con

Insert Graph of proposed changes.

New

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New design Con

Flight filter profile

Fliter base showing Mott Sintered metal filter cup and "Om ring cavity.

ing New Design

Compare outgassing rates to tests performed during MLA.

Since MLA filters arrived clean no cleaning was necessary. Came direct from sintering furnace.

New filters undergo machining and welding.

Test of workmanship and cleaning technique.

Insert video of test.

LO PRESS CYL TORR

1- LO PRESS CYL TORR ~

Begin with 2% Simple Green in DI water @ 40C in ultrasonic cleaner. Follow with just DI. Then rinse with Isopropyl Alcohol (IPA) Dry w/N2. Place part in 50:50 solution of IPA and Acetone @ 40C and ultrasonic cleaner. Rinse wlhexane take NVR sample and dry w/ N2. Place in oven at 550C for 1 hour.

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Ready r LOLA Beam Expander

Receiver Telescope 1 I

Laser Cavity Vent

Aft optics