What made this pen even more special was the plate that you see on the barrel.  Moon dust retrieved by Apollo XV astronauts James B. Irwin and David R. Scott was embedded into powdered gold through a process known as sintering, and formed into small panels.  These panels were then mounted on the barrel.

The panel's inscription reads

Traces of Lunar Material
Apollo 15

Based upon PR from the firm, at first it was thought that only 3 of these special pens were made and presented to the US State Department.  President Nixon kept one and took the other two on his historic trip to China in 1972, opening the door to normal US-China relations.  The President presented them to Yao Wen-yuan, Municipal Representative of the City of Shanghai, and Nan P'ing, the Chairman of Chekiang Provincial Revolutionary Committee.    Thus this unique Parker 75 pen was involved with the trip that paved the way for normalized relations with the People's Republic of China.

It was later learned that Parker secretly made an additional two FPs.  Apparently one escaped captivity and surfaced at the Chicago 2000 pen show auction.  

Here is the photograph that Parker made of this special pen.