First-Hand:David Flinchbaugh on Lunar Laser Experiments

On that very historic day, I was watching my television set intently to see as much detail as possible of the Astronaut activities, transmitted by their old-fashioned color-wheel type camera. I remember that some temporary damage to that specially-modified Hasselblad camera occurred due to a brief inadvertent aiming at the Sun. However, our small electro-optical pioneering team at Orlando Research Corp. (now Control Laser Corp.) had designed, manufactured, assembled, tested, calibrated, and delivered a powerful 15-watt continuous-wave blue-green Argon-ion laser to the Cloudcroft Astronomical Observatory in New Mexico, operated jointly by NASA and the U.S. Air Force, just prior to that Apollo launch.

This project kept me very busy for several days and nights: very carefully assembling and aligning all of the optical, electrical, and mechanical components and conducting many hours of outgassing all inner elements of this five-foot long assembly by repeated cycles of r.f. induction heating to very hot glowing temperatures in an extremely high vacuum environment The cleaning and purification cycling included system flushes with laboratory pure Argon gas. Based on a patent by Dr. Bill McMahon, our unique “anodic-bore” ion laser utilized a positively charged axial hollow electrode which further confined and compressed the red hot electrical ion-electron plasma discharge along the long central aperture to improve the efficiency of imparting energy into the powerful laser visible optical output. This c-axis oriented precision-machined pyrolytic graphite bore also featured radiation-cooling fins, all surrounded by a flowing water-cooling, fused-silica jacket outside of the inner assembly. The output windows and mounting surfaces were polished so precisely that no contaminating glue or adhesive was used to seal them together…a rigorous cleaning procedure allowed us to use only the molecular surface atomic attraction forces to form a vacuum-tight, clean seal. Other key IEEE members of our team included Dr.Mc Mahon and John Tracy. You probably have seen some of our powerful lasers at the Walt Disney World Laser Light Displays at night illuminating the clouds of this Central Florida Orlando Community

Our mission with Apollo 11 was to establish a visual contact, for the first time in history, with humans on another astronomical body, as well as to pinpoint their landing site on the lunar surface. Our highly collimated, small diameter, visible Ar+++ laser beam was expanded through a large (30”diameter) refracting telescope at the Cloudcroft Observatory on Earth, so that the naturally-occurring divergence travelling about 240,000 miles from the earth to the Moon would spread this intense beam to only about one mile in diameter when it reached the surface of the moon nearly 240,000 miles away. This experiment would achieve two historical firsts: 1) the first precision observation of a tiny, but very bright beam of light pinpointing its location coming from the Earth directly to the first men on the moon, and 2) illuminating and precisely locating the first lunar landing exploration base from the Earth.

You may recall that the Astronauts set up an array of optical retro-reflectors which was designed to return any light beam incident upon them directly back toward the source from whichit came. Because of inclement weather for several days, no visual observations were successful until the following week. Also, because of difficulties landing the lunar module in the exact place initially chosen, they ended up several miles off course while making a safe landing, with the ability for a safe and successful return takeoff. During the following week, a red beam from a powerful, pulsed ruby laser was directed toward the moon from the Mt. Palomar Observatory in California, and it was used to search for the retro-reflector array. That team finally succeeded in finding, for the first time, exactly where they had landed!. That was and wonderful and an exciting mission, indeed!

Dr. David E. Flinchbaugh, Ph.D., P.E