On Saturday August 25, 2012, a true American hero lost his life. Neil Armstrong was the first person to bravely leave our world behind and set foot on another. On July 21, 1969, he walked on the moon.

To be a young girl witnessing this amazing--and I don't use that term lightly--this amazing feat would have changed my life in ways unimaginable. But I wasn't alive in 1969. And by the time I even became aware of NASA's existence, a total of twelve people had stepped foot on the lunar surface. They were individual explorers, as are all of the fearless men and women in the space program. But their personal accomplishments mean more to me as a whole. They embody a spirit of exploration, uniting a nation--no, the world--and proving to us just what is possible.

Neil wasn't the only astronaut who passed away this year. On February sixth, Janice Voss, science director for NASA's Kepler Space Observatory, died. She left our planet on five separate occasions to fly in space. And Alan Poindexter, Navy Captain and shuttle pilot on two trips to the international space station, lost his life on July first. On July 23, Sally Ride, the first American woman in space passed away. To this day, she remains the youngest astronaut to leave Earth in her taillights.

Neil, Janice, Alan, Sally, and all of the brave men and women who have contributed to space exploration over the years, this is for you:

I've written this letter to express my debt of gratitude. I can speak only on my behalf, but I cannot fathom that other young minds weren't also inspired by your strength, your courage, and your humility. You represent a spirit of exploration, a hunger for worlds unknown, stories untold, that those who may follow in your footsteps might otherwise be afraid to embrace.

Today we live in a world ravaged by war, poverty, consumption, and greed. Our politicians and leaders are shackled by the weight of superstition, favor, and promises impossible to keep. But you four, you remind us that even in a time of social unrest, even when we fear we've lost our way, our aspirations can be greater than the opposition, we can boldly go into the great beyond, and knowledge, reason--science--can be our guide.

You viewed your own successes modestly. You were reluctant heroes who lead private lives with your families, friends, and loved ones. And although you may not have known it at the time, you made great sacrifices--you risked your lives--for future generations, for people like me, so that we may be inspired to find our candle in the dark. To reach beyond the stars. And for that, I thank you from the bottom of my heart and the depths of my mind.

Many astronauts live their lives quietly, humbly, insisting they're simply doing the job they were called upon to do. This humility was epitomized by Neil Armstrong. Upon his passing, his family issued this statement: "For those who may ask what they can do to honor Neil, we have a simple request. Honor his example of service, accomplishment and modesty, and the next time you walk outside on a clear night and see the moon smiling down at you, think of Neil Armstrong and give him a wink."

Well here's looking at you, Neil. You and all of our fallen heroes will be greatly missed.

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  • View of food packets for the Gemini 7 space flight packaged and ready for loading on the Gemini spacecraft.

  • The Gemini-Titan 4 prime crew, astronauts James A. McDivitt (left), command pilot; and Edward H. White II, pilot, are pictured during water egress training at Ellington Air Force Base, Texas.

  • Astronauts Charles Conrad (right), command pilot, and Richard F. Gordon (left), pilot, demonstrate tether procedure between their Gemini 11 spacecraft and the Agena Target Docking Vehicle at the post flight press conference. They use models of their spacecraft and its Agena to illustrate maneuvers.

  • Astronaut Edwin E. Aldrin Jr., backup crew pilot of the Gemini 9 space flight, practices donning the Astronaut Maneuvering Unit (AMU) back pack in bldg 5 of the Manned Spacecraft Center, Houston.

  • Artist concept of Gemini spacecraft and Command Module with two astronauts seated at the controls.

  • Effects of the weightless environment on cell division, the basic growth process for living tissue, studied during the Gemini-Titan 3 flight on March 23, 1965.

  • Astronaut James A. McDivitt, commander of Gemini IV, suited in preparation for weight and balance tests. The objective of the Gemini IV mission was to evaluate and test the effects of four days in space on the crew, equipment and control systems. Pilot Edward White II successfully accomplished the first U.S. spacewalk during the Gemini IV mission.

  • Astronaut Edwin E. Aldrin Jr., backup crew pilot of the Gemini 9 space flight, practices donning the Astronaut Maneuvering Unit (AMU) back pack in bldg 5 of the Manned Spacecraft Center, Houston.

  • The Gemini VI, scheduled as a two-day mission, was launched December 15, 1965 from Pad 19, carrying astronauts Walter M. Schirra Jr., Command Pilot, and Thomas P. Stafford, Pilot. Gemini VI rendezvoused with Gemini VII, already orbiting the Earth.

  • Gemini-Titan 4 (GT-4) lift-off carrying James McDivitt and Ed White for a four-day mission. This flight included the first spacewalk by an American astronaut, performed by Ed White.

  • Atlas Agena target vehicle liftoff for Gemini 11 from Pad 14. Once the Agena was in orbit, Gemini 11 rendezvoused and docked with it.

  • Aerial view of the Gemini/Titan-II launch vehicle #1 liftoff at Cape Kennedy, Florida.

  • Labeled photograph of the Middle East was taken by the crew of the Gemini 4 flight. Areas in Egypt, Syria, Iraq, Israel, and Saudi Arabia are labeled.

  • A bank of clouds over the western Pacific Ocean was photographed by Astronaut Frank Borman and James A. Lovell during the Gemini 7 mission. In the background the moon can be seen.

  • Astronaut Alan B. Shepard Jr., chief, astronaut office, NASA's Manned Spacecraft Center in Houston, chomps vigorously on a cigar during relaxing moments following the Gemini-6 liftoff.

  • View of the tracking screen at the front of the Mission Control Center during the Gemini-5 spaceflight.

  • Astronaut Roger B. Chaffee is shown at console in the Mission Control Center, Houston, Texas during the Gemini-Titan 3 flight.

  • The wives of Gemini 4 astronauts James A. McDivitt and Edward H. White II visited the Mission Control in Houston. Left to right are: Mrs. Patricia McDivitt and Mrs. Patricia White. The wives were taking the opportunity to speak to their astronaut husbands as they passed over the United States.

  • NASA successfully completed its first rendezvous mission with two Gemini spacecraft-Gemini VII and Gemini VI-in December 1965. This photograph, taken by Gemini VI crewmembers Walter Schirra and Thomas Stafford, shows Gemini VII in orbit 160 miles (257 km) above Earth. The main purpose of Gemini VI was the rendezvous with Gemini VII. The main purpose of Gemini VII, on the other hand, was studying the long-term effects of long-duration (up to 14 days) space flight on a two-man crew. The pair also carried out 20 experiments, including medical tests. Although the principal objectives of both missions differed, they were both carried out so that NASA could master the technical challenges of getting into and working in space.

  • The Augmented Target Docking Adapter (ATDA) as seen from the Gemini 9 spacecraft. The docking adapter protective cover failed to fully separate on the ATDA and prevented the docking of the two spacecraft. The ATDA was described by the Gemini 9 crew as an "angry alligator."

  • The Agena Target Vehicle as seen from the Gemini 8 spacecraft during rendezvous. This was the first time two spacecraft successfully docked, which was a critical milestone if a mission to the Moon was to become a reality.

  • This photograph taken on December 15, 1965 shows the Gemini 7 spacecraft as it was observed from the hatch window of the Gemini 6 spacecraft during rendezvous manuevers and station keeping at a distance of approximately 9 feet apart.

  • The Gemini 10 spacecraft is successfully docked with the Agena Target Vehicle. The Agena display panel is clearly visible as is glow from Agena's primary propulsion system.

  • Edwin E. Aldrin Jr., pilot of the Gemini 12 spacecraft performs extravehicular activity (EVA) during the second day of the four day mission in space. Aldrin is positioned next to the Agena work station.

  • An unusual view of the Gemini 9 spacecraft taken by Eugene Cernan during his Extravehicular Activity (EVA). His umbilical and spacecraft are visible though he is not.

  • Edward H. White II, pilot of the Gemini 4 spacecraft, floats in the zero gravity of space with an earth limb backdrop. The extravehicular activity was performed during the third revolution of the Gemini 4 spacecraft and represents the first time an American has stepped outside the confines of his spacecraft. White is attached to the spacecraft by a 25-ft. umbilical line and a 23-ft. tether line, both wrapped in gold tape to form one cord. In his right hand White carries a Hand-Held Self-Maneuvering Unit (HHSMU). The visor of his helmet is gold plated to protect him from the unfiltered rays of the sun.

  • Astronaut Edward H. White II, pilot for the Gemini-Titan 4 space flight, floats in zero gravity of space. The extravehicular activity was performed during the third revolution of the Gemini 4 spacecraft. White is attached to the spacecraft by a 25-ft. umbilical line and a 23-ft. tether line, both wrapped in gold tape to form one cord. In his right hand White carries a Hand-Held Self-Maneuvering Unit (HHSMU). The visor of his helmet is gold plated to protect him from the unfiltered rays of the sun.

  • On June 3, 1965 Edward H. White II became the first American to step outside his spacecraft and let go, effectively setting himself adrift in the zero gravity of space. For 23 minutes White floated and maneuvered himself around the Gemini spacecraft while logging 6500 miles during his orbital stroll. White was attached to the spacecraft by a 25 foot umbilical line and a 23-ft. tether line, both wrapped in gold tape to form one cord. In his right hand White carries a Hand Held Self Maneuvering Unit (HHSMU) which is used to move about the weightless environment of space. The visor of his helmet is gold plated to protect him from the unfiltered rays of the sun.

  • Astronaut Edward H. White II, pilot for the Gemini-Titan 4 space flight, floats in zero gravity of space. The extravehicular activity was performed during the third revolution of the Gemini 4 spacecraft. White is attached to the spacecraft by a 25-ft. umbilical line and a 23-ft. tether line, both wrapped in gold tape to form one cord. In his right hand White carries a Hand-Held Self-Maneuvering Unit (HHSMU). The visor of his helmet is gold plated to protect him from the unfiltered rays of the sun.

  • On June 3, 1965 Edward H. White II became the first American to step outside his spacecraft and let go, effectively setting himself adrift in the zero gravity of space. For 23 minutes White floated and maneuvered himself around the Gemini spacecraft while logging 6500 miles during his orbital stroll. White was attached to the spacecraft by a 25 foot umbilical line and a 23-ft. tether line, both wrapped in gold tape to form one cord. In his right hand White carries a Hand Held Self Maneuvering Unit (HHSMU) which is used to move about the weightless environment of space. The visor of his helmet is gold plated to protect him from the unfiltered rays of the sun.

  • Waves of clouds along the east flanks of the Andes Mountains cast off an orange glow by the low angle of the sun in the West. The dark area to the left is the Earth's terminator. This view was photographed by astronaut Frank Borman and James A. Lovell during the Gemini 7 mission, looking South from Northern Bolivia across the Andes. The Intermontane Salt Basins are visible in the background.

  • Astronauts Neil A. Armstrong and David R. Scott sit with their spacecraft hatches open while awaiting the arrival of the recovery ship, the USS Leonard F. Mason after the successful completion of their Gemini VIII mission. They are assisted by USAF Pararescuemen Eldrige M. Neal, Larry D. Huyett, and Glenn M. Moore. The overhead view shows the Gemini 8 spacecraft with the yellow flotation collar attached to stabilize the spacecraft in choppy seas. The green marker dye is highly visible from the air and is used as a locating aid.

  • As a helicopter hovers above, the Gemini-12 spacecraft with parachute open descends to the Atlantic with astronauts Jim Lovell and Edwin "Buzz" Aldrin aboard.

  • Navy divers exit their helicopter to recover the Gemini 5 spacecraft and astronauts shortly after splashdown.

  • Astronaut Charles Conrad, Jr., command pilot of the Gemini 11 space flight, is hoisted aboard a recovery helicopter from the U.S.S. Guam. Astronaut Richard F. Gordon, Jr., pilot, sits in life raft below waiting to be picked up.

  • Dr. Louis P. Ballenberger, Captain, USN, begins a preliminary physical examination of astronaut L. Gordon Cooper Jr., Gemini-5 command pilot, following the successful recovery of the Gemini-5 crew in the splashdown area in the Atlantic Ocean.

  • Gemini 5 astronaut Charles 'Pete' Conrad Jr. looking out of the helicopter window after recovery from his spacecraft after the splashdown.