To honor Neil Armstrong, here's a short passage on the challenges faced in the LM's descent to the lunar surface, which so many of us watched in black and white on TV on the night of July 20, 1969 (I fell asleep before Neil and Buzz actually set foot on the moon's surface ... but I knew they had made it safely there).
As the LM got very close to the moon, Armstrong and Aldrin would enter the most hazardous portion of the descent. Somewhere in the last 200 feet, they would be too low to abort successfully if the descent engine quit, for the LM would be going too fast for the ascent engine to arrest the lander's plunge and start the ascent stage upward again. The astronauts, borrowing a term from helicopter pilots, called this part of the descent the "dead man's curve." ...
In these final moments Armstrong's gaze would be directed almost entirely at the moon, and he would rely on Aldrin's steady reports on altitude, horizontal speed, and descent rate. The first part of the LM to touch the moon would be the three long metal probes attached to the footpads; at that moment, a blue light labeled LUNAR CONTACT would glow on the instrument panel. Aldrin would be watching for the contact light, ready to call it out. At that moment, Armstrong would shut down the engine, and the LM would fall the remaining three feet to the surface. (pp. 167-168)
To give you a sense of just how risky this business was, Michael Collins orbiting overhead had been trained in 18 different methods of rescue and recovery of the LM should something go wrong during descent or ascent. This landing had never been done before and the risks were high. I strongly recommend you get a copy of this book and find out about all the other risks and threats that truly made these 24 men and all those who supported them back on earth real heroes of exploration.
Here's hoping we return to deeper space soon, in honor of Neil and the other 23, and for the benefit of ourselves and the rest of the world.
Oh by the way, today, August 31, 2012, there will be the second full moon of the month. This is the rare "blue moon." It is also the day that Neil Armstrong will be laid to rest. How appropriate for such a rare breed of explorer.