~150,000 other people died today, too. Okay, Armstrong was hugely more famous than any of them, probably the most famous person to die this year, but what did he do for rationality, or AI, or other LessWrong interests?(which I figure do include space travel, admittedly. Presumably he wasn't signed up for cryogenic preservation) the post doesn't say.
Yes, death is bad, and Armstrong is/was famous, possibly uniquely famous, but I don't think eulogies of famous people are on-topic.
Eulogies on arbitrary people might help with motivation, and if you're doing that you might as well chose one with a minor advantage like not needing a long introduction to make the reader empathize, rather than choosing purely at random.
The sad news broke tonight : Neil Armstrong, the first human to ever walk another world, died today. We lost him forever. He died before we could defeat death.
Once again the horror of death strikes. This time, in addition from wiping from us forever a hero of humanity, he wiped from us forever a memory that will never exist again. Never again will a human being be able to experience being the first to walk another world. That beautiful experience is lost forever too, along with all the memories, dreams, desires and wishes that made Neil Armstrong.
But thanks to him, humanity made a giant leap. We'll fill the stars and conquer death. The spark of intelligence and sentience will not extinguish. That's the best we can do to honour him.
Source : http://www.reuters.com/article/2012/08/25/us-usa-neilarmstrong-idUSBRE87O0B020120825