It's a great story because it's a straightforward technological speculation which then takes a twist.

That said, Arthur C. Clarke's The Star -- http://www.uni.edu/morgans/astro/course/TheStar.pdf -- is weaker on the technology but stronger on the heartstring-tugging. It is also a great story, in a similar vein.

And relevant to The Star, but not really in the same vein, there's James Blish's novel A Case of Conscience ... http://en.wikipedia.org/wiki/A_Case_of_Conscience