Sci-fi: Space explorer returns to Earth and, because of time dilation, finds that years in politics and culture have passed by. He always leaves to go back into space, coming “home” more and more infrequently.

[Words]

Eventually he returns to find that people on Earth are too embroiled in their immediate problems and politics that the space program has been abandoned or put on hold.

He takes off into space again, and when he returns from it, many years (100?) have passed. The space program is no more, and he as a space explorer has been forgotten.

I think he takes off into space for one final time, forever.

I think I might have read it in 2000, plus or minus 5 years.

It was not Forever War. :)

Thank you.

[slauderdale]

I haven't read them, but John Scalzi's Old Man's War is a series with a premise similar to Joe Haldeman's "The Forever War." (Time dilation, continuous shipping out.)

Time for the Stars by Robert Heinlein also features a character (one of set of twins, selected for space exploration because he can communicate with his brother back on Earth via telepathy) who comes back to Earth after various adventures: the kind of space exploration that they've been doing (slower than light) has been rendered obsolete by new faster than light technology, and he and his fellow crew members are almost like time travelers who no longer fit in. Sounds different from your scenario, but with thematic similarities.

[Words]

Thank you for those possibilities! I’m wondering if I read Old Man’s War and then forgot all about it...it happens to me. I’m fairly sure I haven’t read Heinlein’s Time for the Stars though.

[Andy]

Starfarers by Poul Anderson? Starfarers

[Words]

Ah. Okay, Starfarers seems like it might be the book, and it’s around the right timeframe. I won’t know for sure until I read (reread?j the book, though. I guess I should mark this possibly solved in the title..? And fix my grammar too I suppose. Thank you Andy!

[Andy]

Great. Hope it turns out to actually be your book.

[SamSpayedPI]

It's available at the Internet Archive. You need to be a member to "take out" books, but membership is free; you only need to give them an email address.

[Debra]

This sounds so familiar to me, though when I went to Starfarers, that didn't sound like the book. The one I remember it was only the one man who went traveling. I'm following in case someone else remembers another title.

[Lobstergirl, au gratin]

Words, was that your book? This has been in Possibly Solved for 6 years.