Found: Sci-Fi book Space Race preventing Nuclear War

This book was set in a Cold War analog, I believe in the USSR equivalent. It may or may not have been YA. It would have been published pre-1997 since I know I read it while in school. I mostly remember that at the end the girl was part of an alien reasearch group trying to study why some civilizations wiped themselves out in nuclear war. They averted catastrophy by pointing the authorities at the Mars equivalent in the solar system and the two sides of the Cold War were uniting to develop interplanetary space travel to "defend" themselves from the common enemy.

The book was a paperback maybe in the 300-500 page size. I think there were other related books although I can't recall if it was a true series of books.

IIRC it was shelved with the YA books but my library was notorious for its weird shelving system. For example the Honor Harrington books by David Weber were spread between YA, Sci-Fi and regular fiction.

This might well be The Far Side of Evil by Sylvia Louise Engdahl. Be aware she rewrote part of it and self-pubbed the new version in the 2000's, so the original cover is quite different. It was published in the 70s.

Thank you, sorry for taking so long to respond, I got kittens and got distracted from this. That's the book I was thinking of. I did a google image search and I recognized one of the covers. Thank you so much.