1. She reset the story in the first quarter of the Twenty-First Century instead of in the last quarter of the Twentieth, shifting the action futureward by a full generation.
2. The Reds have become the Russians and Greater Russia has replaced the Soviet Union.
3. Space travel has not gone beyond the first lunar landings instead of having not gotten beyond the first attempts to put satellites into orbit. Instead of being ridiculed as impossible, space travel is publicly ridiculed as infeasible.