At the end, they are found by a search party from a large group of survivors at Los Alamos, where they are using nuclear power to provide heat and have begun using rockets to search for other survivors (radio being ineffective at long range without an ionosphere).
At the end, they are discovered by a rescue team from a large group of survivors at Los Alamos, where they utilize nuclear energy to generate heat and employ rockets to search for other survivors (radio being ineffective over long distances without an ionosphere).