MOONSHIP TEST SUCCEEDS— Key Engine Fires Well on 2d Trial", Chicago Tribune, January 23, 1968, p1 After it reached a 138 miles orbit, the LM-1 separated from the rocket stage and tests were made of its descent engine (which would guide the astronauts to a soft landing on the Moon) and its ascent engine (which was required not only to return the module to orbit, but also to fire through the descent engine if necessary to abort a failure).