"HE AIMED FOR the stars," Mort Sahl is supposed to have said of Werner von Braun, "but sometimes he hit England." And that pretty much says it. For most Americans, and others, it has never been possible over the past several decades to hear mention of the name of Wernher von Braun space pioneer, without thinking, uncomfortably, of Wernher von Braun, rocket-builder by appointment to Adolf Hitler. For this was a man who became an American national hero in the 1960s after being an American national enemy in the 1940s. The transformation was remarkably complete. Yet, even those who most valued his leadership in the space age - and his enormous contributions to this country's accomplishments - found it impossible to forget his contributions to the Nazi war effort, and difficult to reconcile the two.

There is, it seems to us, a simple answer. From his youth, Mr. von Braun wanted to do nothing but build rockets that would reach the moon and the stars. He built them for whomever he could and for whatever immediate purpose was demanded of them. And so it was that he did build the V-2 rockets for Germany, his homeland, and the V-2s were the last-ditch weapons the Nazis employed against the British in World War II. But later, some of his other rockets did reach the moon, and those were the ones he built for the United States - the country to which he chose to come when the war ended. Here, his rockets orginally formed the base of a defense policy resting on guided missiles. But when the space age arrived with Sputnik I, it was his Jupiter that enabled this country to catch up with that initial Russian advantage and his Saturn that provided the power with which this country's international leadership in space flight was achieved.

Mr. von Braun was, without any doubt, a remarkable scientist, manager and dreamer. No one man could have produced all those rockets alone. But it was his technical ability, experience and uncanny ability to organize others that made him the central figure in the space program. And it was his eloquent expression of that childhood dream of space travel that made him a national figure. The landing on the moon was, to him, only the first step in opening up the universe. We suspect it didn't matter too much to him whose flag that first spaceship planted. What mattered was that mankind had at long last broken free of the grasp of the planet Earth. It is in that context - as one of the new breed of international scientists - that Mr. von Braun's life should be judged. Yes, he labored for Nazi Germany. And yes, he labored for the United States. And he would probably have labored as happily for the Russians if, after World War II, he had happened to surrender to them. You can think of him as a hired gun, if you like. But you can also think of him as he apparently thought of himself - as a man indentured only to a dream. He followed it where it led him. And, unlike most of us, he saw a large part of it come true.