Of course Homer is rather nervous when the judges approach and start asking him questions, but he is able to answer them very well and notices that one of them has a German accent.  Homer then learns that he actually works with von Braun directly and sees him every day.  The judge then asks Homer some very tough and very direct questions which he feels he answers very well.  The big moment comes though when, after they've finished asking their questions, the young guy tells him that von Braun is actually there at the science fair that day.  Sadly Homer never gets to meet him and chases him around only to find that he has stopped by Homer's display while he was gone...