The Astrodome in Houston could become a convention and science center under a $1.35 billion proposal unveiled by county officials and complex operators Monday. However, taxpayers will have to pick up at least a third of the bill. "This is a great landmark for the city of Houston," said Edgar Colon, chairman of the Harris County Sports and Convention Corp. "We would like to see it stay that way and hopefully see it returned to its rightful place as the 'Eighth Wonder of the World.' " The $1.35 billion plan, which Miller called a "dream property" named Astrodome Renaissance, would include a science center, conference center, planetarium and county and city museum.