During the heady days of the late 1970’s/early 1980’s Solar Power Satellite program, a number of fairly large launch vehicles were designed to haul the vast amounts of material needed in orbit. One that received a fair amount of press was a Boeing single stage to orbit design. Basically shaped like a Mercury capsule, this design became known as “Big Onion.” It’s unclear exactly how it got that name, and by whom; no official Boeing model number is known for it.
The Big Onion and the other heavy lifters of the time were not as powerful as the Post-Saturn vehicles studied a decade earlier. Where the earlier designs had million-pound payloads, “Big Onion” and its ilk topped out at around half a million. The purpose was low cost transport of vast quantities of material, not the largest possible payload in one shot.