495,000 pounds launched into low earth orbit with 7 stages built along these lines.

1. 2.
3. 4. 5.
6. 7.

Seven tanks seen from above

1 and 6 feeds 3
2 and 7 feeds 5
5 and 3 feeds 4.

In this way 1,2, 6 and 7 drain.

This is stage one.

They drop away and fly back to the launch centre. 3 and 5 then drain.

This is stage two.

When empty they drop away and fly back to the launch centre.

Element 4 continues on to orbit carrying 495,000 pounds.