Simplify the following text for a Grade 7 native English-speaking person.
Original: Juno is one of the larger asteroids , perhaps tenth by size and containing approximately 1.0 % the mass of the entire Main asteroid belt . It is the second-most-massive S-type asteroid after 15 Eunomia .
Simplified: Juno is an S-type asteroid , and is estimated to contain 1 % of the total mass of the asteroid belt .