The crater bottom became lined with melted rock and fragments awaiting additional impacts to jettison chunks of this melted breccia off the asteroid.
(The crater bottom; became; lined with melted rock and fragments) (The crater bottom; lined; with melted rock and fragments) (melted rock and fragments; awaiting; additional impacts to jettison chunks of this)
The crater bottom The crater bottom melted rock and fragments
became lined awaiting
lined with melted rock and fragments
with melted rock and fragments
additional impacts to jettison chunks of this