Assertion: rocket's stage | /r/HasProperty | an its tanker
Facets:
value: for transfer operations
type: PURPOSE
Source sentences:
text: The first stage was always to be an "ITS booster" while the second stage would have been either an "Interplanetary Spaceship" (for beyond-Earth-orbit missions) or an "ITS tanker" (for on-orbit propellant transfer operations).