will be able to deliver at a lower cost than the space shuttle can
以较低的成本运送
deliver作运送这一解释的时候应该是及物动词吧
所以我觉得补全以后是,… will be able to deliver a heavier load of instruments into orbit than the space shuttle can, and (will be able to deliver a heavier load of instruments into orbit) at a lower cost (than the space shuttle can).