Hey
ShekGMATHappy to share my views on this interesting question.
You're somewhat correct in your analysis; however, I feel you're missing an important nuance. Allow me to elaborate by comparing choice D with choice E, which is slightly better than choice A in this respect.
D: A newly developed jumbo rocket, which is expected to carry the United States into its next phase of space exploration, will be able to deliver a heavier load of instruments into orbit than the space shuttle
can, and at a lower cost.
E: A newly developed jumbo rocket, which is expected to carry the United States into its next phase of space exploration, will be able to deliver a heavier load of instruments into orbit than the space shuttle and to cost less.
Let's ignore the incorrect phrase 'to cost less' at the end of choice E and focus solely on the missing 'can'.
Shortening D & E further, we get:
D: A newly developed jumbo rocket will be able to deliver a heavier load than the space shuttle can.
E: A newly developed jumbo rocket will be able to deliver a heavier load than the space shuttle.
The problem with the missing 'can' in choice E is that 'the space shuttle' is now being interpreted as a reference for the amount of weight the new rocket will be able to carry.
In other words, the newly developed rocket will be able to transport more weight than that of a space shuttle.But this is incorrect because, logically, the author intends to compare the newly developed jumbo rocket with the space shuttle in the aspect of the amount of weight they can transport and the respective costs involved.
This is why,
we must place 'can' after 'space shuttle' to avoid this miscommunication and ensure the comparison remains strictly between the new rocket and the existing space shuttle.
I hope this improves your understanding.
Happy Learning!
Abhishek