If you throw away the rocket, sure, you're doubling the cost if you have to do trips. If the rocket is reusable, then the vehicle cost gets amortized over the

If you throw away the rocket, sure, you're doubling the cost if you have to do trips. If the rocket is reusable, then the vehicle cost gets amortized over the total number of trips, and the per-trip cost gets closer to just the cost of fuel (hopefully at least an order of magnitude less than a new vehicle+fuel on each flight).