If Mars colonization falls through, what economically viable uses are there for Starship?
Everything every other launcher does (and more). According to this article:
In a cost per kilogram of payload basis, a single use Super Heavy Starship can bring the cost down nearly ten times to about 150 dollars per kilogram. However, high reuse of the Super Heavy Starship will bring the cost
down to $10-20 per kilogram.
For reference, Falcon 9’s costs 69.75 million dollars per (RTLS) launch. Dividing that by the payload to LEO gives a 7287 dollars cost per kilogram to orbit. So by simply switching to Starship, a customer needs to pay either roughly 2% for single use or roughly 0.14-0.27% percent if heavily reused, as measured in cost per kilogram. Considering that Starship has a capacity of 250,000 kilograms when expended or 150,000 kilograms when reused, even if you purchase a decided launch and carry the same payload as you would on Falcon 9, you would still pay roughly 23.1% of the Falcon 9 launch using the single use version and 0.907-1.814% of the cost of the Falcon 9 launch if it is heavily reused. This works out to around 53.64 million saved on a single use and somewhere from $69.12-69.43 million saved when heavily reused.
Falcon 9 isn’t alone, I know of no orbital rocket that is expected to be cheaper (in terms of total launch costs) than a reused starship. I can’t imagine why, once starship is reliable and consistent, anyone would use another rocket.
In reality, many customers would actually use the extra payload capacity or share their launch with other customers, further increasing their savings.
An example of this is Starlink, which (provided the that SpaceX lowering launch costs means the cost to launch a rocket for themselves is proportionally lower) assuming that it would use a reusable Starships full capacity (why wouldn’t it, it already flies in batches anyways), would save somewhere from 99.984-99.992% (or much more on other rockets).
So, once Starship becomes consistent and reliable, what sane customer wouldn’t use Starship over Falcon 9? Why wouldn’t you get the better launcher with the 99.992% off tag?
Quickly looking a few things up tells me that the average cost per kilogram for cargo airlines is around 3-7 dollars. The average price for an average economy class one-way domestic ticket is around 135 dollars. Doing some math shows that (very roughly), using Falcon 9 over a heavily reused Starship (in the above scenario) is about as much more expensive (defined as percentage of money wasted) as buying a 1 kilogram package (that's traveling domestically) an 2-3 economy class tickets, or slightly less expensive than buying it one business class ticket, rather than placing it in a cargo plane. I certainly don’t know anyone who does that, and I doubt you do either.
