How much does SpaceX save by reusing a Falcon rocket? originally appeared on Quora: the place to gain and share knowledge, empowering people to learn from others and better understand the world.

Answer by Jim Cantrell, CEO and Founder of Vector Space Systems, on Quora:

If you go through the R&D costs of developing a reusable launch vehicle, the opportunity costs (in terms of fuel used for return and the lost revenue opportunity for more payload to orbit) of returning the launcher to the first stage, and the costs of refurbishment between flights, generally accepted practice shows that you have to re-use the booster or launch the vehicle 5-10 times before you make your money back if you account for all the costs.

Many papers have been written on this topic and this is a well established 'rule of thumb'. This doesn't even account for the price reduction that many customers flying on a 'used' first stage will likely demand.

Thus I am thinking that very few, if any, of the SpaceX Falcon 9 first stages are going to be re-used for more than 3 or so flights and that SpaceX will therefore not break even on the reusability portion of the equation.

Why then would SpaceX want to have a landing reusable rocket? Two reasons.

First, this is an obvious Mars landing technology and if this is one of SpaceX's goals (as I believe it is since this was the main reason that the company was started), the landing system development costs can be counted against a number of other accounts not related to reusability.

Secondly, and I think that this is the dominant answer, reusability allows a marked increase in flight rates. Reverse engineered financial models of SpaceX show that to reach a good strong positive cash flow, they need more than the traditional 10-12 launches per year that sized rocket has demonstrated. Reusability should easily double the amount of flights possible from a mere production and logistics standpoint.

With reusability, 20-25 flights a year puts SpaceX into a much more positive cash flow position and thus I believe that this is a very important driver. I believe that the first stage has been identified as one of the bottle necks to flying more often mainly due to its production, transport and attendant infrastructure. Reusability is a great brand image generator, but, more importantly, it enables SpaceX to double their flight rate and make more money, all the while preparing for Mars landings with the reusability technology.

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Published on: Sep 26, 2017