It’s common knowledge that SpaceX goal is to create a fleet of spacecraft shuttling from Earth to Mars.
One milestone they intend to achieve beforehand is having a fleet of 1st stage boosters shuttling from Earth to LEO/GTO. They'll use their two designs as they reach maturity, the Falcon 9 (also used as the heavy boosters) and Falcon Heavy core (with partial cross-feed). This will allow SpaceX to have firsthand experience on how to manage a fleet of 1st stage boosters.
Together with this information:
- Client flight manifests are piling up, 25 launches for 2016 that are bound to spill over into 2017.
- In partnership with Google (and its $1B influx), doubling the Internet capacity with 4000 new satellites over 15 years.
- Current 3 weeks average launch pad and new build turnaround.
- Ideally need 12 flights yearly to keep the company financially afloat.
Reusability in its infancy, with Elon currently saying they've passed the 70% recovery success rate mark and ~90% in 2017 (was at 40% just 7 months ago). It’s not a factual metric, just Elon’s educated guess. With the goal of being well at ~100% before 2024, obviously.
Their yearly production capacity is of 40 1st stage reusable -9 boosters (and 20 2nd stage but with no intention of reusability), bringing it to 10 new builds for Falcon 9 and Heavy a year.
- The Merlin rocket has a limited number of re-ignitions in them (engine cycle). Making the boosters reusable up to 10 times.
If the mature aircraft industry can be of an analogy here, fleet size to destination ratio is slightly below 2:1 (Although a commercial aircraft is reusable 40 000 times ‘metal fatigue gets it after 30 years’ and has a turnaround of well under 1 day.)
Lower bound answer: That would mean that their 1st stage booster fleet could be as low as 2 Falcon 9s and 2 Falcon Heavies, provided the turnaround is at least as low as the demand of the fleet to be reflowed. Bearing in mind that those 8 boosters will need to be replaced at a yearly rate.
Upper bound answer: The other extreme is that they will keep producing to their max capacity, ever expanding their fleet. But I find that unsustainable as economically they will be producing higher than the demand (only two destinations). Also they would need at some point to shift some of this manpower into building the BFR instead.
Which brings me to ask, how big of a booster fleet will SpaceX be settling for? They’re anticipating an even demand for Falcon 9 and Heavy. Did SpaceX provide any info on the subject?