Progress on rapid booster reuse

[DanClemmensen]

Please check me on this. In a perfect world without quantization effects (2 coasts, three pads...) we should be able able to compute the number of active boosters needed.

Let L be the number of boosters launched per year. (FH counts as two boosters).
Let T be the booster turnaround time in days. Time is from a launch to the next launch.
Let A be the number of active boosters.

The launch frequency F is 365/L.

A=T/F.

Example: L=140, T=21.
Then F=365/140=2.6
A=21/2.6= 8.05

Due to various real-world factors, the actual number is higher.

Separately, the number of boosters to produce each year is L/N, where N is number of lifetime launches. 140/25= 5.6 boosters/year, plus one FH core per FH launch.

[Exastro]

As always, the turnaround time is only an upper bound. We don't know how long the actual refurbishment time is.
Given that they're yet to stall waiting for a booster, they should have quite some margin between the two.

Sorry for the vagueness, but I seem to recall Musk telling an interviewer that it takes a few days, and maybe up to a week or so, to refurbish a booster after a flight.

IIRC this interview came shortly after Starship Flight 4.

[AmigaClone]

As always, the turnaround time is only an upper bound. We don't know how long the actual refurbishment time is.
Given that they're yet to stall waiting for a booster, they should have quite some margin between the two.

Sorry for the vagueness, but I seem to recall Musk telling an interviewer that it takes a few days, and maybe up to a week or so, to refurbish a booster after a flight.

IIRC this interview came shortly after Starship Flight 4.

During SpaceX's stream of the launch of Starlink Group 4-16 (the previous record holder and the first time a booster had launched twice in a month) the announcer mentioned that for that particular launch SpaceX took 9 days to refurbish it. In the NASASpaceFlight about that 29 April 2022 launch, it was mentioned that they were working on methods to reduce the time spent refurbishing a stage to about a week.

It would not surprise me to learn that SpaceX had reached that goal some time ago.

[meekGee]

As always, the turnaround time is only an upper bound. We don't know how long the actual refurbishment time is.
Given that they're yet to stall waiting for a booster, they should have quite some margin between the two.

Sorry for the vagueness, but I seem to recall Musk telling an interviewer that it takes a few days, and maybe up to a week or so, to refurbish a booster after a flight.

IIRC this interview came shortly after Starship Flight 4.

I believe that.

I can see how if it takes a week to turn it around, you'd keep enough boosters in the fleet for a 3-4 week de-facto rotation period, to take care of all sorts of real-life issues, from per-coast issues, occasional extra work needed, payload related delays, etc.

Also their quest to reduce processing time is also a quest to reduce processing costs.

[seb21051]

Not related, but one wonders how many F9/FH launches there will have been by the time it is retired?
I am probably not the first one to ponder this.

[AmigaClone]

Not related, but one wonders how many F9/FH launches there will have been by the time it is retired?
I am probably not the first one to ponder this.

Seven years ago there was a poll asking that question. Over 72% of the respondents underestimated the number of launches between those two vehicles by giving a number up to 400 launches.

The biggest factor in the total number of F9/FH launches will likely involve the answer to the question: "What is the number of future F9 launches dedicated to Starlink?"

Depending on that number I can see between a total of anywhere from around 700 to over 1000 launches.

[AmigaClone]

Today booster B1076 became the first booster to launch 10 times in one calendar year. In fact, this launch was scheduled about 11 months, and 31 hours after this booster's first launch this year.

As a side note, this booster had the second fastest refurbishment time, although it just barely beat what had been the fastest turnaround time two weeks ago.