The title pretty much sums it all up. I remember somebody once remarked about the space shuttle program that “the space shuttle was originally designed to be a space truck. But the shuttle is to trucks what a Lamborghini is to a family car.“. This was primarily due to the difficulty in designing a truly reusable space craft. A Space Shuttle orbiter required about 90,000 man hours of maintenance after it returned to Earth, to make it flight ready again, and this more or less meant a complete tear down and overhaul of the entire orbiter as well as the SRBs. That was 40 years ago. I’m wondering if the SpaceX Falcon 9 series of liquid fueled rocket boosters has improved upon those metrics, compared to traditional disposable liquid fuel rocket boosters.
We don't know.
One thing we do know is that SpaceX launches are fairly cheap compared to their competitors. Whether that is because of reuse, because their rockets are generally cheaper independent of reuse, or they are simply operating at a loss to shock the market, we don't know.
As mentioned by geoffc, SpaceX is a private company, not even publicly traded, so the information they are required to disclose is minimal. Hence, we can only speculate.
We know what SpaceX charges for a flight on an expendable booster, and we know what SpaceX charges for a flight on a reusable booster, thus we know that they charge less for a flight on a reusable booster than on an expendable one. And that is about all we know. In particular, we don't even know whether the prices that SpaceX is charging have any relation to the actual cost.
In particular, it is entirely possible that SpaceX is overcharging for flights on a reusable booster just because they are still much cheaper than the competition even if they make a massive profit. It is also possible that they operate at a loss in order to shock and undercut their competition.
Or, they might be running a mix where they sell their expendable version at a loss in order to undercut the competition and make up for that by selling reusable ones at a big margin. So, we can't simply subtract the price of a reusable launch from the price of an expendable launch and say that's how much cheaper they are.
We also know that they received money from various government organizations for various development programs, which may or may not also have benefited their commercial customers, and thus may influence the price.
Another thing we don't know is how much effort there is in refurbishing a booster. We know that the fastest they have re-flown a booster is 51 days, but that does not necessarily mean that it also took 51 days to refurbish the booster, and even if it did, it doesn't mean that this is the fastest possible turnaround time. They seem to be rotating the use of the boosters, so they are not actively trying to re-fly a single booster as fast as possible. As long as they can service them fast enough to keep their launch cadence (which is already record-breaking), they have no need to refurbish the boosters even faster.
While most of the information is private, since SpaceX is not even a publicly traded company, there is some information we can discern.
In 2020 SpaceX launched 26 times (1 for In Flight Abort, was a launch but not to orbit). Of those, 5 were new boosters, and 21 were previously flown vehicles.
Thus the factory did not have to make 26 boosters for the year, only 5. (And they finished a Falcon Heavy with three cores as well, but did not fly in 2020). Unless the cost of refurbishment is greater than manufacturing a new core, we can assume this was a savings. (That statement however is not yet proven, nor documented).
While I do not have a source handy, my understanding is that each core takes on the order of 11 months from first acquisition of materials to completion.
In 2020 we saw refurbishment times of around 2 months with almost breaking the record of 51 days.
Again without evidence for reasons stated above, it would be a reasonable assumption that 2 months of labour would cost less than 11 months, unless 5 times the people are working on refurbishment versus new construction. (Of course there are all sorts of issues with that assumption, but it seems plausible.)
On the other hand, in addition to refurbishment, there is the cost of maintaining a fleet of ships for downrange ocean landings. There are several ships on each coast maintained for recovery operations. This is a mix of ASDS barges for landings, but also the GO/Ms * fleet for towing the barges, fairing recovery, and capsule recovery.
But then the RTLS missions are clearly cheaper since the Landing Zone 1 and 2 are fixed costs that do not really cost much yearly to maintain and of 25 landing attempts in 2020 it broke down as:
- 2 failures (plus in flight abort)
- 4 RTLS (Return To Launch Site)
- 6 Just Read The Instructions (ASDS)
- 13 Of Course I Still Love You (ASDS)
Thus the costs of recovery and refurbishment probably vary slightly based on where the booster lands.
Additionally, while the first stage is recovered, the upper stage is discarded. The fairings are probably a different set of economics. The first stage is usually considered to be 2/3 of the cost of the mission, usually around \$40 million. Whereas fairings are priced at around \$6 million. (Since all these change over time, they are basically meaningless absolute numbers).
Thus refurbishment costs of a \$40 million dollar component vs a \$6 million pair of components clearly can have different outcomes. (Thus the focus of the first stage recovery, which seems well proven, vs fairing recovery which is still being developed).
To summarize, it seems likely that the costs of reusing a first stage are lower than a new first stage, there is not hard data to support it, but the basic assumptions seem to suggest it would be cheaper.
The Falcon 9 in expendable configuration is cheaper by a significant margin than other rockets. However, reusability makes it even cheaper, though the extra fuel and gear needed much reduces the maximal payload. The only publicly available information on the economy of flight proven rockets is a recent reply to tweet from Michael Baylor:
Payload reduction due to reusability of booster & fairing is <40% for F9 & recovery & refurb is <10%, so you’re roughly even with 2 flights, definitely ahead with 3— Elon Musk (@elonmusk) August 19, 2020
So it seems the cost of refurbishment of a booster could be below $6 million. The cost of a second launch could be well below \$15 million when fairings are reused.
With regard to the Space Shuttle, the Lamborghini comparison is not just about the fact that it was meant to be reusable. It was extremely ambitious in terms of its capabilities - in order to carry a large payload along with five crew members, the orbiter had to be quite a big machine.
My impression is that trying to build that much lift capacity under the design constraints they had led to engineering tradeoffs that made the whole thing less robust, which in turn required the extensive refurbishing. This doesn't prove that SpaceX is cheaper, but it does make the case that there was a lot of room to get cheaper just by being less ambitious.
This related question talks about the amount of maintenance the main engines required, as an example.