![]() ![]() We also have more specific figures available because Elon Musk revealed the marginal cost of launching a reused Falcon 9 in a May 2020 interview for Aviation Week (starting at 17:53). 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 And if the booster flies at least three times, the savings are undeniable. As a result, after two launches, the total cost and combined payload capacity are roughly comparable to one launch of an expendable rocket. He says that while reusability of the Falcon 9 reduces maximum payload capacity by less than 40%, recovering and refurbishing the booster represents less than 10% of the overall costs. However, Elon Musk disagrees with this analysis. ULA also argues that an expendable rocket has a higher payload capacity because it does not need to reserve some of the fuel for landing and at the same time it doesn’t need a stronger airframe, landing legs, grid fins and other hardware that increases the rocket’s total mass which in turn reduces maximum payload capacity. But since ULA launches less than ten times a year, it’s actually more economical for them to manufacture a new rocket for each launch. For example, United Launch Alliance, a SpaceX competitor, did its own analysis and concluded that reusability pays off only if each produced booster flies at least ten times. ![]() The current fastest reuse took 51 days, but this record will likely be broken several times in the coming months and years due to SpaceX’s increasing launch cadence.įalcon 9 boosters during refurbishment (Credit: Discovery)Įver since SpaceX began reusing rocket boosters, people have been debating how much it actually costs the company and whether it makes economic sense. Preparing the booster for its next launch currently takes about two months on average, but that doesn’t necessarily mean SpaceX can’t do it faster, if needed. Additionally, in a recent Discovery documentary, we could see SpaceX workers cleaning the landing legs between launches. They check the welds and look for cracks or other irregularities. However, “some individual parts like turbine wheels need to be replaced over time, similar to a jet engine,” he added.Īs for the propellant tanks that make up the main structure of Falcon’s first stage, we know from the past that SpaceX performs X-ray inspections between launches. On a similar note, Elon Musk revealed that SpaceX technicians “almost never need to replace” whole Merlin engines between launches of a booster. Therefore, it’s possible that the desooting doesn’t need to be done on all engines after every launch. Additionally, SpaceX recently stopped doing pre-launch static fires on some Starlink missions, which further reduces wear and tear on the engines. You see, some of the engines do more burns over the course of one launch than others, because only three of the nine engines on the booster are reignited as part of the landing process. Unfortunately, it’s unclear from Musk’s tweet whether the desooting is done on all Merlins after every launch, or only after a certain number of ignitions of each engine. Merlin 1D (left) and Raptor rocket engines (Credit: / Twitter) ![]() According to Musk, when it comes to Raptor’s easy reusability, “not having long chain hydrocarbons & lowering preburner combustion temperature make a big difference”. In contrast, the Raptor engine that powers the Starship spacecraft and Super Heavy booster is a much more complex engine than the Merlin, but because it uses methane which burns much more cleanly than kerosene, it is easier to reuse because there is no desooting needed. It is therefore necessary to desoot the turbines between launches, which Elon Musk described as “ difficult“. The Merlin engines burn kerosene which results in soot buildup. So what does Falcon 9 booster refurbishment actually entail? The exact process is still shrouded in mystery, but we have some clues. Of course, as Musk adds, some parts of the rocket would need to be replaced or upgraded over time to accomplish this feat. Therefore, it is encouraging that Elon Musk has currently said that there was “no obvious limit” to how many times a booster could launch and that “100+ flights are possible”. Since then, Block 5 has flown 39 times in total, so SpaceX now certainly has a better idea of how the boosters are actually faring and whether Block 5 is meeting expectations. At the time, Elon Musk claimed that each rocket booster should theoretically be able to launch up to 100 times. ![]() The first Falcon 9 Block 5 launch in May 2018 (Credit: SpaceX)īlock 5 is the latest variant of the Falcon rocket which flew for the first time in May 2018. ![]()
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