SpaceX reuse the Falcon 9 & Falcon Heavy core boosters to reduce the cost of reaching orbit.
On the 21st of December 2015, SpaceX made history by landing their first Falcon 9 booster back on land.
After years of development and testing, SpaceX were one step closer to dramatically reducing the cost of spaceflight.
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Since then, over 57 boosters have been landed with over half of them being reused.
But how many times can SpaceX reuse Falcon 9 boosters?
And what does it take to refurbish each booster between flights?
In April 2018, SpaceX launched the new and improved ‘Block 5’ Falcon 9. This new version brought a number of upgrades to the engine heat shield, grid fins and landing legs, with an aim to reduce the amount of refurbishment and maximize the number of flights per booster.
Although this upgrade cut out the need for a lot of refurbishment, the average turnaround time for a booster has only dropped from 356 days to 72.
On July 20th SpaceX launched ANASIS-2 South Korean Military satellite, the booster flown was recently used in Demo-2 mission it was quickest turnaround time being 51 days, beating the space shuttle Atlantis’s record of 54 days.
The Space Shuttle on the other hand achieved a record of just 55 days between flights back in 1985, with regular refurbishment times of less than 100 days.
However, after the Challenger disaster, the safety standards increased and this put extra pressure on refurbishment.
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The process became an enormously expensive task, requiring over 9,000 employees to make the Shuttle ready for flight.
With SpaceX aiming to achieve a refurbishment time of just 24 hours, they will need to match the turnaround process of airliners, with each rocket only needing a quick inspection between flights.
When the first stage booster returns to Earth either by land or by sea, it’s lifted onto a trailer and transported back to the SpaceX hangar.
This can take multiple days to complete since each of the four landing legs need to be removed manually.
Although they are designed to be quickly retracted, SpaceX have only been able to do this on two occasions.
Once the booster is back in the hangar, the refurbishment process begins with each engine going through a number of rigorous tests to make sure that every component is ready for flight.
According to Musk, each Merlin engine could perform up to 1000 flights without major refurbishment
The fuel tanks and pressure vessels go through a series of ultrasonic tests to check for tiny cracks that could lead to a failure once the rocket is pressurized for flight.
Once the booster has passed the inspection process, it performs a static fire test with all 9 engines, before being attached to the payload.
At the moment, all of these checks still need to be completed as they venture into the unknown territory of multiple reuses.
Each mission will give them more knowledge on how many flights each booster can perform, and over time, the refurbishment process should become more refined.
So far, Falcon core boosters have successfully landed 57 times in 67 attempts. A total of 24 boosters have flown a second mission, including two pairs as Falcon Heavy side-boosters, six boosters have gone on to fly a third mission, five boosters have flown a fourth mission and three have flown five times.
Although the Falcon 9 could theoretically fly up to 100 times with minimal refurbishment, each booster is only expected to perform a total of around 30 flights over the next decade.
However, with SpaceX working on a much more powerful and fully reusable rocket, the Falcon 9 could become obsolete much sooner than expected.
SpaceX is currently building the first prototypes of their ‘Starship’ rocket in Texas and Florida.
And with customers already lined up, they aim to launch their first commercial payload in 2021.
Not only will SpaceX use Starship for Mars and commercial satellite missions, they also want to use Starship for travel here on Earth, providing flights to anywhere in the world in well under an hour.
Unlike the Falcon 9, Starship is designed to be fully reusable with an aim to complete thousands of flights before any major refurbishment is needed.
If SpaceX can get Starship up and running, it could replace the Falcon 9 all together since it would be capable of launching much heavier payloads for a fraction of the cost.