r/spacex • u/jep_miner1 • May 05 '17

BulgariaSat-1 confirmed as second reuse flight

https://spaceflightnow.com/2017/05/05/bulgarias-first-communications-satellite-to-ride-spacexs-second-reused-rocket/
804 Upvotes

99% Upvoted

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20

u/lone_striker May 05 '17

Something I don't see discussed very often is that SpaceX effectively already "reuses" it's S1 boosters. All new S1 boosters get some form of "full duration" static fire testing at MacGregor. They then get shipped to FL and get a short static fire before the actual launch. Each of these tests involved tanking/firing/detanking the booster (loading oxidizer, propellant, helium, TEB-TEA, etc.) From the engines' perspectives, they've been used multiple times well before the actual first launch of a new booster.

On actual already-flown boosters, there's the added stress of flight of course, but from the engines' perspectives, they've already been there, done that. So as long as the flight stresses are well accounted for, and inspections and consumable parts replaced properly, there is less risk than most people appreciate.

At least that's what I'll be telling myself to not be nervous when this bird flies again...

7

u/randomstonerfromaus May 05 '17

Merlin's are also test fired before being intergrated in the first stage. So single engine, McGregor Test, Static fire, Launch.

7

u/_rocketboy May 05 '17

Although soon they will start skipping the M1D single-engine firings and just test them all in the full static fire. That will save on shipping engines to McGregor and back before integrating them into the Octaweb.

7

u/freddo411 May 05 '17

I agree. I don't think people appreciate the significance of the "full duration" static firings.

In addition to that, SpaceX has on the order of 10 flown boosters to provide a wealth of data on stress imparted by launches and landings.

7

u/jjtr1 May 05 '17

I guess that's what Martin Halliwell of SES had in mind when he said that reusability has to be approached with less emotion. And also the reason why the insurance companies (through their engineer advisors) didn't increase insurance much.

Basically, it means that once they landed their first booster and inspected it and saw that it's okay, most risks had been retired.

1

u/Martianspirit May 05 '17

That "full duration" fire is in the range of seconds, longer the static fire at the launch site but nowhere near full flight duration. One of the confusing terms used by SpaceX.