SpaceX News

[paperburn1]

Well aren't these engines supposed to be easily replaced if there's a problem anyway. Just like a recertified car engine, test check anything that is not perform to standards is replaced then sold to the consumer for reuse.

[Skipjack]

Well aren't these engines supposed to be easily replaced if there's a problem anyway. Just like a recertified car engine, test check anything that is not perform to standards is replaced then sold to the consumer for reuse.

Well, the goal is (down the road) to reuse the vehicle without much inspection and refurbishment (less than a day between launches0. Of course that would be after a lot of stages have been brought back, inspected and improvements have been made where necessary.
If they got debris into the engine, they might have to consider a different material for the landing bad. I assume (and we can hope) that this is only a minor issue, this time or easily fixable for future vehicles.

[paperburn1]

Does anybody know if all nine engines are firing during landing or is it just a portion of the engines firing during landing. I would assume they would not need all nine as the weight of the structure is greatly reduced

[krenshala]

My understanding is one to three engines firing for the boostback burn (just after stage separation). I'm not sure if the burn in the middle is a single engine or three. But it only needs a single engine for the suicide burn on landing. By the time it gets back to where the pad is, a single engine firing at 70% (the lowest throttle setting, as I understand it) is still >1 for thrust to weight ratio.

[Skipjack]

My understanding is one to three engines firing for the boostback burn (just after stage separation). I'm not sure if the burn in the middle is a single engine or three. But it only needs a single engine for the suicide burn on landing. By the time it gets back to where the pad is, a single engine firing at 70% (the lowest throttle setting, as I understand it) is still >1 for thrust to weight ratio.

I thought the lowest throttle setting was 60%?

[Maui]

I think it's mostly speculation since SpaceX does not officially disclose this number. Whatever the number is, it results in higher thrust than weight at landing so they cannot hover; they have to hit ~0 v at they same time they hit 0 alt.

EDIT: Googled a little and it appears that perhaps its the vacuum variant that can be throttled down to 60% while the sea level version can only go to 70%.

[paperburn1]

Just like the old lunar lander game

[D Tibbets]

Actually, the Lunar Lander could hover. Neil Armstrong (or was it Buzz Aldren Jr?) utilized this when he encountered boulders in the landing zone.

Dan Tibbets

[Maui]

Just like the old lunar lander game

Speaking of; check it!
http://moonlander.seb.ly/

[Tom Ligon]

I gather they crunched the first stage again, but I was screwing around attempting to get Flash Player reinstalled and missed it. Sounds like the satellite is in orbit.

[ladajo]

I watched, primary mission went well. Landing video feed cut out seconds before launch. Later, they said it made the barge, but hit hard and broke a landing leg. I am kot surprised given years at sea managing heli landimgs in rough weather. They reported 12 to 15 swells. Watching the video feed showed significant pitching. Probably caught it on an up cycle in the final sequence. Essentially impossible to predict. That is why we use RAST on ships to bring the bird down.

[ladajo]

Just saw a post from Musk, he says landing speed was good, leg locking pin did not engage. 4 ft off center mark on barge.

[paperburn1]

Just saw a picture of the barge and it looks like most of the rocket is intact but it does look like there was a fire on deck disappointing but not very as I saw the video of the sea state I'm surprised it went this well.

[Maui]

Perfect landing. darn that there's always something else that can go wrong:
https://www.instagram.com/p/BAqirNbwEc0/

EDIT: Ha. Auto-language editor converts PG language to G.

[Skipjack]

Perfect landing. darn that there's always something else that can go wrong:
https://www.instagram.com/p/BAqirNbwEc0/

EDIT: Ha. Auto-language editor converts PG language to G.

This is why it makes sense to do a lot of incremental testing and improvements as you go. You can try to make the perfect plan that considers everything and plan for a decade or more without building and flying anything and then still fail because of something like this.