this footage give a real sense of how close they are to getting it right
Watching it made me realize I only had an abstract idea of how difficult it was to even attempt this. It's insanely hard, and they're so close!
Space X CR6 First stage landing
41–50 of 205 posts
Re: Space X CR6 First stage landing
#42I almost think it would be easier to let it do what this video shows, and build a giant metal net to just prevent it from sinking. Or is that harder than landing on a small platform?
My thoughts too, but I guess any ingress of sea water makes it necessary to junk the engines. Also, once you've solved the 'landing problem' once, presumably the method can be reused on each and every subsequent landing; if you are looking at many such landings it becomes worth doing it 'once' and properly.
Re: Space X CR6 First stage landing
#43Seems that the control system only tries to guide it on the X & Y axis, but if I was controlling it and saw it coming in at that steep angle, I'd fire hard on the Z axis to try to raise it up, fix the angle, and then lower it down again. Is it correct to say that this landing control system never tries raising the craft vertically?
They can't turn it off and on. They can restart it once and it has too much minimum thrust to hover.
Re: Space X CR6 First stage landing
#44Non-engineers see this as a failure. Engineers and scientists see this as an awe-inspiring success from which to learn, iterate and try again. I don't fault reporters for exagerated headlined focusing on failure. They don't know any better. That is not what their lives are about and most might be challenged to understand that nothing in that video constitutes failure in the context of evolving a design. In fact, fail…
This.
This video is one of the most beautiful things I have ever seen. This is not a failure. This is an incredibly rich mine of data on how to do better next time.
This is how we improve the world, and it's beautiful.
Re: Space X CR6 First stage landing
#45Why did it explode in such a dramatic fashion? I thought the booster was almost entirely empty when it returns to the barge.
There is always some extra fuel and oxidizer, as it is used to slow the vehicle, and is needed until touchdown. If the vehicle were to run out of propellant before landing, it would crash. In addition, the LOX makes any combustion spectacular.
In addition, the tanks are slightly pressurized which adds to the effect.. probably 30-50psi begging to be released :)
Re: Space X CR6 First stage landing
#46this footage give a real sense of how close they are to getting it right
Watching it made me realize I only had an abstract idea of how difficult it was to even attempt this. It's insanely hard, and they're so close!
It's called a "suicide burn" for a reason. Even with just one engine, the thrust/weight ratio for the nearly-empty stage makes landing difficult. The engine can't throttle down enough.
So you can't just come to a near-hover, and then ease you way onto the landing pad. You have to cancel your velocity right at touchdown, with little margin for error.
Re: Space X CR6 First stage landing
#47We know it does three separate burns while coming back down (Boostback, entry burn, landing burn).
I wonder if each burn starts with the RCS thrusters to turn the stage "nose up".
i.e. when it's free falling, does it always roll around and fall nose down, requiring RCS to get it back to nose up?
It would be awesome to see footage from the entire return trip. Do they have cameras mounted on stage 1?
Re: Space X CR6 First stage landing
#48Question: Why don't they land into the water instead of a hard surface? (Wouldn't this give them more leeway in terms of impulse?)
Edit: i.e. landing on a net stretched (under the lake/ocean-surface) by 3 or 4 ships - reel the net it in to raise stage out of the water, I'm pretty sure seawater is not significantly corrosive from 2-3 hours of exposure.
Re: Space X CR6 First stage landing
#49We know it does three separate burns while coming back down (Boostback, entry burn, landing burn). I wonder if each burn starts with the RCS thrusters to turn the stage "nose up". i.e. when it's free falling, does it always roll around and fall nose down, requiring RCS to get it back to nose up? It would be awesome to see footage from the entire return trip. Do they have cameras mounted on stage 1?
From what I've seen there are vanes on the top that guide it down, keeping it upright during reentry and descent.
Re: Space X CR6 First stage landing
#50I wonder if you could put thrust deflectors on the legs, then vary the fold out to help stabilise it just before landing.