The bottom 1/3 is totally black - except where the paint was protected by the tucked in pod legs. I swear it looks like a giant chimney from a power utility landing on that barge.
Wow. Interesting to see the paddle correction just before landing.
Exponential wow ! That camera is looking right down the whole length of the barrel. You can also see brief use of the mini-thrusters ( the ones that flip the stage over after separation to then do the boost back ) for about one second early in the video ( the white puffs coming from near the right hand vane as shown ) :
That definitely got flicked off dead centre by last moment gusts ie. the extremely late control choice was b/w an upright landing off-target, or a tilted on-target landing. Well chosen. :-))
For those other aerospace companies who haven't already gone 'Oh crap, this mob is just way ahead of the curve' they'd have to do that now ....
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
That definitely got flicked off dead centre by last moment gusts ie. the extremely late control choice was b/w an upright landing off-target, or a tilted on-target landing. Well chosen. :-))
Thanks for the snapshot, also the wind component was probably why the little hop downwind on landing. I guess it must be difficult to chose an a direction for landing, so as the say say in aviation, "they greased it"!
I wonder if the barge is stationary or travels downwind to reduce the wind effect.
Working the paddles. A fascinating video. SpaceX seems to cover all aspects of flight with imaging. Others may have also but we just never got to see them.
It's a fascinating problem. The rocket has tremendous power but only along one axis. By comparison the control effects along the other two axes are minor, and because they primarily give rotation rather than translation they determine the direction of the main thrust. However there is engine gimballing as well. Plus you have to anticipate the effect of control delays so as to act appropriately where the rocket will be then as opposed to the moment of calculation. So "Are those films in real time" is YES ! :-)
In turn the effect of the vanes is ( roughly ) proportional to speed^2 so has great importance up high - to bring the craft down from hypersonic - but barely much in the last 100ft say. And always the ( gravitational potential ) energy gained during ascent must be bled when returned as kinetic. I think the one prior to this ( no boost back loop ) that took out a section of the barge was right out of the envelope of management. Perhaps one day they will release the footage ( I'm sure they have it ) and we will see what delta-v was needed.
Aaaah ! If only I was a young man again ie. that SpaceX is hiring.
Cheers, Mike.
( edit ) I've looked hard for primary actual data on the Falcon Nine's first stage centre of mass - alot are talking of it, but no one seems to know detail alas. This point will descend toward the base as fuel is consumed and ideally will achieve it's minimum possible value on landing ( all fuel used ). I mention this as it determines the pivot for the rotational controls. That is the upper frictional surfaces plus the little thrusters will have a greater effect in this aspect ( an effectively longer lever ) on pointing the rocket exhaust as fuel is used. The upshot is that what you might otherwise think of as 'constants of the problem' aren't, mainly are functions of time. This is mildly reminiscent of racing cars where various 'balance' points shift as fuel is burnt. However it is much more prominent with rocketry due to fractionally higher fuel mass burn rates.
On the upside ( at a guess ) I reckon that fuel slosh is much less of an issue coming down than going up.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
There was an analogous issue with the Apollo 11 landing. It became apparent during late descent that there was a field of rocks on & about the target zone. These were not known via prior survey ( under the resolution of Earth based telescopes ). So they had to quickly divert and this led to the famous short fuel margin upon actual landing. Upon later debrief Neil and Buzz discussed what useful advice they could give to subsequent pilots if that instance recurred. Basically the question is do you then go short or long, deviate to left or right upon discovery of said obstructions. On their day they had gone long and a bit laterally ( I forgot to which side ). Anyway on reflection they advised to go short for several clear reasons :
(a) you keep more fuel in hand at any given moment that way.
(b) you can always see a given rock field in front of you and thus not be unsure as to whether you have passed all rocks behind you.
(c) it seems more psychologically comfortable to be 'getting on with it' rather than feeling one is losing options by delay.
Anyway the relevance here to SpaceX is which would you account for ? Going long or short here is with respect to wind direction .....
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
The bottom 1/3 is totally
)
The bottom 1/3 is totally black - except where the paint was protected by the tucked in pod legs. I swear it looks like a giant chimney from a power utility landing on that barge.
It has landed on a barge. See
)
It has landed on a barge. See video at theregister.co.uk
Tullio
Here is a link to the Beam
)
Here is a link to the Beam module.
SpaceX Twitter release of
)
SpaceX Twitter release of on-board video of landing.
Wow. Interesting to see the paddle correction just before landing.
RE: SpaceX Twitter release
)
Exponential wow ! That camera is looking right down the whole length of the barrel. You can also see brief use of the mini-thrusters ( the ones that flip the stage over after separation to then do the boost back ) for about one second early in the video ( the white puffs coming from near the right hand vane as shown ) :
That definitely got flicked off dead centre by last moment gusts ie. the extremely late control choice was b/w an upright landing off-target, or a tilted on-target landing. Well chosen. :-))
For those other aerospace companies who haven't already gone 'Oh crap, this mob is just way ahead of the curve' they'd have to do that now ....
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
As I said elsewhere, Obama
)
As I said elsewhere, Obama was right in opening space to private firms.
Tullio
RE: That definitely got
)
Thanks for the snapshot, also the wind component was probably why the little hop downwind on landing. I guess it must be difficult to chose an a direction for landing, so as the say say in aviation, "they greased it"!
I wonder if the barge is stationary or travels downwind to reduce the wind effect.
Working the paddles. A
)
Working the paddles. A fascinating video. SpaceX seems to cover all aspects of flight with imaging. Others may have also but we just never got to see them.
It's a fascinating problem.
)
It's a fascinating problem. The rocket has tremendous power but only along one axis. By comparison the control effects along the other two axes are minor, and because they primarily give rotation rather than translation they determine the direction of the main thrust. However there is engine gimballing as well. Plus you have to anticipate the effect of control delays so as to act appropriately where the rocket will be then as opposed to the moment of calculation. So "Are those films in real time" is YES ! :-)
In turn the effect of the vanes is ( roughly ) proportional to speed^2 so has great importance up high - to bring the craft down from hypersonic - but barely much in the last 100ft say. And always the ( gravitational potential ) energy gained during ascent must be bled when returned as kinetic. I think the one prior to this ( no boost back loop ) that took out a section of the barge was right out of the envelope of management. Perhaps one day they will release the footage ( I'm sure they have it ) and we will see what delta-v was needed.
Aaaah ! If only I was a young man again ie. that SpaceX is hiring.
Cheers, Mike.
( edit ) I've looked hard for primary actual data on the Falcon Nine's first stage centre of mass - alot are talking of it, but no one seems to know detail alas. This point will descend toward the base as fuel is consumed and ideally will achieve it's minimum possible value on landing ( all fuel used ). I mention this as it determines the pivot for the rotational controls. That is the upper frictional surfaces plus the little thrusters will have a greater effect in this aspect ( an effectively longer lever ) on pointing the rocket exhaust as fuel is used. The upshot is that what you might otherwise think of as 'constants of the problem' aren't, mainly are functions of time. This is mildly reminiscent of racing cars where various 'balance' points shift as fuel is burnt. However it is much more prominent with rocketry due to fractionally higher fuel mass burn rates.
On the upside ( at a guess ) I reckon that fuel slosh is much less of an issue coming down than going up.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
There was an analogous issue
)
There was an analogous issue with the Apollo 11 landing. It became apparent during late descent that there was a field of rocks on & about the target zone. These were not known via prior survey ( under the resolution of Earth based telescopes ). So they had to quickly divert and this led to the famous short fuel margin upon actual landing. Upon later debrief Neil and Buzz discussed what useful advice they could give to subsequent pilots if that instance recurred. Basically the question is do you then go short or long, deviate to left or right upon discovery of said obstructions. On their day they had gone long and a bit laterally ( I forgot to which side ). Anyway on reflection they advised to go short for several clear reasons :
(a) you keep more fuel in hand at any given moment that way.
(b) you can always see a given rock field in front of you and thus not be unsure as to whether you have passed all rocks behind you.
(c) it seems more psychologically comfortable to be 'getting on with it' rather than feeling one is losing options by delay.
Anyway the relevance here to SpaceX is which would you account for ? Going long or short here is with respect to wind direction .....
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal