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View Full Version : Reference: REAL rocket 'landing'



jeric_synergy
04-15-2015, 05:21 PM
http://www.wired.com/2015/04/analysis-falcon-9-crash-landing/?mbid=social_fb

magiclight
04-16-2015, 04:26 AM
Even with quotes around 'landing' I don't think that qualify as that.

vonpietro
04-16-2015, 01:42 PM
I was wondering why they just went with engine and vents to slow this rocket down.
It could have little panels that pop open which have thrusters inside at the top to help keep it from tipping, make the entire section rotatable and you can point your thruster 360 degree and limit it to two opposing instead of 4, or make all 4 and just rotate it slightly where needed.

also why not a chute to help slow down and drag like 60% of the way down, eject it near the landing site and then let the rocket help it down the rest.
this way you save fuel and slow it down dramatically while allowing less fuel to be on board to perform the maneuver.
If not being able to control the direction of the craft is the issue with the chute - use one that you can guide, not the round one the sail one, or use the round one only 33% of the way, and the rockets to guide the rest.
I'm sure there is something that can be deployed to slow the decent other than a fuel wasting engine.

by the way - its not the first time they attempted to do this kind of reusable vehicle. It was a whole initiative in 1992. The video bought the project an extra year of life.
https://www.youtube.com/watch?v=TOsS4SzEWVU

My first big gig. I did the animation at 7:40 in the video a long time ago in a state far far away.
the future is now... again. =)

jeric_synergy
04-16-2015, 04:25 PM
Did you watch the HD video, or the low-rez Vine? In short, they did.

vonpietro
04-16-2015, 04:36 PM
Ah, good job then. i only saw the landing - and there was no chute.

jeric_synergy
04-17-2015, 01:13 AM
No, there's no chute-that's really the whole point. But there are thrusters at the top, you can see them firing, alas, unsuccessfully.

vonpietro
04-17-2015, 01:30 AM
i like the idea of being able to rotate the thrusters around - so they point in the direction it's falling in.

still why not a drag chute for say 50% of the decent? how is that not a good idea? (no fuel to burn with a chute)

magiclight
04-17-2015, 02:13 AM
The main reason for no chutes is that at the moment you pull out a chute, even with a drogue chute, you loose a lot of guidance control, you are pretty much in the hands of wind and weather.

Another problem is weight, parachutes, even the nice ones are pretty violent from a structural perspective and may need a heavier structure.

And it's much cooler to land without chutes....

Ernest
04-17-2015, 07:14 AM
AAAAAH! So close!

Wade
04-17-2015, 07:43 AM
With the wind as indicated by the white caps on the waves I am very surprised they hit their target. It almost looked as if the wind blew it over after the landing. There might be a tweak need to account for landing in 25 knot winds. My guess they will soon have this working in most conditions.

jeric_synergy
04-17-2015, 11:14 AM
i like the idea of being able to rotate the thrusters around - so they point in the direction it's falling in.
Mechanically that would be hugely complex. And that=heavy. There's multiple thrusters.

still why not a drag chute for say 50% of the decent? how is that not a good idea? (no fuel to burn with a chute)
Perhaps the guys who are LITERALLY rocket scientists have their reasons. 0_o

vonpietro
04-19-2015, 09:39 AM
a good idea is a good idea. It just has to work =)

rocket scientists keep trying till it works.

smaller size, lighter, until that good idea suddenly is feasible.

jeric_synergy
04-19-2015, 11:46 AM
Yeahhhhh, but your idea was NOT a good idea. It is the opposite. It is a BAD idea.

Just sayin'. ;)

I want them to catch, tame, and train a kraken to steady the rocket once it's down. Now, THAT'S a good idea (and fun to animate).

.
.

(The first stage is 138 feet tall-- something really needs to grab that thing. (Although most of the weight MUST be near the bottom...))

magiclight
04-19-2015, 12:46 PM
Almost everything is at the bottom, the tanks are pretty much empty so it's just an empty shell, the weight is the engine at the bottom.

vonpietro
04-19-2015, 12:51 PM
if i animated it and show you - you'll see its a good idea. It could be made of nothing but carbon fiber materials too just because everything is better if its carbon fiber.

also

why not some sort of spoiler that spreads out near the top like an umbrella, it could be against the hull and like the landing gear just springs out at landing time


ok, maybe i'm just thinking what would look good.

Megalodon2.0
04-19-2015, 02:10 PM
This is the one I remember from the early 90's. Seemed to work well, but it obviously wasn't perfect.

https://www.youtube.com/watch?v=JzXcTFfV3Ls

jeric_synergy
04-20-2015, 01:36 AM
why not some sort of spoiler that spreads out near the top like an umbrella, it could be against the hull and like the landing gear just springs out at landing time

ok, maybe i'm just thinking what would look good.
If the 'spoiler' pops out at landing time, that's the time when the rocket is going slowest, so the spoiler is least effective. At the end all it'll do is catch the wind and make it even MORE likely to topple.

SpaceX has tested its 'Grasshopper' successfully many times, maybe it's the barge that's the issue: it's in a more hostile, windy environment, and it may move with the waves. I can't imagine a practical mechanism to grab and steady the rocket, but I'm hoping they'll call it "The Kraken".

vonpietro
04-20-2015, 02:18 AM
hmm - then the umbrella would be instead of the chute - and could even jettison near landing time. =)

On the barge -
aircraft carriers have drag lines to slow the aircraft -
perhaps a drag line on the barge - but instead vertical - all they have to do is get the rocket near it - and these drag lines shoot straight up with poles. Maybe 4 poles that fly upwards really fast - the ring nice and big, and when they reach the top and the rocket is within the ring zone - it cinches. The poles only rise when the rocket is near the barge in final position. (a way to safe guard tipping) Or maybe it doesn't cinch, just stays up there and provides a safety net for tipping situation.

then the rocket still descending is now within the ring zone that shot up and if it tilts - the rings keep it from flipping over.

a vertical drag line of sorts =)


You can put a fairly complex rig underneath to counteract wave motion and bend with the rocket's movements.

jeric_synergy
04-20-2015, 01:38 PM
::sigh:: You're not an engineer, are you?

These would be spectacular to ANIMATE, but sound beyond impractical for real life.

Genetic engineering kraken, or perhaps hiring Cthulhu on a day-laborer basis, sounds more practical.

vonpietro
04-20-2015, 01:54 PM
maybe a future animation project to convince the masses

jeric_synergy
04-20-2015, 02:31 PM
One issue is something my engineer boss told me about the characteristics of cylinders, material, and 'oil-canning'. Basically it's how plane fuselages are INCREDIBLY strong along the long axis, but very fragile sideways. The numbers were hard to believe, but he's a very meticulous engineer. Consider how you can put a book on a cylinder of a single piece of paper.

So, anything that 'threatens' the SIDES of the rocket is to be avoided at all costs. Firing/throwing massive rigging PAST a descending, moving structure is probably a non-starter.

Something that could grab the landing legs would probably be 'better', but even then the moment arm of the 138' foot tall fuel tank (mostly) above them has to be taken into account. I don't know how the rocket is supposed to be secured to the barge as it steams back to land, but whatever that system is is already engineered to take the calculated stresses. Something that secured THAT, automagically at landing, would be likely.

BUT, Wiley Coyote mechanisms are fun to watch.

vonpietro
04-20-2015, 02:38 PM
ok how about this.

a huge tank rises into place and the rocket lands into the tank.

the tank is full of that super expanding foam stuff - like the stuff stallone was encased in in the movie demolition man.

so when the rockets gets majority into the tank - bam - its inflated with this super foam.

hehe

do they even have something that would do that (demolition man foam)

jeric_synergy
04-20-2015, 03:18 PM
So you have a mechanism that can rise up from ANY point on the barge?

(Actually, I can think of a way to make this work....)

There are some foams that react extremely quickly: the question is can you make a foam that's LESS damaging than seawater?

What I'd do is: a series of lightweight vertical barriers that set flush with the deck of the barge, once the rocket is down they spring up around the rocket itself, WHEREVER IT IS, under computer control, and robotic nozzles fill that area with the foam agent and its catalyst. Probably only have to go up 1/3rd the height of the structure (~5 meters). The barriers only have to confine the liquids for the short time they take to foam up. Possibly even fabric would work for the barriers.

For a Cowboy-Bebop look I'd prefer nozzles on robotic arms, but realistically, nozzles in the deck itself would probably work just as well/better. Not as cool a look though.

So, hop on that vonpietro. ;)

vonpietro
04-20-2015, 03:56 PM
ok blender fluids for the foam,
anyone got a model of the rocket.

i'll whip up a barge. =)

i'll have something maybe mid may =)