/sci/ - Science & Math

Wouldn't it be a lot easier to use Parachutes

Nice animation, but something confuses me. Why waste fuel just to have a reusable booster that can land itself? The same goes for the other modules.

Never gonna happen.

Sage.

>>3826296

>saging the most /sci/ Related thread
ISHYDDT

>>3826294
The cost of the fuel is far far less than the cost of building a new rocket

>>3826311

>The cost of the fuel is far far less than the cost of building a new rocket

3% of the cost of most rockets actually.

>>3826311
But we already have reusable rockets. They don't need to land themselves. Seems like added complexity and expense to me.

>>3826327

You mean crash themselves?

SpaceX is the biggest scam since Enron.

>>3826331
That's what I expect to happen from a rocket that tries to land itself.

>>3826343

The Blue Origin rocket has sort of demonstrated this, but yeah, they have yet to drop one from orbital velocity.

>>3826327

Which rockets are reusable? the SSME?, the Engine that needs to be taken out of the Shuttle. Completely rebuilt and then put back? or the Shuttles SRB that is just an empty casing that parachutes back into the ocean

>>3826341
>SpaceX is the biggest scam since subprime mortgages
fixed to be more contemporary

What they probably don't show us is an intermediate stage with a parachute. Anything design that just tries to directly slow itself down after dropping from orbit is pants on head stupid.

>SPACEX WILL DOMINATE THE UNIVERSE

And you will still never into space without a million dollars per trip.

>>3826380
>I work for NASA, this design is shit, shit I tell you. SHIT.

stay classy "/sci/entist".

>>3826411
It is shit. Every pound sent into space costs alot. Think about all the extra tonnes of rocket fuel thats gonna be needed to land each stage. Think about the larger engines that are gonna be needed to bring all rocket fuel into space. Think about the extra fuel that that rocket'll need to bring up the heaver engines.

I'f theres an intermediate parachute stage, like that anon suggested, it wouldnt be a retarded design.

>>3826434
>Fuck you. Look, look at my NASA PhD. Look at it motherfucker, I am rocket scientist, you are not, you are shit, you are design is shit. Go eat peas you fuck Russian wannaby.

Stay Classy.

We need non-rocket spacelaunches.

From an aircraft, from a stratospheric spaceport buoyed up by weather balloons, from a magnetic induction catapult on a mountain...

Even a space elevator. But fuck rockets. You'll never get efficient launches when you spend the entire first stage just getting off the ground.

What the hell?! All the components just fly back to the earth using rockets?

What?

This cant be!

Yes there must be an intermediate parachute stage... but if there was that stage, why use the rockets to land at all?

>>3826481
and how do you propose we do this?

>>3826461
question is, why wouldn't you use a parachute?
It can only save energy.

>>3826481

Someone here once said that a huge majority of the energy used in space launch is just getting the rocket to reach escape velocity. Meaning that simply going higher is going to save you the trouble of lifting the rocket to a high altitude, which isnt the main challenge of space flight to begin with.

>>3826493
parachutes are for babby's first rockets. we are better than babbys. be proud of our science

>>3826498
But you still have to burn fuel getting the rocket to a high altitude using planes.

ITT:

Anonymous posters on a wapanese-themed imageboard trying to seem edgy and intelligent by "poking holes" in the design of a launch vehicle recovery stage.

>HurrDurr Seriously guys, this multi-million dollar rocket corporation knows shit about rockets.
>I, On the other hand..

>>3826498

>>escape velocity

A space launch's purpose gets you into orbit, not beyond.

All you need is altitude and speed. The problem is that while rockets are good for building up speed in orbit, they're terrible at exploiting the atmosphere to get off the ground, like an aircraft would.

I guess the weight of the extra fuel for getting it back to the pad would be cheaper than a recovering ship for a sea landing

>>3826548
That I seriously doubt.

>>3826523

You don't seriously think a plane going to the stratosphere is more expensive than a rocket, do you?

>>3826535

I would love an explanation as to why they used fuel. Simply asking for an explanation does not imply that I am insulting the idea, and it doesn't equate to criticism.

>>3826544

I dont know the specifics. I assume that there is a speed, and if you are going above that speed you escape the earth, and if you are going below that speed you fall back to earth. Im referring to whatever that speed is that puts you in orbit that you cant go significantly above or below.

>>3826555
That depends. How much does it cost to build and service such a ridiculously huge plane?

>>3826560
>I would love an explanation as to why they used fuel.
To produce thrust...

From an interested but not particularly well versed observer, yours truly:

Seems like a lot of effort when using parachutes and a splashdown water landing would be far easier and cheaper.
That said, if they know something that I don't....them being, y'know, a company that builds and launches spacecraft might know, then props to them. Hopefully this isn't just a gimmicky video designed to drum up investment and they secretly know it will never work in practice.

>For everyone else who is a-herping and a-derping in this thread, pic related.

>>3826574
parachute can produce thrust too...

>>3826560

well actually there's a lot of wiggle room. Basically as your speed increases so does the orbital altitude. Escape velocity is where you concentrate a lot of thrust at one point in the orbit. Your predicted path will go from a nice circle-like path to a whacked out ellipse and then a hyperbola. Once you're there, you're leaving earth.

But if you keep a fairly constant engine burn going you can raise your orbital altitude and speed while staying in orbit, for quite a fair distance.

I highly recommend the free spaceflight sim "orbiter" and the related manual if you're interested in testing this for yourself.

>>3826574

Why are they producing thrust during decent? Why not use a parachute which requires no fuel and does the same thing?

>>3826596
because we fucking can you dirt russian.

USA. USA. USA.

>>3826596

A parachute is near-impossible to aim with. It seems like they were trying to land it in a specific area.

>>3826596

They have to get out of orbit somehow, I doubt they would want to travel to the west coast of Africa to retrieve the core

>>3826596
Isn't it obvious?

So they can land on other planets.

>>3826607
Never heard of an airfoil?

>>3826498
As I understand it, the amount of fuel spent in going up pales in comparison to the amount spent generating tangential velocity to get into orbit. Launching from the top of mountains or from high-altitude planes doesn't actually save anything compared to the increased complexity (and therefore cost) of those techniques. In the case of high altitude plane launch, its even more of a net loss since you're expending all that jet fuel to get the rocket up to altitude, and fighting drag as more time is spent in the lower altitudes.

>>3826568

>>ridiculously huge

Why?

Have you seen SpaceShipTwo/WhiteKnightTwo?

That used a carrier plane, looked about the side of the space shuttle.

A good old stratospheric bomber could be modified to carry one I'm sure.

I think that space travel needs to have three main components: launch vehicles, orbital rendezvous stations and deep spaceships.

The deep spaceships are the heavy ones, flown up in parts. The launch vehicles and rendezvous are just low earth orbit.

>>3826585

I bet investors are smarter than that. I also just suspect that SpaceX knows something I dont.

>>3826595

Oh I see what you are saying. Simply burning fuel would just throw you into a wider orbit. So is escape velocity defined more by acceleration than speed? (maybe that sounds ridiculous)

>>3826620
>spaceshiptwo

confirmed for retard, all opinion invalid.

would it be possible to make a spaceship that like starts out high in the atmosphere before engaging the rocket to get the rest of the way

like have like a very large airplane that carries a rocket, have the airplane fly up to, idk, high airplane cruising altitude, then have the rocket separate off like a missile and launch itself up into orbit, that way it wouldnt have to use nearly as much fuel or anything itself?

>>3826585

Voice of reason.

>>3826652
Yes.

>>3826625

I'm actually not too sure about just what is required to break free of orbit. 'Escape velocity' as an actual speed applies to something unpowered, so a cannonball rather than a rocket. It's the speed that an unpowered vehicle needs to be at to break free without further propulsion.

Not sure exactly what a rocket needs but it would seem to be anything that changes the eccentricity of the orbit to such a degree that the trajectory is hyperbolic.

that was beatiful OP

>>3826670

http://en.wikipedia.org/wiki/Orbital_eccentricity

Ah here we are. So an eccentricity of 0 is a perfect circle, 1 is a parabola (the easiest escape orbit), 2 is a hyperbola.

guys

guys,

listen, guys,

guys.

what if,

what if we launch.

guys, pay attention please.

what if,

what if we launch the rocket with barely enough fuel to get the engine started. then

then, we,

are you listening?

I'm about to blow your mind,

then we launch another rocket,

carrying the fuel

and transfer the fuel to the space rocket while everything's in the air

this way essentially we are carrying less weight into space. thus saving money

what do you guys think?

>>3826620

Ladies and Gentleman, I give you

WhiteKnightThree

>>3826682
What if we just connect the rocket to the ground with a huge fuel line, and then when it reaches orbit, BAM instant space elevator.

>>3826697
because liquid doesn't go up you dumbass.

>>3826689
>yfw snap

if we can build that, we can build space elevators. gtfo

>>3826682
Wouldn't the second rocket carrying the fuel and the fuel used by 2 rockets end up making this dumb?

>>3826705
Pumps!

>>3826707
Rocket pumps!

>>3826709
That's the joke.

>>3826697

Why dont we do that?! THATS A GREAT IDEA

>>3826707

You tell him!

>>3826700

The WhiteKnight One and Two and snap and continue to fly, one side wont make it back to the landing sight though, due to lack of a pilot

>>3826726
>implying the wing is two piece construction
>implying having to replace the whole fucking vehicle isn't dumb as fuck.
>implying it won't snap every single time because LOL WE CAN JUST SCALE IT UP NO PROBLEM.

Where are my resources placed in orbit from asteroid mining?

>>3826777
In the future.

>sound in a vacuum

lol and they think they can build a space station...

this is all convoluted miliatry industrial complex bullshit. there's no need for all these rockets and space stations. getting to space is something even the ancient greeks were capable of...

pic related

Lotta dumb in this thread...

Air launch doesn't help much. Most of a rocket's fuel is used to go sideways to reach the Mach 17 orbital velocity (not "escape velocity" as mentioned earlier), not gain altitude. The altitude and airspeed does not reduce the fuel requirements much, so the rocket still has to be very large. That's why the only air launched orbital rocket (Pegasus) is relatively small. Most launch facilities are at sea level.

>>3827424
>clearly just for the presentation purposes
>stay aspie

>>3826613
an airfoil parachute is a good idea (and was researched for the cancelled Crew Return Vehicle spaceplane, an ISS lifeboat). But you then still need landing gear, and you are at the mercy of weather conditions when you land.

I was thinking what to specialize for the next year, either aircraft or space science. Now I know

Fuck big old chemical rockets. Spaceplanes are where it's at.

One drawback of powered landing: it blasts the fuck out of the landing area. Have you seen the Armadillo landing videos? When they do powered landings, you can see chunks of concrete being blasted away as it hovers and lands... and that is for their tiny engine! Imagine the damage a Merlin-1D would do!

There would also be less vibration protection, because there is no flame chute or water suppression system when landing.

Oooh, I had a good idea just now. They could land in a shallow wading pool!

>>3828305
Fuck both. Space Catapult's are where it's at.

> private firms doing space research thread
> 60 posts later, science fiction
sounds about right

>>3829195
What are you calling fiction, you double engineer?