/sci/ - Science & Math

[Anonymous No.3454900]

Spaceplanes will never be build because current rockets are the pinnacle in fuel-efficient spaceflight. Also, spaceflight won't get cheaper because the energy needed to lift and accelerate a specific object into orbit is always the same.

[Anonymous No.3454910]

>pinnacle of fuel efficient spaceflight
Inherently false claim, troll harder

[Anonymous No.3454922]

>Spaceplanes will never be build
Maybe.
>current rockets are the pinnacle in fuel-efficient spaceflight
No they aren't.
>spaceflight won't get cheaper
Yes it will.
>energy needed to lift and accelerate a specific object into orbit is always the same.
Yes, but the energy can be expended in more efficient ways than just blowing shit up in a semi-controlled reaction.

[Anonymous No.3454939]

The space shuttles were classified as spaceplanes, so in that sense your are terribly mistaken.
If you said super-efficient SSTO interplanetary rendezvous spaceplanes, you might have a point. But you asserted that they will NEVER be built, which is a baseless claim regardless.

[Anonymous No.3454945]

inb4 Skylon spaceplane

[Anonymous No.3454948]

If you know a better way to get to orbit than rockets then be my guest.

[Anonymous No.3454950]

Fuck you we'll build all the space planes we want.

[Anonymous No.3454971]

>>3454939
>classified as spaceplanes
>classifying a heavy satellite with wings as a spaceplane

I'll put wings on a truck, then throw it off a cliff and can call that a plane as long as the wings will make it fall in a not-so-straight line?

[Anonymous No.3454979]

>>3454971
Everything that has ever gone into LEO is a satellite. The fact that the space shuttle could return and fly back up shows it is a space plane.

[Anonymous No.3454988]

>>3454948
>mass driver
>space elevator
>launch loop(controversial)
>space fountain
>laser propulsion
>space blimp(controversial)
Want some more?

[Anonymous No.3455004]

>mildly windy day
>lol i no u guis were counting on that launch but we just can't

Rockets require nearly perfect conditions to not end in disaster. Space planes are far more tolerant of things like weather given that they fly above it.

[Anonymous No.3455028]

>>3454979
>fly back up

It rides piggy-back on a rocket. The fact that it returns with wings makes it little better than a Sojus-capsule. And it's just reused because the whole structure is too expensive. Used Sojus units could probably also be refurbished in order to reuse them. But it's cheaper to build new ones.

[Anonymous No.3455034]

>>3455028
The rockets are part of the launch mechanism because the shuttle isn't fuel efficient enough to contain all it needs to launch, actually.

[Anonymous No.3455038]

>>3454988
If they are so great why don't we have them yet?

[Anonymous No.3455045]

>>3455038
If you're so correct why does cheese remind me of the windows XP log off sound?

[Anonymous No.3455051]

>>3455034
>the shuttle isn't fuel efficient enough to contain all it needs to launch

Same goes for all upper stages.

[Anonymous No.3455058]

>>3455051
Which cannot be relaunched. The shuttle can.
Just because the fuel containers are replaced doesn't mean it isn't a space plane. It is a plane, it can go into LEO and return. SCIENCE.

[Anonymous No.3455131]

>>3455058
>Which cannot be relaunched.

Actually, they could, they just aren't because it' cheaper to build a new one. For the shuttle it's cheaper to refurbish the heat shield than build a whole new frame.

I still say it's not a plane because it's virtually just a payload shot into orbit on a predetermined flightpath.

[Anonymous No.3455140]

>>3455131
so is a space plane.

[Anonymous No.3455156]

>>3455140
True space planes will be able to significantly alter their flight path (specifically within the atmosphere) so I'll have to disagree with you here.

The shuttle is a flying brick, not a plane, and barely even a glider.

[Anonymous No.3455168]

>>3455156
That's not the definition of a space plane though. The shuttle can alter its position while in orbit, and when descending. Maybe not to the extent you've decided is significant, but certainly to a degree. Given that escape velocity is mach 10 I don't see why you'd expect decent manouverability from any space plane.

[Anonymous No.3455194]

>>3455168
I expect a space plane to function like a plane, but with strong enough propulsion to exit the atmosphere and capable of returning.

The shuttle can't perform the first function to any significant degree. It can't change target landing strips, it can't enter holding patterns.

[Anonymous No.3455206]

>The shuttle can alter its position while in orbit, and when descending.

Most spacecraft can maneuver in orbit. And while the shuttle has wings, it still doesn't have the fexibility of a plane during the landing phase. The wings are just a means to slow its descent just like parachutes which would be impractical for a large object like a shuttle.

[Anonymous No.3455214]

>>3455206
It does have chutes.
The wings have flaps, there's a degree of manouverability. As said, we're limited by the fact we have to take off at at least mach 10 and withstand over 1900k.

[Anonymous No.3455211]

Also don't expect the generation that will allow mankind to get into deeper space to be atmosphere rated. It's not a wise decision

[Anonymous No.3455238]

>>3455211
We will need something that serves is capable of leaving those vehicles and returning without leaving parts of it behind for exploration purposes.

[gay kid No.3455241]

>>3454900
sr 71 was at the edge of orbit, a small rocket on the underside would've pushed it into orbit.

this was invented in the 60's

get owned

[Anonymous No.3455249]

>>3455238
why?

[Anonymous No.3455273]

>>3455214
>It does have chutes.

Those are just a method for braking on the runway when it's touched down. The parachutes on other spacecraft are there to slow the actual descent.

I just don't call it a plane because aerodynamic lift doesn't come into play until its gliding phase, and then it's just a glider, it doesn't even use any kind of engine. Technically, even parachuting spacecraft are some sort of (para)glider.

[Anonymous No.3455278]

>>3455238
Yes, yes
but then we will have 2 different ship designs, with different goals as well, allowing them to have optimized designs

[Anonymous No.3455303]

>>3455273
and I say your definitions are kinda arbitrary. IMO, the spaceshipone/shuttle type designs are space planes. They fly in space, and they have wings and the ability to manoeuvre themselves.

[Anonymous No.3455304]

>>3455241
>On 28 July 1976, SR-71 serial number 61-7962 broke the world record for its class: an "absolute altitude record" of 85,069 feet (25,929 m)

Too bad space begins at 100,000 m. So much for "edge of orbit".

[Anonymous No.3455342]

>>3455303
Well, SpaceShipOne can reach "space" (i.e. fly higher than 100km) but it's still suborbital and can't stay up there longer than a few minutes.

It's not really arbitrary, I just require it to reach orbit and use aerodynamic lift during ascent and descent, as well as the ability to conduct atmospheric flight under own power. The last point separates actual planes from sailgliders.

[Anonymous No.3455389]

Scramjet + rocket propelled spacecraft

On ground they're launched from a mass driver, reaching multiple machs so the scramjet can become operational. Scramjet will take the spacecraft up to 30 kms and mach 10, where the spacecraft's rocket engines are ignited and it'll go up to orbit.

What could possibly go wrong here?

[Anonymous No.3455443]

>>3455194
>I expect a space plane to function like a plane, but with strong enough propulsion to exit the atmosphere and capable of returning.
In other words, you don't actually know what "space plane" means, you just assumed from the name that it should act like a plane.

Understandable, but you really should read up on a topic before starting an argument on a topic.

[Anonymous No.3455470]

>>3455304

It's above the thick part of atmospere
the guy has a point

[Anonymous No.3455490]

__________________________________
Everyone above this line is an idiot.

[Anonymous No.3455492]

>>3455490
>__________________________________
>Everyone above this line is an idiot.
har now you are also an idiot

[Anonymous No.3455500]

>>3455389
A lot, but it's a very interesting idea.

Too bad the acceleration imparted by the mass driver would pulp any human passengers.

[Anonymous No.3455504]

>>3455443
If a space plane doesn't function than it shouldn't be called a plane. You wouldn't call a piece of fruit and automobile would you?

[Anonymous No.3455510]

>>3455504
if it was a piece of fruit with an engine that was mobile then it would qualify as one.

[Anonymous No.3455516]

In my opinion, at this time, a two stage design is best.

Stage one is a large aircraft that transports the orbital vehicle to the edge of the atmosphere, releases it, then lands.

Stage 2 is the orbital vehicle and payload. It uses liquid fueled rockets to get away from the atmosphere, then switches over to something like the vasimr design if you plan to leave orbit (lunar missions, etc). If designed correctly, stage 2 could be capable of powered flight during the landing procedure.

[Anonymous No.3455520]

ITT: OP gets told in the first few posts and subsequentely starts trolling people over semantics

[Anonymous No.3455524]

>>3455516
>edge of the atmosphere
you mean edge of the troposphere dude

[Anonymous No.3455553]

>>3455500
nope.

>Libelle G-suit, which allows aircraft pilots to remain conscious and functioning at more than 10 G acceleration by surrounding them with water in a rigid suit.

also, liquid immersion protects up to 20Gs without needing a liquid breathing apparatus.

[Anonymous No.3455589]

>>3455516
>edge of the atmosphere
>heavy bomber flying 10.000km high

why releasing stage 2 at all?

[Anonymous No.3455608]

>>3455589
>10.000km
>not sure if trolling or just European and backwards

[Anonymous No.3455612]

>>3455524
>>3455589
edge of atmosphere as in past the bulk of the matter in the atmosphere (the thick part in the first 20-30,000 m), not past the whole thing.

Far enough that aerodynamic lift and drag are no longer the significant forces in play.

[Anonymous No.3455646]

>>3454971
yes.

[Anonymous No.3455663]

>>3455608
it's ten thousand kilometers you illiterate faggot

>>3455612
don't call it edge of the atmosphere if you are talking about first two layers out of five

[Anonymous No.3455685]

>>3455663
So European and backwards.
Internationally, "," is used for grouping digits and "." is used for signifying decimals. On mainland Europe, it's the other way round. Given you're talking in english, which uses international, on an american hosted board (America using international) inspired by Japanese subcultures (Japan also using international) kindly quit being retarded and use proper notation.

[Anonymous No.3455723]

>>3455685
if you want to be grammar nazi, note than I'm not TALKING to you, cunt.

seriously, picking on some trivial shit I wasn't even aware of.

[Anonymous No.3455743]

>>3455685
Japanese culture has nothing to do with the international notation.

[Anonymous No.3455748]

>>3455723
>if you want to be grammar nazi, note than I'm not TALKING to you, cunt.
>If you want to be something, not something completely UNRELATED to it, you cunt.
>I'm not TALKING to you
pic related
>seriously, picking on some trivial shit I wasn't even aware of.
Seriously, making non-trivial mistakes then denying things that are obviously true and treating people who correct you like shit makes you look about 13 years old. Cut it out.
>>3455743
Japan does.

[Anonymous No.3455750]

>>3455553
Do you happen to know the specs of a mass driver required to launch a space-shuttle-sized payload into space, at 20gs max accel?

[Anonymous No.3455757]

>>3455750
I'm just gonna interject that the shuttle's cargo bay is massively oversized and rarely fully utilised. Something about 2/3 the size would easily suffice.

[Anonymous No.3455759]

>>3455757
Fine with me, since this is theoretical at the moment.

[Anonymous No.3455763]

>>3455748
>Japan does.
It has no additional bearing on the point that anon was trying to make.

[Anonymous No.3455764]

>>3455748
it is trivial
why should I write three zeros behind 10 when talking about kilometers for fucks sake

[Anonymous No.3455771]

Sure would be cool if we could invent some kind of gravity nullification/damping field.

[Anonymous No.3455772]

>>3455763
I'm pre-empting any statement against using international notation based upon the nature of the board. The fact that the design comes from Japan, which uses international, is important in that.
>>3455764
You think three orders of magnitude are trivial? seriously?
Notation to a set number of decimal places is pretty common in science.

[Anonymous No.3455792]

This thread is so full of dumb, I feel like I'm reading YouTube comments.

pic related, the DreamChaser space plane, sent to orbit on an Atlas V rocket

[Anonymous No.3455797]

>>3455792
X-37B>DreamChaser. It has a better name, for one.

[Anonymous No.3455820]

>>3454900
>spaceflight won't get cheaper because the energy needed to lift and accelerate a specific object into orbit is always the same.

Do you realize that the biggest cost of today's spaceflight has nothing to do with physics? It is the cost of the labor force required to construct the rocket, maintain the launch pad, and do the legal paperwork. (Plus the amortized cost of designing the rocket in the first place.) That is the key realization which is leading SpaceX to bring down launch costs: reduce manual labor at every stage. Example: instead of the army of workers required for a shuttle launch, a Falcon 9 launch has a staff of two dozen at the launch pad for both integration and launch operations. SpaceX automates everything they can get away with.

[Anonymous No.3455821]

>>3455500
Why should it?
You can reach mach 10 with a mass driver a bit over five kilometers long and 1g acceleration along it's entire length.

Sure it would be uncomfortable, but hardly bone-crushing.

[Anonymous No.3455838]

>>3455821
Nope.
Moving 5KM at an acceleration of 1G (rounded up 10 10m/s for generosity) will only get you to 320m/s.

[Anonymous No.3455841]

>>3455772
>You think three orders of magnitude are trivial? seriously?

no man, stating altitude of the edge of atmosphere with three decimals would just make me a complete retard because there is no way to define it with such accuracy. Thanks for your hard work.

by the way if we talk strictly about part of the atmosphere that IS considered atmosphere and NOT space, then tha'ts Karman line. (100km high)

[Anonymous No.3455848]

>>3455841
well done, you can use wikipedia.
In future, if you make a mistake own up to it instead of acting like a stubborn ass. The only reason you didn't say "I meant '.' " is that you're arrogant and immature.

[Anonymous No.3455857]

>>3455241
>SR-71 was at the edge of orbit, a small rocket on the underside would've pushed it into orbit.

NOPE

The SR-71 Blackbird was a sexy fast beast, the fastest jet to have been used regularly, but it is still an order of magnitude slower than what is required to reach orbit. A "small rocket" would have an insignificant effect on its velocity; the SR-71 was a pretty big plane.

That said, the XCOR Lynx is a rocket plane being designed to be the first stage of a small launch system. The Lynx would rocket to high altitude, then release a smaller rocket to take a small payload into orbit, before itself gliding down for a landing.

[Anonymous No.3455877]

>>3455838
Sorry, made a bad decimal error there. 474 kilometers it is.

On the other hand, why boost the scramjet to mach 10 on the ground? If we just boost it up to ignition speed of mach 4-5, 119 kilometers of track would be enough.

[Anonymous No.3455887]

>>3455797
>X-37B
an unmanned spacecraft designed to run experiments and bring them back, was abandoned by NASA because of its cost and the air force dug it up to prove how big their dicks are.

>dreamchaser
a manned spacecraft with good prospects for future missions.

[Anonymous No.3455903]

>>3455857
>XCOR Lynx
Oh great, the one spaceplane design which I hate purely on the base of aesthetics.

Pic related, it's what inspired the design.

[Anonymous No.3455912]

>>3455848
the only reason I didn't said that is becasue we don't use that shit here at all
we just write it 10000.

>European backwards

I've jumped the gun because I thought someone is playing master race again becuase I used metric units
hope we are clear now

[Anonymous No.3455913]

>>3455877
Sounds more like it.
I wasn't proposing the scramjet, but I don't get that either. Presumably there's some method of converting a conventional RAMjet into a scramjet mid flight (they seem structurally similar) which would allow a JATO system to get up to a few thousand knots and then for the fast jets to kick in, eventually allowing post orbital speeds to be reached.

[Anonymous No.3455936]

>>3455913
Yeah, I started to wonder about that result myself, remembering the lines about the terrestrial catapult in The Moon is a Harsh Mistress.

Thanks for spotting it.

[Anonymous No.3455946]

>>3455912
ok, you're a cool guy again.
European decimal notation is like the imperial of the US/UK.

[Anonymous No.3455987]

>>3455946
ok fine, try putting a number into a program with commas then.

[Anonymous No.3456000]

>>3455987
Find me one from finland and I will.
I'm not arguing with you in the post you're replying to. Not sure why you'd think I was.

[Anonymous No.3455997]

>>Also, spaceflight won't get cheaper because the energy needed to lift and accelerate a specific object into orbit is always the same.

The cost to put 1lb into orbit is dependent on how cheap your spacecraft is to put into orbit. If you can produce 15,000lbs of thrust for $15k, it costs $1k per pound. If you can produce 15,000lbs of thrust for $1.5k, then it will cost you $100 per pound. Thus the price would be cheaper.

It's an economics and engineering issue, not a physics issue.

[Anonymous No.3456013]

>>3456000
you are now talking to another person

[Anonymous No.3456016]

>>3456013
fuck this gay earth
-Carl Sagan

[Anonymous No.3456029]

>>3456016
such is life of anonymous.
you never know who you are talking to.
our conversation ended with your post. not sure why someone started digging it again,

[None !iBNJP14QiA No.3456040]

>>3456029
I don't know
My favourite part is that if I do this people automatically jump to the conclusion I'm a massive attention whore

[Anonymous No.3456053]

>current rockets
>fuel efficient spaceflight

derp

does /sci/ like Kerbal Space Program?

[Anonymous No.3456079]

>>3456053
Honestly, rocket engines are about the most efficient use of energy to do work (heat engines) that exist. It just takes a LOT of work to get to orbit.

Even more efficient are the ion engines like VASIMR and the ones on the Dawn probe which just arrived at asteroid Vesta.

[Anonymous No.3456179]

>>3456079
The only rocket engines more efficient than chemical engines that come close to having the thrust capable of lifting a rocket off the surface of the Earth are nuclear thermal rockets, and even then they don't have the greatest thrust-to-weight ratio and if you so much as try to use them, you'll have every environmentalist in the world screaming at you.

The problem is more with the cost to build and launch rockets, as >>3455820 pointed out. You can get around this either by making the launch vehicle reusable, thus eliminating the cost of building a new vehicle for each launch, or by making the launch vehicle ridiculously cheap to build and just mass producing them. There's problems with both approaches. Creating a reusable launch vehicle isn't as easy as it seems (as the Space Shuttle showed), and likewise, the current level of demand in the global launch market isn't enough to sustain a cheap, mass-produced approach. That being said, this does not preclude the possibility of technology or launch demand changing. You can never guarantee what will happen in the future.

[Anonymous No.3456386]

>>3456179
The thing is, if you expend the energy by using for example a catapult, you don't need to loft the fuel needed to produce the energy. You spend the energy on the ground and, though inefficient, the catapult will have the advantage of economy of scale.

By using airbreathing engines to climb a part of the way, you also don't need to lift the oxidizer to produce the energy for that part of the flight.

When you use rockets, though in a way efficient, you always have to lift all the fuel and all the oxidizer for all the stages.

Also, if you managed to use the catapult even partially with solar or other less-polluting power generation, you will have negated at least that small amount of pollution that a rocket engine would have produced.

I know the amount of pollution caused by rockets is negligible at worst, some greenies want to ban spaceflight on those grounds anyway.

[Anonymous No.3457353]

>>3456386
That's true, but like I said, the technology needed to create an air-breathing launch vehicle or a mass driver will take some time to develop. For example, getting into orbit requires a delta-v of about 9-10 km/s. That's around mach 27 or so. To reduce your fuel load and therefore make it easier to get into orbit with a single stage, you're going to need to get your vehicle to somewhere around mach 5 or mach 6 before switching to conventional rocket engines. Assuming you're using a hydrogen-fueled engine with a specific impulse of about 430s or so, if you accelerate to mach 5, you end up needing a payload mass fraction of 0.14 or lower. This is fairly typical for conventional rocket stages.

The problem is getting to mach 5. Only small, experimental scramjets that have already been boosted to hypersonic speed by conventional rockets have operated at this speed, and there's a number of problems with operating at mach 5+. The main problem is with overheating, though there are people working on the problem. For example, Reaction Engines, the guys working on the Skylon, just recently created a pre-cooler for their engine that's supposed to cool the air to cryogenic temperatures. Though there's still a lot of work to be done.

[Anonymous No.3457370]

>>3457353 continued

Now, you could use a catapult to get your vehicle to supersonic or hypersonic speeds, but again, nobody's ever built something so big, and you'll also have problems with heating. If you're vehicle's traveling at mach 5 at around sea level, it's going to get very hot very quickly.

If you combine the two, as you suggested, it may make things easier. Your catapult gets you to mach 2 or mach 3, which is a bit more manageable temperature-wise, and then your engines don't have to run as long to get you to mach 5. But regardless of the approach, a system this complicated will take years of technological development. Look at the Skylon spaceplane, for example. It's going to take at least a decade to get a prototype flying, and that's assuming they don't run into any technical problems along the way.

tl;dr: air-breathing spaceplanes and mass drivers are a possibility, but it will take both time and money to get them working.