Can orbit be achieved without rocket assistance in stock KSP?

[General Rarity]

Wow, that is amazing. Not. N body physics is not a feature, you can't get "tugged by moon" unless you are not in moon's sphere of influence.

Probably meant slowly increasing AP in atmosphere with jets, do an 'orbit' till PE, burn again, etc, until you can get the Mun to slingshot you by increasing your AP very far.

[Ippo]

RCS is still rocket propulsion using hypergolic fuel, so it doesn't count as an answer to OP's question.

But yeah, you can either store air in air intakes or use ions (although we could debate if ion engines are just another kind of rocket).

[Corw]

RCS is still rocket propulsion using hypergolic fuel, so it doesn't count as an answer to OP's question.

But yeah, you can either store air in air intakes or use ions (although we could debate if ion engines are just another kind of rocket).

Yes, but RCS is not usually viewed as propulsion system. It is a control system (reaction control system) which can be abused, as shown. Ions, on the other hand are first of all propulsion system.

I know it is semantics and it is quite silly to start with (my plane got to orbit with bit more than half a tank of jet fuel and spent less than 20 units of monoprop to circularize). Easy to fly too

[Yukon0009]

Why no K-drive?

[Ippo]

Yes, but RCS is not usually viewed as propulsion system. It is a control system (reaction control system) which can be abused, as shown.

Check out

. Totally a rocket (quite powerful too).

[Brotoro]

The Apollo CSMs used for the Skylab missions (if I recall correctly) had their RCS systems upgraded so that they could be used as emergency retro propulsion.

[Corw]

Check out

. Totally a rocket (quite powerful too).

I know. And I agree. But if you are using RCS as main propulsion system, you are doing it wrong (in most cases, it is completely viable for very small craft).

[magnemoe]

The logic of what and why things are "cheaty" is beyond me. Overloading on air intakes and "storing" intake air are just as ludicrous as infinigliders and "kraken drives" IMO. Might as well just embrace it all if you're going to accept a jet engine getting a plane into orbit.

OP, I've heard of people using single-engine air-hoggers staying right on the edge of atmosphere and fluttering the engine on and off to get a periapsis that is nearly in orbit, but I don't recall if I've ever seen it done.

Skipping on the atmosphere with an hypersonic plane works well and is something who will work in real life too.

And yes storing air is stupid, guess the game does it for internal reasons, you have flow in an storage and air used. Same way you can not run kethane drill -> converter directly you need an tank to store in. This issue comes up in KSP as max speed of jets is so close to orbital speed, with my planes and flight profiles I'm rarely able to reach more than 1800-1900 m/s on jets either air get to thin or drag too high.

[KerikBalm]

When I use stock... I routinely get well above 1,900 m/s on jets... you can't get anywhere close to orbit in real life on air breathing engines.... even with scramjets.

That said... infinigliding and kraken is abusing bugs in the physics engine... it wasn't design to work like that...

At least that is clear for the kraken, although its less clar for infinigliding, as they must have conciously made control surfaces work differently than wings... the result does not seem to be intentional.

Though, you might argue that storing intake air is also unintentional, and a limitation of the resource system.

As for these claims of using the Mun... I call BS.

From like orbit, you need about 850 m/s to get your Ap out to the Mun.

This works out to about 3,100 m/s orbital velocity... a bit higher.

Turbojets produce ZERO thrust above 2,400 suface velocity, and thus CANNOT get going faster than 2,600 orbital velocity.

2,600 m/s from 69,000 m is not sufficient to get to Mun.

If you could get your AP even halfway to the Mun, it would be a lot easier to just have a radial intake full of air, and use your jets at Apoapsis to raise your PE.

[Turbojohn]

If you get enough speed to go to the moon I guess you could use that to successfully enter orbit

[Renegrade]

I know. And I agree. But if you are using RCS as main propulsion system, you are doing it wrong (in most cases, it is completely viable for very small craft).

I'm doing it wrong!

As for these claims of using the Mun... I call BS.

From like orbit, you need about 850 m/s to get your Ap out to the Mun.

This works out to about 3,100 m/s orbital velocity... a bit higher.

Turbojets produce ZERO thrust above 2,400 suface velocity, and thus CANNOT get going faster than 2,600 orbital velocity.

True! But perhaps they were using FAR - one of the older versions had a typo in the engine nerfs section that took the top off of the TurboJet's velocity curve. I know I put some craft into interplanetary space using pure TurboJets during that era for fun.

Perhaps they were using that version of FAR when they did that.

[Starwhip]

With ladder propulsion you can get off of Eve with no engines, thrusters, or fuel tanks at all!

[cantab]

As far as cheaty ways go, establish an apoapsis outside the atmosphere and a periapsis above I think 23 km, then go to the Space Centre. Job done!

For legitimate options, I think using a mechanical or decoupler catapult to make the final push to orbit is the only way.

Or use a stack of Kerbodyne decouplers. For some stupid reason they're physicsless.

[Red Iron Crown]

For legitimate options, I think using a mechanical or decoupler catapult to make the final push to orbit is the only way.

A trebuchet works nicely, too, while still being somewhat legitimate.

[Jovus]

The easiest way that hasn't been covered so far is to use Hyperedit.

Check out

. Totally a rocket (quite powerful too).

Wow. Those things get really hot.

[MarvinKitFox]

Probably meant slowly increasing AP in atmosphere with jets, do an 'orbit' till PE, burn again, etc, until you can get the Mun to slingshot you by increasing your AP very far.

That used to work until about version .23, at which time the turbojet's curve was adjusted to be fully zero over a certain speed. That speed is about 2400m/s, not enough to get to Mun orbit any more.

[KerikBalm]

I'm pretty sure that didn't work in .22, or even.18

Someone mentioned a FAR bug... that might be what you are talking about

[Camaron]

You could always get up to a comfortable apoapsis and then eject a lightweight pod with a large decoupler or two. You don't have a Jet craft anymore after that though.

[FlyingPete]

Jet/monopropellant propulsion works quite well for small craft- either using normal RCS thrusters or the O-10 engine. The old trick of getting out and pushing with the EVA pack is viable too. Theoretically if you can push your Ap up high enough to encounter the Mun, you can get into orbit with a gravity assist. I'd like to see this attempted

[John FX]

You could always get up to a comfortable apoapsis and then eject a lightweight pod with a large decoupler or two. You don't have a Jet craft anymore after that though.

You could get to the same place with some 'ballast' , maybe some fuel tanks, which you eject to raise your Pe thereby keeping your jets.

[ddenis]

So can it be done using only jet engines or another means?

What do you mean under "other means"?

Because if I follow wikipedia's description:

A rocket (Italian rocchetta‚ Spindle)[1] is a missile, spacecraft, aircraft or other vehicle that obtains thrust from a rocket engine.

Where rocket engine is

A rocket engine, or simply "rocket", is a jet engine[1] that uses only stored propellant mass for forming its high speed propulsive jet.

So, ION drivers, RCS and kerbal's jet packs can be counted as "rockets assistance". Even a jet with stored air can be counted as rocket, based on wikipedia's description.

Edited February 21, 2015 by ddenis

[Ion Man]

You can do it with Ion engines, which I consider as not being 'rocket' engines. You don't use oxygen and just eject mass at a very high speed.

So with a Jet/Ion craft, you can easily get to orbit.

[Norpo]

Maybe this option has already been explored, but what about jet engines, with decouplers to: A: ditch everything else other than the capsule and B: kick the capsule into orbit?

[lincourtl]

Yes, but it used hypergolic propellants rather than the nitrogen for the Shuttle reaction system. AKA, LiquidFuel, and so it wouldn't work for his exact thingamajigger, but I have seen KSP shuttles that use RCS OMS engines!

The space shuttle used monomethylhydrazine with dinitrogen tetroxide for both OMS and RCS.

Edited February 22, 2015 by lincourtl

[Commander Zoom]

Remember Plaid?

Yes, yes I do.

Edited February 22, 2015 by Commander Zoom