Orbit

[POLITE_ALLCAPS_GUY]

Hi. Im new to kerbal space program. So far im able to get a rocket up to 20km into the atmosphere but then end up running out of fuel to plummet to the biosphere.

My biggest goal is to at least get to orbit but jebediah loves a good tank of fuel to drink?

Any tips on how to run your spacecraft on the appropriate amount of fuel to at least get to orbit?

Thanks guys!

[Murph]

Boosters, lots of boosters!

Then booster-boosters, lots of them too!

Best bet is probably to spend a little time watching some of the excellent tutorial videos out there. There's also the Tutorials on the wiki.

Oh yeah, and welcome!

[UmbralRaptor]

I'd argue that the big thing with fuel quantity is throwing enough at the engines to keep your TWR (Thrust to Weight Ratio) from being excessively high. For a single stage, adding more fuel will always improve the mass ratio at the cost of reduced TWR. Even ignoring TWR, each additional tank does less for the craft, with there being an ultimate upper limit on what one stage can do.

My propellant rules of thumb:

LV-T40/45, Aerospike: 1600 L (a pair of FL-T800s, or a rockomax x16)

Skipper: 6,400 L (one orange tank)

Mainsail: 12,800 L (two orange tanks)

[LtHeckard]

You should start by building something simple like this. The pieces that are holding the side mounted rockets on are Radial Decouplers and orbit can be difficult to achieve without them.

[POLITE_ALLCAPS_GUY]

Hmm... My polite allcaps were shrunk down! Thank you guys - great community!

[Taki117]

Also, are you doing a gravity turn or getting mach/reentry effects on ascent? If you don't know what a gravity turn is look it up, very useful thing. And if you are getting mach/reentry effects during ascent you are going far to fast and should take a look at terminal velocity.

[SRV Ron]

Simple three stage from Career, more then enough fuel to orbit Mun and return.

[Dispatcher]

Welcome, PAG (yeah, maybe not the best acronym for your forum handle). You might try flying the stock KSP rocket Kerbal X. It has enough fuel to get you to orbit and back, but only when you get the moves down right. My style of flight: Turn on SAS (press T). Throttle up full. Fire that ignition. The Kerbal X staging requires that you press space again to release the support clamps. As you slowly climb, you will see that the boosters empty at different rates. When each set of boosters depletes, press space to jettison the empties. You will end up with the large single engine in the central stack. When you reach about 10,000 meters altitude, use your D key to cause the ship to fly towards the East. Settle the central dot so your angle is at the circle marked 45 (degrees). As your stages use up fuel, space again to jettison and fire the next stage. When the ship is about 30,000 meters altitude, switch to map view (M). Tab up the Navball and move your view of the planet so that you can see the apoapsis flag on your line of flight. While your cursor is over the flag, you can see the projected apoapsis. When it reaches at least 71,000 meters altitude or so, press X to shut off your fuel. Press D again until the dot in the center of the Navball view is just above the horizon line of the ball (the dot is still in the blue field). Once your ship icon is close to the apoapsis flag (say, 10 seconds to go), throttle up again. You will see the flightpath grow into a circle and the periapsis flag will appear. Wait until the flags swap positions and press X again. You will likely be in a decent orbit at that time. Your results may vary.

Or, watch the plentiful video tutorials out there on the subject, as suggested in prior posts. Good luck!

Edit: my suggestion assumes you are in sandbox mode. For Career, what some others say.

[zxczxczbfg]

Basically, as these guys have all stated, make it BIG. Also, try to stage it so that the "main engines" jettison as you leave the atmosphere so you don't end up burning a tiny amount of fuel from your still-attached main engines and having to jettison them mid-burn. (It also saves on debris.) If you plan to get ol' Jeb back to Kerbin eventually, you should also include some kind of maneuvering/deorbit stage, probably with the LV-909, which is quite efficient but lacking in thrust, perfect for deorbits, exo-atmospheric maneuvers, and landings, but not much else.

EDIT: As DonLorenzo says several posts below, yeah, telling you to "make it BIG" is probably not a good idea for long term rocket design, but in the short term it will give you a nice margin of safety in case you mess something up.

Edited December 23, 2013 by zxczxczbfg

[technion]

You should start by building something simple like this. The pieces that are holding the side mounted rockets on are Radial Decouplers and orbit can be difficult to achieve without them.

In career mode, getting enough science to actually unlock those decouplers would be very hard to do without ever making orbit. In a tier 0 scenario, the easiest option I started with was building the bottom stage to consist of just one tank, then having all the boosters around it stage away with it.

[UmbralRaptor]

If you don't want to resort to booster-related shenanigans at TL0, you could just build an SSTO.

(Yes, it's capable of getting into a 70 km orbit, and landing safely)

[Kasuha]

In career mode, getting enough science to actually unlock those decouplers would be very hard to do without ever making orbit. In a tier 0 scenario, the easiest option I started with was building the bottom stage to consist of just one tank, then having all the boosters around it stage away with it.

I don't agree. To unlock tier 1, all you need is to deploy the pod on launchpad, make crew report, EVA report and take sample.

To unlock all basic decouplers you need 2-3 suborbital flights to different biomes - Launchpad, KSC, Shores, Water, Highlands and Mountains are all within 20 kilometers.

[DonLorenzo]

There's no need to 'make it big'. That's terrible advice.

Here's an old video i made about orbits, and getting there

[ravener]

basically, go for decuplers. start with a little ship and build stage upon stage under that, as long as each new stage can lift the whole rocket they each add delta v. without even going asparagus you can get up to 12000 m/s deltav (change in velocity, about 4000m/s of delta v is needed for orbit.).

[DannySwish]

You'd be amazed what you can do with very small ships. I'm still learning that lesson. I agree with trying to achieve orbit with one of the stock ships at first (I'm not sure if they're available in Career mode, just go to Sandbox if you have to). Check out Scott Manley tutorials. I believe I learned mostly through trial and error, then realized how I could do better through videos like his. You'll be amazed at how easy it is once you give it some practice.

Here's my little tutorial: Using a stock ship (Kerbal X should do I guess) so we know that the ship itself is capable of orbit, launch full-thrust straight up until you reach 10,000 meters. Then, turn the ship to the right and point it somewhere between the top of the NavBall and the horizon on the NavBall (where the blue part meets the orange part). Blue means you're pointed up, orange means down. What you're doing here is what's called a gravity turn. Keep an eye on what stages are finishing their fuel and jettison them. Keep an eye on how high your apoapsis rises in the Map view, and cut thrust wherever you are once it gets somewhere about 70km (you can instantly cut all thrust by hitting X). That is where the atmosphere ends. Contrary to popular n00b belief, you do NOT need to burn waaaay out there. Low orbits are far better for pretty much everything, as they have benefits that may go over your head for now, so don't worry about that too much for now. Once you reach your apoapsis (or maybe just a little bit before), begin burning right on the horizon line. Your prograde vector (the green circle with three prongs) should be sitting there, indicating what direction you're moving in. Try to keep the heading perfectly at 90º if you want a nice equatorial orbit. What you're doing here is called the circularization burn. You burn until you hit at least 70km on your periapsis. Congrats, you've made orbit! Don't worry about trying a few times to get there.

Edited December 19, 2013 by DannySwish

[celem]

Also, like as a design rule of thumb....

If your engine is still running, but you simply fall out of the sky, then you need more or bigger engines running at that point, or to be pushing less weight.

If you just run out of fuel to run the lovely shiny engines then you need more fuel.

Always remember that everytime you add fuel (or any mass) that isn't burning in the bottom-most stage of your rocket that every stage below it will have to lift it along the way. A rocket where the mid-stages are just fine from an optimal launch can fail if the pad-ignition stage climbs really painfully slowly or ridiculously fast. (theres an optimum speed at various altitudes)

Less really is more. The size of the launcher needed to get a payload into orbit increases dramatically both in volume and complexity as the desired payload weight increases. Practice on nothing more than a pod, tiny fuel tank and tiny engine (to bring the guy home when you WIN)

Usually for a new-player. If they are failing to hit orbit then I would say 'smaller' rather than 'bigger'. As in smaller payload before bigger launcher.

Edited December 19, 2013 by celem

[michaelhester07]

You can use the stack decouplers to stack the small Solid boosters. My only problem is controlling the rocket with that setup but you can keep it fairly straight.

Do a capsule with a parachute, the 400 size liquid fuel tank and the LV-30 for your first launch. EVA, soil, get back in, crew report, launch it and then recover it. That unlocks the stack separator.

Use the stack separator to add another copy of the 400+lv30. mount 3 of the SRBs on the side of that. Use stack separators below those and add 3 more srbs below. That should make for 6 stages: stage 6 fires 3 SRBs, stage 5 separates them. Stage 4 does the center LV30 and the 3 srbs. Stage 3 separates that (make sure you burn all the gas on that LV30). Stage 2 separates that and stage 1 inserts you into orbit after you burn about half of it.

If you turn 45 degrees east (but your center marker of the navball on the 90) you'll do a good enough gravity turn to get to orbit. Once the speed indicator switches over to "orbit" burn to half of your stage 1 if it's still there. Switch to your map and plan a burn prograde until the Ap mark swaps with the Pe mark. After that burn you're in orbit.

Once you unlock the LV45 things get easier to control.

*edit: the gravity turn should be at 10km altitude... that's when you break above the thickest part of the soup that's kerban's atmosphere.

Edited December 19, 2013 by michaelhester07
grav turn altitude