Orbit

[TwiztedMunky]

I seriously need help making orbit, I seem to always fly off into space no matter how hard I try, Can anyone help me?

[Capt'n Skunky]

I seriously need help making orbit, I seem to always fly off into space no matter how hard I try, Can anyone help me?

Start to angle your rocket after getting some altitude. If you've ever watched a rocket launch, you should have noticed it doesn't go straight up the whole way, at some point it will start to tilt over. At what altitude you need to start going over and how far depends on a number of things like how high you want your orbit, how much payload you're pushing, and how much fuel your carrying.

You can also try the rather crude method of shutting your engines off and waiting for most of your vertical speed to bleed off. Then pitch over and throttle up to get into orbit.

Arrr!

Capt'n Skunky

[UmbralRaptor]

I seriously need help making orbit, I seem to always fly off into space no matter how hard I try, Can anyone help me?

How fast are you going (horizontally) at what altitudes?

[Jarnis]

How fast are you going (horizontally) at what altitudes?

And yes, this is very very important. Math says that if you are off even by 20-30m/s from the correct horizontal speed, you either...

-- End up in back down in the atmosphere before you complete the orbit (too slow)

or

-- End up in a very long and elliptic orbit that may look like you are just heading into space.

Overdo it by 1000m/s and... no, you are probably not coming back. Ever.

Orbital calculator is your friend.

http://files.arklyffe.com/orbcalc.html

(or just use this table; http://www.kerbalspaceprogram.com/wiki/index.php?title=Tutorial:Orbiting_(Basic)#Orbital_Table )

[Tiberion]

Make sure you use the small detail in the UI to help you. The gauge beside the altitude counter shows your vertical speed, with 0 being on the left side of the circle, and if the needle is above, you're going up, and below means you are descending.

The speedometer shows how fast you are going in the direction you are traveling. So if you are traveling up at an angle of 20 degrees or so at 100 m/s, you might only be gaining 5 meters per second of altitude, so that would be your vertical velocity. This means that when you blast straight up at 1000 m/s and you need to get into orbit, you need to make your vertical velocity 0 (or close to it, on the dial next to the altitude) and your actual speed on the gauge match the orbital speed that matches your altitude on the chart they linked earlier.

Then on the Navigation ball, the yellow crosshairs shows what direction your ship is traveling. Keep in mind that its not like airplanes, you don't just travel in the direction your nose is pointing, to change direction you have to apply thrust in that direction, ESPECIALLY in space. So if you are still gaining altitude even after pitchover, and you want to slow it down, you can point the engine straight up and burn the engines for a few seconds, and then flip around and burn poinitng up if you over-correct. You can even fly 'backwards' with the engine pointing in the horizontal direction you are going and burn to slow down without altering your heading.

That is why its important to save fuel when getting into orbit, so you can make these maneuvers, including a de-orbit thrust, which is done by facing backwards and and pointing nose down a little, then burning to both slow your speed (which will cause your orbit to decay and you to skim lower) and to give you a small push to start descending.

Certainly, you CAN just stop and then point straight down and blast away, but its not a 'optimal' and eventually the game will punish you for coming in too steep or fast.

Here's a good video to learn the basics:

Its an older video, so that exact setup might not work exactly, but the ideas all still hold.

[shadowfax]

You\'ll have to adjust the instructions in that video a bit. Now that we have atmosphere above 30-something-k, if you try to make a stable orbit at 50 you\'ll deorbit quickly due to atmospheric drag. A good way to get a cheap and dirty 'I don\'t care what kind of orbit it is as long as it\'s an orbit and not an escape or a crash' orbit is to go straight up until around 10-12k, then slowly pitch the nose over so that you\'re pointed at the horizon at about 25k. Keep accelerating to around 2300k at which point you should be somewhere between 60 and 70k up, depending on your rocket configuration. At this point you should (if you built it right) have plenty of fuel left in your ascent stage to tweak your orbit (it will be highly elliptical, but not obnoxiously so).

[Millitron]

Atmosphere doesn\'t seem to be above the 34.5Km it used to be. It is a much smoother transition, but it\'s still all gone by past 34.5Km.

The thinner atmosphere should make orbiting easier in the newer versions that in the older versions.

[Entroper]

Atmosphere doesn\'t seem to be above the 34.5Km it used to be. It is a much smoother transition, but it\'s still all gone by past 34.5Km.

The thinner atmosphere should make orbiting easier in the newer versions that in the older versions.

In the newer version, there is still atmosphere all the way up to 68 km, but above 60 km, it\'s hardly noticeable. Orbits in the 55 km range start to decay fairly quickly, and anything below 50 km will end up on the ground in minutes without boost.

[Millitron]

I\'m not so sure. I got the newest version today, orbited around 150Km. I did my retro burn, and began my de-orbit. I watched my G meter carefully as I wanted to verify for myself that the atmosphere was higher. I didn\'t notice the G meter rise at all until 34.5Km. Past 34.5Km, it began to rise, suggesting I was finally hitting the atmosphere. It did not rise anywhere near as quickly as it used to, which suggests that the transition is much smoother.

Could I have just gotten a bad download or something? Also, I just copied the new files over the old ones, rather than a full, from-scratch installation. Could that cause the discrepancy?

[Zeroignite]

It\'s possible, for a slow and mostly vertical reentry path, that gravity was accelerating you downwards strongly enough to compensate for/overcome the lighter atmospheric drag. I only really notice significant G increases in the upper atmosphere on fast reeentries, and even then the bulk of the slowing is between 25 and 15 km.

[Entroper]

You\'re not likely to see the G-meter move above 35 km because the drag just isn\'t strong enough. One pixel on the G-meter is maybe what, 0.05 Gs? If you\'re decelerating at 0.1 m/s^2, that is, the last digit of your velocity is falling by one every second, that\'s only 0.01 Gs, not enough to show up on the meter.

Use the orbital tables and try to maintain a circular orbit at exactly 60 km. Within a few minutes, you\'ll start to descend as your horizontal speed is scrubbed off ever so slowly.

[Jarnis]

I\'m not so sure. I got the newest version today, orbited around 150Km. I did my retro burn, and began my de-orbit. I watched my G meter carefully as I wanted to verify for myself that the atmosphere was higher. I didn\'t notice the G meter rise at all until 34.5Km. Past 34.5Km, it began to rise, suggesting I was finally hitting the atmosphere. It did not rise anywhere near as quickly as it used to, which suggests that the transition is much smoother.

Could I have just gotten a bad download or something? Also, I just copied the new files over the old ones, rather than a full, from-scratch installation. Could that cause the discrepancy?

The G-meter on the UI is fairly insensitive and inaccurate.

[SteevyT]

I can confirm that there is atmosphere all the way out to ~68km, I\'ve been trying to do accurate re-entries with just the pod, but I also want to come in as shallow as I can. When watching the apokee and perikee markers (mouse hovered over to see altitudes), I can see that the altitudes of both are changing when the pod gets below 68km.

[DeadlyPear]

The way I orbit is at about 50,000 meters I start tilting so I reach about a 45 degree angle by 65,000 and then I tilt so it is basically on its side at about 80,000 meters and using the orbit calculator or the M key in the experimental release I see if I have a good orbit and shut off all thrust and fly around the planet.

[Ivan Ivanovich]

First of all, you will NEVER enter orbit by just going straight up. The idea behind an orbit is to go to the side, not to go up. Ideally, you could orbit simply by going at a certain speed at ground level. Since air resistance will slow you down, this doesn\'t work out. It would in vacuum, though. For Kerbal, at ground level you\'d have to go about 2425m/s to be in an 'orbit'. But, as stated, air drag disallows that.

The atmosphere stops at pretty much 68km height, as has been stated. It stops being a huge drag at about 35km height, where it REALLY slows you down if you\'re not flying with your rocket burning. Above 35km, as long as you have thrust air drag is getting less and less as you approach 68k height.

To reach an orbit, you have to balance two needs. First, to get out of that blasted atmosphere as quickly as you can, which is logically the case if you go vertical to its plane. I.e. straight up. Second, to build up horizontal speed to get an orbit going. In general, this is usually easiest achieved by these steps:

1. Go straight up to about 15-20k height, depending on how much vertical speed your rocket builds up during that time. You want to have as many boosters on your rocket as it can handle without subjecting your astronauts to like a bazillion G and without getting completely uncontrollable. You don\'t need THAT much control as long as you\'re boosted, all you have to be able to do is to keep your rocket pointing UP.

2. At about 15-20k height, start banking towards the direction you wish to go. Or, in Kerbal terms, just look where the rocket wants to go and go with the flow.

3. Bank slowly. You shouldn\'t be banked past 30 degrees off vertical before you hit about 20-25k height. Watch your actual direction marker (the circle), it should be a hint below the way your rocket points, but ONLY a hint! Don\'t adjust your banking to match the circle, if it drops too fast, you\'re banking too fast or flying too slowly.

4. At about 40k height, your direction marker should point about 20 degree above the horizon and you should have about 1000-1500 m/s speed on your clock. You can start to level out by now if these parameters are met, else, keep the direction at about 30 degrees above horizon.

5. Try to level out no later than 60k. Usually you have about 10-20k vertical distance to go simply by virtue of horizontal speed. Keep the thrust up to get the speed to about 2200m/s, then wait for your rocket to reach its apogee and match the speed to stay in orbit.

Congratulations, you\'ve reached an orbit. It might not be circular, but as long as perigee is above 70k (hit M to check the apogee/perigee readings) you\'ll stay in space as long as you wish.

With time, you\'ll get the hang of it and you\'ll be able to adjust your thrust and banking to hit the orbital heights you\'re aiming at fairly reliably.

[JupiterII]

I seriously need help making orbit, I seem to always fly off into space no matter how hard I try, Can anyone help me?

With the new map I find it so much easier. Just fly up and turn sideways at about 40 000 meters but keep your nose pointed up a little. Once you get about 2500m/s speed wait until your above 70 000m or vice versa. Check the map and if you periapsis is above 70 000m you should stay in orbit forever. If it\'s anywhere above 40 000m you should stay in orbit for a while.

[icefire]

Going into orbit with the new atmosphere model.

Nothing in terms of explanation, but I figured I would just throw it out there.

[Rascal Nag]

A few ways to do it. You can slowly pitch over to horizontal as you go up, get to some height and then go straight to horizontal, or, my favorite for really heavy and unwieldy rockets, go straight up with the first stage or two, then when you hit apoapsis burn horizontally. This helps because it\'s very, very difficult to get a really heavy and tall rocket to tilt the way to want. Though if you can, the best option is (99.999% of the time) the first one, a slow tilt.

Also one thing I did before the orbital map was get to 1500 m/s or so, wait til I started falling, then thrusted a bit to get that little bit of height back, and kept repeating this. It got me an orbit with a difference in Pe and Ap of only about 200m, so it worked.

[SchildConstruct]

I seriously need help making orbit, I seem to always fly off into space no matter how hard I try, Can anyone help me?

I\'m assuming you are playing 0.11.

Rocketry 101 (you seem to have this one down pat 8), but I want to establish terminology.)

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Lowest stage: Boosters + Sustaining Stage.

Middle stage: Sustaining Stage.

Top stage: Orbital stage.

The exact layout varies, but the following, with vanilla parts, works:

Orbital Stage: 2 liquid fuel tanks, plus engine.

Sustaining Stage: 3x3 liquid fuel tanks + engines (via tri-coupler). Add a strut to make things less wobbly--I go from the middle of the top fuel tank to the middle of the opposing, lower fuel tank. Add SAS to taste on top of the whole contraption.

Boosters: 3x1 attached to the sustaining stage via radial coupler. Season to taste.

Stage Configuration: The Boosters and Sustaining Stage fire together. The next stage are the decouplers for the boosters to get rid of the dead weight.

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Pre-flight checklist:

- Turn on SAS

- 50% Throttle

- Fasten Kerbal chains safety harness

- IGNITION!

In flight:

- Gain altitude. Once your boosters have burnt out, detach them, and put the pedal to the metal (100% throttle).

- Maintain as much throttle until you reach about 30\'000m height.

- Take the foot off, especially if you are on your orbital stage already!

- Start angling. Take off SAS, use Precision Controls (Caps lock by default). Take it sloooow. Trade vertical speed for horizontal speed slowly.

- If you are on your orbital stage, and you like to overshoot your pitch and yaw and rotation, like me, switch on SAS again.

- Once you reach apoapsis (check M key for the rough height above ground, watch altimeter and wait until it hits zero), and put the pedal to the metal again. You have to gain a lot of speed in little time (it pays to have the engine running at a minimal throttle during ascend to apoapsis if you are going high) to get into an orbit. See https://gist.github.com/1075144 for pre-calculated values of speed you should have.

- If your orbit is too eccentric (i.e. elliptical) for your taste, fire a prograde burn (meaning: in your direction of flight) for a few seconds to circularise your orbit. If you can\'t become circular at your first go, don\'t worry: just wait until you are at Apoapsis again.

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De-Orbit:

- rotate orbital unit retrograde (against the direction of flight).

- At Periapsis (the lowest point of your orbit), fire your engines. How much and how long depends on whether or not you want to break Kerbal neck, have Kerbal roast, or feel gracious: The flatter your entry, the fewer g forces and less heat you\'ll have to deal with (once this is implemented, anyway). You should have enough fuel to slow your unit down enough for:

- Gravity will do the work for you, and pull you back onto the ground.

- Open parachute when in the middle of the atmosphere (roughly; speed should be around 800 m/s to 1000 m/s). Let the atmosphere do the work of slowing you down.

While outdated, this video on getting to orbit is still helpful:

Have fun, and be crispy!

[Ivan Ivanovich]

To make it easier, here\'s a rocket that should get you into orbit fairly reliably. It\'s also rock solid stable, so you should not have to touch the controls during the first critical moments of ascend, the SAS and the fins can steer it just fine. Just remember to jettison the boosters as they burn out and let the rocket climb, try to keep the speed at about 200m/s while you\'re in the denser areas of the atmosphere, then increase gradually to about 350m/s. At about 35,000 meters, start banking towards the direction you want to take your orbit. Take your time, you have plenty thereof. Now you can also start increasing your speed since a good deal thereof will go horizontally and we\'ll need about 2300m/s in the end.

Around 45-50k altitude, you will probably have reached an upwards momentum that should take you to an apogee of about 80,000m (check the map if you\'re unsure). Turn off your engine and wait until you\'re almost at the apogee, then fire your rockets prograde (i.e. in the direction of the green direction marker), pedal to the metal, until you are fast enough for an orbit (said 2300m/s). You\'ll fall a little, don\'t worry, that\'s to be expected, and it also allows a much easier, almost circular orbit. You might be at the second liquid stage by now, which is fine.

LKO is easily possible with this rocket, circular orbits up to about 500k should be doable. I also used it for the elliptical challenge (i.e. elliptical orbits with perigee of 70k and apogee of ... well, whatever the escape velocity ALMOST is) are very possible with it.

You\'ll notice that it has no liquid engine in its last stage. This is because the RCS is very capable of getting you back onto Kerbal. The easiest way to accomplish this is to fire your RCS retrograde at apogee until your perigee dips to about 40k. From then on, the atmosphere is doing the rest.