Difference between revisions of "Tutorial: How to Get into Orbit"

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'''Getting into orbit''' over Kerbin is rather simple, but it will require some knowledge and preparation. Space begins at 70,000m above the planet Kerbin. Stay above that for an entire flight around the planet and you're in orbit.
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{{Caution|
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*The instructions listed almost invariably fail for larger [[Rocket]]s, since it assumes a very small [[rocket|Rocket]] with good maneuvering.
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}}
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This tutorial describes a simple launch profile to get a vehicle to [[Orbit]] over [[Kerbin]], and back again.
  
The process to get into orbit follows a simple progression:
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==Specifications==
# Launch straight up to 10 km
 
# Change your Pitch to 45° east and keep the engines on until your projected Apoapsis is above 70 km
 
# Change your pitch to horizontal just before you reach the Apoapsis
 
# Burn at Apoapsis until your Periapsis is above 70 km
 
 
 
===Specifications===
 
 
*'''Length:''' 15–20 minutes
 
*'''Length:''' 15–20 minutes
 
*'''Difficulty:''' Harder than a suborbital flight, easier than an orbital intercept.
 
*'''Difficulty:''' Harder than a suborbital flight, easier than an orbital intercept.
 
*'''Skills needed:''' Seat of the pants
 
*'''Skills needed:''' Seat of the pants
*'''For version:''' Every version (tested on 0.23)
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*'''For version:''' 1.0.2
 
 
==Steps==
 
===Step 0 - Rocket Design===
 
A liquid fueled rocket with at least two stages preferably. Anything less will either only get you suborbital or an unwieldy expensive super large fuel tank that's only good for being an orbiting billboard.
 
  
The cheapest orbiter you can build with the current stock game (0.22) is:
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==Rocket Design==
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[[File:Cheapest Kerbin Orbit Rocket Tut.png|thumb|right|180px|Rocket assembled and ready to launch. [[TT18-A Launch Stability Enhancer]]s optional. 0.25]]
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The rocket should preferably be liquid fueled with at least two stages. An example of a simple manned orbiter:
  
*Unmanned: [[Probodobodyne OKTO2]] or Manned: [[Command Pod Mk1]] with [[Mk16 Parachute]] and [[TR-18A Stack Decoupler]]
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*[[Command Pod Mk1]]
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*[[Mk16 Parachute]]
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*[[Heat_Shield_(1.25m)]]
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*[[TD-12 Decoupler]]
 
*[[FL-T400 Fuel Tank]]
 
*[[FL-T400 Fuel Tank]]
 
*[[LV-909 Liquid Fuel Engine]]
 
*[[LV-909 Liquid Fuel Engine]]
*[[TR-18A Stack Decoupler]]
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*Another [[TD-12 Decoupler]]
 
*[[FL-T800 Fuel Tank]]
 
*[[FL-T800 Fuel Tank]]
 
*[[LV-T30 Liquid Fuel Engine]]
 
*[[LV-T30 Liquid Fuel Engine]]
  
For fun, use the LVT-30 engine for your first stage as it doesn't have thrust vectoring and thus will challenge you to actually fly the craft into orbit using your WASD keys keeping your navball on target. Your control module by default provides enough SAS control by itself to prevent you from going out of control for this mission.
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In order to make sure the staging sequence is correct, see our guide on [[Tutorial:Game_Manual#Rocket_Staging|Rocket Staging]].
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==Steps to Orbit and Back==
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===Launch Preparation===
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# Set thrust to maximum by hitting Z.
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# Toggle on [[SAS]] by hitting T.
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# Hit M to go to [[Map View]]. Tilt the view so that you're looking straight down [[Kerbin]]'s North pole, which will give a clear view of the trajectory arc towards the East and the [[Apoapsis]] label.
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# Switch back to the normal viewmode by hitting M to enjoy the [[launch|Launch]] spectacle.
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===Accelerate to 100 m/s===
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[[Launch]] by hitting the space bar and keep the rocket pointed straight up until the vehicle's speed is 100 m/s. Use the [[Navball]] to keep the [[Navball#Level_indicator|level indicator]] centered on the blue hemisphere.  
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===Pitch 10 degrees East===
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When the rocket's speed reaches 100 m/s, start a gravity turn by pressing the D key until the rocket is pitched 10 degrees towards the East. The heading ("HDG") on the Navball should now be 90 degrees.
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While the rocket accelerates, gravity will bend the trajectory downwards. On the Navball this can be observed as the [[Navball#Prograde_and_retrograde|Prograde marker]] dropping further down. Follow it by keeping the level indicator within the circle of the prograde marker at all times especially while in the lower atmosphere, but at about 30km the reaction wheels should be able to compensate. If craft nears the apoapsis too fast, which can be seen in a dropping time to apoapsis, it might be necessary to point “above” the prograde marker, away from the brown half.
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===Stage===
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The fuel of the first stage will run out before 20km altitude. Hit the space bar to discard it and to activate the second stage. Continue to accelerate at full throttle.
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Hit M to switch to map view. Click the Navball toggle at the bottom of the screen to make it visible again. Continue to watch the Navball and steer the rocket to keep it aligned it with prograde.
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===Get apoapsis above 70 km===
  
Make sure your staging sequence is the way you want it, else you can add your flight to the countless list of catastrophic mission failures.
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In map view, hover the mouse over the "AP" label on the highest point of the trajectory to monitor the apoapsis height; cut off the engine with X when it reaches 70 km (70,000 meters).
  
===Step 1 - Launch Prep===
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Let the rocket coast towards apoapsis after cutting off the engine.
Prepare your launch.  
 
  
1. Set your map view with the M key to see your rocket at the launch site from space, tilted so you are looking north. You want to be able to see your apoapsis marker during your gravity turn so you can gauge when to cut your engines and coast up to it prior to burning your orbiting maneuver.
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===Get periapsis above 70 km===
  
2. Set your thrust to maximum by holding Shift.
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As the rocket approaches apoapsis, orient it once more to align with the prograde marker. At 30 seconds before apoapsis, reignite the engine at full throttle with Z. The apoapsis will begin to shift ahead; aim to keep it roughly the same amount of time ahead by throttling up or down with Shift and Control.
  
3. Toggle on SAS by hitting T.
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The projected trajectory will begin to widen until the PE label appears on the other side of the planet. A stable orbit will be reached when both apoapsis and periapsis are above 70 km.  
  
===Step 2 - The Launch===
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===De-orbiting===
Say your countdown if you wish, and hit spacebar to launch into...well, space...without the bar (you'll make a space station with a bar at this end of the galaxy later).
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Wait until the craft is at apoapsis and orient it for a de-orbit burn by aligning the level indicator on the navball with the chartreuse yellow [[Navball#Prograde_and_retrograde|retrograde marker]]. Now burn until the periapsis is around 30 km. Discard the engine and fuel tank by staging, leaving only the command pod with its heat shield and parachute.
  
===Step 3 - Get up to 10,000 meters===
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If fuel is scarce, any periapsis below 70 km will eventually result in de-orbiting. However, it may take many passes through the atmosphere before the vehicle finally slows down enough.
Keep your rocket pointed straight up (use your navball to keep your dot on the top dot on the blue part of the navball) until you hit around 9,900 meters. Your first engine should cut out before this, just jettison it with the spacebar and burn your final engine. Throttle your second engine down to 2/3rds power since the atmosphere is weaker here and won't slow you down as much, and you will save precious fuel.
 
  
===Step 4 - Gravity Turn 45 degrees East until 70km Apoapsis===
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===Re-entry===
Now for the fun part. Assuming you are pointing straight up, press the D key several times to angle your ship over toward the east. Watch the navball as it rotates under the gold V-shaped marker along the 90 degree east line. Continue pressing D to angle the rocket over toward the ground until you reach the 45-degree east mark (halfway down the blue part of the navball). Press the T key to enable SAS to help you keep it there, but don't rely on it. You will need to make course corrections until you get past 70 km altitude and enter space. At this point you should be going into space at a 45-degree angle from the ground, and in an easterly direction. Doing so will gain you speed and not waste the fuel you will need to get into orbit.
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During re-entry into the atmosphere, the capsule will heat up and lose speed. Keep the level indicator aligned with the retrograde marker to let the heat shield take the brunt of the heat.
  
===Step 5 - Get Your Apoapsis above 70km===
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Wait until the capsule's speed drops below 200 m/s, or the parachute sign on the left turns from red to grey, and deploy the parachute.
While climbing up to 70 km or 70,000 meters, it's now time to switch to your map view and control your ship from there entirely. Hopefully your navball is toggled on, else click on the collapsed tab at the bottom of the map view.
 
  
You will need to keep burning your fuel until you see your apoapsis marker reach 70 km. You can see how high it is by hovering your mouse over it. Once it hits 70 km (I usually shoot for 75 km to buy me some head room) your craft will be able to coast up to it without any further fuel. Feel free to cut your engines with the X key and save some fuel for your orbital burn.
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==Common problems and solutions==
  
===Step 6 - Orient for On-Orbit Burn===
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===Rocket tumbles or goes out of control===
As you approach apoapsis (preferably 30 seconds prior), orient your ship to the 0-degree latitude mark (the thin dividing line between the blue and brown halves on the navball), heading east. Again, you should be in your map view when you start your burn. Press the Tab key to center your view on Kerbin and zoom out so you can see your orbit as it forms.
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The most common problem of new players is their rockets going out of control while in the atmosphere. There are multiple causes and slightly different solutions. First, make sure that SAS is on.
  
===Step 7 - Burn into Orbit===
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If that doesn't work, then the cause is often a lack of control surfaces and aerodynamics. You will want to place something like the [[AV-R8_Winglet|AV-R8 Winglet]] at the bottom of your rocket. This gives it both stability and control. Using an engine that has a gimbal, such as the [[LV-T45_%22Swivel%22_Liquid_Fuel_Engine|LV-T45]] will also give you more control.
Once you are 10–30 seconds away from your [[apoapsis]], begin your on-orbit burn using the Shift key to throttle up. You can use full or partial throttle; your choice. Full throttle takes less time but runs a small risk of overshooting your apoapsis and wasting precious return fuel. If you aren't concerned, go full throttle, baby, at any point near apoapsis and claim a stake with the stars. You only need to burn your fuel long enough to see the [[periapsis]] marker appear on the other side of the orbit from the apoapsis. When your orbit grows to a full circle, cut your engine with the X key. Congrats, you made it into orbit. It's usually a good idea to keep burning your fuel until your new periapsis marker is above 70 km. If it's below that altitude, your orbit will cause your craft to fall into the atmosphere and [[aerobrake]], eventually returning to Kerbin. If your periapsis is above 70 km, congrats, you will orbit Kerbin forever. If you have a manned flight and fuel is low, keep your periapsis below 70 km to ensure a safe return to Kerbin.
 
  
==Finishing word==
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Another common cause is aggressive piloting. When pitching over or making other corrections, it is important to make small adjustments. Always keep your nose close to the green prograde marker. In other words, make a small adjustment, wait until you're moving in the same direction as your nose is pointing, and then make another small adjustment.
After orbiting for a while, and depending upon your remaining fuel (with this design, you won't have much, if any) you can choose to return to Kerbin. Orient your craft for a de-orbit burn by aligning the gold V-shaped indicator on the [[navball]] over the green retrograde marker and burn backwards ([[retrograde]]) to the direction of your travel to slow down enough that periapsis falls well below 70 km. For maximum efficiency, wait until you are at your apoapsis point, lest you be stuck in space with a manned crew forever.
 
  
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The final common cause is travelling too quickly while in the lower atmosphere. This causes more aerodynamic pressure on your craft, which may overwhelm the control provided by winglets and engines. If you see flames during ascent, this is a likely cause. The best way to solve this is not to lower your throttle, but instead to add more fuel. The extra fuel also gives you more room to recover from mistakes.
  
[[Category:Tutorials|Tutorial: How to Get into Orbit]]
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{{Tutorials}}
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[[Category:Tutorials|How to get into Orbit]]

Latest revision as of 20:00, 2 May 2019

Proceed with caution:

  • The instructions listed almost invariably fail for larger Rockets, since it assumes a very small Rocket with good maneuvering.

This tutorial describes a simple launch profile to get a vehicle to Orbit over Kerbin, and back again.

Specifications

  • Length: 15–20 minutes
  • Difficulty: Harder than a suborbital flight, easier than an orbital intercept.
  • Skills needed: Seat of the pants
  • For version: 1.0.2

Rocket Design

Rocket assembled and ready to launch. TT18-A Launch Stability Enhancers optional. 0.25

The rocket should preferably be liquid fueled with at least two stages. An example of a simple manned orbiter:

In order to make sure the staging sequence is correct, see our guide on Rocket Staging.

Steps to Orbit and Back

Launch Preparation

  1. Set thrust to maximum by hitting Z.
  2. Toggle on SAS by hitting T.
  3. Hit M to go to Map View. Tilt the view so that you're looking straight down Kerbin's North pole, which will give a clear view of the trajectory arc towards the East and the Apoapsis label.
  4. Switch back to the normal viewmode by hitting M to enjoy the Launch spectacle.

Accelerate to 100 m/s

Launch by hitting the space bar and keep the rocket pointed straight up until the vehicle's speed is 100 m/s. Use the Navball to keep the level indicator centered on the blue hemisphere.

Pitch 10 degrees East

When the rocket's speed reaches 100 m/s, start a gravity turn by pressing the D key until the rocket is pitched 10 degrees towards the East. The heading ("HDG") on the Navball should now be 90 degrees.

While the rocket accelerates, gravity will bend the trajectory downwards. On the Navball this can be observed as the Prograde marker dropping further down. Follow it by keeping the level indicator within the circle of the prograde marker at all times especially while in the lower atmosphere, but at about 30km the reaction wheels should be able to compensate. If craft nears the apoapsis too fast, which can be seen in a dropping time to apoapsis, it might be necessary to point “above” the prograde marker, away from the brown half.

Stage

The fuel of the first stage will run out before 20km altitude. Hit the space bar to discard it and to activate the second stage. Continue to accelerate at full throttle.

Hit M to switch to map view. Click the Navball toggle at the bottom of the screen to make it visible again. Continue to watch the Navball and steer the rocket to keep it aligned it with prograde.

Get apoapsis above 70 km

In map view, hover the mouse over the "AP" label on the highest point of the trajectory to monitor the apoapsis height; cut off the engine with X when it reaches 70 km (70,000 meters).

Let the rocket coast towards apoapsis after cutting off the engine.

Get periapsis above 70 km

As the rocket approaches apoapsis, orient it once more to align with the prograde marker. At 30 seconds before apoapsis, reignite the engine at full throttle with Z. The apoapsis will begin to shift ahead; aim to keep it roughly the same amount of time ahead by throttling up or down with Shift and Control.

The projected trajectory will begin to widen until the PE label appears on the other side of the planet. A stable orbit will be reached when both apoapsis and periapsis are above 70 km.

De-orbiting

Wait until the craft is at apoapsis and orient it for a de-orbit burn by aligning the level indicator on the navball with the chartreuse yellow retrograde marker. Now burn until the periapsis is around 30 km. Discard the engine and fuel tank by staging, leaving only the command pod with its heat shield and parachute.

If fuel is scarce, any periapsis below 70 km will eventually result in de-orbiting. However, it may take many passes through the atmosphere before the vehicle finally slows down enough.

Re-entry

During re-entry into the atmosphere, the capsule will heat up and lose speed. Keep the level indicator aligned with the retrograde marker to let the heat shield take the brunt of the heat.

Wait until the capsule's speed drops below 200 m/s, or the parachute sign on the left turns from red to grey, and deploy the parachute.

Common problems and solutions

Rocket tumbles or goes out of control

The most common problem of new players is their rockets going out of control while in the atmosphere. There are multiple causes and slightly different solutions. First, make sure that SAS is on.

If that doesn't work, then the cause is often a lack of control surfaces and aerodynamics. You will want to place something like the AV-R8 Winglet at the bottom of your rocket. This gives it both stability and control. Using an engine that has a gimbal, such as the LV-T45 will also give you more control.

Another common cause is aggressive piloting. When pitching over or making other corrections, it is important to make small adjustments. Always keep your nose close to the green prograde marker. In other words, make a small adjustment, wait until you're moving in the same direction as your nose is pointing, and then make another small adjustment.

The final common cause is travelling too quickly while in the lower atmosphere. This causes more aerodynamic pressure on your craft, which may overwhelm the control provided by winglets and engines. If you see flames during ascent, this is a likely cause. The best way to solve this is not to lower your throttle, but instead to add more fuel. The extra fuel also gives you more room to recover from mistakes.