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

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'''Getting into orbit''' over Kerbin requires some knowledge and preparation. Space begins at 70,000 meters above the planet Kerbin. Stay above that for an entire flight around the planet and you're in orbit.
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* A single sharp turn from vertical to 45° at 10km has never been a proper [[gravity turn]].  It just happened to work in the old, bad, placeholder atmospheric physics. It was really a bug that it worked at all, it always should have been very likely to fail.
 
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* The vastly improved atmospheric physics in 1.0 mean that this is now bad advice, and is likely to result in mission failure more often than not, including for rockets which are actually perfectly viable if flown correctly.
 
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}}
 
  
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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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==Specifications==
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The process to get into orbit follows a simple progression:
 
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# Launch straight up to 10 km
 
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# Change your Pitch to 45° east and keep the engines on until your projected [[Apoapsis]] is above 70 km
 
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# Change your pitch to horizontal just before you reach the Apoapsis
 
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# Burn at Apoapsis until your Periapsis is above 70 km
 
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===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
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*'''For version:''' Every version (tested on 0.23)
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*'''For version:''' 1.02
  
 
==Steps==
 
==Steps==
 
===Step 0 - Rocket Design===
 
===Step 0 - Rocket Design===
 
[[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]]
 
[[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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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 (unless you are bringing heavy payloads to orbit of course)
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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 (unless you are bringing heavy payloads to orbit of course).
  
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The cheapest orbiter you can build with the current stock game (0.22) {{outdated}} is:
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An example of a simple manned orbiter:
  
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*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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*[[TR-18A Stack Decoupler]]
 
*[[FL-T400 Fuel Tank]]
 
*[[FL-T400 Fuel Tank]]
 
*[[LV-909 Liquid Fuel Engine]]
 
*[[LV-909 Liquid Fuel Engine]]
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*[[TR-18A Stack Decoupler]]
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*another [[TR-18A Stack Decoupler]]
 
*[[FL-T800 Fuel Tank]]
 
*[[FL-T800 Fuel Tank]]
 
*[[LV-T30 Liquid Fuel Engine]]
 
*[[LV-T30 Liquid Fuel Engine]]
  
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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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Make sure the staging sequence is correct; see [[Tutorial:Game_Manual#Rocket_Staging]].
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===Step 1 - Launch Preparation===
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1. Hit M to go to map view. Tilt the view so that it looks North, which will give a clear view of the trajectory arc towards the East and the Apoapsis label.
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2. Set thrust to maximum by hitting Z.
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3. Toggle on SAS by hitting T.
  
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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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===Step 2 - 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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===Step 1 - Launch Prep===
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===Step 3 - Pitch 10 degrees East===
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Prepare your launch.  
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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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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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===Step 4 - Get Apoapsis above 70 km===
  
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2. Set your thrust to maximum by holding Shift.
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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.
  
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3. Toggle on SAS by hitting T.
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Hit M to switch to map view. If necessary, 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 throughout this phase.
  
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===Step 2 - The Launch===
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Hover the mouse over the "AP" label to monitor the apoapsis height; cut off the engine with X when it reaches more than 80 km (80,000 meters). 70 km is sufficient but 80 km will provide some margin and more time for the next step.
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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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===Step 3 - Get up to 10,000 meters===
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The apoapsis may stop rising at some point if the first stage runs out of fuel. In that case, switch back to normal view with M. Hit space to drop the first stage and activate the second one.
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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.
 
  
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===Step 4 - Gravity Turn 45 degrees East until 70km [[Apoapsis]]===
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===Step 6 - Get periapsis above 70 km===
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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 your apoapsis gets 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. If you want to aim for a more fuel-efficient ascent, you can try pitching down to 30 degrees when your apoapsis reaches 40 km.
 
  
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As of Version 1.0, atmospheric drag has been increased, so it may be difficult and not worth the fuel to begin your turn until above 18-20 km.
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The engine should now be cut off; let the rocket coast towards Apoapsis.
  
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===Step 5 - Get Your Apoapsis above 70km===
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10–30 seconds before reaching Apoapsis, orient the rocket once more to align with the prograde marker and go 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.
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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.
 
  
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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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The projected trajectory will begin to widen until the periapsis label appears on the other side of the planet. A stable orbit will be reached when both apoapsis and periapsis are above 70 km.  
  
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===Step 6 - Orient for On-Orbit Burn===
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If the first stage had not been dropped yet, it may run out of fuel during this phase. If that happens, switch back to normal view and hit space to drop it and activate the next stage.
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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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===Step 7 - De-orbiting===
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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.
  
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===Step 7 - Burn into Orbit===
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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.
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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 and the apopapsis and periapsis markers start to switch positions, 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.
 
  
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==Finishing word==
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===Step 8 - Re-entry===
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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 [[File:Retrograde.svg|24x24px|frameless|default]] 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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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.
  
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Wait until the capsule's speed drops below 200 m/s, and deploy the parachute.
  
 
[[Category:Tutorials|Tutorial: How to Get into Orbit]]
 
[[Category:Tutorials|Tutorial: How to Get into Orbit]]

Revision as of 16:16, 29 May 2015

Getting into orbit over Kerbin requires some knowledge and preparation. Space begins at 70,000 meters above the planet Kerbin. Stay above that for an entire flight around the planet and you're in orbit.

Specifications

  • Length: 15–20 minutes
  • Difficulty: Harder than a suborbital flight, easier than an orbital intercept.
  • Skills needed: Seat of the pants
  • For version: 1.02

Steps

Step 0 - Rocket Design

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

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 (unless you are bringing heavy payloads to orbit of course).

An example of a simple manned orbiter:

Make sure the staging sequence is correct; see Tutorial:Game_Manual#Rocket_Staging.

Step 1 - Launch Preparation

1. Hit M to go to map view. Tilt the view so that it looks North, which will give a clear view of the trajectory arc towards the East and the Apoapsis label. 2. Set thrust to maximum by hitting Z. 3. Toggle on SAS by hitting T.

Step 2 - 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.

Step 3 - 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.

Step 4 - Get Apoapsis above 70 km

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.

Hit M to switch to map view. If necessary, 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 throughout this phase.

Hover the mouse over the "AP" label to monitor the apoapsis height; cut off the engine with X when it reaches more than 80 km (80,000 meters). 70 km is sufficient but 80 km will provide some margin and more time for the next step.

The apoapsis may stop rising at some point if the first stage runs out of fuel. In that case, switch back to normal view with M. Hit space to drop the first stage and activate the second one.

Step 6 - Get periapsis above 70 km

The engine should now be cut off; let the rocket coast towards Apoapsis.

10–30 seconds before reaching Apoapsis, orient the rocket once more to align with the prograde marker and go 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 periapsis label appears on the other side of the planet. A stable orbit will be reached when both apoapsis and periapsis are above 70 km.

If the first stage had not been dropped yet, it may run out of fuel during this phase. If that happens, switch back to normal view and hit space to drop it and activate the next stage.

Step 7 - 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.

Step 8 - 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, and deploy the parachute.

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