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

Latest revision as of 12:10, 8 May 2023

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

Set thrust to maximum by hitting Z.
Toggle on SAS by hitting T.
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.
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.

Note: If the rocket contains a manned pilot module (especially those of command pods) then the craft should be very stable, and should even be flyable without SAS (and, depending on your build, may or may not need SAS assistance to achieve orbit).

If the rocket does NOT contain a manned pilot module (even more so with the Probodobodyne Stayputnik as it has no SAS), then it is very likely (almost guaranteed) it WILL go out of control. It is preferred to add multiple reaction wheels (about 15N/m required) and multiple gimbal engines. Career players that are low on tech can stack smaller reaction wheels to mitigate the lack of torque. A good example of this phenomenon is the GDLV3. Flying it without SAS, you will quickly find yourself losing control. Replacing the entire aeroshell with the Mk1-3 Command Pod (plus decoupler and chutes) will give it excellent handling even without SAS.

It might be because the command pods' weight will shift the center of mass, which allow the craft to be more stable (and it seems like the case: a Command Pod Mk1 on a Size 2 rocket will be less maneuverable than one with Mk1-3 Command Pod.

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 yellow 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.

It might also because you flipped your root part for some reasons, if you can, flip your root part back while keeping the other parts flipped.

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.

@@ Line 1: / Line 1: @@
-== How to Get into Orbit ==
+{{Caution|
-Getting into orbit is rather simple, but it will require some knowledge and preparation. Space begins at 70,000m above the planet Kerbal. Stay above that for an entire flight around the planet and you're in orbit.
+*The instructions listed almost invariably fail for larger [[Rocket]]s, since it assumes a very small [[rocket|Rocket]] with good maneuvering.
+}}
+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:
+==Specifications==
-# Launch straight up to 10km
+*'''Length:''' 15–20 minutes
-# Change your Pitch to 45° east and keep the engines on until your projected Apoapsis is above 70km
+*'''Difficulty:''' Harder than a suborbital flight, easier than an orbital intercept.
-# Change your pitch to horizontal just before you reach the Apoapsis
+*'''Skills needed:''' Seat of the pants
-# Burn at Apoapsis until your Periapsis is above 70km
+*'''For version:''' 1.0.2
+==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]]
+The rocket should preferably be liquid fueled with at least two stages. An example of a simple manned orbiter:
+*[[Mk16 Parachute]]
+*[[Command Pod Mk1]]
+*[[Heat_Shield_(1.25m)]]
+*[[TD-12 Decoupler]]
+*[[FL-T400 Fuel Tank]]
+*[[LV-909 Liquid Fuel Engine]]
+*Another [[TD-12 Decoupler]]
+*[[FL-T800 Fuel Tank]]
+*[[LV-T30 Liquid Fuel Engine]]
+In order to make sure the staging sequence is correct, see our guide on [[Tutorial:Game_Manual#Rocket_Staging|Rocket Staging]].
-===Specifications===
+==Steps to Orbit and Back==
-*'''Length:''' 15-20 minutes
-*'''Difficulty:''' Harder than a suborbital flight, easier than building a space station.
+===Launch Preparation===
-*'''Skills needed:''' Seat of the pants
-*'''For version:''' Every version (tested on 0.20.2)
+# Set thrust to maximum by hitting Z.
+# Toggle on [[SAS]] by hitting T.
+# 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.
+# Switch back to the normal viewmode by hitting M to enjoy the [[launch|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 [[Navball#Level_indicator|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 [[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.
+===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&nbsp;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&nbsp;km.
-==Steps==
+===De-orbiting===
-===Step 0 - Rocket Design===
+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&nbsp;km. Discard the engine and fuel tank by staging, leaving only the command pod with its heat shield and parachute.
-Any liquid fueled rocket with at least two stages. Anything less, and you're only doing a suborbital flight. The simplest is a control module of some sort, manned or unmanned, one small liquid fuel tank, engine, a decoupler between stages, one double size liquid fuel tank, and engine. For fun, use the LVT-30 engines as they don'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.
-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.
+If fuel is scarce, any periapsis below 70&nbsp;km will eventually result in de-orbiting. However, it may take many passes through the atmosphere before the vehicle finally slows down enough.
-===Step 1 - Launch Prep===
+===Re-entry===
-Prepare your launch.
+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.
-. Set your map view 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.
+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.
-. Set your thrust to maximum by holding Shift.
+==Common problems and solutions==
-. Toggle on SAS by hitting t.
+===Rocket tumbles or goes out of control===
-===Step 2 - The Launch===
+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.
-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).
-===Step 3 - Get up to 10,000 meters===
+Note: If the rocket contains a manned pilot module (especially those of command pods) then the craft should be very stable, and should even be flyable without SAS (and, depending on your build, may or may not need SAS assistance to achieve orbit).
-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. Thottle 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===
+If the rocket does NOT contain a manned pilot module (even more so with the [[Probodobodyne Stayputnik]] as it has no SAS), then it is very likely (almost guaranteed) it WILL go out of control. It is preferred to add multiple reaction wheels (about 15N/m required) and multiple gimbal engines. Career players that are low on tech can stack smaller reaction wheels to mitigate the lack of torque.
-Now for the fun part. Assuming you are pointing straight up, hit the d key to turn your ship using your navball until your dot is able to slide left and right on the 90 degree east line. Then tip on that line down toward the ground until you hit the 45 degree east mark. Hit your t key for SAS to help you keep it there, but don't rely on it. You will need to make course corrections until you get past 70km 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.
+A good example of this phenomenon is the [[GDLV3]]. Flying it without SAS, you will quickly find yourself losing control. Replacing the entire aeroshell with the [[Mk1-3 Command Pod]] (plus decoupler and chutes) will give it excellent handling even without SAS.
-===Step 5 - Get Your Apoapsis above 70km===
+It might be because the command pods' weight will shift the center of mass, which allow the craft to be more stable (and it seems like the case: a [[Command Pod Mk1]] on a Size 2 rocket will be less maneuverable than one with [[Mk1-3 Command Pod]].
-While climbing up to 70km 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 70km. You can see how high it is by hovering your mouse over it. Once it hits 70km (I usually shoot for 75km 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.
-===Step 6 - Orient for On-Orbit Burn===
+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.
-As you approach apoapsis (preferably before 30 seconds prior) orient your ship to the 0 degree latitudinal mark, heading east. Again, you should be in your map view when you start your burn. Hit tab to center your view on Kerban and zoom out so you can see your orbit as it forms.
-===Step 7 - Burn into Orbit===
+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 yellow  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.
-Once you are 10-30 seconds away from your apoapsis, begin your on-orbit burn using the Shift key to throttle up. Full throttle is best at lower altitude apoapsises since you don't want to burn past apoapsis lest you waste precious return fuel if that's your intent. 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 until you see a periapsis marker appear on the other side of the orbit from the apoapsis, and you see a full orbit circle, then 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 70km. If it's below, then your orbit will cause your craft to aerobrake, eventually returning to Korban.  If your periapsis is ever above 70km, congrats, you will orbit Kerban forever. If you have a manned flight, and fuel is low, then only burn until your periap is below 70km to ensure a safe return to Korban.
-==Finishing word==
+It might also because you flipped your root part for some reasons, if you can, flip your root part back while keeping the other parts flipped.
-After orbiting for a while, depending on your fuel (with this design you won't have much if any at all) you can orient for a deorbit burn by burning backwards in the direction of your travel, once you are at your apoapsis point for maximum efficiency lest you be stuck in space with a manned crew forever.
+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.
-[[Category:Tutorials]]
+{{Tutorials}}
+[[Category:Tutorials|How to get into Orbit]]

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

Latest revision as of 12:10, 8 May 2023

Contents

Specifications

Rocket Design

Steps to Orbit and Back

Launch Preparation

Accelerate to 100 m/s

Pitch 10 degrees East

Stage

Get apoapsis above 70 km

Get periapsis above 70 km

De-orbiting

Re-entry

Common problems and solutions

Rocket tumbles or goes out of control

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