Difference between revisions of "Tutorial: How to Get into Orbit"
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| − | + | {{Caution| | |
| + | *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. | ||
==Specifications== | ==Specifications== | ||
| Line 9: | Line 12: | ||
==Rocket Design== | ==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]] | ||
| − | + | The rocket should preferably be liquid fueled with at least two stages. An example of a simple manned orbiter: | |
| − | |||
| − | An example of a simple manned orbiter: | ||
| + | *[[Mk16 Parachute]] | ||
*[[Command Pod Mk1]] | *[[Command Pod Mk1]] | ||
| − | |||
*[[Heat_Shield_(1.25m)]] | *[[Heat_Shield_(1.25m)]] | ||
| − | *[[ | + | *[[TD-12 Decoupler]] |
*[[FL-T400 Fuel Tank]] | *[[FL-T400 Fuel Tank]] | ||
*[[LV-909 Liquid Fuel Engine]] | *[[LV-909 Liquid Fuel Engine]] | ||
| − | * | + | *Another [[TD-12 Decoupler]] |
*[[FL-T800 Fuel Tank]] | *[[FL-T800 Fuel Tank]] | ||
*[[LV-T30 Liquid Fuel Engine]] | *[[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]]. | |
==Steps to Orbit and Back== | ==Steps to Orbit and Back== | ||
| Line 30: | Line 31: | ||
# Set thrust to maximum by hitting Z. | # Set thrust to maximum by hitting Z. | ||
| − | # Toggle on SAS by hitting T. | + | # Toggle on [[SAS]] by hitting T. |
| − | # Hit M to go to | + | # 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 normal | + | # Switch back to the normal viewmode by hitting M to enjoy the [[launch|Launch]] spectacle. |
===Accelerate to 100 m/s=== | ===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. | + | [[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=== | ===Pitch 10 degrees East=== | ||
| Line 42: | Line 43: | ||
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. | 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 | + | 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=== | ===Stage=== | ||
| Line 76: | Line 71: | ||
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. | 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. | + | 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|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. | ||
| + | |||
| + | 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. | ||
{{Tutorials}} | {{Tutorials}} | ||
| + | [[Category:Tutorials|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
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 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.
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