Difference between revisions of "Tutorial: How to Get into Orbit"
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===Accelerate to 100 m/s=== | ===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. | 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=== | ||
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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. | 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. |
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| + | ===Throttle back around mach 1=== | ||
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| + | As the rocket goes transonic over 300 m/s, shockwaves will cause condensation trails to appear around the rocket. Save fuel by throttling back now with Ctrl. Maintain speed around 350 m/s for a while and keep the rocket aligned with prograde. | ||
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| + | When the rocket passes 10 km altitude, resume accelerating at full throttle. | ||
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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. | ||
| − | + | 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). | |
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. | 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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===Get Periapsis above 70 km=== | ===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. | 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. | ||
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===De-orbiting=== | ===De-orbiting=== | ||
Revision as of 18:34, 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.
Contents
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
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 (unless you are bringing heavy payloads to orbit of course).
An example of a simple manned orbiter:
- Command Pod Mk1
- Mk16 Parachute
- Heat_Shield_(1.25m)
- TR-18A Stack Decoupler
- FL-T400 Fuel Tank
- LV-909 Liquid Fuel Engine
- another TR-18A Stack Decoupler
- FL-T800 Fuel Tank
- LV-T30 Liquid Fuel Engine
Make sure the staging sequence is correct; see Tutorial:Game_Manual#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 it looks North, which will give a clear view of the trajectory arc towards the East and the Apoapsis label.
- Switch back to normal view 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.
Throttle back around mach 1
As the rocket goes transonic over 300 m/s, shockwaves will cause condensation trails to appear around the rocket. Save fuel by throttling back now with Ctrl. Maintain speed around 350 m/s for a while and keep the rocket aligned with prograde.
When the rocket passes 10 km altitude, resume accelerating at full throttle.
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).
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.
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, and deploy the parachute.
