Difference between revisions of "Tutorial: Walkthrough for Ye Compleat Beginner"

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m (Step 6 - Avoiding the Atmosphere: normal orbit changes are not "irregular")
(Extra credit: altitude and speed are not the same thing.)
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== Extra credit ==
 
== Extra credit ==
In space, speed and altitude are the same thing. In other words, your altitude determines your speed, and your speed determines your altitude. It's impossible to stay in your current orbit and go any faster or slower. You always orbit at exactly the "right" speed for that altitude. Speeding up won't make you go faster; it will push you into a higher orbit (farther from the planet). Likewise, slowing down will force you into a lower orbit (closer to the planet). There is no way to "chase" another spacecraft orbiting at the same altitude as you; you'll never catch each other.  
+
In space, speed and altitude are closely related. In orbit, your altitude determines your speed, and your speed determines your altitude. It's impossible to stay in your current orbit and go any faster or slower. You always orbit at exactly the "right" speed for that altitude. Speeding up won't make you go faster; it will push you into a higher orbit (farther from the planet). Likewise, slowing down will force you into a lower orbit (closer to the planet). There is no way to "chase" another spacecraft orbiting at the same altitude as you; you'll never catch each other.  
  
 
Your orbit is likely not a perfect circle; more of an ellipse. That's fine, and often even preferred. You can adjust the "roundness" of your orbit by thrusting either [[prograde]] (forwards, in the direction of travel) or [[retrograde]] (backwards, against the direction of travel). Remember, there's no "steering" on a spacecraft. It doesn't matter what direction you're facing when you're drifting, only what direction your engine is pointed when it's firing.  
 
Your orbit is likely not a perfect circle; more of an ellipse. That's fine, and often even preferred. You can adjust the "roundness" of your orbit by thrusting either [[prograde]] (forwards, in the direction of travel) or [[retrograde]] (backwards, against the direction of travel). Remember, there's no "steering" on a spacecraft. It doesn't matter what direction you're facing when you're drifting, only what direction your engine is pointed when it's firing.  

Revision as of 04:35, 18 April 2014

Walkthrough for Ye Compleat Beginner

Never played Kerbal pace Program before? Confused by all the jargon, controls, and tricky mathematics? This tutorial will walk you through absolutely every step required to launch your first two rockets.

Specifications

  • Length: 5–30 minutes
  • Difficulty: Easy
  • For version: Every version


Your First Launch

This will walk you through starting the game, choosing a rocket, launching it, and returning it safely to Earth. Or Kerbin. Then you'll send three bold Kerbonauts into orbit, possibly forever.

Step 1 - Start Kerbal Space Program

The very first step is to "launch" the game, of course. Be prepared; Kerbal Space Program (KSP) can take a very long time to load. That yellow dot you see near the lower-left corner of your screen (underneath the cute sayings such as, "untangling space tape; inventing witty loading hints; testing springs," etc.) is actually the beginning of a long progress bar. Depending on your PC, it may take 1–3 minutes for the game to load.

  • Choose Start Game. (If you wish, you can detour into Settings first and change things like your keyboard bindings—but doing so will complicate this and other tutorials, which assume you're using the default keyboard setup.)
  • Choose Start New.
  • Give yourself a name.
  • Choose Sandbox (not Career)
  • Click Start.

The next time you play, you'll choose Resume Saved instead of Start New. This will resume your game from where you left off.

Step 2 - On the Launchpad

Now you get a nice overhead view of the massive Kerbal Space Center complex. We're going to start right in by launching one of the game's premade rockets. Click on the launch pad near upper-right of your screen. You'll know you've selected the launch pad because it says Launch Pad in lower-left corner of your screen. Click once on Kerbal 2 (Stock). The "Stock" label means it's one of the game's premade rockets. Later, you'll build your own rockets and they'll appear on this list. Click the green Launch button near upper-right corner.

Now you see your stubby little rocket on the launch pad. Almost ready to go! Before you do, let's play with some of the basic controls. Click and hold the right mouse button and move the mouse to move the camera viewpoint. Press + and - keys on your numeric keypad to zoom your view in and out. If your mouse has a scroll wheel, you can also use it to zoom in and out. Your three happy Kerbonauts appear in lower-right corner, ready for launch. Take a look at your rocket. The three spindly towers are not part of rocket itself; they're support structure holding it up.

Step 3 - An Abortive First Launch

Tap the Space bar once. Your rocket drops to ground and... nothing. What happened? Every rocket launch happens in stages, and each stage is triggered by tapping the space bar. The Kerbal 2 rocket is designed with 3 stages. The very first stage releases the rocket from its supporting structure and ignites the rocket engine. However, the engine is currently set to 0% power. We forgot to throttle-up the engine. We'll fix that and try again.

Step 4 - A Good Launch

Press the ESC key to pause the game. Choose Revert Flight then Revert to Launch. This rewinds time and resets everything back to the start of the launch procedure. Hold down the left Shift key for a few seconds. This increases the throttle settings on your rocket's engine to 100%. When you're fully throttled-up, tap the Space bar once. Now your rocket launches!

In about 5 seconds (at about 1500 meters of altitude), your rocket runs out of fuel. Tap Space once to trigger the next stage. You may hear a bang as the explosive bolts fire, but not much else appears to happen. Try pressing the A S D W directional keys. Your capsule should move away from the now-empty booster engine. Both are coasting free.

Tap Space a third time to trigger your parachute. Depending on your altitude, the chute may open fully or only partially. It will automatically open the rest of the way when you reach 500m above ground level (not sea level).

If you're sharp-eyed and pan the camera around (hold right mouse button) you may see your booster rocket fall to the ground and shatter into pieces. (If it still had fuel aboard, it would explode, too).

Your capsule and its three happy Kerbonauts will drift down until touching down gently at about 68 meters (that's the ground level of the Space Center). Your parachute will disappear automatically. Move your mouse up to the very top of the screen and click green Recover Vessel. Done! Congratulations on your first suborbital flight!

Your Second Launch: Getting Into Orbit

Can't you just aim straight up to get into orbit? Alas, no. Even with a bigger rocket, you can't just aim at the sky and hope for the best. Achieving orbit requires a simple, but important, maneuver. Let's start by selecting a bigger rocket.

Step 1 - Choose a Bigger Rocket

Return to the Kerbal Space Center, choose the Launch Pad, and select the Kerbal X (Stock) premade rocket, then click the green Launch button. This is a much taller, multi-stage rocket, with nine stages, numbered 0 through 8. It has a gantry support system holding it up, similar to the Kerbal 2. This will be important in a moment.

Step 2 - Launch

  • Tap T once to enable the onboard SAS stability system. This will keep your rocket from drifting off-course.
  • Hold Shift to throttle up to 100%, as before.
  • Tap Space once to fire the engines. The rocket will remain in place, held back by its gantry supports.
  • Quickly tap Space again to release the supports. We have liftoff!

Step 3 - Staging Multiple Engines

Notice that you have seven engines burning at once. The green status bars on the left of your screen show their relative fuel levels. They're not all the same. Some engines have smaller fuel tanks than the others, and will empty much sooner. We should jettison the empties as soon as possible to avoid carrying dead weight. Specifically, the two middle engines seem to be burning fuel the quickest. Watch those two bars, and when they're empty (probably around 600–700 meters up), tap Space once to trigger the next stage. The Kerbal X rocket is designed to jettison its two smallest engines at that stage. The remaining engines will keep burning.

The remaining five engines are also burning at different rates. When the bottom two fuel bars are empty, tap Space to jettison them.

You now have three engines, which are - yet again - burning at different rates. Watch and jettison the dead weight by tapping Space when appropriate.

Step 4 - Gravity Turn

You're somewhere around 6000 meters straight up, running on one engine. The planet Kerbin below you is starting to look curved. Look at the blue navball at the bottom of your screen. Click the green text above it to change it from Surface mode to Orbit mode.

When you get to about 10,000 m (don't sweat the exact number), start tapping the D key until the rocket tips over to the right at about a 45-degree angle. It looks unstable, but it will be fine. The navball will start to rotate and the gold V-marker in the center will get closer to yellow circle 'target' marker. Tap D occasionally as necessary to keep the two markers lined up and your rocket on target.

When you get to around 30,000 m and your fuel is about two-thirds spent, repeatedly press the left Ctrl key to throttle back to about 50% power. Press M to switch to Map view. Hold the right mouse button and move the mouse around until you can see the entire planet, including the pale blue arc that shows your rocket's trajectory. Note that this line goes up and back down—straight into the ground. Not good. We need to make a course correction.

Look for the blue marker along the blue trajectory line labeled Kerbin apoapsis. (Apoapsis, or apogee, is the high point of a spacecraft's orbit.) This will be the highest point on your journey if you remain on your present course and speed.

The navball probably isn't visible in your map view, so click the little arrow at the bottom of the screen to bring it up. Use your mouse to hover over the apoapsis marker. Watch as its altitude rises. When that number gets to 100,000 or so (keep it under 120,000), cut engines completely by pressing X.

(If you happen to run out of fuel before then, tap Space once to jettison the engine, then tap Space again to ignite the next engine).

You are now drifting, but your momentum is still carrying you upward—for a while. Notice that your controls (the A S D W keys) are very sluggish. That's the on-board inertial-stability system still working, even when the engine is off. Once you re-fire the engine, control will become much more snappy again. If you've got time, tap M to switch back to "normal" (staging) view and enjoy the view from near-space.

Step 5 - Achieving Orbit

With about 10 seconds to go before reaching the apoapsis marker, orient your rocket to point directly at the navball's yellow circle target marker, which is probably straddling the navball's blue/brown horizon line. Make sure you're not accidentally pointed at the green marker with the X through it; that's the reverse (retrograde) marker.

Throttle up to half speed again by pressing left Shift repeatedly. Watch carefully as the pale blue trajectory line stretches and grows. Eventually it will circle around the planet. Zoom out so you can see the whole planet. (If you notice your progress suddenly stops even though you're throttled-up, you probably just ran out of fuel. No problem; jettison the tank by tapping Space and fire the final-stage engine by tapping Space one more time.) Keep your spacecraft aimed at yellow circle marker on the navball, but get ready to cut the engine with X.

Poof! A blue periapsis marker will appear suddenly on far side of Kerbin. Use your mouse to hover over this new periapsis marker and watch it as its altitude rises quickly. When it reaches about 20,000 m or so, cut your engine with X. Hooray! You're now orbiting the planet Kerbin!

Step 6 - Avoiding the Atmosphere

There's just one problem: atmosphere. Kerbin's atmosphere extends to about 65,000 m, so any spacecraft orbiting below that altitude will pass through the air, slow down, and eventually burn up. We need to raise the low point (periapsis) to at least 70,000 m.

Keep yourself aimed at the circular yellow prograde marker on the navball, keep the engine on low throttle, and keep your mouse hovered over periapsis marker until it reads 70,000 or more. The two periapsis and apoapsis markers may start moving around planet like the hands on a clock while you're doing this. That's fine, and is due to the engine burn changing the shape of your orbit. When both periapsis and apoapsis are somewhere above 75,000, cut engines wth X.

Step 7 - Enjoy the View

You're golden. You will now orbit literally forever, with no input required from you whatsoever. That's the beauty of physics. You can speed up time by tapping > (actually the . key) and watch yourself orbit.

You can press M to revert to staging view and enjoy the view. If you're on the dark side of the planet (which you will be for half the time), it may be hard to see your spacecraft. You can speed up time in this view, too. Try out different viewing angles. Watch the sun rise over Kerbin.

Notice that, even though your engines are off, the ship is more maneuverable than it was before. That's because it's smaller. When you jettisoned the previous engine you lost about half of the total mass (weight) of the spacecraft, making it easier for the inertial-stability system to turn what's left.

To see the view from inside the space capsule, click the portrait of one of the Kerbonauts and select IVA (intra-vehicular activity). Do not click EVA! Right-click once and move your mouse around to look around inside the cockpit. Press C to return to normal outside view.

If you want to leave this craft in orbit and start over with another rocket and another spaceflight, just press Esc and choose Space Center. This flight will remain in orbit indefinitely until you choose to return to it another day. You can track its progress from the Space Center's Tracking Station at any time. Before long, you might have dozens of flights in progress all at once, and the Tracking Station allows you to jump in and control any of them at any time. Note that time doesn't stop when you're away from your spacecraft; they'll continue to orbit (or whatever they were doing) while you're commanding other missions. This will be important when you start doing two-craft rendezvous, or long-duration missions to other planets.

Extra credit

In space, speed and altitude are closely related. In orbit, your altitude determines your speed, and your speed determines your altitude. It's impossible to stay in your current orbit and go any faster or slower. You always orbit at exactly the "right" speed for that altitude. Speeding up won't make you go faster; it will push you into a higher orbit (farther from the planet). Likewise, slowing down will force you into a lower orbit (closer to the planet). There is no way to "chase" another spacecraft orbiting at the same altitude as you; you'll never catch each other.

Your orbit is likely not a perfect circle; more of an ellipse. That's fine, and often even preferred. You can adjust the "roundness" of your orbit by thrusting either prograde (forwards, in the direction of travel) or retrograde (backwards, against the direction of travel). Remember, there's no "steering" on a spacecraft. It doesn't matter what direction you're facing when you're drifting, only what direction your engine is pointed when it's firing.

As you orbit the planet you'll notice that your navball gradually rotates, making one complete spin for each full orbit. That's because the navball is designed to orient you in relation to the planet, not the sun or the stars or any fixed point in space. As you rotate around the planet, your position relative to it changes all the time, hence the motion of the navball.

The yellow circular marker on the navball marks prograde, or "straight ahead," in the sense of moving in the direction of your orbit. Because your orbit is circular and not a straight line, that marker always moves. Facing "ahead" on one side of the planet means facing "backwards" when you're on the opposite side.

If you want to speed up (thereby raising your orbital altitude), align your spacecraft's nose with the prograde marker and fire your engines. Aiming your spacecraft in any other direction will either tilt your orbit, speed you up, slow you down, or some combination of these.

Return from orbit and splashdown

When you're ready to return to Kerbin, you'll need to force your orbit to "decay" enough that you drop back into the planet's atmosphere. From there, the air will slow you down and cause you to drop to the surface, where your parachutes (you did remember to pack a parachute, right?) will ensure a soft landing. You'll need about one-eighth of a tank of fuel to de-orbit. If you're completely out of fuel, you're out of luck and doomed to orbit Kerbin forever.

Assuming you do have adequate fuel, wait until you reach your apoapsis marker. Although you can de-orbit from anywhere, it's more fuel- and time-efficient to start your de-orbit burn from the highest point on your orbit: the apoapsis.

Make sure the navball is set to Orbit mode, not Surface mode. Turn so you're facing the retrograde marker on the navball (the green circle with the X through it), which is probably straddling the navball's blue/brown horizon line. It makes no difference whether the blue side or brown side is up, down, left or right; only that you are aligned with the retrograde, or "backwards," marker, which means you'll be firing the engine against the direction of travel.

Press M to switch to map view. As you approach the apoapsis (high point) marker, watch your periapsis (low point) marker. Throttle up gently (press Shift several times) and watch as periapsis drops as your speed slows. Keep the engine running until periapsis reaches 25,000 meters. This is well into Kerbin's atmosphere, so even though the blue trajectory line still shows you circling that planet, that won't actually happen. If you've got enough fuel, you can continue your retrograde burn until the trajectory line really does dead-end on surface of the planet instead of circling around it. Either way, you're going to land.

Now sit back and wait for your orbit to decay. (You can speed up time by repeatedly pressing > to hasten things along. The game will automatically revert to 1x time when your altitude drops to 70,00 meters and you begin to enter the atmosphere.)

Be sure to jettison your final engine! You don't want a fiery re-entry with all that fuel aboard. Tap the Space bar one last time to lose your only source of propulsion. You're in gravity's hands now. Your speed is probably around 2000–3000 m/s and increasing. You're falling—fast. For a proper NASA-style re-entry, you can orient your capsule back-end first by aiming at the retrograde marker on your navball. (It doesn't actually make any difference, but it looks cool.)

Somewhere around 30,000 m you'll notice that your speed is decreasing, not increasing. Even though you're still falling like a rock, the atmosphere is now slowing you down. Also at about 30,000 meters you'll start to see the reentry glow as your capsule heats up in the atmosphere. The glow dies away at about 18,000 meters, as your speed drops to about 1000 m/s. You're hurtling Kerbin-wards at a few hundred meters/sec, but slowing down due to atmospheric braking.

You'll need to open your parachute at some point. Parachutes in KSP are pretty flexible: you can open them at almost any altitude and they'll do their job. Obviously, you want to open it before you land, but not so early that it burns up during re-entry, and not so late that it doesn't slow you sufficiently. Somewhere after 10,000 meters but before 3000 meters is a good rule of thumb. Remember that your altimeter shows height above sea level, not ground level. If you're coming in over the mountains, be sure to mentally subtract a few thousand meters from your apparent altitude.

Go ahead and tap Space one last time to pop your parachute. It will deploy in the partially closed "drogue" mode and start slowing you down. When you are exactly 500 m above ground level, it will automatically open the rest of the way. If you pan your camera around, you might be able to see your jettisoned engine re-entering on its own, then exploding on the surface. Once your capsule has a safe splashdown/splatdown on water/land, you can click Recover Vessel (at the very top of the screen) to end the mission successfully.

(If you're on dry land and feel like showboating, click one of the Kerbonauts and select EVA to have him exit the capsule. You can walk him around using the directional keys, A S D W.)