How do I take off?

If you've never done it before, taking off can be quite a challenge. You need to keep control of your craft, and at the same time keep good awareness of where you are and what you are doing. Once you've lost your sense of direction, it can be pretty difficult to recover at first. But with a bit of practice, it can become second nature.

Choosing a spacecraft

If you've never taken off before, try using one of the futuristic craft either the Deltaglider or the ShuttlePB. The skills you need are pretty much the same as you need for the more realistic spacecraft like the space shuttle, but they are more forgiving for the beginner. If you can achieve a neat and tidy takeoff with one of these, your chances of succeeding with the shuttle later will be pretty good. On the whole I'd recommend the deltaglider because of its easy-to-use panel.

The essential controls

One of the most useful keys for takeoff is the '5' in the middle of the number pad on the right of your keyboard. This is the 'Kill Rotation' key. During takeoff, this key is very useful if you find your spacecraft wandering in a direction you don't want it to. Often the easiest way to change your orientation is to start a change with either your joystick or the arrow keys on the keypad, and finish it with a touch of the 'KillRot' key.

The other useful number pad keys are

  • 2 - 8
  • 4 - 6
  • 1 - 3
  • Ctrl + and ctrl -
  • *
  • 0 - .
Pitch up and down
Roll left and right
Yaw left and right
Main and retro engines
Kill main/retro thrusters
Hover engines up and down

You can just as easily use a joystick for these operations, or the buttons you can see on the deltaglider panel. There is far more detail about controls in the manual, which you can find in the doc folder of your orbiter installation.

Before takeoff

You will need to use the multi-functional displays (MFD's) to navigate. In the deltaglider, just select what you need on the two viewscreens. On any other ship, you will need to select what you need using the keyboard. The one's you will need here are

MFD Selection key
Surface MFD Shift-S
Launch/Land MFD Shift-L
Orbit MFD Shift-O

Your keyboard has two shift keys, and the MFD will come up on the left or the right depending on which one you use. There are more MFD's, and in the long run you'll want to use them all. You'll find all you need to know in the manual.

Before departure, change the MFD's so you have the surface MFD on one side, and the orbit MFD on the other.

The orbit MFD also has a couple of modes which you must select correctly in order to take off.

Shift-P Change projection - there are three choices, ecliptic, ship and sometimes target. Choose ship to take off.
Shift-M Selects the display mode. Choose the one with the diagram and the numbers.
Shift-T Adds a target. Essentially this adds the orbit of another body onto your orbit graph. Don't select one for now.

The surface MFD has quite a few useful pieces of information.

Pitch is the angle of the nose above the horizon.
Heading is the compass bearing which the nose is pointing to
Roll is the angle of the wings to the surface. Most of the time this should be flat during takeoff. You can use this to turn the deltaglider like an aeroplane.

It also states your vertical and overall speed relative to the surface.


What is a takeoff?

The familiar picture of a space rocket roaring straight up into the sky can give the wrong impression. The main task ahead of you is to boost your speed sideways up to around 7.7 kilometres per second. Sideways speed is what's needed, not upward. The only reason that spacecraft go up at first is that the Earth's atmosphere prevents movement at high speeds. We therefore start by going upwards to get out of the atmosphere, because while we are in the thick of it, it's impossible to reach the speeds we need. But as soon as that's no longer true, our emphasis should shift to accelerating sideways, and our vertical speed should actually drop.

Fortunately for us, the atmosphere thins out quickly with altitude. Roughly, it halves in density every 5 kilometres. This thinner air provides less resistance to motion. In practice, from about 60 kilometres upwards, it becomes possible to accelerate to speeds that are substantial fractions of the speed you need. At around 140 kilometres up, air resistance has dropped to the point where it is possible to orbit the Earth.

Your aim at takeoff is to get into a low, more or less circular orbit a couple of hundred kilometres above the Earth. The orbit MFD, now it's set up correctly, will show you how you are getting on.

Because the Earth rotates, you are already traveling east at around 400 metres per second. We shall therefore accelerate eastwards when we get the chance, to build on the head start that the Earth has given us.

Stage 1 - Getting off the ground

Fire the hover engines, retract the undercarriage (G) and, when safely clear of buildings, fire the main engines - full power. Pitch the nose up, and get onto an Easterly (90') heading. Once the nose is safely up, get the hover engines off. Aim to get the nose up to at least 70'. 

Stage 2 - Up through the atmosphere

As you go up through the atmosphere at this high pitch, you speed will slowly rise. The slowness is significantly due to the drag of the surrounding air. As you rise and the air thins, your speed will increase, and so will your acceleration. Let your vertical speed (VSpd on the surface MFD) climb to over 500 metres per second. Once you reach this point, you can start to lower the nose. Reduce pitch to around 50' nose-up at first.

Stage 3 - Above the atmosphere - now is the time to accelerate

Above about 70 kilometres, you can reduce pitch so that your vertical acceleration (VAcc on surface MFD) is slightly negative. Somewhere between -1 and -2 ms^-2 is good - you can vary this a bit depending on how high an orbit you want to get into. You can let this wander a bit, but try and keep it between -1 and -2. I think that the easiest way to do this is to use 8 and 2 (and 5) on the Numpad. This will ensure that you are at least 140 kilometres up before you stop rising altogether. Keep the engines on full power accelerating on your eastbound heading as fast as possible. At this point, you should start to see your orbit in the orbit MFD getting fatter and fatter.

Once your vertical speed gets to zero (which it should), you should try to keep it there or thereabouts. Use pitch to control your vertical speed whilst you accelerate. As you accelerate, you will need to lower the pitch progressively.

Finally, you will see your orbit in the orbit MFD rise above the circle of the Earth's surface everywhere. Once you are happy with your orbit, switch the engines off. A good orbit looks like the one on the right.

Coping with mistakes

If you accidentally find your spacecraft spinning off in totally the wrong direction, you can usually recover yourself in one of the futuristic craft. Just press 'killrot', reorient yourself, and carry on. You will have wasted some fuel, but you probably won't crash, and should have no problems achieving orbit.

The other thing that may happen is that you end up with an eccentric orbit which goes high above the Earth's surface in one place, but still dips below it in others. This is what you will get if you don't control your vertical speed properly. However, all is not necessarily lost. Switch off the engines and coast round to the top (apoapsis) of your orbit. There, use the prograde autopilot  ('[' key), and fire the main engines again, and you can raise the low part of your orbit as far as you want.

In realistic spacecraft, you won't have the fuel to do these things, but it's OK to do this while you're learning.