· After touchdown, engage left and right wheel brakes ( and ) until you come to a full
stop.
Space flight:
So far we have treated the glider much like a conventional aircraft. Now it is time to aim a bit
higher ...
· Take off as before. Turn east (use the compass ribbon at the top edge of the HUD, or the
one in the Surface MFD display), and pitch up to 50°.
· As you gain altitude, you will notice that your craft starts to behave differently, due to the
reduction in atmospheric pressure. One of the effects is a loss of lift, which causes the
flight path indicator (the Å HUD marker) slowly to drift down. Another effect is the loss of
response from your aerodynamic control surfaces.
· At about 30km altitude your glider will start to drop its nose even while you are pulling
back on the stick. Now activate the RCS (Reaction Control System) by right-clicking the
“RCS Mode” selector (on the right side of the instrument panel) or by pressing
Numpad. You are now controlling your craft with attitude thrusters.
· Pitch down to about 20°. After leaving the dense part of the atmosphere, you need to gain
tangential velocity to achieve orbit. Your flight path indicator should stay above 0°.
· Now is a good time to activate the Orbit mode in one of your MFDs. This shows the shape
of your current orbit (the green curve) in relation to the planet surface (the gray circle), together
with a list of orbital parameters along the left side of the display. You should switch
the display to “current orbital plane” projection mode, by clicking on the “PRJ” button until
“Prj: SHP” is shown in the top right corner of the display.
· At the moment, your orbit will be a rather eccentric ellipse, which for the most part is below
Earth’s surface. This means that you are still on a ballistic trajectory rather than in a
stable orbit. As you keep gaining tangential velocity, the orbit will start to expand. Once
the green curve is completely above the planet surface (and sufficiently high above the
atmosphere) you will have entered orbit.
· At this point, the most important pieces of information from the Orbit display are the orbital
velocity (“Vel”) and apoapsis radius (“ApR”). For a low Earth orbit, you need to achieve a
velocity of at least 7800 m/s. Once you reach this value, you will see the orbit rising rapidly
above Earth’s surface. At the same time, the apoapsis distance (the highest point of
the orbit) will start to grow. Keep firing your engines until ApR reaches about 6.670M. This
corresponds to an altitude of 300km. Now cut the engines.
· You are now nearly in orbit. All that remains to do is raise the periapsis (the lowest point
of the orbit) to a stable altitude. This is done best when you reach apoapsis, which should
be half an orbit (or about 45 minutes) from your current position. Time to switch into an
external camera mode and enjoy the view!
· It is also a good idea to switch the HUD from surface to orbit mode now. Do this by clicking
the “OBT” button in the top left corner of the instrument panel, or by pressing
twice. In this mode, the HUD flight path ladder is aligned with the orbital plane instead of
the horizon plane, and there is a ribbon showing your orbital azimuth angle. It also shows
indicators for prograde (the direction of your orbital velocity vector) and retrograde (the
opposite direction).
· When you approach apoapsis, turn your craft prograde. You can see how close you are
to the apoapsis point by checking the ApT (time to apoapsis) value in the Orbit MFD. If it
takes too long, press to engage time acceleration, and to switch back. To turn prograde,
you can activate the RCS manually, but it is easier to leave it to the automatic attitude
control, by simply pressing the “Prograde” button on the right of the instrument
panel (or!).
· Now fire your main engines for final orbit insertion. The two parameters to watch are the
orbit eccentricity (“Ecc”) and periapsis radius (“PeR”). The eccentricity value should get
smaller, indicating that the orbit becomes more circular, while the periapsis radius approaches
the apoapsis radius (ApR). Once the eccentricity value reaches a minimum,
turn the main engines off. You can also deactivate the prograde attitude mode by clicking
“Prograde” again.
· Congratulations! You made it into orbit!
編集者：
Design of Spacefrontier(2009-12-01 06:07:42)