General Question Are the Space Shuttle thrusters on the front functional?

[jmr1068204]

I'm experimenting with some things and I got curious...how do I use the thrusters on the very front (under the windows) of the Space Shuttle? I also see some thrusters on either side of the very front (near the tip) of the shuttle. Are these functional in Orbiter and used during Prograde/Retrograde or just for show? If so for either of these, what are the keyboard controls for them?

Secondly, I'm curious about the "Hold ALT" button. Is this just for planes or does it function with rockets and the Space Shuttle when in Prograde orbit around Earth?



Thanks!

 

[Urwumpe]

HOLD ALT isn't even functional for planes - it is only for vehicles with hover thrusters. The Shuttle thus can't use it.

Even if you have a vessel with hover thrusters, you can not use them for getting constant orbital altitude. You can hover in an altitude, but this costs you fuel and only works when your orbit altitude would be descending with out it (you are between apogee and perigee).

An orbit with constant orbit altitude is called circular orbit. You can achieve it by circularization maneuvers. And it does not exist in the real world and in Orbiter.

Confused? Circular orbits are only a theoretical construct. If you would have a solar system without planets, you could achieve an almost circular orbit around the only source of gravity, in reality and in Orbiter, the many other gravity fields (gravity has infinite range, but its force drops by the "inverse square law") will accelerate you out of any momentary circular orbit that you reached.

It is good enough to have such a low eccentricity that the differences from the perfect circle are not important anymore. What is important depends on the flight plan that you have in mind. For catching up with a space station, eccentricity is not that important at all. For preparing for an ejection burn, even with advanced MFDs like Interplanetary MFD to assist you, starting with as little eccentricity as possible is better, since missing one opportunity for ejection does not result in completely ruined targeting data.

And finally: Remember that perfection costs as much fuel as the opposite. If you spend tons of fuel for getting a perfect circular orbit and maintain it, that eventually saves you a few kg of fuel during the ejection burn, it is sure easy to see why this was the wrong decision. It takes some training and preparation to be able to tell, how much perfection you really needed.

 

[Wrangler]

I'm experimenting with some things and I got curious...how do I use the thrusters on the very front (under the windows) of the Space Shuttle? I also see some thrusters on either side of the very front (near the tip) of the shuttle. Are these functional in Orbiter and used during Prograde/Retrograde or just for show? If so for either of these, what are the keyboard controls for them?

I have yet to find a non-functional thruster on the space shuttle... :lol:

The thrusters on the Nose of the Space shuttle are part of the Reaction control system of the space shuttle, managing both translation and rotational movements of the spacecraft. Please refer to the attached screenshot, where I have attempted to get them all to work. We can only see one side of the nose, but rest assured that the ones on the other side will also work, if so commanded.

 

[Astronut25]

I'm experimenting with some things and I got curious...how do I use the thrusters on the very front (under the windows) of the Space Shuttle? I also see some thrusters on either side of the very front (near the tip) of the shuttle. Are these functional in Orbiter...

Refer to Orbiter.pdf in Doc folder page 34

paraphrased

number pad keys
"/": toggle rotation/translation mode
 
Translation mode:
2/8: up/down
1/3: left/right
6/9: forward/back

Check if you're in translation mode, then press 9 on the numpad.

 

[Rtyh-12]

When you are in the atmosphere, you can turn your spacecraft (or airplane) by using the aerodynamic control surfaces (rudders, ailerons, etc.). These change the direction of the airflow around your craft. This makes your ship spin around, hopefully in a controlled fashion

While ascending, you'll notice that you'll start having trouble turning your ship. That's because there isn't enough air around your ship to throw around (in technical terms, the dynamic pressure is decreasing. The static pressure is also decreasing. The difference between these two is that static pressure measures the air... well, pressure, while the dynamic pressure measures the air flow, which increases with static pressure but also with speed). Eventually, aerodynamic control surfaces become pointless.

That's where the RCS (Reaction Control System) comes in. These are basically little rockets that turn your ship. For instance, suppose you want to pitch up (move your nose up). The front RCS thrusters will push your nose upwards and the rear thrusters will push your tail downwards. Of course, you can also pitch down, bank left and right and yaw left and right (there are quite a lot of RCS thrusters, both on the Space Shuttle and on the DeltaGlider, XR-2, etc.).

You can also use your RCS to move the ship without rotating it. This is called translation. Suppose that, instead of pushing the front upwards and the back downwards, the RCS thrusters push both ends of the craft upwards. End result is, you move upwards. Just remember that RCS thrusters are usually really weak, so only use them if you need a lot of precision, but not a lot of power (most obvious example, during docking).

Both of these two RCS modes are controlled via the numpad. The RCS is turned on/off by pressing Ctrl-/. By default, it's in rotation mode. You can switch between rotation/translation modes by pressing /. Refer to the manual for more detailed controls.