Simviation Forums

Hi all,

I have already asked this in another thread, but unfortunately my question was not saw.

So here it goes again:
In FSX, with the map or by slew, we can now go to orbital altitudes, and the map display will allow entering very big values for altitude. But what about speed ?

- Are you able to enter an altitude of 120 kms and a speed of 8 kms per second ?

- If you can set that, does your aircraft stays in orbit ?

Thanks for the infos

Whether you can or not I seriously doubt that the physics will be anything like realistic. A quick check however is to set a very high altitude and see if you still have an indicated airspeed. If you do then FSX is still modeling an atmosphere and orbiting will be impossble due to atmospheric drag (or at least very unrealistic).

Also how would you control your attitude that high? Without air over your control surfaces you wouldn't be able to do anything but tumble out of control unless MS has modeled an RCS system.

And even if you can orbit in FSX I don't see myself uninstalling Orbiter in favor of FSX. Microsoft is just too prone to taking shortcuts to produce a realistic model of space flight. Besides where can you go once you reach orbit? In Orbiter you have the whole solar system to explore.

I can't gain any control until I fall under 200,000 feet.

Who talked about controlling ?
I just want to know if, with correct altitude and speed, the plane orbits or not

I tried to, but the max speed I could set in the map was 1200 kais

I wouldn't expect to be abled to go into space and orbit, but I do expect you to be abled to fly a NASP, which is kinda a orbit but skimming the atmosphere.

With that you would be able to do some X-15 flights and recreate Spaceship One's flight. If you want real space flight however Orbiter is still the ticket. It's also free.

http://orbit.medphys.ucl.ac.uk/orbit.html

Orbiter is great, I know it already. Nevertheless, the planet is good looking from 150 kms high ONLY.
And again, I do not want to do anything complex in space, I just want to know if a plane can orbit or not.

PS:For info, space physics are very simple to model, MUCH simpler than physics in the atmosphere.

PS:For info, space physics are very simple to model, MUCH simpler than physics in the atmosphere.

I wouldn't be too sure about that. One would have to calculate:

1. Velocity and mass of the vessel.

2. Amount of gravity produced by celestial body in which the vessel orbits.

3. The amount of gravity produced by the sun.

4. The amount of gravity produced by other celestial bodies and their influence on other bodies.

5. Gravitational anomalies.

6. The amount of mass in which the vessel loses over time as its fuel is expended.

You can imagine the math from here on out. Why do you think only the best and brightest can work in NASA?

Space physics are MUCH MORE complicated than atmospheric physics.  

I wouldn't be too sure about that. One would have to calculate:

1. Velocity and mass of the vessel.

Just like any sim

2. Amount of gravity produced by celestial body in which the vessel orbits.

One single vector, just like any other sim.

3. The amount of gravity produced by the sun.

Another vector, exactely the same principle as the planet you are orbiting around, no differences at all.

4. The amount of gravity produced by other celestial bodies and their influence on other bodies.

Same as the sun, one vector each.

5. Gravitational anomalies.

agree on this one, but I would like to know which sims are currently handling that ? Very few I think, no even Orbiter.

6. The amount of mass in which the vessel loses over time as its fuel is expended.

Just modifing one single variable.

You can imagine the math from here on out. Why do you think only the best and brightest can work in NASA?

Those maths are exactely the same as those used for atmosphere flying. This is simply movement equations. Remember your physics lessons at school ?
Now the thing is, when you are in the atmosphere, you have everything you have in space, and ADDITIONNALY, you have the effects of the atmosphere on the movements of your plane: drag, effects of control surfaces, effect on engine thrust etc...
Atmosphere flying is MUCH more complex than space flying. When you are in the atmosphere, you are into space...but there is additionnaly some gaz all around you, so you have to compute the additionnal effects.

Physics is the same whether you are in the atmosphere or space. It's the aerodynamics that you have to deal with in atmosphere. I do have to admit that it would be really cool to combine a space shuttle addon and a scenery like Aerosoft's Cape Canaveral scenery in FSX. Start it about 40 miles up somewhere over the Gulf of Mexico and make the approach and landing.

EDIT: You just better hope that ATC doesn't tell you to "go around".

5. Gravitational anomalies.

 

agree on this one, but I would like to know which sims are currently handling that ? Very few I think, no even Orbiter.

The 2006 Orbiter version has non-spherical gravity and gravity gradient torque.

Very few I think, no even Orbiter.

Dude, when was the last time you flew in Orbiter? If you look in the main menu, it has features for non-spherical gravitational sources [like Matt just pointed out].

You should read JPL's "Basics of Space Flight". Quite an interesting read it is.

http://www2.jpl.nasa.gov/basics/

Yep, just checked this. I even had Orbiter 2006 on my drive, but completely forgot about that feature.
Anyway, I wonder if it would really be that usefull in FSX, where only the earth is modelled.
Of course, the more functionnalities, the better, but anyway it would already be very glad to have a basic flight environment.

MS has no excuse for not including it. They have already done it (quite well, I must add) in the past. Remember MS Space Simulator ? I have spent days on that sim. Never understood why they didn't use it as a base for the FS series, woud have been very nice I think. There was:
- full earth planet
- full moon
- full solar system in fact...
- fairly consistent galaxy (wth generic planets and stars models, but correct positions)
- space stations
- ship-station, ship-ship and station-station docking
etc...
Would be nice if they could include that in FS series... that's not military, so why not ?

How long ago was this "Microsoft Space Sim"?

How long ago was this "Microsoft Space Sim"?

Not so long, and the graphics were really not that bad, really not
I'm not too sure, but it seems to me that Space Sim and FS5 were on the same period... am I right ?

PS: They did it, they did it, that's all. Time is not an excuse  ;D