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Achievable orbit from launch location

by ank_gl
Tags: achievable, launch, location, orbit
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ank_gl
#1
Oct31-13, 06:14 PM
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Hi Astro gurus,

Is there any limitation on the inclination of the achievable orbit because of the latitude of the launch location? For example, latitude of Baikonur is roughly 46 E. Does that limit somehow the inclinations of the orbits that can be achieved from Baikonur?

I think there should be no limitation as it should be possible to achieve any velocity vector at some position, & hence any possible set of orbital elements should be possible. More so, if a ballistic missile can hit target in any direction, it means different sets of orbital elements are possible.
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russ_watters
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Oct31-13, 06:48 PM
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As long as you have a big enough rocket. But for a given rocket, the payload capacity will depend on the inclination (and altitude).
SteamKing
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Oct31-13, 07:04 PM
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Yes there are limitations. See:

http://spaceflight.nasa.gov/shuttle/...ts/launch.html

http://www.orbiterwiki.org/wiki/Launch_Azimuth

ICBMs don't necessarily try to achieve orbit. They are designed to fly extremely long ballistic paths from launch point to target.

BobG
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Nov1-13, 01:58 PM
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Achievable orbit from launch location

Quote Quote by ank_gl View Post
Hi Astro gurus,

Is there any limitation on the inclination of the achievable orbit because of the latitude of the launch location? For example, latitude of Baikonur is roughly 46 E. Does that limit somehow the inclinations of the orbits that can be achieved from Baikonur?

I think there should be no limitation as it should be possible to achieve any velocity vector at some position, & hence any possible set of orbital elements should be possible. More so, if a ballistic missile can hit target in any direction, it means different sets of orbital elements are possible.
(bolding mine)

This is true. The limitations refer to the ability to launch directly into a particular orbit (in which case, the inclination can't be less than the launch latitude).

It's a pretty big limitation given the fuel requirements to change the inclination at low Earth orbit. You want your speeds to be as low as possible when you change inclination, and that usually means you want to be as far away from the Earth as possible when you change inclination.

While ballistic missiles don't actually complete even one orbit, you could still think of their trajectory as an orbit that just happens to intersect the Earth and, yes, they can have orbital elements. However, the inclination of those "orbits" will never be less than the launch latitude. Launching to the East gives you your minimum inclination. Launching either North or South increases your inclination. Launching due West would give you your maximum inclination - at least if you use 0 to 180 as your inclination range. If you're one of those people that refer to orbits as 80 degrees prograde or 80 degrees retrograde, then I guess 90 degrees would be your maximum inclination. (Terminology isn't completely standardized.)
ank_gl
#5
Nov2-13, 12:25 AM
P: 735
As long as you have a big enough rocket. But for a given rocket, the payload capacity will depend on the inclination (and altitude).
Thanks Russ. So you mean that the limiting factor is the fuel?

Yes there are limitations. See:

http://spaceflight.nasa.gov/shuttle/...ts/launch.html

http://www.orbiterwiki.org/wiki/Launch_Azimuth

ICBMs don't necessarily try to achieve orbit. They are designed to fly extremely long ballistic paths from launch point to target.
Thanks Steamking. Well, that doesn't answer my question. But anyways, good links.

This is true. The limitations refer to the ability to launch directly into a particular orbit (in which case, the inclination can't be less than the launch latitude).
Aha, thats what I think is the case.

It's a pretty big limitation given the fuel requirements to change the inclination at low Earth orbit. You want your speeds to be as low as possible when you change inclination, and that usually means you want to be as far away from the Earth as possible when you change inclination.
I agree, but the cost you mentioned is for changing the inclination while in an orbit. I am talking about setting the initial conditions such that any orbit is achievable. But I do see why the minimum inclination is the latitude of launch location.

I kinda see why one would want to have the same inclination as the latitude, as the velocity of earth would be added to the rocket velocity, provided one is launching prograde.

Thanks BobG

BTW, I found a nice link too touching a similar topic. http://orbitrax.com/?p=3061


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