ISS Launch Windows

[NEOWatcher]

I'm not sure how to ask this one, so please bear with me.
Short question: How close to overhead of the launch site does the orbit of the ISS need to be to be within the window.
Long version: The ISS passes 16 times per day, so each pass is around 1500 miles apart. So if the shuttle can adjust its orbit (laterally?) by 750 miles, then I would assume a 50% chance of a launch window on any given day (if you want to launch in daylight). At 75 miles this would be 5%.
Are there other factors are required for launch window?
I know you can speed up and slow down relatively easily by changing altitudes (or the other way around)
Also; if there is lateral variation between orbit and launch, then does the launch turn into the orbit, or go into somewhat parallel orbit and then kind of slide sideways into the correct one?

Would the factors be similar in getting a geostationary orbit by not launching from the equator?

And the reason I ask? I heard the other day about the delay of the shuttle and the next launch window to the ISS being (some months?). So I was just trying to understand how that is determined.

[Manchurian Taikonaut]

Shuttle must lift off in daytime and daylight flights allow the shuttle to be photographed for problems, a launch window to send the shuttle aloft occurs in around 15th of September, and a few days in November

[NEOWatcher]

Shuttle must lift off in daytime and daylight flights allow the shuttle to be photographed for problems, a launch window to send the shuttle aloft occurs in around 15th of September, and a few days in November

That's where my thinking started. Only a few days every month and a half cant be due just to daylight.

[Hamlet]

The launch is also restricted to those times when the ISS orbit crosses over KSC moving south to north. This is to ensure that the shuttle's flight path takes it over the Atlantic Ocean.

Here's a nice article that explains some of the factors that go into planning a launch window.

[NEOWatcher]

The launch is also restricted to those times when the ISS orbit crosses over KSC moving south to north. This is to ensure that the shuttle's flight path takes it over the Atlantic Ocean.

Here's a nice article that explains some of the factors that go into planning a launch window.

Thanks; that's a good explaination (I was a little confused at thier explaination of precession, but I think I understand it. The spinning top didn't help).
There's still one question. I was curious about perpendicular distance to the orbit. How far off is that, and how does the launch "turn" or intercept it.
This paragraph sounds like it covers the distance along the orbit, but the "slices through..." comment makes me wonder.

Scientists must find a time when the Earth edge of that plane slices through the Kennedy Space Center launch site in Florida. They can't miss by more than a single degree. The Earth rotates 1 degree of its 360-degree spin in five minutes, so the launch must occur within five minutes.

Forgive me since I'm a visual person. Words sometimes fail me.

[Roy Batty]

Scientists must find a time when the Earth edge of that plane slices through the Kennedy Space Center launch site in Florida. They can't miss by more than a single degree. The Earth rotates 1 degree of its 360-degree spin in five minutes, so the launch must occur within five minutes.

4 minutes surely? (1440 mins in a day / 360).
Edited to add:
I've now read from various sources that a launch window can be under 5 or 10 mins (but i'm sure the Earths rotation doesn't vary that much :wink

With regards to perpendicular distance orbit insertion, the shuttle reachs a minimal eliptical orbit at first with lower & higher altitudes & then undergoes a series of post orbit burns to raise, circularise & equalise (thus slowing catchup speed) its orbit to the ISS .. burns mainly occur at its maximum orbit altitude each time. I'll provide a link better explaining this with examples when I find one.

Edited to add link & minor text corrections:
Simplistic, but with diagrams (i'm visual too 8) )

[NEOWatcher]

Perhaps I need to ramble a little more to make it clear... I'm looking for sideways...
I understand the altitude and speed considerations with eliptical orbits, but that only deals with when the orbits are in the same plane. I'm wondering how precisely the Plane of the orbit needs to intersect with KSC. Can it instead intersect Orlando? Titusville? Somewhere in between?
<edit>
Ok, how about this. Consider the following picture.

If KSC were the dot on the "i" (inclination angle), how far away can that be from the orbit, and what mechanism puts in into the same plane.

(now I do understand that that "i" is moving in respect to the plane, but lets assume the image is the snapshot when ISS is within the 1 degree of lattitude needed)

[Roy Batty]

Apologies.. I misunderstood the 'perpendicular' bit
(though I think in your last sentence just now you meant longitude not lattitude.. else i would be the same 1 degree already mentioned?)
I'm looking but I reckon others with a lot better knowledge of the orbital mechanics involved in a launch will inform us both of the answer first 8)

Edited:
Removed edit & posted again.

[NEOWatcher]

snipped
(though I think in your last sentence just now you meant longitude not lattitude..

I'm not sure what I mean anymore, but I'm glad I finally explained the question.

It gets frustrating when you're not even sure of how to ask something. ](*,)

[Roy Batty]

This site explains some:
http://neurolab.jsc.nasa.gov/inclin.htm
Seems the ISS is on an approximate inclination of 51 degrees.
I think the shuttle is launched at the appropriate trajectory as required and as governed by its mission & safety requirements.
The higher inclinations require more fuel & hence less payload. Interesting to read that a 90 degree polar mission was considered once.

I'm interested as to what this within '1 degree' exactness is, mentioned before though.. is it longitude, lattitude, inclination or what ? (the article seemed to imply longitude).

[NEOWatcher]

This site explains some:
http://neurolab.jsc.nasa.gov/inclin.htm

That's interesting about how the different inclinations are used.
I'm not quite sure about the quote "In 24 hours, and after 16 orbits, the Shuttle flies over the same ground-position of the Earth again. " I would think that's based on altitude and speed rather than inclination. As long as you cross the equator before you get half way around, I would think any inclination is possible.

I'm interested as to what this within '1 degree' exactness is, mentioned before though.. is it longitude, lattitude, inclination or what ? (the article seemed to imply longitude).

I'm glad to hear I wasn't the only one confused by that statement.

[Roy Batty]

That's interesting about how the different inclinations are used.
I'm not quite sure about the quote "In 24 hours, and after 16 orbits, the Shuttle flies over the same ground-position of the Earth again. " I would think that's based on altitude and speed rather than inclination. As long as you cross the equator before you get half way around, I would think any inclination is possible.

Erm, i'm not sure it is saying that the groundtrack shift is based on inclination.

But we can agree that the shuttle is actually launched on the right trajectory for the inclination desired ie turn into orbit as per your original post (which was clear once I re-read it) though? 8)

[Hamlet]

It might help to imagine two planes. One is the orbital plane of the ISS extending from orbit to the Earth and inclined at 51.6 degrees. Now imagine another plane extending from KSC to orbit also inclined at 51.6 degrees. The best time to launch is when the Earth rotates so that the KSC plane lines up with the ISS plane. This happens twice a day, but one alignment is not good since it would require the shuttle to launch to the southeast instead of to the northeast.

The shuttle can launch a little before or a little after the optimal alignment and still get to the right plane by burning more fuel and steering into the correct plane. For any time outside of the the launch window, the shuttle does not have enough fuel to perform the plane change required. In this situation the shuttle could still be in a 51.6 degree orbit, but the orbit would not be coincident with the ISS, the two orbits would only intersect at two points.

I'm not very good at drawing so I can't provide pictures. I hope I didn't confuse things more.

[NEOWatcher]

It might help to imagine two planes. One is the orbital plane of the ISS extending from orbit to the Earth and inclined at 51.6 degrees
Snip

I think it's starting to get clearer, and again from the article..

Scientists must find a time when the Earth edge of that plane slices through the Kennedy Space Center launch site in Florida. They can't miss by more than a single degree. The Earth rotates 1 degree of its 360-degree spin in five minutes, so the launch must occur within five minutes.

It makes it sound like that's the distance (Either side of 1 degree or 5min * 24K/720[half degrees] = 166 miles )

Now, about the coriolis affect. I would assume thats adjusted in the initial launch trajectory.

I'm not very good at drawing so I can't provide pictures. I hope I didn't confuse things more.

I know... Not only drawing, but then posting. It took me a while to find my example, but it was still quicker and clearer.

[Roy Batty]

I'm not very good at drawing so I can't provide pictures. I hope I didn't confuse things more.

Not at all as far as i'm concerned, thanks. But perhaps you could shed more light on that 1 degree & 5 mins mentioned in the article you originally posted a link to?

[Roy Batty]

Now, about the coriolis affect. I would assume thats adjusted in the initial launch trajectory.

Ooh just add more questions would you! :wink:
I think the Coriolis effect has a negligible impact during the shuttle launch, as it punches through the atmosphere too fast (though that effect is dependent on angle of inclination I suppose).

[NEOWatcher]

Thanks...
I was just trying to get a visual grasp on it, and I think I have enough understanding now. Although; more details are always helpful. Also I'm sure there are many other things to consider (such as, a gradual change in ISS orbit)
An animation would be very cool to show this, especially with the earth moving.