Why does the space shuttle have to worry about sun angles in regards to launch window?

And also why are launch windows so small? seems if the launch isn't met, there is a delay of a month or so.

I would think there are a variety of reasons.

This article

http://www.space.com/missionlaunches/071...

indicates that it is the docking conditions on the ISS. Once you launch, you are in a mostly fixed orbit. The shuttle does not have enough fuel to follow the ISS to the other side of Earth. So they have to launch so that they get in orbit just at the right time when the ISS is close. And then the ISS has to be properly oriented so the shuttle can dock. At the same time the solar panels on the ISS have to be properly aligned. Not an easy problem to solve and it probably restricts the launch windows to a couple (ten) minutes a few times a day.

But I would also think that they want to have proper light to see what is happening during the launch. Certainly since the foam problem has turned deadly.

two reasons why they need sunlight

one reason is because the crew on the International space station needs sunlight to photograph the orbiter's black thermal protection system on the belly of the orbiter, and another reason is because of the foam that falls off of the space shuttle's external tank during launch and ascent.

as to why the launch windows are so small, the ISS's orbit is changing constantly due to the rotation of the earth, the shuttle can only launch when the station is close to Kennedy Space Centre or when it's orbit carries it over the Kennedy Space Centre. the reason being, is to save fuel, it's much easier to get in an orbit that is over top (or close to over top) of the launch site than one that is too far away, as a result, they (the shuttle) may not have enough for the de-orbit burn

this is why the space shuttle's launch windows are so short and why they only launch every couple of months.