So what you are talking about sort of happens sometimes, but only rarely and under the correct parameters, and not strictly because of gravity. Confusion arises in the simplification and use of layman's terms, I think. Th effect of gravity is not enough when the relative approach speed is high. Poor explanation, but best I can do.

So what you are talking about sort of happens sometimes, but only rarely and under the correct parameters, and not strictly because of gravity. Confusion arises in the simplification and use of layman's terms, I think. Th effect of gravity is not enough when the relative approach speed is high. Poor explanation, but best I can do.

So, when we hear about a planet capturing asteroids and such with its gravity, effectively making them moons, then that's just all bull? I don't know if Chandrayaan-1 will "do an engine burn" or not (although that's how man-made objects are generally put into orbit, so I *guess* it will). But are you trying to say that the physics of space do not allow a large body to gravitationally capture satellites?; because that is plainly an incorrect assertion.

The way a spacecraft goes into orbit is by doing an engine burn to lose speed, which most efficiently occurs when the object is at closest approach (periapsis). This burn puts the spacecraft into orbit, it's not somehow captured later.

Another reason is that different science goals demand different things from the imaging software. Again, you just can't prepare one camera for all possible science goals in space missions.

Still, there are examples of reuse. Some instruments do get recycled between missions.

Have been since year five or so when I first saw a picture of Denmark from space in our geography book and everyone laughed at me for not being able to see it.