When the Enterprise enters standard orbit what is that orbit? Is it a low orbit going around a world sixteen times a day? Or is it "geosynchronous" orbit going around once a day? The problem is the range of the transporter. 22nd century was 6,200 miles. 23rd was 16,000 miles. 24th was 24,800 miles. A geosynchronous orbit is 22,236 miles above sea level. This means that before the Enterprise D the transporters couldn't reach the ground from a geosynchronous orbit. A low orbit has it own problems, at any given time the ship might not be in position to beam people up or down. At how an acute angle to the surface can you still beam? If the ship is just above the horizon a lock might not work. And would you always want to use the transporter at it's maximum possible range or would a lesser distance be safer? I've come to believe that in Kirk's time the Enterprise wasn't always orbiting the planet, but was instead hovering on it's impulse engines above a fixed point on the planet's surface. For example Assignment: Earth, the Enterprise was stationary two hundred miles directly above the New York City. At that altitude she would have been orbiting at five miles a second, but at a hover she is moving forward at only at a third of a mile per second, matching the city below her. Impulse engines that could propel the ship at hundreds of gees through space can easily provide one continuous gee to hover. In the episodes Naked Time and Court Martial when the Enterprise's engines are cut the ship doesn't continue to orbit for months and years, but instead begins to fall towards the planet's surface. Do you think the Enterprise is always orbiting the planet?