Starport

A United Galactic Federation-standardized means of facilitated interplanetary trade and travel. While strict in some ways, the Starport Authority(UGFSPA) guidelines are loose enough that pre-established starports from other, spacefaring civilizations, need only minimal updating when they come under UGF jurisdiction.

Rating

Starports follow a thankfully simple alphabetical rating system.
Class A
Excellent quality installation, with refined fuel and unrefined readily available. Includes facilities for annual maintenance, as well as starship, and non-starship construction and repair.
Class B
Good quality installation, refined fuel available. Annual maintenance overhaul facilities, shipyard capable of constructing non-starships present.
Class C
Routine quality installation, with only unrefined fuel available. Reasonable repair facilities are present.
Class D
Poor quality installation, only unrefined fuel available. No repair or shipyard facilities present.
Class E
Frontier installation, which is essentially a bare spot of bedrock with no fuel, facilities, or bases present.
Class X
No starport available.

Starport Size

The rating system, as is, doesn't allow for the exact specifications of the size of a port, and so, the UGFSPA has made size rating a thing on expanded documentation.
Tiny
The smallest of star ports. The port is run by fewer than a dozen employees, mostly on a part time basis; on a nearly barren world where the port's employees are most or all of the world's population, most of their time is spent on non-port activities such as surveying the world and growing food. The port is designed around seeing only a few ships per month with a maximum size of under 800 tons. The facilities defined by the classification are all available, but there will be few or no choices and service may be slow.
Small
Small ports are operated by fewer than 100 employees. The landing pads and operation facilities are sized for the small starships. Ship traffic will be a few ships per week, with some regular service each month.
Medium
These ports are the most common size of port, with between 100 and 10,000 employees. The port see regular daily traffic, centered around the medium sized starhips, and a dozens of smaller ships per day. Some medium ports also host the largest ships on a regular basis.
Large
These are found only along the major trade routes throughout the major empires of charted space. They see regular traffic of the largest of merchant liners, along with many other sizes of ships, and do so with up to a million employees.
Very Large
These are the largest ports found anywhere in charted space, they are correspondingly rare. They have over a million employees to handle the constant heavy traffic. Port this size have to be split into several locations.

This page makes heavy reference to Traveller's UWP, specifically Starports