In the SF RPG Universe,
various die rolls determine how long players must wait for a ship to a
given destination. From section 32.4 of the
A Green jump route is a well-travelled commercial lane with passenger and freight service occurring daily (or more often). If a character or party wishes to travel this route, roll percentile dice to determine how many hours he must wait for a ship with available space.
An Amber jump route is an infrequently travelled commercial lane traversed by freighters and an occasional passenger vessel. Roll two dice to determine how many days a character must wait for available space on this route.
A Red jump route is a rarely travelled course traversed by a few exploratory and resupply ships. Roll percentile dice to determine how many days a character must wait for available space on this route.
So we must wait 1-100 hours for a green route ship, 2-20 days for an amber, and 1-100 days for a red.
If a character must wait 1-100 hours for a ship, it follows that ships come about once every 100 hours. This is per destination, so we can calculate the number of ships in a given period by noting the total number of green, amber and red routes from a given planet.
For example, in one set of systems I generated, the planet Terraster (in the Delta Pavonis system) has four green, 10 amber and 15 red interstellar routes. The math is as follows:
| Route | Number | Hours | Per 10 days |
|---|---|---|---|
| Green | 4 | 100 | 96.00 |
| Amber | 10 | 264 | 9.09 |
| Red | 15 | 2400 | 1.50 |
| Total | 106.59 | ||
So we have a little over 100 ships taking off (and presumably also landing) in 10 days, or about 10 ships per day.
But that's just interstellar ships. Terraster also has a green route and four red routes to other planets and moons around Delta Pavonis. That make it about 131 ships every 10 days, or a little more than one ship every two hours.
This is based on assuming that waiting 2-20 days for an amber-route ship means one every 11 days. This isn't quite accurate; 11 days is the average wait. Nonetheless, mathematically speaking it works out about the same.