Anything that travels too fast in an atmosphere generates an enormous amount of friction, which produces tremendous heat. (Temperatures of 2,280 degrees Fahrenheit have been recorded.) Objects trying to enter a planetary atmosphere safely must shed velocity. However, decelerating consumes large amounts of fuel, and many ships (especially at Progress Level 5) simply don't have enough. As an alternative, scientists have developed ways to slow ships in reentry by using the atmospheric friction itself. Ablative shielding or ceramic tiles take care of any excess heat. Even so, entering a planet's atmosphere is a tricky business; the angle of entry is precise, and deviation either way causes the heat to build up too quickly for the heat shields to reflect away from the ship. Worse yet, during the most intense heating, the ship is surrounded by a thin layer of plasma that blocks radio signals, and the crew have no contact with ground control.
Entering planetary atmosphere safely requires a Pilot check (DC 20) each round for the 1d10+20 rounds it takes to slow the ship using friction alone. Success means that the ship takes only 3d6 points of fire damage each round. Failure means that the ship's angle is too low, and that it is not shedding velocity fast enough; the ship takes 6d6 points of fire damage each round until the pilot succeeds at the Pilot check to correct the angle of descent. If the check fails by 5 or more, the angle is too steep, and the ship takes 10d6 points of fire damage each round until the pilot succeeds at the Pilot check to correct the angle. Each round spent at too low an angle does not count toward the number of rounds required to land the ship; the ship isn't making any downward progress. Conversely, each round spent at too steep an angle counts as 2 rounds, indicating that the ship is descending much faster than it should.