The gravitational acceleration decreases with altitude, as shown by the solid line in Figure 1 (left). g is equal to 9.5 m/s2 at 100 km altitude, which is 9% larger than 8.7 m/s2. However, at 500 km altitude, g is close to 8.45 m/s2, which is close to 3% smaller than 8.7 m/s2.