A form of this quantity is given by the square root of mu over a, and its square is the characteristic energy; that is this quantity’s “hyperbolic excess.” Since the rate of specific energy change is this quantity dotted with acceleration, specific energy gains are highest when this quantity is highest by the Oberth effect. Space mission planning often computes the “budget” in this quantity’s delta, which can be calculated using the (*) Tsiolkovsky rocket equation. The square root of 2GM over r gives a threshold value for this quantity (10[2])in a gravitational (10[1])field. For a constant-mass object, the object’s mass times the change in this quantity gives the impulse (10[1])on the object. For 10 points, to exit Earth’s gravity, an object must attain the “escape” form of what quantity? ■END■