出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/07/21 20:02 UTC 版)
Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. It represents the impulse (change in momentum) per unit amount of propellant used. The unit amount may be given either per unit mass (such as kilograms), or per unit Earth-weight (such as kiloponds, since g is used for the latter definition). The higher the specific impulse, the less propellant is needed to gain a given amount of momentum.