specific impulse, ISP


ECSS-E-ST-35C Rev. 1


ratio of thrust to mass flow rate


  • NOTE 1 The specific impulse is expressed in Ns/kg or m/s.
  • NOTE 2 In engineering, another definition is often still used where the specific impulse is defined as the ratio of thrust to weight flow rate. This leads to an Isp in seconds (s). The numerical value of Isp (s) is obtained by dividing the Isp expressed in m/s by the standard surface gravity, g0 = 9,806 65 m/s2.
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