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Propulsion System - Key Equations

Key Equations​

Tsiolkovsky Rocket Equation​

Δv=g0⋅Isp⋅ln⁡(m0mf)\Delta v = g_0 \cdot I_{sp} \cdot \ln\left(\frac{m_0}{m_f}\right)
  • g0=9.806 m/s2g_0 = 9.806\,\mathrm{m/s^2} (sea-level gravity)
  • m0m_0 = initial mass (wet), mfm_f = final mass (dry + unusable propellant)
  • Solves required propellant mass for a given ΔV and IspI_{sp}.

Total Impulse vs. Specific Impulse​

Itotal=mp⋅g0⋅IspI_{\text{total}} = m_p \cdot g_0 \cdot I_{sp}

where mpm_p is usable propellant mass.
Use ItotalI_{\text{total}} to check that the selected thrusters can deliver the required momentum change over the mission.