# What is the area of the SSME nozzle knowing only thrust at sea level and in vacuum? Tags: engines, engine-design, nozzle, ssme - Score: 9 - Views: 823 - Answers: 1 - Answered: yes - Asked by: Julio Gonzalez-Saenz (91 rep) - Asked: 2022-09-25 - Edited: 2022-09-25 - Site: space ## Question Looking at the SSME Wikipedia RS-25 Space Shuttle Engines, the data shown that the thrust at sea level ($F_{sl}$) is 1.816*10$^6$ N, while the thrust in vacuum ($F_{vac}$) is 2.278*10$^6$ N. Knowing only these two pieces of information, I need to find out the exit plane area of the Nozzle. I understand $\dot{m}_{sl} = \dot{m}_{vac}$, but I cannot find the correct relationship to include the formula of Thrust $F_{*} = \rho*A_e*v^2_{e}$. I found this question in the book I am currently studying. It is problem 1.2 of "Astronautics. The Physics of Space Flight", Second Edition, Ulrich Walter. ## Answers ### Answer by Organic Marble (score: 12) You can use the method I explained at the start of this answer: Falcon 9 Merlin 1d thrust calculated through every moment of flight Quoting from that, you use the thrust equation: $ \ \ \ F = \dot{m}_\mathrm e V_\mathrm e + (p_\mathrm e - p_0) A_\mathrm