/r/MarsSociety
The Mars Society is the world's largest and most influential space advocacy organization dedicated to the human exploration and settlement of the planet Mars. Established by Dr. Robert Zubrin and others in 1998, the group works to educate the public, the media and the government on the benefits of exploring Mars and creating a permanent human presence on the Red Planet.
The Mars Society -- to explore and settle a new world! Visit our website at www.marssociety.org.
This reddit community was created on 11/3/2011 by james burk (jburk on reddit)
/r/MarsSociety
8,745 Subscribers
NASA confirms “independent review” of Orion heat shield issue
20:12 UTC
Excercise
I know it is an homework excercise but I already tried all the isoentropic relations, the problem is not the Isp, I can't find a relation to calculate the thrust as I am missing some important parameters, such as Ae, At, mdot, and thrust. This is the text of the excercise:
A bipropellant rocket engine is required for Mars landing. It will be the main engine driving the soft landing of a capsule on the martian soil to carry a scientific payload. The ground environment where the lander will operate is characterized by the following properties:
Temperature: -60°C
Pressure: 610 Pa
Composition: mainly CO2
Acceleration due to gravity force: 3.7 m/s2
Show the formula and compute the thrust and the specific impulse for this propulsion unit if the following properties are obtained. (Assume isentropic expansion)
Chamber pressure: Pc = 15 bar
Exit-to-chamber nozzle pressure ratio: OPTIMAL EXPANSION
Nozzle exit velocity: Ve = 2450 m/s
Specific heat ratio: 1.3
Molar mass of exhaust gases: 24 g/mol
06:21 UTC